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• Which MAC address is the right one?

  - by Paul Dinh

  Result by 'getmac': C:\>getmac Physical Address Transport Name =================== ========================================================== 72-03-C6-48-59-34 \Device\Tcpip_{8AEB3263-18C4-449E-A80F-BC2541DDC2A9} 00-21-9B-D5-6F-EE \Device\Tcpip_{C2F9CE19-D68F-4105-9766-45CBE6D82331} 00-22-68-D2-9B-F7 \Device\Tcpip_{A2701130-9221-43FE-8F14-7B1114F84DC3} Result by 'ipconfig /all': C:\>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : xps-m1530 Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Mixed IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No Ethernet adapter Wireless Network Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Dell Wireless 1395 WLAN Mini-Card Physical Address. . . . . . . . . : 00-22-68-D2-9B-F7 Dhcp Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Autoconfiguration IP Address. . . : 169.254.246.4 Subnet Mask . . . . . . . . . . . : 255.255.0.0 Default Gateway . . . . . . . . . : Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Marvell Yukon 88E8040 PCI-E Fast Eth ernet Controller Physical Address. . . . . . . . . : 00-21-9B-D5-6F-EE Dhcp Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes IP Address. . . . . . . . . . . . : 192.168.1.112 Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.1.1 DHCP Server . . . . . . . . . . . : 192.168.1.1 DNS Servers . . . . . . . . . . . : 8.8.8.8 8.8.4.4 Lease Obtained. . . . . . . . . . : 01 November 2012 9:00:36 AM Lease Expires . . . . . . . . . . : 04 November 2012 9:00:36 AM There is a MAC address on the back of my laptop, but the sticker is no longer there. So I use the 'getmac' command to get the MAC addresses. But which address shown by 'getmac' above is the one matching the MAC in the sticker on the back of my laptop? Or am I mistaken something? 00-21-... is the ethernet adapter, 00-22-... is the wireless adapter, and 72-03-... is what?

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• Service Discovery in WCF 4.0 &ndash; Part 1

  - by Shaun

  When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc..   Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN.   Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes.   Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method.   Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7:  8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17:  18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22:  23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27:  28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32:  33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37:  38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42:  43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47:  48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5:  6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6:  7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11:  12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18:  19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12:  13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6:  7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19:  20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26:  27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34:  35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53:  54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61:  62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69:  70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77:  78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85:  86: TAsyncResult asyncResult = result as TAsyncResult; 87:  88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92:  93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97:  98: asyncResult.endCalled = true; 99:  100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104:  105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109:  110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114:  115: return asyncResult; 116: } 117:  118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124:  125: this.completedSynchronously = completedSynchronously; 126:  127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142:  143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148:  149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7:  8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17:  18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22:  23: } 24:  25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32:  33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38:  39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46:  47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52:  53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56:  57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63:  64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13:  14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26:  27: host.Open(); 28:  29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37:  38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message.   Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4:  5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11:  12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13:  14: host.Open(); 15:  16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint.   On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6:  7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13:  14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16:  17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28:  29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service.   Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Custom ASP.NET Routing to an HttpHandler

  - by Rick Strahl

  As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add  a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a  RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name,           new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){    RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}",                     new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) );     routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}",                     new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){    string parmString = routeData.Values[parameter.Name] as string;    adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes):   which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies.  (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  AJAX  HTTP  

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• Red Gate Coder interviews: Alex Davies

  - by Michael Williamson

  Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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• The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

  - by Ralf Westphal

  Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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• value types in the vm

  - by john.rose

  value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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• Metro: Creating an IndexedDbDataSource for WinJS

  - by Stephen.Walther

  The goal of this blog entry is to describe how you can create custom data sources which you can use with the controls in the WinJS library. In particular, I explain how you can create an IndexedDbDataSource which you can use to store and retrieve data from an IndexedDB database. If you want to skip ahead, and ignore all of the fascinating content in-between, I’ve included the complete code for the IndexedDbDataSource at the very bottom of this blog entry. What is IndexedDB? IndexedDB is a database in the browser. You can use the IndexedDB API with all modern browsers including Firefox, Chrome, and Internet Explorer 10. And, of course, you can use IndexedDB with Metro style apps written with JavaScript. If you need to persist data in a Metro style app written with JavaScript then IndexedDB is a good option. Each Metro app can only interact with its own IndexedDB databases. And, IndexedDB provides you with transactions, indices, and cursors – the elements of any modern database. An IndexedDB database might be different than the type of database that you normally use. An IndexedDB database is an object-oriented database and not a relational database. Instead of storing data in tables, you store data in object stores. You store JavaScript objects in an IndexedDB object store. You create new IndexedDB object stores by handling the upgradeneeded event when you attempt to open a connection to an IndexedDB database. For example, here’s how you would both open a connection to an existing database named TasksDB and create the TasksDB database when it does not already exist: var reqOpen = window.indexedDB.open(“TasksDB”, 2); reqOpen.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); }; reqOpen.onsuccess = function () { var db = reqOpen.result; // Do something with db }; When you call window.indexedDB.open(), and the database does not already exist, then the upgradeneeded event is raised. In the code above, the upgradeneeded handler creates a new object store named tasks. The new object store has an auto-increment column named id which acts as the primary key column. If the database already exists with the right version, and you call window.indexedDB.open(), then the success event is raised. At that point, you have an open connection to the existing database and you can start doing something with the database. You use asynchronous methods to interact with an IndexedDB database. For example, the following code illustrates how you would add a new object to the tasks object store: var transaction = db.transaction(“tasks”, “readwrite”); var reqAdd = transaction.objectStore(“tasks”).add({ name: “Feed the dog” }); reqAdd.onsuccess = function() { // Tasks added successfully }; The code above creates a new database transaction, adds a new task to the tasks object store, and handles the success event. If the new task gets added successfully then the success event is raised. Creating a WinJS IndexedDbDataSource The most powerful control in the WinJS library is the ListView control. This is the control that you use to display a collection of items. If you want to display data with a ListView control, you need to bind the control to a data source. The WinJS library includes two objects which you can use as a data source: the List object and the StorageDataSource object. The List object enables you to represent a JavaScript array as a data source and the StorageDataSource enables you to represent the file system as a data source. If you want to bind an IndexedDB database to a ListView then you have a choice. You can either dump the items from the IndexedDB database into a List object or you can create a custom data source. I explored the first approach in a previous blog entry. In this blog entry, I explain how you can create a custom IndexedDB data source. Implementing the IListDataSource Interface You create a custom data source by implementing the IListDataSource interface. This interface contains the contract for the methods which the ListView needs to interact with a data source. The easiest way to implement the IListDataSource interface is to derive a new object from the base VirtualizedDataSource object. The VirtualizedDataSource object requires a data adapter which implements the IListDataAdapter interface. Yes, because of the number of objects involved, this is a little confusing. Your code ends up looking something like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); The code above is used to create a new class named IndexedDbDataSource which derives from the base VirtualizedDataSource class. In the constructor for the new class, the base class _baseDataSourceConstructor() method is called. A data adapter is passed to the _baseDataSourceConstructor() method. The code above creates a new method exposed by the IndexedDbDataSource named nuke(). The nuke() method deletes all of the objects from an object store. The code above also overrides a method named remove(). Our derived remove() method accepts any type of key and removes the matching item from the object store. Almost all of the work of creating a custom data source goes into building the data adapter class. The data adapter class implements the IListDataAdapter interface which contains the following methods: · change() · getCount() · insertAfter() · insertAtEnd() · insertAtStart() · insertBefore() · itemsFromDescription() · itemsFromEnd() · itemsFromIndex() · itemsFromKey() · itemsFromStart() · itemSignature() · moveAfter() · moveBefore() · moveToEnd() · moveToStart() · remove() · setNotificationHandler() · compareByIdentity Fortunately, you are not required to implement all of these methods. You only need to implement the methods that you actually need. In the case of the IndexedDbDataSource, I implemented the getCount(), itemsFromIndex(), insertAtEnd(), and remove() methods. If you are creating a read-only data source then you really only need to implement the getCount() and itemsFromIndex() methods. Implementing the getCount() Method The getCount() method returns the total number of items from the data source. So, if you are storing 10,000 items in an object store then this method would return the value 10,000. Here’s how I implemented the getCount() method: getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); } The first thing that you should notice is that the getCount() method returns a WinJS promise. This is a requirement. The getCount() method is asynchronous which is a good thing because all of the IndexedDB methods (at least the methods implemented in current browsers) are also asynchronous. The code above retrieves an object store and then uses the IndexedDB count() method to get a count of the items in the object store. The value is returned from the promise by calling complete(). Implementing the itemsFromIndex method When a ListView displays its items, it calls the itemsFromIndex() method. By default, it calls this method multiple times to get different ranges of items. Three parameters are passed to the itemsFromIndex() method: the requestIndex, countBefore, and countAfter parameters. The requestIndex indicates the index of the item from the database to show. The countBefore and countAfter parameters represent hints. These are integer values which represent the number of items before and after the requestIndex to retrieve. Again, these are only hints and you can return as many items before and after the request index as you please. Here’s how I implemented the itemsFromIndex method: itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); } In the code above, a cursor is used to iterate through the objects in an object store. You fetch the next item in the cursor by calling either the cursor.continue() or cursor.advance() method. The continue() method moves forward by one object and the advance() method moves forward a specified number of objects. Each time you call continue() or advance(), the success event is raised again. If the cursor is null then you know that you have reached the end of the cursor and you can return the results. Some things to be careful about here. First, the return value from the itemsFromIndex() method must implement the IFetchResult interface. In particular, you must return an object which has an items, offset, and totalCount property. Second, each item in the items array must implement the IListItem interface. Each item should have a key and a data property. Implementing the insertAtEnd() Method When creating the IndexedDbDataSource, I wanted to go beyond creating a simple read-only data source and support inserting and deleting objects. If you want to support adding new items with your data source then you need to implement the insertAtEnd() method. Here’s how I implemented the insertAtEnd() method for the IndexedDbDataSource: insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); } When implementing the insertAtEnd() method, you need to be careful to return an object which implements the IItem interface. In particular, you should return an object that has a key and a data property. The key must be a string and it uniquely represents the new item added to the data source. The value of the data property represents the new item itself. Implementing the remove() Method Finally, you use the remove() method to remove an item from the data source. You call the remove() method with the key of the item which you want to remove. Implementing the remove() method in the case of the IndexedDbDataSource was a little tricky. The problem is that an IndexedDB object store uses an integer key and the VirtualizedDataSource requires a string key. For that reason, I needed to override the remove() method in the derived IndexedDbDataSource class like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); When you call remove(), you end up calling a method of the IndexedDbDataAdapter named removeInternal() . Here’s what the removeInternal() method looks like: setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); } The removeInternal() method calls the IndexedDB delete() method to delete an item from the object store. If the item is deleted successfully then the _notificationHandler.remove() method is called. Because we are not implementing the standard IListDataAdapter remove() method, we need to notify the data source (and the ListView control bound to the data source) that an item has been removed. The way that you notify the data source is by calling the _notificationHandler.remove() method. Notice that we get the _notificationHandler in the code above by implementing another method in the IListDataAdapter interface: the setNotificationHandler() method. You can raise the following types of notifications using the _notificationHandler: · beginNotifications() · changed() · endNotifications() · inserted() · invalidateAll() · moved() · removed() · reload() These methods are all part of the IListDataNotificationHandler interface in the WinJS library. Implementing the nuke() Method I wanted to implement a method which would remove all of the items from an object store. Therefore, I created a method named nuke() which calls the IndexedDB clear() method: nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); } Notice that the nuke() method calls the _notificationHandler.reload() method to notify the ListView to reload all of the items from its data source. Because we are implementing a custom method here, we need to use the _notificationHandler to send an update. Using the IndexedDbDataSource To illustrate how you can use the IndexedDbDataSource, I created a simple task list app. You can add new tasks, delete existing tasks, and nuke all of the tasks. You delete an item by selecting an item (swipe or right-click) and clicking the Delete button. Here’s the HTML page which contains the ListView, the form for adding new tasks, and the buttons for deleting and nuking tasks: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>DataSources</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.1.0.RC/css/ui-dark.css" rel="stylesheet" /> <script src="//Microsoft.WinJS.1.0.RC/js/base.js"></script> <script src="//Microsoft.WinJS.1.0.RC/js/ui.js"></script> <!-- DataSources references --> <link href="indexedDb.css" rel="stylesheet" /> <script type="text/javascript" src="indexedDbDataSource.js"></script> <script src="indexedDb.js"></script> </head> <body> <div id="tmplTask" data-win-control="WinJS.Binding.Template"> <div class="taskItem"> Id: <span data-win-bind="innerText:id"></span> <br /><br /> Name: <span data-win-bind="innerText:name"></span> </div> </div> <div id="lvTasks" data-win-control="WinJS.UI.ListView" data-win-options="{ itemTemplate: select('#tmplTask'), selectionMode: 'single' }"></div> <form id="frmAdd"> <fieldset> <legend>Add Task</legend> <label>New Task</label> <input id="inputTaskName" required /> <button>Add</button> </fieldset> </form> <button id="btnNuke">Nuke</button> <button id="btnDelete">Delete</button> </body> </html> And here is the JavaScript code for the TaskList app: /// <reference path="//Microsoft.WinJS.1.0.RC/js/base.js" /> /// <reference path="//Microsoft.WinJS.1.0.RC/js/ui.js" /> function init() { WinJS.UI.processAll().done(function () { var lvTasks = document.getElementById("lvTasks").winControl; // Bind the ListView to its data source var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; // Wire-up Add, Delete, Nuke buttons document.getElementById("frmAdd").addEventListener("submit", function (evt) { evt.preventDefault(); tasksDataSource.beginEdits(); tasksDataSource.insertAtEnd(null, { name: document.getElementById("inputTaskName").value }).done(function (newItem) { tasksDataSource.endEdits(); document.getElementById("frmAdd").reset(); lvTasks.ensureVisible(newItem.index); }); }); document.getElementById("btnDelete").addEventListener("click", function () { if (lvTasks.selection.count() == 1) { lvTasks.selection.getItems().done(function (items) { tasksDataSource.remove(items[0].data.id); }); } }); document.getElementById("btnNuke").addEventListener("click", function () { tasksDataSource.nuke(); }); // This method is called to initialize the IndexedDb database function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } }); } document.addEventListener("DOMContentLoaded", init); The IndexedDbDataSource is created and bound to the ListView control with the following two lines of code: var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; The IndexedDbDataSource is created with four parameters: the name of the database to create, the version of the database to create, the name of the object store to create, and a function which contains code to initialize the new database. The upgrade function creates a new object store named tasks with an auto-increment property named id: function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } The Complete Code for the IndexedDbDataSource Here’s the complete code for the IndexedDbDataSource: (function () { /************************************************ * The IndexedDBDataAdapter enables you to work * with a HTML5 IndexedDB database. *************************************************/ var IndexedDbDataAdapter = WinJS.Class.define( function (dbName, dbVersion, objectStoreName, upgrade, error) { this._dbName = dbName; // database name this._dbVersion = dbVersion; // database version this._objectStoreName = objectStoreName; // object store name this._upgrade = upgrade; // database upgrade script this._error = error || function (evt) { console.log(evt.message); }; }, { /******************************************* * IListDataAdapter Interface Methods ********************************************/ getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); }, itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); }, insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); }, setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, /***************************************** * IndexedDbDataSource Method ******************************************/ removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); }, nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); }, /******************************************* * Private Methods ********************************************/ _ensureDbOpen: function () { var that = this; // Try to get cached Db if (that._cachedDb) { return WinJS.Promise.wrap(that._cachedDb); } // Otherwise, open the database return new WinJS.Promise(function (complete, error, progress) { var reqOpen = window.indexedDB.open(that._dbName, that._dbVersion); reqOpen.onerror = function (evt) { error(); }; reqOpen.onupgradeneeded = function (evt) { that._upgrade(evt); that._notificationHandler.invalidateAll(); }; reqOpen.onsuccess = function () { that._cachedDb = reqOpen.result; complete(that._cachedDb); }; }); }, _getObjectStore: function (type) { type = type || "readonly"; var that = this; return new WinJS.Promise(function (complete, error) { that._ensureDbOpen().then(function (db) { var transaction = db.transaction(that._objectStoreName, type); complete(transaction.objectStore(that._objectStoreName)); }); }); }, _get: function (key) { return new WinJS.Promise(function (complete, error) { that._getObjectStore().done(function (store) { var reqGet = store.get(key); reqGet.onerror = that._error; reqGet.onsuccess = function (item) { complete(item); }; }); }); } } ); var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); WinJS.Namespace.define("DataSources", { IndexedDbDataSource: IndexedDbDataSource }); })(); Summary In this blog post, I provided an overview of how you can create a new data source which you can use with the WinJS library. I described how you can create an IndexedDbDataSource which you can use to bind a ListView control to an IndexedDB database. While describing how you can create a custom data source, I explained how you can implement the IListDataAdapter interface. You also learned how to raise notifications — such as a removed or invalidateAll notification — by taking advantage of the methods of the IListDataNotificationHandler interface.

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• ?12c database ????Adaptive Execution Plans ????????

  - by Liu Maclean(???)

  12c R1 ????SQL??????- Adaptive Execution Plans ????????,???????optimizer ??????(runtime)???????????????, ????????????????????? SQL???????? ????????????, ?????????????????????????????????????????????????????????????adaptive plan ????????????????????????????????????,?????subplan???????????????????? ??????, ???????? ???????????????,?????????, ?????? ???????????????”???”????, ???????????????????buffer ???????  ????????????,?????,??????????????????? ???optimizer ?????????????????????????,?????????????????????????????????????????plan???? ??12C?????????????, ???????????????????,?????? ???????????? ????????????2???: Dynamic Plans????: ???????????????????????;??????,???optimizer??????????subplans??????????????, ???????????????????,?????????????? Reoptimization????: ?Dynamic Plans????,Reoptimization??????????????????????Reoptimization??,?????????????????????????,??reoptimization????? OPTIMIZER_ADAPTIVE_REPORTING_ONLY ???? report-only????????????????TRUE,?????????report-only????,???????????????,??????????????? Dynamic Plans ??????????????,????????????????????????, ?????????????,???????????,????????????????????????????????????????? ?????????????final plan??????????????default plan, ??final plan?default plan???????,????????????? subplan ???????????????,???????????????????????? ??????,???????statistics collector ?buffer???????????statistics collector?????????????????,???????????????????????????? ?????????????????????????????????????????,??????????,?????????????? ???????????,???????buffer???? ???????????????,?????????????????????????????,??????buffer,??????final plan? ????????,???????????????????????,????????????????? ?V$SQL??????IS_RESOLVED_DYNAMIC_PLAN??????????final plan???default plan? ??????dynamic plan ???????SQL PLAN directives?????? declare cursor PLAN_DIRECTIVE_IDS is select directive_id from DBA_SQL_PLAN_DIRECTIVES; begin for z in PLAN_DIRECTIVE_IDS loop DBMS_SPD.DROP_SQL_PLAN_DIRECTIVE(z.directive_id); end loop; end; / explain plan for select /*MALCEAN*/ product_name from oe.order_items o, oe.product_information p where o.unit_price=15 and quantity>1 and p.product_id=o.product_id; select * from table(dbms_xplan.display()); Plan hash value: 1255158658 www.askmaclean.com ------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 4 | 128 | 7 (0)| 00:00:01 | | 1 | NESTED LOOPS | | | | | | | 2 | NESTED LOOPS | | 4 | 128 | 7 (0)| 00:00:01 | |* 3 | TABLE ACCESS FULL | ORDER_ITEMS | 4 | 48 | 3 (0)| 00:00:01 | |* 4 | INDEX UNIQUE SCAN | PRODUCT_INFORMATION_PK | 1 | | 0 (0)| 00:00:01 | | 5 | TABLE ACCESS BY INDEX ROWID| PRODUCT_INFORMATION | 1 | 20 | 1 (0)| 00:00:01 | ------------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 3 - filter("O"."UNIT_PRICE"=15 AND "QUANTITY">1) 4 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID") alter session set events '10053 trace name context forever,level 1'; OR alter session set events 'trace[SQL_Plan_Directive] disk highest'; select /*MALCEAN*/ product_name from oe.order_items o, oe.product_information p where o.unit_price=15 and quantity>1 and p.product_id=o.product_id; ---------------------------------------------------------------+-----------------------------------+ | Id | Operation | Name | Rows | Bytes | Cost | Time | ---------------------------------------------------------------+-----------------------------------+ | 0 | SELECT STATEMENT | | | | 7 | | | 1 | HASH JOIN | | 4 | 128 | 7 | 00:00:01 | | 2 | NESTED LOOPS | | | | | | | 3 | NESTED LOOPS | | 4 | 128 | 7 | 00:00:01 | | 4 | STATISTICS COLLECTOR | | | | | | | 5 | TABLE ACCESS FULL | ORDER_ITEMS | 4 | 48 | 3 | 00:00:01 | | 6 | INDEX UNIQUE SCAN | PRODUCT_INFORMATION_PK| 1 | | 0 | | | 7 | TABLE ACCESS BY INDEX ROWID | PRODUCT_INFORMATION | 1 | 20 | 1 | 00:00:01 | | 8 | TABLE ACCESS FULL | PRODUCT_INFORMATION | 1 | 20 | 1 | 00:00:01 | ---------------------------------------------------------------+-----------------------------------+ Predicate Information: ---------------------- 1 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID") 5 - filter(("O"."UNIT_PRICE"=15 AND "QUANTITY">1)) 6 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID") ===================================== SPD: BEGIN context at statement level ===================================== Stmt: ******* UNPARSED QUERY IS ******* SELECT /*+ OPT_ESTIMATE (@"SEL$1" JOIN ("P"@"SEL$1" "O"@"SEL$1") ROWS=13.000000 ) OPT_ESTIMATE (@"SEL$1" TABLE "O"@"SEL$1" ROWS=13.000000 ) */ "P"."PRODUCT_NAME" "PRODUCT_NAME" FROM "OE"."ORDER_ITEMS" "O","OE"."PRODUCT_INFORMATION" "P" WHERE "O"."UNIT_PRICE"=15 AND "O"."QUANTITY">1 AND "P"."PRODUCT_ID"="O"."PRODUCT_ID" Objects referenced in the statement PRODUCT_INFORMATION[P] 92194, type = 1 ORDER_ITEMS[O] 92197, type = 1 Objects in the hash table Hash table Object 92197, type = 1, ownerid = 6573730143572393221: No Dynamic Sampling Directives for the object Hash table Object 92194, type = 1, ownerid = 17822962561575639002: No Dynamic Sampling Directives for the object Return code in qosdInitDirCtx: ENBLD =================================== SPD: END context at statement level =================================== ======================================= SPD: BEGIN context at query block level ======================================= Query Block SEL$1 (#0) Return code in qosdSetupDirCtx4QB: NOCTX ===================================== SPD: END context at query block level ===================================== SPD: Return code in qosdDSDirSetup: NOCTX, estType = TABLE SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92197, objtyp = 1, vecsize = 6, colvec = [4, 5, ], fid = 2896834833840853267 SPD: Inserted felem, fid=2896834833840853267, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = YES, keep = YES SPD: qosdCreateFindingSingTab retCode = CREATED, fid = 2896834833840853267 SPD: qosdCreateDirCmp retCode = CREATED, fid = 2896834833840853267 SPD: Return code in qosdDSDirSetup: NOCTX, estType = TABLE SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = JOIN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SKIP_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = JOIN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_SCAN SPD: Return code in qosdDSDirSetup: NOCTX, estType = INDEX_FILTER SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92197, objtyp = 1, vecsize = 6, colvec = [4, 5, ], fid = 2896834833840853267 SPD: Modified felem, fid=2896834833840853267, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = YES, keep = YES SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92194, objtyp = 1, vecsize = 2, colvec = [1, ], fid = 5618517328604016300 SPD: Modified felem, fid=5618517328604016300, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = NO, keep = NO SPD: Generating finding id: type = 1, reason = 1, objcnt = 1, obItr = 0, objid = 92194, objtyp = 1, vecsize = 2, colvec = [1, ], fid = 1142802697078608149 SPD: Modified felem, fid=1142802697078608149, ftype = 1, freason = 1, dtype = 0, dstate = 0, dflag = 0, ver = NO, keep = NO SPD: Generating finding id: type = 1, reason = 2, objcnt = 2, obItr = 0, objid = 92194, objtyp = 1, vecsize = 0, obItr = 1, objid = 92197, objtyp = 1, vecsize = 0, fid = 1437680122701058051 SPD: Modified felem, fid=1437680122701058051, ftype = 1, freason = 2, dtype = 0, dstate = 0, dflag = 0, ver = NO, keep = NO select * from table(dbms_xplan.display_cursor(format=>'report')) ; ????report????adaptive plan Adaptive plan: ------------- This cursor has an adaptive plan, but adaptive plans are enabled for reporting mode only.  The plan that would be executed if adaptive plans were enabled is displayed below. ------------------------------------------------------------------------------------------ | Id  | Operation          | Name                | Rows  | Bytes | Cost (%CPU)| Time     | ------------------------------------------------------------------------------------------ |   0 | SELECT STATEMENT   |                     |       |       |     7 (100)|          | |*  1 |  HASH JOIN         |                     |     4 |   128 |     7   (0)| 00:00:01 | |*  2 |   TABLE ACCESS FULL| ORDER_ITEMS         |     4 |    48 |     3   (0)| 00:00:01 | |   3 |   TABLE ACCESS FULL| PRODUCT_INFORMATION |     1 |    20 |     1   (0)| 00:00:01 | ------------------------------------------------------------------------------------------ SQL> select SQL_ID,IS_RESOLVED_DYNAMIC_PLAN,sql_text from v$SQL WHERE SQL_TEXT like '%MALCEAN%' and sql_text not like '%like%'; SQL_ID IS -------------------------- -- SQL_TEXT -------------------------------------------------------------------------------- 6ydj1bn1bng17 Y select /*MALCEAN*/ product_name from oe.order_items o, oe.product_information p where o.unit_price=15 and quantity>1 and p.product_id=o.product_id ???? explain plan for ????default plan, ??????optimizer???final plan,??V$SQL.IS_RESOLVED_DYNAMIC_PLAN???Y,????????????? DBA_SQL_PLAN_DIRECTIVES?????????????SQL PLAN DIRECTIVES, ???12c? ???MMON?????DML ???column usage??????????,????SMON??? MMON????SGA??PLAN DIRECTIVES??? ?????DBMS_SPD.flush_sql_plan_directive???? select directive_id,type,reason from DBA_SQL_PLAN_DIRECTIVES / DIRECTIVE_ID TYPE REASON ----------------------------------- -------------------------------- ----------------------------- 10321283028317893030 DYNAMIC_SAMPLING JOIN CARDINALITY MISESTIMATE 4757086536465754886 DYNAMIC_SAMPLING JOIN CARDINALITY MISESTIMATE 16085268038103121260 DYNAMIC_SAMPLING JOIN CARDINALITY MISESTIMATE SQL> set pages 9999 SQL> set lines 300 SQL> col state format a5 SQL> col subobject_name format a11 SQL> col col_name format a11 SQL> col object_name format a13 SQL> select d.directive_id, o.object_type, o.object_name, o.subobject_name col_name, d.type, d.state, d.reason 2 from dba_sql_plan_directives d, dba_sql_plan_dir_objects o 3 where d.DIRECTIVE_ID=o.DIRECTIVE_ID 4 and o.object_name in ('ORDER_ITEMS') 5 order by d.directive_id; DIRECTIVE_ID OBJECT_TYPE OBJECT_NAME COL_NAME TYPE STATE REASON ------------ ------------ ------------- ----------- -------------------------------- ----- ------------------------------------- --- 1.8156E+19 COLUMN ORDER_ITEMS UNIT_PRICE DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE 1.8156E+19 TABLE ORDER_ITEMS DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE 1.8156E+19 COLUMN ORDER_ITEMS QUANTITY DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE DBA_SQL_PLAN_DIRECTIVES????? _BASE_OPT_DIRECTIVE ? _BASE_OPT_FINDING SELECT d.dir_own#, d.dir_id, d.f_id, decode(type, 1, 'DYNAMIC_SAMPLING', 'UNKNOWN'), decode(state, 1, 'NEW', 2, 'MISSING_STATS', 3, 'HAS_STATS', 4, 'CANDIDATE', 5, 'PERMANENT', 6, 'DISABLED', 'UNKNOWN'), decode(bitand(flags, 1), 1, 'YES', 'NO'), cast(d.created as timestamp), cast(d.last_modified as timestamp), -- Please see QOSD_DAYS_TO_UPDATE and QOSD_PLUS_SECONDS for more details -- about 6.5 cast(d.last_used as timestamp) - NUMTODSINTERVAL(6.5, 'day') FROM sys.opt_directive$ d ??dbms_spd??? SQL PLAN DIRECTIVES, SQL PLAN DIRECTIVES???retention ???53?: Package: DBMS_SPD This package provides subprograms for managing Sql Plan Directives(SPD). SPD are objects generated automatically by Oracle server. For example, if server detects that the single table cardinality estimated by optimizer is off from the actual number of rows returned when accessing the table, it will automatically create a directive to do dynamic sampling for the table. When any Sql statement referencing the table is compiled, optimizer will perform dynamic sampling for the table to get more accurate estimate. Notes: DBMSL_SPD is a invoker-rights package. The invoker requires ADMINISTER SQL MANAGEMENT OBJECT privilege for executing most of the subprograms of this package. Also the subprograms commit the current transaction (if any), perform the operation and commit it again. DBA view dba_sql_plan_directives shows all the directives created in the system and the view dba_sql_plan_dir_objects displays the objects that are included in the directives. -- Default value for SPD_RETENTION_WEEKS SPD_RETENTION_WEEKS_DEFAULT CONSTANT varchar2(4) := '53'; | STATE : NEW : Newly created directive. | : MISSING_STATS : The directive objects do not | have relevant stats. | : HAS_STATS : The objects have stats. | : PERMANENT : A permanent directive. Server | evaluated effectiveness and these | directives are useful. | | AUTO_DROP : YES : Directive will be dropped | automatically if not | used for SPD_RETENTION_WEEKS. | This is the default behavior. | NO : Directive will not be dropped | automatically. Procedure: flush_sql_plan_directive This procedure allows manually flushing the Sql Plan directives that are automatically recorded in SGA memory while executing sql statements. The information recorded in SGA are periodically flushed by oracle background processes. This procedure just provides a way to flush the information manually. ????”_optimizer_dynamic_plans”(enable dynamic plans)????????,???TRUE??DYNAMIC PLAN? ???FALSE???????????? ????,Dynamic Plan????????????Nested Loop?Hash Join???case ,????????Nested loop???????????HASH JOIN,?HASH JOIN????????????????? ????????subplan?????,???? pass?? ?join method???,?????STATISTICS COLLECTOR???cardinality?,???????HASH JOIN?????Nested Loop,????????????subplan?????access path; ???????Sales??????????????????,????HASH JOIN,??SUBPLAN??customers?????????;?????Nested Loop,???????cust_id?????Range Scan+Access by Rowid? Cardinality feedback Cardinality feedback????????11.2????,????????re-optimization???;  ???????????,Cardinality feedback?????????????????????????? ???????????????????,?????????????????,??????????Cardinality feedback????????????? ????????????????????????? ??????????????Cardinality feedback ??: ????????,???????????,??????????,????????????????selectivity ??? ????????????: ??????,?????????????????????????????????,??????????????????? ????????????????????????????????????????,?????????????????????????? ?????????,???????????????,?????????? ??????????Cardinality ????,??????join Cardinality ????????? Cardinality feedback???????cursor?,?Cursor???aged out????? SELECT /*+ gather_plan_statistics */ product_name FROM order_items o, product_information p WHERE o.unit_price = 15 AND quantity > 1 AND p.product_id = o.product_id Plan hash value: 1553478007 ---------------------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads | OMem | 1Mem | Used-Mem | ---------------------------------------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 13 |00:00:00.01 | 24 | 20 | | | | |* 1 | HASH JOIN | | 1 | 4 | 13 |00:00:00.01 | 24 | 20 | 2061K| 2061K| 429K (0)| |* 2 | TABLE ACCESS FULL| ORDER_ITEMS | 1 | 4 | 13 |00:00:00.01 | 7 | 6 | | | | | 3 | TABLE ACCESS FULL| PRODUCT_INFORMATION | 1 | 1 | 288 |00:00:00.01 | 17 | 14 | | | | ---------------------------------------------------------------------------------------------------------------------------------------- SELECT /*+ gather_plan_statistics */ product_name FROM order_items o, product_information p WHERE o.unit_price = 15 AND quantity > 1 AND p.product_id = o.product_id Plan hash value: 1553478007 ------------------------------------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | OMem | 1Mem | Used-Mem | ------------------------------------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 13 |00:00:00.01 | 24 | | | | |* 1 | HASH JOIN | | 1 | 13 | 13 |00:00:00.01 | 24 | 2061K| 2061K| 413K (0)| |* 2 | TABLE ACCESS FULL| ORDER_ITEMS | 1 | 13 | 13 |00:00:00.01 | 7 | | | | | 3 | TABLE ACCESS FULL| PRODUCT_INFORMATION | 1 | 288 | 288 |00:00:00.01 | 17 | | | | ------------------------------------------------------------------------------------------------------------------------------- Note ----- - statistics feedback used for this statement SQL> select count(*) from v$SQL where SQL_ID='cz0hg2zkvd10y'; COUNT(*) ---------- 2 SQL>select sql_ID,USE_FEEDBACK_STATS FROM V$SQL_SHARED_CURSOR where USE_FEEDBACK_STATS ='Y'; SQL_ID U ------------- - cz0hg2zkvd10y Y ????????Cardinality feedback????,???????????????????????????,????????????order_items???????? ????2??????plan hash value??(??????????),?????2????child cursor??????gather_plan_statistics???actual : A-ROWS  estimate :E-ROWS????????? Automatic Re-optimization ???dynamic plan, Re-optimization???????????????  ?  ??????????????? ????????????????????????????????  ???????????,??????????????, ???????????????????? ???????????  Re-optimization??, ????????????????????? Re-optimization????dynamic plan??????????  dynamic plan????????????????????, ???????????????????? ????,??????????join order ??????????????,?????????????join order????? ??????,????????Re-optimization, ??Re-optimization ??????????????????? ?Oracle database 12c?,join statistics?????????????????????,??????????????????????Re-optimization???????????adaptive cursor sharing????? ????????????????,???????????? ????? ???????statistics collectors ????????????????????Re-optimization??????2?????????????,???????????????? ??????????????Re-optimization?????,?????????????????????? ???v$SQL??????IS_REOPTIMIZABLE?????????????????????Re-optimization,??????????Re-optimization???,?????Re-optimization ,???????reporting????? IS_REOPTIMIZABLE VARCHAR2(1) This columns shows whether the next execution matching this child cursor will trigger a reoptimization. The values are:   Y: If the next execution will trigger a reoptimization R: If the child cursor contains reoptimization information, but will not trigger reoptimization because the cursor was compiled in reporting mode N: If the child cursor has no reoptimization information ??1: select plan_table_output from table (dbms_xplan.display_cursor('gwf99gfnm0t7g',NULL,'ALLSTATS LAST')); SQL_ID  gwf99gfnm0t7g, child number 0 ------------------------------------- SELECT /*+ SFTEST gather_plan_statistics */ o.order_id, v.product_name FROM  orders o,   ( SELECT order_id, product_name FROM order_items o, product_information p     WHERE  p.product_id = o.product_id AND list_price < 50 AND min_price < 40  ) v WHERE o.order_id = v.order_id Plan hash value: 1906736282 ------------------------------------------------------------------------------------------------------------------------------------------- | Id  | Operation             | Name                | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |  OMem |  1Mem | Used-Mem | ------------------------------------------------------------------------------------------------------------------------------------------- |   0 | SELECT STATEMENT      |                     |      1 |        |    269 |00:00:00.02 |    1336 |     18 |       |       |          | |   1 |  NESTED LOOPS         |                     |      1 |      1 |    269 |00:00:00.02 |    1336 |     18 |       |       |          | |   2 |   MERGE JOIN CARTESIAN|                     |      1 |      4 |   9135 |00:00:00.02 |      34 |     15 |       |       |          | |*  3 |    TABLE ACCESS FULL  | PRODUCT_INFORMATION |      1 |      1 |     87 |00:00:00.01 |      33 |     14 |       |       |          | |   4 |    BUFFER SORT        |                     |     87 |    105 |   9135 |00:00:00.01 |       1 |      1 |  4096 |  4096 | 4096  (0)| |   5 |     INDEX FULL SCAN   | ORDER_PK            |      1 |    105 |    105 |00:00:00.01 |       1 |      1 |       |       |          | |*  6 |   INDEX UNIQUE SCAN   | ORDER_ITEMS_UK      |   9135 |      1 |    269 |00:00:00.01 |    1302 |      3 |       |       |          | ------------------------------------------------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): ---------------------------------------------------    3 - filter(("MIN_PRICE"<40 AND "LIST_PRICE"<50))    6 - access("O"."ORDER_ID"="ORDER_ID" AND "P"."PRODUCT_ID"="O"."PRODUCT_ID") SQL_ID  gwf99gfnm0t7g, child number 1 ------------------------------------- SELECT /*+ SFTEST gather_plan_statistics */ o.order_id, v.product_name FROM  orders o,   ( SELECT order_id, product_name FROM order_items o, product_information p     WHERE  p.product_id = o.product_id AND list_price < 50 AND min_price < 40  ) v WHERE o.order_id = v.order_id Plan hash value: 35479787 -------------------------------------------------------------------------------------------------------------------------------------------- | Id  | Operation              | Name                | Starts | E-Rows | A-Rows |   A-Time   | Buffers | Reads  |  OMem |  1Mem | Used-Mem | -------------------------------------------------------------------------------------------------------------------------------------------- |   0 | SELECT STATEMENT       |                     |      1 |        |    269 |00:00:00.01 |      63 |      3 |       |       |          | |   1 |  NESTED LOOPS          |                     |      1 |    269 |    269 |00:00:00.01 |      63 |      3 |       |       |          | |*  2 |   HASH JOIN            |                     |      1 |    313 |    269 |00:00:00.01 |      42 |      3 |  1321K|  1321K| 1234K (0)| |*  3 |    TABLE ACCESS FULL   | PRODUCT_INFORMATION |      1 |     87 |     87 |00:00:00.01 |      16 |      0 |       |       |          | |   4 |    INDEX FAST FULL SCAN| ORDER_ITEMS_UK      |      1 |    665 |    665 |00:00:00.01 |      26 |      3 |       |       |          | |*  5 |   INDEX UNIQUE SCAN    | ORDER_PK            |    269 |      1 |    269 |00:00:00.01 |      21 |      0 |       |       |          | -------------------------------------------------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): ---------------------------------------------------    2 - access("P"."PRODUCT_ID"="O"."PRODUCT_ID")    3 - filter(("MIN_PRICE"<40 AND "LIST_PRICE"<50))    5 - access("O"."ORDER_ID"="ORDER_ID") Note -----    - statistics feedback used for this statement    SQL> select IS_REOPTIMIZABLE,child_number FROM V$SQL  A where A.SQL_ID='gwf99gfnm0t7g'; IS CHILD_NUMBER -- ------------ Y             0 N             1    1* select child_number,other_xml From v$SQL_PLAN  where SQL_ID='gwf99gfnm0t7g' and other_xml is not nul SQL> / CHILD_NUMBER OTHER_XML ------------ --------------------------------------------------------------------------------            1 <other_xml><info type="cardinality_feedback">yes</info><info type="db_version">1              2.1.0.1</info><info type="parse_schema"><![CDATA["OE"]]></info><info type="plan_              hash">35479787</info><info type="plan_hash_2">3382491761</info><outline_data><hi              nt><![CDATA[IGNORE_OPTIM_EMBEDDED_HINTS]]></hint><hint><![CDATA[OPTIMIZER_FEATUR              ES_ENABLE('12.1.0.1')]]></hint><hint><![CDATA[DB_VERSION('12.1.0.1')]]></hint><h              int><![CDATA[ALL_ROWS]]></hint><hint><![CDATA[OUTLINE_LEAF(@"SEL$F5BB74E1")]]></              hint><hint><![CDATA[MERGE(@"SEL$2")]]></hint><hint><![CDATA[OUTLINE(@"SEL$1")]]>              </hint><hint><![CDATA[OUTLINE(@"SEL$2")]]></hint><hint><![CDATA[FULL(@"SEL$F5BB7              4E1" "P"@"SEL$2")]]></hint><hint><![CDATA[INDEX_FFS(@"SEL$F5BB74E1" "O"@"SEL$2"              ("ORDER_ITEMS"."ORDER_ID" "ORDER_ITEMS"."PRODUCT_ID"))]]></hint><hint><![CDATA[I              NDEX(@"SEL$F5BB74E1" "O"@"SEL$1" ("ORDERS"."ORDER_ID"))]]></hint><hint><![CDATA[              LEADING(@"SEL$F5BB74E1" "P"@"SEL$2" "O"@"SEL$2" "O"@"SEL$1")]]></hint><hint><![C              DATA[USE_HASH(@"SEL$F5BB74E1" "O"@"SEL$2")]]></hint><hint><![CDATA[USE_NL(@"SEL$              F5BB74E1" "O"@"SEL$1")]]></hint></outline_data></other_xml>            0 <other_xml><info type="db_version">12.1.0.1</info><info type="parse_schema"><![C              DATA["OE"]]></info><info type="plan_hash">1906736282</info><info type="plan_hash              _2">2579473118</info><outline_data><hint><![CDATA[IGNORE_OPTIM_EMBEDDED_HINTS]]>              </hint><hint><![CDATA[OPTIMIZER_FEATURES_ENABLE('12.1.0.1')]]></hint><hint><![CD              ATA[DB_VERSION('12.1.0.1')]]></hint><hint><![CDATA[ALL_ROWS]]></hint><hint><![CD              ATA[OUTLINE_LEAF(@"SEL$F5BB74E1")]]></hint><hint><![CDATA[MERGE(@"SEL$2")]]></hi              nt><hint><![CDATA[OUTLINE(@"SEL$1")]]></hint><hint><![CDATA[OUTLINE(@"SEL$2")]]>              </hint><hint><![CDATA[FULL(@"SEL$F5BB74E1" "P"@"SEL$2")]]></hint><hint><![CDATA[              INDEX(@"SEL$F5BB74E1" "O"@"SEL$1" ("ORDERS"."ORDER_ID"))]]></hint><hint><![CDATA              [INDEX(@"SEL$F5BB74E1" "O"@"SEL$2" ("ORDER_ITEMS"."ORDER_ID" "ORDER_ITEMS"."PROD              UCT_ID"))]]></hint><hint><![CDATA[LEADING(@"SEL$F5BB74E1" "P"@"SEL$2" "O"@"SEL$1              " "O"@"SEL$2")]]></hint><hint><![CDATA[USE_MERGE_CARTESIAN(@"SEL$F5BB74E1" "O"@"              SEL$1")]]></hint><hint><![CDATA[USE_NL(@"SEL$F5BB74E1" "O"@"SEL$2")]]></hint></o              utline_data></other_xml> ??2: SELECT /*+gather_plan_statistics*/ * FROM customers WHERE cust_state_province='CA' AND country_id='US'; SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST')); PLAN_TABLE_OUTPUT ------------------------------------- SQL_ID b74nw722wjvy3, child number 0 ------------------------------------- select /*+gather_plan_statistics*/ * from customers where CUST_STATE_PROVINCE='CA' and country_id='US' Plan hash value: 1683234692 -------------------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads | -------------------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 29 |00:00:00.01 | 17 | 14 | |* 1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 8 | 29 |00:00:00.01 | 17 | 14 | -------------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter(("CUST_STATE_PROVINCE"='CA' AND "COUNTRY_ID"='US')) SELECT SQL_ID, CHILD_NUMBER, SQL_TEXT, IS_REOPTIMIZABLE FROM V$SQL WHERE SQL_TEXT LIKE 'SELECT /*+gather_plan_statistics*/%'; SQL_ID CHILD_NUMBER SQL_TEXT I ------------- ------------ ----------- - b74nw722wjvy3 0 select /*+g Y ather_plan_ statistics* / * from cu stomers whe re CUST_STA TE_PROVINCE ='CA' and c ountry_id=' US' EXEC DBMS_SPD.FLUSH_SQL_PLAN_DIRECTIVE; SELECT TO_CHAR(d.DIRECTIVE_ID) dir_id, o.OWNER, o.OBJECT_NAME, o.SUBOBJECT_NAME col_name, o.OBJECT_TYPE, d.TYPE, d.STATE, d.REASON FROM DBA_SQL_PLAN_DIRECTIVES d, DBA_SQL_PLAN_DIR_OBJECTS o WHERE d.DIRECTIVE_ID=o.DIRECTIVE_ID AND o.OWNER IN ('SH') ORDER BY 1,2,3,4,5; DIR_ID OWNER OBJECT_NAME COL_NAME OBJECT TYPE STATE REASON ----------------------- ----- ------------- ----------- ------ ---------------- ----- ------------------------ 1484026771529551585 SH CUSTOMERS COUNTRY_ID COLUMN DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE 1484026771529551585 SH CUSTOMERS CUST_STATE_ COLUMN DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY PROVINCE MISESTIMATE 1484026771529551585 SH CUSTOMERS TABLE DYNAMIC_SAMPLING NEW SINGLE TABLE CARDINALITY MISESTIMATE SELECT /*+gather_plan_statistics*/ * FROM customers WHERE cust_state_province='CA' AND country_id='US'; ELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST')); PLAN_TABLE_OUTPUT ------------------------------------- SQL_ID b74nw722wjvy3, child number 1 ------------------------------------- select /*+gather_plan_statistics*/ * from customers where CUST_STATE_PROVINCE='CA' and country_id='US' Plan hash value: 1683234692 ----------------------------------------------------------------------------------------- | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | ----------------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 29 |00:00:00.01 | 17 | |* 1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 29 | 29 |00:00:00.01 | 17 | ----------------------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter(("CUST_STATE_PROVINCE"='CA' AND "COUNTRY_ID"='US')) Note ----- - cardinality feedback used for this statement SELECT SQL_ID, CHILD_NUMBER, SQL_TEXT, IS_REOPTIMIZABLE FROM V$SQL WHERE SQL_TEXT LIKE 'SELECT /*+gather_plan_statistics*/%'; SQL_ID CHILD_NUMBER SQL_TEXT I ------------- ------------ ----------- - b74nw722wjvy3 0 select /*+g Y ather_plan_ statistics* / * from cu stomers whe re CUST_STA TE_PROVINCE ='CA' and c ountry_id=' US' b74nw722wjvy3 1 select /*+g N ather_plan_ statistics* / * from cu stomers whe re CUST_STA TE_PROVINCE ='CA' and c ountry_id=' US' SELECT /*+gather_plan_statistics*/ CUST_EMAIL FROM CUSTOMERS WHERE CUST_STATE_PROVINCE='MA' AND COUNTRY_ID='US'; SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'ALLSTATS LAST')); PLAN_TABLE_OUTPUT ------------------------------------- SQL_ID 3tk6hj3nkcs2u, child number 0 ------------------------------------- Select /*+gather_plan_statistics*/ cust_email From customers Where cust_state_province='MA' And country_id='US' Plan hash value: 1683234692 ------------------------------------------------------------------------------- |Id | Operation | Name | Starts|E-Rows|A-Rows| A-Time |Buffers| ------------------------------------------------------------------------------- | 0 | SELECT STATEMENT | | 1 | | 2 |00:00:00.01| 16 | |*1 | TABLE ACCESS FULL| CUSTOMERS | 1 | 2| 2 |00:00:00.01| 16 | ----------------------------------------------------------------------------- Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter(("CUST_STATE_PROVINCE"='MA' AND "COUNTRY_ID"='US')) Note ----- - dynamic sampling used for this statement (level=2) - 1 Sql Plan Directive used for this statement EXEC DBMS_SPD.FLUSH_SQL_PLAN_DIRECTIVE; SELECT TO_CHAR(d.DIRECTIVE_ID) dir_id, o.OWNER, o.OBJECT_NAME, o.SUBOBJECT_NAME col_name, o.OBJECT_TYPE, d.TYPE, d.STATE, d.REASON FROM DBA_SQL_PLAN_DIRECTIVES d, DBA_SQL_PLAN_DIR_OBJECTS o WHERE d.DIRECTIVE_ID=o.DIRECTIVE_ID AND o.OWNER IN ('SH') ORDER BY 1,2,3,4,5; DIR_ID OW OBJECT_NA COL_NAME OBJECT TYPE STATE REASON ------------------- -- --------- ---------- ------- --------------- ------------- ------------------------ 1484026771529551585 SH CUSTOMERS COUNTRY_ID COLUMN DYNAMIC_SAMPLING MISSING_STATS SINGLE TABLE CARDINALITY MISESTIMATE 1484026771529551585 SH CUSTOMERS CUST_STATE_ COLUMN DYNAMIC_SAMPLING MISSING_STATS SINGLE TABLE CARDINALITY PROVINCE MISESTIMATE 1484026771529551585 SH CUSTOMERS TABLE DYNAMIC_SAMPLING MISSING_STATS SINGLE TABLE CARDINALITY MISESTIMATE

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• C# WCF Server retrieves 'List<T>' with 1 entry, but client doesn't receive it?! Please help Urgentl

  - by Neville

  Hi Everyone, I've been battling and trying to research this issue for over 2 days now with absolutely no luck. I am trying to retrieve a list of clients from the server (server using fluentNHibernate). The client object is as follow: [DataContract] //[KnownType(typeof(System.Collections.Generic.List<ContactPerson>))] //[KnownType(typeof(System.Collections.Generic.List<Address>))] //[KnownType(typeof(System.Collections.Generic.List<BatchRequest>))] //[KnownType(typeof(System.Collections.Generic.List<Discount>))] [KnownType(typeof(EClientType))] [KnownType(typeof(EComType))] public class Client { #region Properties [DataMember] public virtual int ClientID { get; set; } [DataMember] public virtual EClientType ClientType { get; set; } [DataMember] public virtual string RegisterID {get; set;} [DataMember] public virtual string HerdCode { get; set; } [DataMember] public virtual string CompanyName { get; set; } [DataMember] public virtual bool InvoicePerBatch { get; set; } [DataMember] public virtual EComType ResultsComType { get; set; } [DataMember] public virtual EComType InvoiceComType { get; set; } //[DataMember] //public virtual IList<ContactPerson> Contacts { get; set; } //[DataMember] //public virtual IList<Address> Addresses { get; set; } //[DataMember] //public virtual IList<BatchRequest> Batches { get; set; } //[DataMember] //public virtual IList<Discount> Discounts { get; set; } #endregion #region Overrides public override bool Equals(object obj) { var other = obj as Client; if (other == null) return false; return other.GetHashCode() == this.GetHashCode(); } public override int GetHashCode() { return ClientID.GetHashCode() | ClientType.GetHashCode() | RegisterID.GetHashCode() | HerdCode.GetHashCode() | CompanyName.GetHashCode() | InvoicePerBatch.GetHashCode() | ResultsComType.GetHashCode() | InvoiceComType.GetHashCode();// | Contacts.GetHashCode() | //Addresses.GetHashCode() | Batches.GetHashCode() | Discounts.GetHashCode(); } #endregion } As you can see, I have allready tried to remove the sub-lists, though even with this simplified version of the client I still run into the propblem. my fluent mapping is: public class ClientMap : ClassMap<Client> { public ClientMap() { Table("Clients"); Id(p => p.ClientID); Map(p => p.ClientType).CustomType<EClientType>(); ; Map(p => p.RegisterID); Map(p => p.HerdCode); Map(p => p.CompanyName); Map(p => p.InvoicePerBatch); Map(p => p.ResultsComType).CustomType<EComType>(); Map(p => p.InvoiceComType).CustomType<EComType>(); //HasMany<ContactPerson>(p => p.Contacts) // .KeyColumns.Add("ContactPersonID") // .Inverse() // .Cascade.All(); //HasMany<Address>(p => p.Addresses) // .KeyColumns.Add("AddressID") // .Inverse() // .Cascade.All(); //HasMany<BatchRequest>(p => p.Batches) // .KeyColumns.Add("BatchID") // .Inverse() // .Cascade.All(); //HasMany<Discount>(p => p.Discounts) // .KeyColumns.Add("DiscountID") // .Inverse() // .Cascade.All(); } The client method, seen below, connects to the server. The server retrieves the list, and everything looks right in the object, still, when it returns, the client doesn't receive anything (it receive a List object, but with nothing in it. Herewith the calling method: public List<s.Client> GetClientList() { try { s.DataServiceClient svcClient = new s.DataServiceClient(); svcClient.Open(); List<s.Client> clients = new List<s.Client>(); clients = svcClient.GetClientList().ToList<s.Client>(); svcClient.Close(); //when receiving focus from server, the clients object has a count of 0 return clients; } catch (Exception e) { MessageBox.Show(e.Message); } return null; } and the server method: public IList<Client> GetClientList() { var clients = new List<Client>(); try { using (var session = SessionHelper.OpenSession()) { clients = session.Linq<Client>().Where(p => p.ClientID > 0).ToList<Client>(); } } catch (Exception e) { EventLog.WriteEntry("eCOWS.Data", e.Message); } return clients; //returns a list with 1 client in it } the server method interface is: [UseNetDataContractSerializer] [OperationContract] IList<Client> GetClientList(); for final references, here is my client app.config entries: <system.serviceModel> <bindings> <netTcpBinding> <binding name="NetTcpBinding_IDataService" listenBacklog="10" maxConnections="10" transferMode="Buffered" transactionProtocol="OleTransactions" maxReceivedMessageSize="2147483647" maxBufferSize="2147483647" receiveTimeout="00:10:00" sendTimeout="00:10:00"> <readerQuotas maxDepth="51200000" maxStringContentLength="51200000" maxArrayLength="51200000" maxBytesPerRead="51200000" maxNameTableCharCount="51200000" /> <security mode="Transport"/> </binding> </netTcpBinding> </bindings> <client> <endpoint address="net.tcp://localhost:9000/eCOWS/DataService" binding="netTcpBinding" bindingConfiguration="NetTcpBinding_IDataService" contract="eCowsDataService.IDataService" name="NetTcpBinding_IDataService" behaviorConfiguration="eCowsEndpointBehavior"> </endpoint> <endpoint address="MEX" binding="mexHttpBinding" contract="IMetadataExchange" /> </client> <behaviors> <endpointBehaviors> <behavior name="eCowsEndpointBehavior"> <dataContractSerializer maxItemsInObjectGraph="2147483647"/> </behavior> </endpointBehaviors> </behaviors> </system.serviceModel> and my server app.config: <system.serviceModel> <bindings> <netTcpBinding> <binding name="netTcpBinding" maxConnections="10" listenBacklog="10" transferMode="Buffered" transactionProtocol="OleTransactions" maxBufferSize="2147483647" maxReceivedMessageSize="2147483647" sendTimeout="00:10:00" receiveTimeout="00:10:00"> <readerQuotas maxDepth="51200000" maxStringContentLength="51200000" maxArrayLength="51200000" maxBytesPerRead="51200000" maxNameTableCharCount="51200000" /> <security mode="Transport"/> </binding> </netTcpBinding> </bindings> <services> <service name="eCows.Data.Services.DataService" behaviorConfiguration="eCowsServiceBehavior"> <host> <baseAddresses> <add baseAddress="http://localhost:9001/eCOWS/" /> <add baseAddress="net.tcp://localhost:9000/eCOWS/" /> </baseAddresses> </host> <endpoint address="DataService" binding="netTcpBinding" contract="eCows.Data.Services.IDataService" behaviorConfiguration="eCowsEndpointBehaviour"> </endpoint> <endpoint address="MEX" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services> <behaviors> <endpointBehaviors> <behavior name="eCowsEndpointBehaviour"> <dataContractSerializer maxItemsInObjectGraph="2147483647" /> </behavior> </endpointBehaviors> <serviceBehaviors> <behavior name="eCowsServiceBehavior"> <serviceMetadata httpGetEnabled="True"/> <serviceThrottling maxConcurrentCalls="10" maxConcurrentSessions="10"/> <serviceDebug includeExceptionDetailInFaults="False" /> </behavior> <behavior name="MexBehaviour"> <serviceMetadata /> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> I use to run into "socket closed / network or timeout" errors, and the trace showed clearly that on the callback it was looking for a listening endpoint, but couldn't find one. Anyway, after adding the UseNetSerializer that error went away, yet now I'm just not getting anything. Oh PS. if I add all the commented out List items, I still retrieve an entry from the DB, but also still not receive anything on the client. if I remove the [UseNetDataContractSerializer] I get the following error(s) in the svclog : WARNING: Description Faulted System.ServiceModel.Channels.ServerSessionPreambleConnectionReader+ServerFramingDuplexSessionChannel WARNING: Description Faulted System.ServiceModel.Channels.ServiceChannel ERROR: Initializing[eCows.Data.Models.Client#3]-failed to lazily initialize a collection of role: eCows.Data.Models.Client.Addresses, no session or session was closed ... ERROR: Could not find default endpoint element that references contract 'ILogbookManager' in the ServiceModel client configuration section. This might be because no configuration file was found for your application, or because no endpoint element matching this contract could be found in the client element. If I add a .Not.LazyLoad to the List mapping items, I'm back at not receiving errors, but also not receiving any client information.. Sigh! Please, if anyone can help with this I'd be extremely grateful. I'm probably just missing something small.. but... what is it :) hehe. Thanks in advance! Neville

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• Multiple database with Spring+Hibernate+JPA

  - by ziftech

  Hi everybody! I'm trying to configure Spring+Hibernate+JPA for work with two databases (MySQL and MSSQL) my datasource-context.xml: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"> <!-- Data Source config --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" p:driverClassName="${local.jdbc.driver}" p:url="${local.jdbc.url}" p:username="${local.jdbc.username}" p:password="${local.jdbc.password}"> </bean> <bean id="dataSourceRemote" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" p:driverClassName="${remote.jdbc.driver}" p:url="${remote.jdbc.url}" p:username="${remote.jdbc.username}" p:password="${remote.jdbc.password}" /> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" p:entity-manager-factory-ref="entityManagerFactory" /> <!-- JPA config --> <tx:annotation-driven transaction-manager="transactionManager" /> <bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager"> <property name="persistenceXmlLocations"> <list value-type="java.lang.String"> <value>classpath*:config/persistence.local.xml</value> <value>classpath*:config/persistence.remote.xml</value> </list> </property> <property name="dataSources"> <map> <entry key="localDataSource" value-ref="dataSource" /> <entry key="remoteDataSource" value-ref="dataSourceRemote" /> </map> </property> <property name="defaultDataSource" ref="dataSource" /> </bean> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" p:showSql="true" p:generateDdl="true"> </bean> </property> <property name="persistenceUnitManager" ref="persistenceUnitManager" /> <property name="persistenceUnitName" value="localjpa"/> </bean> <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" /> </beans> each persistence.xml contains one unit, like this: <persistence-unit name="remote" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.DefaultNamingStrategy" /> <property name="hibernate.dialect" value="${remote.hibernate.dialect}" /> <property name="hibernate.hbm2ddl.auto" value="${remote.hibernate.hbm2ddl.auto}" /> </properties> </persistence-unit> PersistenceUnitManager cause following exception: Cannot resolve reference to bean 'persistenceUnitManager' while setting bean property 'persistenceUnitManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'persistenceUnitManager' defined in class path resource [config/datasource-context.xml]: Initialization of bean failed; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert property value of type [java.util.ArrayList] to required type [java.lang.String] for property 'persistenceXmlLocation'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [java.util.ArrayList] to required type [java.lang.String] for property 'persistenceXmlLocation': no matching editors or conversion strategy found If left only one persistence.xml without list, every works fine but I need 2 units... I also try to find alternative solution for work with two databases in Spring+Hibernate context, so I would appreciate any solution new error after changing to persistenceXmlLocations No single default persistence unit defined in {classpath:config/persistence.local.xml, classpath:config/persistence.remote.xml} UPDATE: I add persistenceUnitName, it works, but only with one unit, still need help UPDATE: thanks, ChssPly76 I changed config files: datasource-context.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:util="http://www.springframework.org/schema/util"> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" p:driverClassName="${local.jdbc.driver}" p:url="${local.jdbc.url}" p:username="${local.jdbc.username}" p:password="${local.jdbc.password}"> </bean> <bean id="dataSourceRemote" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" p:driverClassName="${remote.jdbc.driver}" p:url="${remote.jdbc.url}" p:username="${remote.jdbc.username}" p:password="${remote.jdbc.password}"> </bean> <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"> <property name="defaultPersistenceUnitName" value="pu1" /> </bean> <bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager"> <property name="persistenceXmlLocation" value="${persistence.xml.location}" /> <property name="defaultDataSource" ref="dataSource" /> <!-- problem --> <property name="dataSources"> <map> <entry key="local" value-ref="dataSource" /> <entry key="remote" value-ref="dataSourceRemote" /> </map> </property> </bean> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" p:showSql="true" p:generateDdl="true"> </bean> </property> <property name="persistenceUnitManager" ref="persistenceUnitManager" /> <property name="persistenceUnitName" value="pu1" /> <property name="dataSource" ref="dataSource" /> </bean> <bean id="entityManagerFactoryRemote" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" p:showSql="true" p:generateDdl="true"> </bean> </property> <property name="persistenceUnitManager" ref="persistenceUnitManager" /> <property name="persistenceUnitName" value="pu2" /> <property name="dataSource" ref="dataSourceRemote" /> </bean> <tx:annotation-driven /> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager" p:entity-manager-factory-ref="entityManagerFactory" /> <bean id="transactionManagerRemote" class="org.springframework.orm.jpa.JpaTransactionManager" p:entity-manager-factory-ref="entityManagerFactoryRemote" /> </beans> persistence.xml <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="pu1" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.DefaultNamingStrategy" /> <property name="hibernate.dialect" value="${local.hibernate.dialect}" /> <property name="hibernate.hbm2ddl.auto" value="${local.hibernate.hbm2ddl.auto}" /> </properties> </persistence-unit> <persistence-unit name="pu2" transaction-type="RESOURCE_LOCAL"> <properties> <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.DefaultNamingStrategy" /> <property name="hibernate.dialect" value="${remote.hibernate.dialect}" /> <property name="hibernate.hbm2ddl.auto" value="${remote.hibernate.hbm2ddl.auto}" /> </properties> </persistence-unit> </persistence> Now it builds two entityManagerFactory, but both are for Microsoft SQL Server [main] INFO org.hibernate.ejb.Ejb3Configuration - Processing PersistenceUnitInfo [ name: pu1 ...] [main] INFO org.hibernate.cfg.SettingsFactory - RDBMS: Microsoft SQL Server [main] INFO org.hibernate.ejb.Ejb3Configuration - Processing PersistenceUnitInfo [ name: pu2 ...] [main] INFO org.hibernate.cfg.SettingsFactory - RDBMS: Microsoft SQL Server (but must MySQL) I suggest, that use only dataSource, dataSourceRemote (no substitution) is not worked. That's my last problem

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• nested iterator errors

  - by Sean

  //arrayList.h #include<iostream> #include<sstream> #include<string> #include<algorithm> #include<iterator> using namespace std; template<class T> class arrayList{ public: // constructor, copy constructor and destructor arrayList(int initialCapacity = 10); arrayList(const arrayList<T>&); ~arrayList() { delete[] element; } // ADT methods bool empty() const { return listSize == 0; } int size() const { return listSize; } T& get(int theIndex) const; int indexOf(const T& theElement) const; void erase(int theIndex); void insert(int theIndex, const T& theElement); void output(ostream& out) const; // additional method int capacity() const { return arrayLength; } void reverse(); // new defined // iterators to start and end of list class iterator; class seamlessPointer; seamlessPointer begin() { return seamlessPointer(element); } seamlessPointer end() { return seamlessPointer(element + listSize); } // iterator for arrayList class iterator { public: // typedefs required by C++ for a bidirectional iterator typedef bidirectional_iterator_tag iterator_category; typedef T value_type; typedef ptrdiff_t difference_type; typedef T* pointer; typedef T& reference; // constructor iterator(T* thePosition = 0) { position = thePosition; } // dereferencing operators T& operator*() const { return *position; } T* operator->() const { return position; } // increment iterator& operator++() // preincrement { ++position; return *this; } iterator operator++(int) // postincrement { iterator old = *this; ++position; return old; } // decrement iterator& operator--() // predecrement { --position; return *this; } iterator operator--(int) // postdecrement { iterator old = *this; --position; return old; } // equality testing bool operator!=(const iterator right) const { return position != right.position; } bool operator==(const iterator right) const { return position == right.position; } protected: T* position; }; // end of iterator class class seamlessPointer: public arrayList<T>::iterator { // constructor seamlessPointer(T *thePosition) { iterator::position = thePosition; } //arithmetic operators seamlessPointer & operator+(int n) { arrayList<T>::iterator::position += n; return *this; } seamlessPointer & operator+=(int n) { arrayList<T>::iterator::position += n; return *this; } seamlessPointer & operator-(int n) { arrayList<T>::iterator::position -= n; return *this; } seamlessPointer & operator-=(int n) { arrayList<T>::iterator::position -= n; return *this; } T& operator[](int n) { return arrayList<T>::iterator::position[n]; } bool operator<(seamlessPointer &rhs) { if(int(arrayList<T>::iterator::position - rhs.position) < 0) return true; return false; } bool operator<=(seamlessPointer & rhs) { if (int(arrayList<T>::iterator::position - rhs.position) <= 0) return true; return false; } bool operator >(seamlessPointer & rhs) { if (int(arrayList<T>::iterator::position - rhs.position) > 0) return true; return false; } bool operator >=(seamlessPointer &rhs) { if (int(arrayList<T>::iterator::position - rhs.position) >= 0) return true; return false; } }; protected: // additional members of arrayList void checkIndex(int theIndex) const; // throw illegalIndex if theIndex invalid T* element; // 1D array to hold list elements int arrayLength; // capacity of the 1D array int listSize; // number of elements in list }; #endif //main.cpp #include<iostream> #include"arrayList.h" #include<fstream> #include<algorithm> #include<string> using namespace std; bool compare_nocase (string first, string second) { unsigned int i=0; while ( (i<first.length()) && (i<second.length()) ) { if (tolower(first[i])<tolower(second[i])) return true; else if (tolower(first[i])>tolower(second[i])) return false; ++i; } if (first.length()<second.length()) return true; else return false; } int main() { ifstream fin; ofstream fout; string str; arrayList<string> dict; fin.open("dictionary"); if (!fin.good()) { cout << "Unable to open file" << endl; return 1; } int k=0; while(getline(fin,str)) { dict.insert(k,str); // cout<<dict.get(k)<<endl; k++; } //sort the array sort(dict.begin, dict.end(),compare_nocase); fout.open("sortedDictionary"); if (!fout.good()) { cout << "Cannot create file" << endl; return 1; } dict.output(fout); fin.close(); return 0; } Two errors are: ..\src\test.cpp: In function 'int main()': ..\src\test.cpp:50:44: error: no matching function for call to 'sort(<unresolved overloaded function type>, arrayList<std::basic_string<char> >::seamlessPointer, bool (&)(std::string, std::string))' ..\src\/arrayList.h: In member function 'arrayList<T>::seamlessPointer arrayList<T>::end() [with T = std::basic_string<char>]': ..\src\test.cpp:50:28: instantiated from here ..\src\/arrayList.h:114:3: error: 'arrayList<T>::seamlessPointer::seamlessPointer(T*) [with T = std::basic_string<char>]' is private ..\src\/arrayList.h:49:44: error: within this context Why do I get these errors? Update I add public: in the seamlessPointer class and change begin to begin() Then I got the following errors: ..\hw3prob2.cpp:50:46: instantiated from here c:\wascana\mingw\bin\../lib/gcc/mingw32/4.5.0/include/c++/bits/stl_algo.h:5250:4: error: no match for 'operator-' in '__last - __first' ..\/arrayList.h:129:21: note: candidate is: arrayList<T>::seamlessPointer& arrayList<T>::seamlessPointer::operator-(int) [with T = std::basic_string<char>, arrayList<T>::seamlessPointer = arrayList<std::basic_string<char> >::seamlessPointer] c:\wascana\mingw\bin\../lib/gcc/mingw32/4.5.0/include/c++/bits/stl_algo.h:5252:4: instantiated from 'void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = arrayList<std::basic_string<char> >::seamlessPointer, _Compare = bool (*)(std::basic_string<char>, std::basic_string<char>)]' ..\hw3prob2.cpp:50:46: instantiated from here c:\wascana\mingw\bin\../lib/gcc/mingw32/4.5.0/include/c++/bits/stl_algo.h:2190:7: error: no match for 'operator-' in '__last - __first' ..\/arrayList.h:129:21: note: candidate is: arrayList<T>::seamlessPointer& arrayList<T>::seamlessPointer::operator-(int) [with T = std::basic_string<char>, arrayList<T>::seamlessPointer = arrayList<std::basic_string<char> >::seamlessPointer] Then I add operator -() in the seamlessPointer class ptrdiff_t operator -(seamlessPointer &rhs) { return (arrayList<T>::iterator::position - rhs.position); } Then I compile successfully. But when I run it, I found memeory can not read error. I debug and step into and found the error happens in stl function template<typename _RandomAccessIterator, typename _Distance, typename _Tp, typename _Compare> void __adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex, _Distance __len, _Tp __value, _Compare __comp) { const _Distance __topIndex = __holeIndex; _Distance __secondChild = __holeIndex; while (__secondChild < (__len - 1) / 2) { __secondChild = 2 * (__secondChild + 1); if (__comp(*(__first + __secondChild), *(__first + (__secondChild - 1)))) __secondChild--; *(__first + __holeIndex) = _GLIBCXX_MOVE(*(__first + __secondChild)); ////// stop here __holeIndex = __secondChild; } Of course, there must be something wrong with the customized operators of iterator. Does anyone know the possible reason? Thank you.

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• Setting up a pc bluetooth server for android

  - by Del

  Alright, I've been reading a lot of topics the past two or three days and nothing seems to have asked this. I am writing a PC side server for my andriod device, this is for exchanging some information and general debugging. Eventually I will be connecting to a SPP device to control a microcontroller. I have managed, using the following (Android to pc) to connect to rfcomm channel 11 and exchange data between my android device and my pc. Method m = device.getClass().getMethod("createRfcommSocket", new Class[] { int.class }); tmp = (BluetoothSocket) m.invoke(device, Integer.valueOf(11)); I have attempted the createRfcommSocketToServiceRecord(UUID) method, with absolutely no luck. For the PC side, I have been using the C Bluez stack for linux. I have the following code which registers the service and opens a server socket: int main(int argc, char **argv) { struct sockaddr_rc loc_addr = { 0 }, rem_addr = { 0 }; char buf[1024] = { 0 }; char str[1024] = { 0 }; int s, client, bytes_read; sdp_session_t *session; socklen_t opt = sizeof(rem_addr); session = register_service(); s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM); loc_addr.rc_family = AF_BLUETOOTH; loc_addr.rc_bdaddr = *BDADDR_ANY; loc_addr.rc_channel = (uint8_t) 11; bind(s, (struct sockaddr *)&loc_addr, sizeof(loc_addr)); listen(s, 1); client = accept(s, (struct sockaddr *)&rem_addr, &opt); ba2str( &rem_addr.rc_bdaddr, buf ); fprintf(stderr, "accepted connection from %s\n", buf); memset(buf, 0, sizeof(buf)); bytes_read = read(client, buf, sizeof(buf)); if( bytes_read 0 ) { printf("received [%s]\n", buf); } sprintf(str,"to Android."); printf("sent [%s]\n",str); write(client, str, sizeof(str)); close(client); close(s); sdp_close( session ); return 0; } sdp_session_t *register_service() { uint32_t svc_uuid_int[] = { 0x00000000,0x00000000,0x00000000,0x00000000 }; uint8_t rfcomm_channel = 11; const char *service_name = "Remote Host"; const char *service_dsc = "What the remote should be connecting to."; const char *service_prov = "Your mother"; uuid_t root_uuid, l2cap_uuid, rfcomm_uuid, svc_uuid; sdp_list_t *l2cap_list = 0, *rfcomm_list = 0, *root_list = 0, *proto_list = 0, *access_proto_list = 0; sdp_data_t *channel = 0, *psm = 0; sdp_record_t *record = sdp_record_alloc(); // set the general service ID sdp_uuid128_create( &svc_uuid, &svc_uuid_int ); sdp_set_service_id( record, svc_uuid ); // make the service record publicly browsable sdp_uuid16_create(&root_uuid, PUBLIC_BROWSE_GROUP); root_list = sdp_list_append(0, &root_uuid); sdp_set_browse_groups( record, root_list ); // set l2cap information sdp_uuid16_create(&l2cap_uuid, L2CAP_UUID); l2cap_list = sdp_list_append( 0, &l2cap_uuid ); proto_list = sdp_list_append( 0, l2cap_list ); // set rfcomm information sdp_uuid16_create(&rfcomm_uuid, RFCOMM_UUID); channel = sdp_data_alloc(SDP_UINT8, &rfcomm_channel); rfcomm_list = sdp_list_append( 0, &rfcomm_uuid ); sdp_list_append( rfcomm_list, channel ); sdp_list_append( proto_list, rfcomm_list ); // attach protocol information to service record access_proto_list = sdp_list_append( 0, proto_list ); sdp_set_access_protos( record, access_proto_list ); // set the name, provider, and description sdp_set_info_attr(record, service_name, service_prov, service_dsc); int err = 0; sdp_session_t *session = 0; // connect to the local SDP server, register the service record, and // disconnect session = sdp_connect( BDADDR_ANY, BDADDR_LOCAL, SDP_RETRY_IF_BUSY ); err = sdp_record_register(session, record, 0); // cleanup //sdp_data_free( channel ); sdp_list_free( l2cap_list, 0 ); sdp_list_free( rfcomm_list, 0 ); sdp_list_free( root_list, 0 ); sdp_list_free( access_proto_list, 0 ); return session; } And another piece of code, in addition to 'sdptool browse local' which can verifty that the service record is running on the pc: int main(int argc, char **argv) { uuid_t svc_uuid; uint32_t svc_uuid_int[] = { 0x00000000,0x00000000,0x00000000,0x00000000 }; int err; bdaddr_t target; sdp_list_t *response_list = NULL, *search_list, *attrid_list; sdp_session_t *session = 0; str2ba( "01:23:45:67:89:AB", &target ); // connect to the SDP server running on the remote machine session = sdp_connect( BDADDR_ANY, BDADDR_LOCAL, SDP_RETRY_IF_BUSY ); // specify the UUID of the application we're searching for sdp_uuid128_create( &svc_uuid, &svc_uuid_int ); search_list = sdp_list_append( NULL, &svc_uuid ); // specify that we want a list of all the matching applications' attributes uint32_t range = 0x0000ffff; attrid_list = sdp_list_append( NULL, &range ); // get a list of service records that have UUID 0xabcd err = sdp_service_search_attr_req( session, search_list, \ SDP_ATTR_REQ_RANGE, attrid_list, &response_list); sdp_list_t *r = response_list; // go through each of the service records for (; r; r = r-next ) { sdp_record_t *rec = (sdp_record_t*) r-data; sdp_list_t *proto_list; // get a list of the protocol sequences if( sdp_get_access_protos( rec, &proto_list ) == 0 ) { sdp_list_t *p = proto_list; // go through each protocol sequence for( ; p ; p = p-next ) { sdp_list_t *pds = (sdp_list_t*)p-data; // go through each protocol list of the protocol sequence for( ; pds ; pds = pds-next ) { // check the protocol attributes sdp_data_t *d = (sdp_data_t*)pds-data; int proto = 0; for( ; d; d = d-next ) { switch( d-dtd ) { case SDP_UUID16: case SDP_UUID32: case SDP_UUID128: proto = sdp_uuid_to_proto( &d-val.uuid ); break; case SDP_UINT8: if( proto == RFCOMM_UUID ) { printf("rfcomm channel: %d\n",d-val.int8); } break; } } } sdp_list_free( (sdp_list_t*)p-data, 0 ); } sdp_list_free( proto_list, 0 ); } printf("found service record 0x%x\n", rec-handle); sdp_record_free( rec ); } sdp_close(session); } Output: $ ./search rfcomm channel: 11 found service record 0x10008 sdptool: Service Name: Remote Host Service Description: What the remote should be connecting to. Service Provider: Your mother Service RecHandle: 0x10008 Protocol Descriptor List: "L2CAP" (0x0100) "RFCOMM" (0x0003) Channel: 11 And for logcat I'm getting this: 07-22 15:57:06.087: ERROR/BTLD(215): ****************search UUID = 0000*********** 07-22 15:57:06.087: INFO//system/bin/btld(209): btapp_dm_GetRemoteServiceChannel() 07-22 15:57:06.087: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Wake, 0x8003 #### 07-22 15:57:06.097: INFO/ActivityManager(88): Displayed activity com.example.socktest/.socktest: 79 ms (total 79 ms) 07-22 15:57:06.697: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Sleep, 0x8004 #### 07-22 15:57:07.517: WARN/BTLD(215): ccb timer ticks: 2147483648 07-22 15:57:07.517: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Wake, 0x8003 #### 07-22 15:57:07.547: WARN/BTLD(215): info:x10 07-22 15:57:07.547: INFO/BTL-IFS(215): send_ctrl_msg: [BTL_IFS CTRL] send BTLIF_DTUN_SIGNAL_EVT (CTRL) 10 pbytes (hdl 14) 07-22 15:57:07.547: DEBUG/DTUN_HCID_BZ4(253): dtun_dm_sig_link_up() 07-22 15:57:07.547: INFO/DTUN_HCID_BZ4(253): dtun_dm_sig_link_up: dummy_handle = 342 07-22 15:57:07.547: DEBUG/ADAPTER(253): adapter_get_device(00:02:72:AB:7C:EE) 07-22 15:57:07.547: ERROR/BluetoothEventLoop.cpp(88): pollData[0] is revented, check next one 07-22 15:57:07.547: ERROR/BluetoothEventLoop.cpp(88): event_filter: Received signal org.bluez.Device:PropertyChanged from /org/bluez/253/hci0/dev_00_02_72_AB_7C_EE 07-22 15:57:07.777: WARN/BTLD(215): process_service_search_attr_rsp 07-22 15:57:07.787: INFO/BTL-IFS(215): send_ctrl_msg: [BTL_IFS CTRL] send BTLIF_DTUN_SIGNAL_EVT (CTRL) 13 pbytes (hdl 14) 07-22 15:57:07.787: INFO/DTUN_HCID_BZ4(253): dtun_dm_sig_rmt_service_channel: success=0, service=00000000 07-22 15:57:07.787: ERROR/DTUN_HCID_BZ4(253): discovery unsuccessful! 07-22 15:57:08.497: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Sleep, 0x8004 #### 07-22 15:57:09.507: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Wake, 0x8003 #### 07-22 15:57:09.597: INFO/BTL-IFS(215): send_ctrl_msg: [BTL_IFS CTRL] send BTLIF_DTUN_SIGNAL_EVT (CTRL) 11 pbytes (hdl 14) 07-22 15:57:09.597: DEBUG/DTUN_HCID_BZ4(253): dtun_dm_sig_link_down() 07-22 15:57:09.597: INFO/DTUN_HCID_BZ4(253): dtun_dm_sig_link_down device = 0xf7a0 handle = 342 reason = 22 07-22 15:57:09.597: ERROR/BluetoothEventLoop.cpp(88): pollData[0] is revented, check next one 07-22 15:57:09.597: ERROR/BluetoothEventLoop.cpp(88): event_filter: Received signal org.bluez.Device:PropertyChanged from /org/bluez/253/hci0/dev_00_02_72_AB_7C_EE 07-22 15:57:09.597: DEBUG/BluetoothA2dpService(88): Received intent Intent { act=android.bluetooth.device.action.ACL_DISCONNECTED (has extras) } 07-22 15:57:10.107: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Sleep, 0x8004 #### 07-22 15:57:12.107: DEBUG/BluetoothService(88): Cleaning up failed UUID channel lookup: 00:02:72:AB:7C:EE 00000000-0000-0000-0000-000000000000 07-22 15:57:12.107: ERROR/Socket Test(5234): connect() failed 07-22 15:57:12.107: DEBUG/ASOCKWRP(5234): asocket_abort [31,32,33] 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: s 31, how 2 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: fd (-1:31), bta -1, rc 0, wflags 0x0 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): __close_prot_rfcomm: fd 31 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): __close_prot_rfcomm: bind not completed on this socket 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): btlif_signal_event: fd (-1:31), bta -1, rc 0, wflags 0x0 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): btlif_signal_event: event BTLIF_BTS_EVT_ABORT matched 07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wrp_close_s_only: wrp_close_s_only [31] (31:-1) [] 07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wrp_close_s_only: data socket closed 07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wsactive_del: delete wsock 31 from active list [ad3e1494] 07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wrp_close_s_only: wsock fully closed, return to pool 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): btsk_free: success 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_write: wrote 1 bytes out of 1 on fd 33 07-22 15:57:12.107: DEBUG/ASOCKWRP(5234): asocket_destroy 07-22 15:57:12.107: DEBUG/ASOCKWRP(5234): asocket_abort [31,32,33] 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: s 31, how 2 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: btsk not found, normal close (31) 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_write: wrote 1 bytes out of 1 on fd 33 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_close: s 33 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_close: btsk not found, normal close (33) 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_close: s 32 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_close: btsk not found, normal close (32) 07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_close: s 31 07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_close: btsk not found, normal close (31) 07-22 15:57:12.157: DEBUG/Sensors(88): close_akm, fd=151 07-22 15:57:12.167: ERROR/CachedBluetoothDevice(477): onUuidChanged: Time since last connect14970690 07-22 15:57:12.237: DEBUG/Socket Test(5234): -On Stop- Sorry for bombarding you guys with what seems like a difficult question and a lot to read, but I've been working on this problem for a while and I've tried a lot of different things to get this working. Let me reiterate, I can get it to work, but not using service discovery protocol. I've tried a several different UUIDs and on two different computers, although I only have my HTC Incredible to test with. I've also heard some rumors that the BT stack wasn't working on the HTC Droid, but that isn't the case, at least, for PC interaction.

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• How to solve "403 Forbidden" on CentOS6 with SELinux Disabled?

  - by André

  I have a machine on Linode that is driving me crazy. Linode does not have SELinux on CentOS6... I'm trying to configure to put my website in "/home/websites/public_html/mysite.com/public" As I don´t have SELinux enable, how can I avoid the "403 Forbidden" that I get when trying to access the webpage? Sorry for my english. Best Regards, Update1, ERROR_LOG [Mon Oct 17 14:04:16 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 14:08:07 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 14:10:25 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 14:10:41 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 14:32:35 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 14:34:45 2011] [error] [client 58.218.199.227] (13)Permission denied: access to /proxy-1.php denied [Mon Oct 17 15:32:25 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 15:37:26 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 15:37:43 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 15:38:32 2011] [error] [client 127.0.0.1] (13)Permission denied: access to / denied [Mon Oct 17 15:42:56 2011] [crit] [client 127.0.0.1] (13)Permission denied: /home/websites/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable [Mon Oct 17 15:43:12 2011] [crit] [client 127.0.0.1] (13)Permission denied: /home/websites/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable [Mon Oct 17 15:45:34 2011] [crit] [client 127.0.0.1] (13)Permission denied: /home/websites/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable [Mon Oct 17 15:51:25 2011] [crit] [client 127.0.0.1] (13)Permission denied: /home/websites/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable Upadate2, /home/websites directory drwx------ 3 websites websites 4096 Oct 17 14:52 . drwxr-xr-x. 3 root root 4096 Oct 17 13:42 .. -rw------- 1 websites websites 372 Oct 17 14:52 .bash_history -rw-r--r-- 1 websites websites 18 May 30 11:46 .bash_logout -rw-r--r-- 1 websites websites 176 May 30 11:46 .bash_profile -rw-r--r-- 1 websites websites 124 May 30 11:46 .bashrc drwxrwxr-x 3 websites apache 4096 Oct 17 13:45 public_html Update3, httpd.conf ### Section 1: Global Environment ServerTokens OS ServerRoot "/etc/httpd" PidFile run/httpd.pid Timeout 60 KeepAlive Off MaxKeepAliveRequests 100 KeepAliveTimeout 15 <IfModule prefork.c> StartServers 8 MinSpareServers 5 MaxSpareServers 20 ServerLimit 256 MaxClients 256 MaxRequestsPerChild 4000 </IfModule> <IfModule worker.c> StartServers 4 MaxClients 300 MinSpareThreads 25 MaxSpareThreads 75 ThreadsPerChild 25 MaxRequestsPerChild 0 </IfModule> #Listen 12.34.56.78:80 Listen 80 LoadModule auth_basic_module modules/mod_auth_basic.so LoadModule auth_digest_module modules/mod_auth_digest.so LoadModule authn_file_module modules/mod_authn_file.so LoadModule authn_alias_module modules/mod_authn_alias.so LoadModule authn_anon_module modules/mod_authn_anon.so LoadModule authn_dbm_module modules/mod_authn_dbm.so LoadModule authn_default_module modules/mod_authn_default.so LoadModule authz_host_module modules/mod_authz_host.so LoadModule authz_user_module modules/mod_authz_user.so LoadModule authz_owner_module modules/mod_authz_owner.so LoadModule authz_groupfile_module modules/mod_authz_groupfile.so LoadModule authz_dbm_module modules/mod_authz_dbm.so LoadModule authz_default_module modules/mod_authz_default.so LoadModule ldap_module modules/mod_ldap.so LoadModule authnz_ldap_module modules/mod_authnz_ldap.so LoadModule include_module modules/mod_include.so LoadModule log_config_module modules/mod_log_config.so LoadModule logio_module modules/mod_logio.so LoadModule env_module modules/mod_env.so LoadModule ext_filter_module modules/mod_ext_filter.so LoadModule mime_magic_module modules/mod_mime_magic.so LoadModule expires_module modules/mod_expires.so LoadModule deflate_module modules/mod_deflate.so LoadModule headers_module modules/mod_headers.so LoadModule usertrack_module modules/mod_usertrack.so LoadModule setenvif_module modules/mod_setenvif.so LoadModule mime_module modules/mod_mime.so LoadModule dav_module modules/mod_dav.so LoadModule status_module modules/mod_status.so LoadModule autoindex_module modules/mod_autoindex.so LoadModule info_module modules/mod_info.so LoadModule dav_fs_module modules/mod_dav_fs.so LoadModule vhost_alias_module modules/mod_vhost_alias.so LoadModule negotiation_module modules/mod_negotiation.so LoadModule dir_module modules/mod_dir.so LoadModule actions_module modules/mod_actions.so LoadModule speling_module modules/mod_speling.so LoadModule userdir_module modules/mod_userdir.so LoadModule alias_module modules/mod_alias.so LoadModule substitute_module modules/mod_substitute.so LoadModule rewrite_module modules/mod_rewrite.so LoadModule proxy_module modules/mod_proxy.so LoadModule proxy_balancer_module modules/mod_proxy_balancer.so LoadModule proxy_ftp_module modules/mod_proxy_ftp.so LoadModule proxy_http_module modules/mod_proxy_http.so LoadModule proxy_ajp_module modules/mod_proxy_ajp.so LoadModule proxy_connect_module modules/mod_proxy_connect.so LoadModule cache_module modules/mod_cache.so LoadModule suexec_module modules/mod_suexec.so LoadModule disk_cache_module modules/mod_disk_cache.so LoadModule cgi_module modules/mod_cgi.so LoadModule version_module modules/mod_version.so Include conf.d/*.conf #ExtendedStatus On User apache Group apache ServerAdmin root@localhost #ServerName www.example.com:80 UseCanonicalName Off DocumentRoot "/var/www/html" # # Each directory to which Apache has access can be configured with respect # to which services and features are allowed and/or disabled in that # directory (and its subdirectories). # # First, we configure the "default" to be a very restrictive set of # features. # <Directory /> Options FollowSymLinks AllowOverride None </Directory> # # Note that from this point forward you must specifically allow # particular features to be enabled - so if something's not working as # you might expect, make sure that you have specifically enabled it # below. # # # This should be changed to whatever you set DocumentRoot to. # <Directory "/home/websites/public_html"> # # Possible values for the Options directive are "None", "All", # or any combination of: # Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews # # Note that "MultiViews" must be named *explicitly* --- "Options All" # doesn't give it to you. # # The Options directive is both complicated and important. Please see # http://httpd.apache.org/docs/2.2/mod/core.html#options # for more information. # Options Indexes FollowSymLinks # # AllowOverride controls what directives may be placed in .htaccess files. # It can be "All", "None", or any combination of the keywords: # Options FileInfo AuthConfig Limit # AllowOverride None # # Controls who can get stuff from this server. # Order allow,deny Allow from all </Directory> # # UserDir: The name of the directory that is appended onto a user's home # directory if a ~user request is received. # # The path to the end user account 'public_html' directory must be # accessible to the webserver userid. This usually means that ~userid # must have permissions of 711, ~userid/public_html must have permissions # of 755, and documents contained therein must be world-readable. # Otherwise, the client will only receive a "403 Forbidden" message. # # See also: http://httpd.apache.org/docs/misc/FAQ.html#forbidden # <IfModule mod_userdir.c> # # UserDir is disabled by default since it can confirm the presence # of a username on the system (depending on home directory # permissions). # UserDir disabled # # To enable requests to /~user/ to serve the user's public_html # directory, remove the "UserDir disabled" line above, and uncomment # the following line instead: # #UserDir public_html </IfModule> # # Control access to UserDir directories. The following is an example # for a site where these directories are restricted to read-only. # #<Directory /home/*/public_html> # AllowOverride FileInfo AuthConfig Limit # Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec # <Limit GET POST OPTIONS> # Order allow,deny # Allow from all # </Limit> # <LimitExcept GET POST OPTIONS> # Order deny,allow # Deny from all # </LimitExcept> #</Directory> # # DirectoryIndex: sets the file that Apache will serve if a directory # is requested. # # The index.html.var file (a type-map) is used to deliver content- # negotiated documents. The MultiViews Option can be used for the # same purpose, but it is much slower. # DirectoryIndex index.html index.html.var # # AccessFileName: The name of the file to look for in each directory # for additional configuration directives. See also the AllowOverride # directive. # AccessFileName .htaccess # # The following lines prevent .htaccess and .htpasswd files from being # viewed by Web clients. # <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy All </Files> # # TypesConfig describes where the mime.types file (or equivalent) is # to be found. # TypesConfig /etc/mime.types # # DefaultType is the default MIME type the server will use for a document # if it cannot otherwise determine one, such as from filename extensions. # If your server contains mostly text or HTML documents, "text/plain" is # a good value. If most of your content is binary, such as applications # or images, you may want to use "application/octet-stream" instead to # keep browsers from trying to display binary files as though they are # text. # DefaultType text/plain # # The mod_mime_magic module allows the server to use various hints from the # contents of the file itself to determine its type. The MIMEMagicFile # directive tells the module where the hint definitions are located. # <IfModule mod_mime_magic.c> # MIMEMagicFile /usr/share/magic.mime MIMEMagicFile conf/magic </IfModule> # # HostnameLookups: Log the names of clients or just their IP addresses # e.g., www.apache.org (on) or 204.62.129.132 (off). # The default is off because it'd be overall better for the net if people # had to knowingly turn this feature on, since enabling it means that # each client request will result in AT LEAST one lookup request to the # nameserver. # HostnameLookups Off #EnableMMAP off #EnableSendfile off # # ErrorLog: The location of the error log file. # If you do not specify an ErrorLog directive within a <VirtualHost> # container, error messages relating to that virtual host will be # logged here. If you *do* define an error logfile for a <VirtualHost> # container, that host's errors will be logged there and not here. # ErrorLog logs/error_log LogLevel warn # # The following directives define some format nicknames for use with # a CustomLog directive (see below). # LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %b" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent # "combinedio" includes actual counts of actual bytes received (%I) and sent (%O); this # requires the mod_logio module to be loaded. #LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio # # The location and format of the access logfile (Common Logfile Format). # If you do not define any access logfiles within a <VirtualHost> # container, they will be logged here. Contrariwise, if you *do* # define per-<VirtualHost> access logfiles, transactions will be # logged therein and *not* in this file. # #CustomLog logs/access_log common # # If you would like to have separate agent and referer logfiles, uncomment # the following directives. # #CustomLog logs/referer_log referer #CustomLog logs/agent_log agent # # For a single logfile with access, agent, and referer information # (Combined Logfile Format), use the following directive: # CustomLog logs/access_log combined ServerSignature On Alias /icons/ "/var/www/icons/" <Directory "/var/www/icons"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order allow,deny Allow from all </Directory> # # WebDAV module configuration section. # <IfModule mod_dav_fs.c> # Location of the WebDAV lock database. DAVLockDB /var/lib/dav/lockdb </IfModule> # # ScriptAlias: This controls which directories contain server scripts. # ScriptAliases are essentially the same as Aliases, except that # documents in the realname directory are treated as applications and # run by the server when requested rather than as documents sent to the client. # The same rules about trailing "/" apply to ScriptAlias directives as to # Alias. # ScriptAlias /cgi-bin/ "/var/www/cgi-bin/" # # "/var/www/cgi-bin" should be changed to whatever your ScriptAliased # CGI directory exists, if you have that configured. # <Directory "/var/www/cgi-bin"> AllowOverride None Options None Order allow,deny Allow from all </Directory> IndexOptions FancyIndexing VersionSort NameWidth=* HTMLTable Charset=UTF-8 AddIconByEncoding (CMP,/icons/compressed.gif) x-compress x-gzip AddIconByType (TXT,/icons/text.gif) text/* AddIconByType (IMG,/icons/image2.gif) image/* AddIconByType (SND,/icons/sound2.gif) audio/* AddIconByType (VID,/icons/movie.gif) video/* AddIcon /icons/binary.gif .bin .exe AddIcon /icons/binhex.gif .hqx AddIcon /icons/tar.gif .tar AddIcon /icons/world2.gif .wrl .wrl.gz .vrml .vrm .iv AddIcon /icons/compressed.gif .Z .z .tgz .gz .zip AddIcon /icons/a.gif .ps .ai .eps AddIcon /icons/layout.gif .html .shtml .htm .pdf AddIcon /icons/text.gif .txt AddIcon /icons/c.gif .c AddIcon /icons/p.gif .pl .py AddIcon /icons/f.gif .for AddIcon /icons/dvi.gif .dvi AddIcon /icons/uuencoded.gif .uu AddIcon /icons/script.gif .conf .sh .shar .csh .ksh .tcl AddIcon /icons/tex.gif .tex AddIcon /icons/bomb.gif core AddIcon /icons/back.gif .. AddIcon /icons/hand.right.gif README AddIcon /icons/folder.gif ^^DIRECTORY^^ AddIcon /icons/blank.gif ^^BLANKICON^^ # # DefaultIcon is which icon to show for files which do not have an icon # explicitly set. # DefaultIcon /icons/unknown.gif # # AddDescription allows you to place a short description after a file in # server-generated indexes. These are only displayed for FancyIndexed # directories. # Format: AddDescription "description" filename # #AddDescription "GZIP compressed document" .gz #AddDescription "tar archive" .tar #AddDescription "GZIP compressed tar archive" .tgz # # ReadmeName is the name of the README file the server will look for by # default, and append to directory listings. # # HeaderName is the name of a file which should be prepended to # directory indexes. ReadmeName README.html HeaderName HEADER.html # # IndexIgnore is a set of filenames which directory indexing should ignore # and not include in the listing. Shell-style wildcarding is permitted. # IndexIgnore .??* *~ *# HEADER* README* RCS CVS *,v *,t # # DefaultLanguage and AddLanguage allows you to specify the language of # a document. You can then use content negotiation to give a browser a # file in a language the user can understand. # # Specify a default language. This means that all data # going out without a specific language tag (see below) will # be marked with this one. You probably do NOT want to set # this unless you are sure it is correct for all cases. # # * It is generally better to not mark a page as # * being a certain language than marking it with the wrong # * language! # # DefaultLanguage nl # # Note 1: The suffix does not have to be the same as the language # keyword --- those with documents in Polish (whose net-standard # language code is pl) may wish to use "AddLanguage pl .po" to # avoid the ambiguity with the common suffix for perl scripts. # # Note 2: The example entries below illustrate that in some cases # the two character 'Language' abbreviation is not identical to # the two character 'Country' code for its country, # E.g. 'Danmark/dk' versus 'Danish/da'. # # Note 3: In the case of 'ltz' we violate the RFC by using a three char # specifier. There is 'work in progress' to fix this and get # the reference data for rfc1766 cleaned up. # # Catalan (ca) - Croatian (hr) - Czech (cs) - Danish (da) - Dutch (nl) # English (en) - Esperanto (eo) - Estonian (et) - French (fr) - German (de) # Greek-Modern (el) - Hebrew (he) - Italian (it) - Japanese (ja) # Korean (ko) - Luxembourgeois* (ltz) - Norwegian Nynorsk (nn) # Norwegian (no) - Polish (pl) - Portugese (pt) # Brazilian Portuguese (pt-BR) - Russian (ru) - Swedish (sv) # Simplified Chinese (zh-CN) - Spanish (es) - Traditional Chinese (zh-TW) # AddLanguage ca .ca AddLanguage cs .cz .cs AddLanguage da .dk AddLanguage de .de AddLanguage el .el AddLanguage en .en AddLanguage eo .eo AddLanguage es .es AddLanguage et .et AddLanguage fr .fr AddLanguage he .he AddLanguage hr .hr AddLanguage it .it AddLanguage ja .ja AddLanguage ko .ko AddLanguage ltz .ltz AddLanguage nl .nl AddLanguage nn .nn AddLanguage no .no AddLanguage pl .po AddLanguage pt .pt AddLanguage pt-BR .pt-br AddLanguage ru .ru AddLanguage sv .sv AddLanguage zh-CN .zh-cn AddLanguage zh-TW .zh-tw # # LanguagePriority allows you to give precedence to some languages # in case of a tie during content negotiation. # # Just list the languages in decreasing order of preference. We have # more or less alphabetized them here. You probably want to change this. # LanguagePriority en ca cs da de el eo es et fr he hr it ja ko ltz nl nn no pl pt pt-BR ru sv zh-CN zh-TW # # ForceLanguagePriority allows you to serve a result page rather than # MULTIPLE CHOICES (Prefer) [in case of a tie] or NOT ACCEPTABLE (Fallback) # [in case no accepted languages matched the available variants] # ForceLanguagePriority Prefer Fallback # # Specify a default charset for all content served; this enables # interpretation of all content as UTF-8 by default. To use the # default browser choice (ISO-8859-1), or to allow the META tags # in HTML content to override this choice, comment out this # directive: # AddDefaultCharset UTF-8 # # AddType allows you to add to or override the MIME configuration # file mime.types for specific file types. # #AddType application/x-tar .tgz # # AddEncoding allows you to have certain browsers uncompress # information on the fly. Note: Not all browsers support this. # Despite the name similarity, the following Add* directives have nothing # to do with the FancyIndexing customization directives above. # #AddEncoding x-compress .Z #AddEncoding x-gzip .gz .tgz # If the AddEncoding directives above are commented-out, then you # probably should define those extensions to indicate media types: # AddType application/x-compress .Z AddType application/x-gzip .gz .tgz # # MIME-types for downloading Certificates and CRLs # AddType application/x-x509-ca-cert .crt AddType application/x-pkcs7-crl .crl # # AddHandler allows you to map certain file extensions to "handlers": # actions unrelated to filetype. These can be either built into the server # or added with the Action directive (see below) # # To use CGI scripts outside of ScriptAliased directories: # (You will also need to add "ExecCGI" to the "Options" directive.) # #AddHandler cgi-script .cgi # # For files that include their own HTTP headers: # #AddHandler send-as-is asis # # For type maps (negotiated resources): # (This is enabled by default to allow the Apache "It Worked" page # to be distributed in multiple languages.) # AddHandler type-map var # # Filters allow you to process content before it is sent to the client. # # To parse .shtml files for server-side includes (SSI): # (You will also need to add "Includes" to the "Options" directive.) # AddType text/html .shtml AddOutputFilter INCLUDES .shtml # # Action lets you define media types that will execute a script whenever # a matching file is called. This eliminates the need for repeated URL # pathnames for oft-used CGI file processors. # Format: Action media/type /cgi-script/location # Format: Action handler-name /cgi-script/location # # # Customizable error responses come in three flavors: # 1) plain text 2) local redirects 3) external redirects # # Some examples: #ErrorDocument 500 "The server made a boo boo." #ErrorDocument 404 /missing.html #ErrorDocument 404 "/cgi-bin/missing_handler.pl" #ErrorDocument 402 http://www.example.com/subscription_info.html # # # Putting this all together, we can internationalize error responses. # # We use Alias to redirect any /error/HTTP_<error>.html.var response to # our collection of by-error message multi-language collections. We use # includes to substitute the appropriate text. # # You can modify the messages' appearance without changing any of the # default HTTP_<error>.html.var files by adding the line: # # Alias /error/include/ "/your/include/path/" # # which allows you to create your own set of files by starting with the # /var/www/error/include/ files and # copying them to /your/include/path/, even on a per-VirtualHost basis. # Alias /error/ "/var/www/error/" <IfModule mod_negotiation.c> <IfModule mod_include.c> <Directory "/var/www/error"> AllowOverride None Options IncludesNoExec AddOutputFilter Includes html AddHandler type-map var Order allow,deny Allow from all LanguagePriority en es de fr ForceLanguagePriority Prefer Fallback </Directory> # ErrorDocument 400 /error/HTTP_BAD_REQUEST.html.var # ErrorDocument 401 /error/HTTP_UNAUTHORIZED.html.var # ErrorDocument 403 /error/HTTP_FORBIDDEN.html.var # ErrorDocument 404 /error/HTTP_NOT_FOUND.html.var # ErrorDocument 405 /error/HTTP_METHOD_NOT_ALLOWED.html.var # ErrorDocument 408 /error/HTTP_REQUEST_TIME_OUT.html.var # ErrorDocument 410 /error/HTTP_GONE.html.var # ErrorDocument 411 /error/HTTP_LENGTH_REQUIRED.html.var # ErrorDocument 412 /error/HTTP_PRECONDITION_FAILED.html.var # ErrorDocument 413 /error/HTTP_REQUEST_ENTITY_TOO_LARGE.html.var # ErrorDocument 414 /error/HTTP_REQUEST_URI_TOO_LARGE.html.var # ErrorDocument 415 /error/HTTP_UNSUPPORTED_MEDIA_TYPE.html.var # ErrorDocument 500 /error/HTTP_INTERNAL_SERVER_ERROR.html.var # ErrorDocument 501 /error/HTTP_NOT_IMPLEMENTED.html.var # ErrorDocument 502 /error/HTTP_BAD_GATEWAY.html.var # ErrorDocument 503 /error/HTTP_SERVICE_UNAVAILABLE.html.var # ErrorDocument 506 /error/HTTP_VARIANT_ALSO_VARIES.html.var </IfModule> </IfModule> # # The following directives modify normal HTTP response behavior to # handle known problems with browser implementations. # BrowserMatch "Mozilla/2" nokeepalive BrowserMatch "MSIE 4\.0b2;" nokeepalive downgrade-1.0 force-response-1.0 BrowserMatch "RealPlayer 4\.0" force-response-1.0 BrowserMatch "Java/1\.0" force-response-1.0 BrowserMatch "JDK/1\.0" force-response-1.0 # # The following directive disables redirects on non-GET requests for # a directory that does not include the trailing slash. This fixes a # problem with Microsoft WebFolders which does not appropriately handle # redirects for folders with DAV methods. # Same deal with Apple's DAV filesystem and Gnome VFS support for DAV. # BrowserMatch "Microsoft Data Access Internet Publishing Provider" redirect-carefully BrowserMatch "MS FrontPage" redirect-carefully BrowserMatch "^WebDrive" redirect-carefully BrowserMatch "^WebDAVFS/1.[0123]" redirect-carefully BrowserMatch "^gnome-vfs/1.0" redirect-carefully BrowserMatch "^XML Spy" redirect-carefully BrowserMatch "^Dreamweaver-WebDAV-SCM1" redirect-carefully # # Allow server status reports generated by mod_status, # with the URL of http://servername/server-status # Change the ".example.com" to match your domain to enable. # #<Location /server-status> # SetHandler server-status # Order deny,allow # Deny from all # Allow from .example.com #</Location> # # Allow remote server configuration reports, with the URL of # http://servername/server-info (requires that mod_info.c be loaded). # Change the ".example.com" to match your domain to enable. # #<Location /server-info> # SetHandler server-info # Order deny,allow # Deny from all # Allow from .example.com #</Location> # # Proxy Server directives. Uncomment the following lines to # enable the proxy server: # #<IfModule mod_proxy.c> #ProxyRequests On # #<Proxy *> # Order deny,allow # Deny from all # Allow from .example.com #</Proxy> # # Enable/disable the handling of HTTP/1.1 "Via:" headers. # ("Full" adds the server version; "Block" removes all outgoing Via: headers) # Set to one of: Off | On | Full | Block # #ProxyVia On # # To enable a cache of proxied content, uncomment the following lines. # See http://httpd.apache.org/docs/2.2/mod/mod_cache.html for more details. # #<IfModule mod_disk_cache.c> # CacheEnable disk / # CacheRoot "/var/cache/mod_proxy" #</IfModule> # #</IfModule> # End of proxy directives. ### Section 3: Virtual Hosts # # VirtualHost: If you want to maintain multiple domains/hostnames on your # machine you can setup VirtualHost containers for them. Most configurations # use only name-based virtual hosts so the server doesn't need to worry about # IP addresses. This is indicated by the asterisks in the directives below. # # Please see the documentation at # <URL:http://httpd.apache.org/docs/2.2/vhosts/> # for further details before you try to setup virtual hosts. # # You may use the command line option '-S' to verify your virtual host # configuration. # # Use name-based virtual hosting. # NameVirtualHost *:80 # # NOTE: NameVirtualHost cannot be used without a port specifier # (e.g. :80) if mod_ssl is being used, due to the nature of the # SSL protocol. # # # VirtualHost example: # Almost any Apache directive may go into a VirtualHost container. # The first VirtualHost section is used for requests without a known # server name. # #<VirtualHost *:80> # ServerAdmin [email protected] # DocumentRoot /www/docs/dummy-host.example.com # ServerName dummy-host.example.com # ErrorLog logs/dummy-host.example.com-error_log # CustomLog logs/dummy-host.example.com-access_log common #</VirtualHost> # domain: mysite.com # public: /home/websites/public_html/mysite.com/ <VirtualHost *:80> # Admin email, Server Name (domain name) and any aliases ServerAdmin [email protected] ServerName mysite.com ServerAlias www.mysite.com # Index file and Document Root (where the public files are located) DirectoryIndex index.html DocumentRoot /home/websites/public_html/mysite.com/public # Custom log file locations LogLevel warn ErrorLog /home/websites/public_html/mysite.com/log/error.log CustomLog /home/websites/public_html/mysite.com/log/access.log combined </VirtualHost>

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• Unable to install Xdebug

  - by burnt1ce

  I've registered xdebug in php.ini (as per http://xdebug.org/docs/install) but it's not showing up when i run "php -m" or when i get a test page to run "phpinfo()". I've just installed the latest version of XAMPP. Can anyone provide any suggestions in getting xdebug to show up? This is what i get when i run phpinfo(). **PHP Version 5.3.1** System Windows NT ANDREW_LAPTOP 5.1 build 2600 (Windows XP Professional Service Pack 3) i586 Build Date Nov 20 2009 17:20:57 Compiler MSVC6 (Visual C++ 6.0) Architecture x86 Configure Command cscript /nologo configure.js "--enable-snapshot-build" Server API Apache 2.0 Handler Virtual Directory Support enabled Configuration File (php.ini) Path no value Loaded Configuration File C:\xampp\php\php.ini Scan this dir for additional .ini files (none) Additional .ini files parsed (none) PHP API 20090626 PHP Extension 20090626 Zend Extension 220090626 Zend Extension Build API220090626,TS,VC6 PHP Extension Build API20090626,TS,VC6 Debug Build no Thread Safety enabled Zend Memory Manager enabled Zend Multibyte Support disabled IPv6 Support enabled Registered PHP Streams https, ftps, php, file, glob, data, http, ftp, compress.zlib, compress.bzip2, phar, zip Registered Stream Socket Transports tcp, udp, ssl, sslv3, sslv2, tls Registered Stream Filters convert.iconv.*, string.rot13, string.toupper, string.tolower, string.strip_tags, convert.*, consumed, dechunk, zlib.*, bzip2.* This program makes use of the Zend Scripting Language Engine: Zend Engine v2.3.0, Copyright (c) 1998-2009 Zend Technologies PHP Credits Configuration apache2handler Apache Version Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 Apache API Version 20051115 Server Administrator postmaster@localhost Hostname:Port localhost:80 Max Requests Per Child: 0 - Keep Alive: on - Max Per Connection: 100 Timeouts Connection: 300 - Keep-Alive: 5 Virtual Server No Server Root C:/xampp/apache Loaded Modules core mod_win32 mpm_winnt http_core mod_so mod_actions mod_alias mod_asis mod_auth_basic mod_auth_digest mod_authn_default mod_authn_file mod_authz_default mod_authz_groupfile mod_authz_host mod_authz_user mod_cgi mod_dav mod_dav_fs mod_dav_lock mod_dir mod_env mod_headers mod_include mod_info mod_isapi mod_log_config mod_mime mod_negotiation mod_rewrite mod_setenvif mod_ssl mod_status mod_autoindex_color mod_php5 mod_perl mod_apreq2 Directive Local Value Master Value engine 1 1 last_modified 0 0 xbithack 0 0 Apache Environment Variable Value MIBDIRS C:/xampp/php/extras/mibs MYSQL_HOME C:\xampp\mysql\bin OPENSSL_CONF C:/xampp/apache/bin/openssl.cnf PHP_PEAR_SYSCONF_DIR C:\xampp\php PHPRC C:\xampp\php TMP C:\xampp\tmp HTTP_HOST localhost HTTP_CONNECTION keep-alive HTTP_USER_AGENT Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/533.2 (KHTML, like Gecko) Chrome/5.0.342.8 Safari/533.2 HTTP_CACHE_CONTROL max-age=0 HTTP_ACCEPT application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 HTTP_ACCEPT_ENCODING gzip,deflate,sdch HTTP_ACCEPT_LANGUAGE en-US,en;q=0.8 HTTP_ACCEPT_CHARSET ISO-8859-1,utf-8;q=0.7,*;q=0.3 PATH C:\Documents and Settings\Andrew\Local Settings\Application Data\Google\Chrome\Application;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\Common Files\DivX Shared\;C:\Program Files\WiTopia.Net\bin SystemRoot C:\WINDOWS COMSPEC C:\WINDOWS\system32\cmd.exe PATHEXT .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH WINDIR C:\WINDOWS SERVER_SIGNATURE <address>Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 Server at localhost Port 80</address> SERVER_SOFTWARE Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 SERVER_NAME localhost SERVER_ADDR 127.0.0.1 SERVER_PORT 80 REMOTE_ADDR 127.0.0.1 DOCUMENT_ROOT C:/xampp/htdocs SERVER_ADMIN postmaster@localhost SCRIPT_FILENAME C:/xampp/htdocs/test.php REMOTE_PORT 3275 GATEWAY_INTERFACE CGI/1.1 SERVER_PROTOCOL HTTP/1.1 REQUEST_METHOD GET QUERY_STRING no value REQUEST_URI /test.php SCRIPT_NAME /test.php HTTP Headers Information HTTP Request Headers HTTP Request GET /test.php HTTP/1.1 Host localhost Connection keep-alive User-Agent Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/533.2 (KHTML, like Gecko) Chrome/5.0.342.8 Safari/533.2 Cache-Control max-age=0 Accept application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 Accept-Encoding gzip,deflate,sdch Accept-Language en-US,en;q=0.8 Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.3 HTTP Response Headers X-Powered-By PHP/5.3.1 Keep-Alive timeout=5, max=80 Connection Keep-Alive Transfer-Encoding chunked Content-Type text/html bcmath BCMath support enabled Directive Local Value Master Value bcmath.scale 0 0 bz2 BZip2 Support Enabled Stream Wrapper support compress.bz2:// Stream Filter support bzip2.decompress, bzip2.compress BZip2 Version 1.0.5, 10-Dec-2007 calendar Calendar support enabled com_dotnet COM support enabled DCOM support disabled .Net support enabled Directive Local Value Master Value com.allow_dcom 0 0 com.autoregister_casesensitive 1 1 com.autoregister_typelib 0 0 com.autoregister_verbose 0 0 com.code_page no value no value com.typelib_file no value no value Core PHP Version 5.3.1 Directive Local Value Master Value allow_call_time_pass_reference On On allow_url_fopen On On allow_url_include Off Off always_populate_raw_post_data Off Off arg_separator.input & & arg_separator.output &amp; &amp; asp_tags Off Off auto_append_file no value no value auto_globals_jit On On auto_prepend_file no value no value browscap C:\xampp\php\extras\browscap.ini C:\xampp\php\extras\browscap.ini default_charset no value no value default_mimetype text/html text/html define_syslog_variables Off Off disable_classes no value no value disable_functions no value no value display_errors On On display_startup_errors On On doc_root no value no value docref_ext no value no value docref_root no value no value enable_dl On On error_append_string no value no value error_log no value no value error_prepend_string no value no value error_reporting 22519 22519 exit_on_timeout Off Off expose_php On On extension_dir C:\xampp\php\ext C:\xampp\php\ext file_uploads On On highlight.bg #FFFFFF #FFFFFF highlight.comment #FF8000 #FF8000 highlight.default #0000BB #0000BB highlight.html #000000 #000000 highlight.keyword #007700 #007700 highlight.string #DD0000 #DD0000 html_errors On On ignore_repeated_errors Off Off ignore_repeated_source Off Off ignore_user_abort Off Off implicit_flush Off Off include_path .;C:\xampp\php\PEAR .;C:\xampp\php\PEAR log_errors Off Off log_errors_max_len 1024 1024 magic_quotes_gpc Off Off magic_quotes_runtime Off Off magic_quotes_sybase Off Off mail.add_x_header Off Off mail.force_extra_parameters no value no value mail.log no value no value max_execution_time 60 60 max_file_uploads 20 20 max_input_nesting_level 64 64 max_input_time 60 60 memory_limit 128M 128M open_basedir no value no value output_buffering no value no value output_handler no value no value post_max_size 128M 128M precision 14 14 realpath_cache_size 16K 16K realpath_cache_ttl 120 120 register_argc_argv On On register_globals Off Off register_long_arrays Off Off report_memleaks On On report_zend_debug On On request_order no value no value safe_mode Off Off safe_mode_exec_dir no value no value safe_mode_gid Off Off safe_mode_include_dir no value no value sendmail_from no value no value sendmail_path no value no value serialize_precision 100 100 short_open_tag Off Off SMTP localhost localhost smtp_port 25 25 sql.safe_mode Off Off track_errors Off Off unserialize_callback_func no value no value upload_max_filesize 128M 128M upload_tmp_dir C:\xampp\tmp C:\xampp\tmp user_dir no value no value user_ini.cache_ttl 300 300 user_ini.filename .user.ini .user.ini variables_order GPCS GPCS xmlrpc_error_number 0 0 xmlrpc_errors Off Off y2k_compliance On On zend.enable_gc On On ctype ctype functions enabled date date/time support enabled "Olson" Timezone Database Version 2009.18 Timezone Database internal Default timezone America/New_York Directive Local Value Master Value date.default_latitude 31.7667 31.7667 date.default_longitude 35.2333 35.2333 date.sunrise_zenith 90.583333 90.583333 date.sunset_zenith 90.583333 90.583333 date.timezone America/New_York America/New_York dom DOM/XML enabled DOM/XML API Version 20031129 libxml Version 2.7.6 HTML Support enabled XPath Support enabled XPointer Support enabled Schema Support enabled RelaxNG Support enabled ereg Regex Library System library enabled exif EXIF Support enabled EXIF Version 1.4 $Id: exif.c 287372 2009-08-16 14:32:32Z iliaa $ Supported EXIF Version 0220 Supported filetypes JPEG,TIFF Directive Local Value Master Value exif.decode_jis_intel JIS JIS exif.decode_jis_motorola JIS JIS exif.decode_unicode_intel UCS-2LE UCS-2LE exif.decode_unicode_motorola UCS-2BE UCS-2BE exif.encode_jis no value no value exif.encode_unicode ISO-8859-15 ISO-8859-15 fileinfo fileinfo support enabled version 1.0.5-dev filter Input Validation and Filtering enabled Revision $Revision: 289434 $ Directive Local Value Master Value filter.default unsafe_raw unsafe_raw filter.default_flags no value no value ftp FTP support enabled gd GD Support enabled GD Version bundled (2.0.34 compatible) FreeType Support enabled FreeType Linkage with freetype FreeType Version 2.3.11 T1Lib Support enabled GIF Read Support enabled GIF Create Support enabled JPEG Support enabled libJPEG Version 7 PNG Support enabled libPNG Version 1.2.40 WBMP Support enabled XBM Support enabled JIS-mapped Japanese Font Support enabled Directive Local Value Master Value gd.jpeg_ignore_warning 0 0 gettext GetText Support enabled hash hash support enabled Hashing Engines md2 md4 md5 sha1 sha224 sha256 sha384 sha512 ripemd128 ripemd160 ripemd256 ripemd320 whirlpool tiger128,3 tiger160,3 tiger192,3 tiger128,4 tiger160,4 tiger192,4 snefru snefru256 gost adler32 crc32 crc32b salsa10 salsa20 haval128,3 haval160,3 haval192,3 haval224,3 haval256,3 haval128,4 haval160,4 haval192,4 haval224,4 haval256,4 haval128,5 haval160,5 haval192,5 haval224,5 haval256,5 iconv iconv support enabled iconv implementation "libiconv" iconv library version 1.13 Directive Local Value Master Value iconv.input_encoding ISO-8859-1 ISO-8859-1 iconv.internal_encoding ISO-8859-1 ISO-8859-1 iconv.output_encoding ISO-8859-1 ISO-8859-1 imap IMAP c-Client Version 2007e SSL Support enabled json json support enabled json version 1.2.1 libxml libXML support active libXML Compiled Version 2.7.6 libXML Loaded Version 20706 libXML streams enabled mbstring Multibyte Support enabled Multibyte string engine libmbfl HTTP input encoding translation disabled mbstring extension makes use of "streamable kanji code filter and converter", which is distributed under the GNU Lesser General Public License version 2.1. Multibyte (japanese) regex support enabled Multibyte regex (oniguruma) version 4.7.1 Directive Local Value Master Value mbstring.detect_order no value no value mbstring.encoding_translation Off Off mbstring.func_overload 0 0 mbstring.http_input pass pass mbstring.http_output pass pass mbstring.http_output_conv_mimetypes ^(text/|application/xhtml\+xml) ^(text/|application/xhtml\+xml) mbstring.internal_encoding no value no value mbstring.language neutral neutral mbstring.strict_detection Off Off mbstring.substitute_character no value no value mcrypt mcrypt support enabled Version 2.5.8 Api No 20021217 Supported ciphers cast-128 gost rijndael-128 twofish arcfour cast-256 loki97 rijndael-192 saferplus wake blowfish-compat des rijndael-256 serpent xtea blowfish enigma rc2 tripledes Supported modes cbc cfb ctr ecb ncfb nofb ofb stream Directive Local Value Master Value mcrypt.algorithms_dir no value no value mcrypt.modes_dir no value no value mhash MHASH support Enabled MHASH API Version Emulated Support ming Ming SWF output library enabled Version 0.4.3 mysql MySQL Support enabled Active Persistent Links 0 Active Links 0 Client API version 5.1.41 Directive Local Value Master Value mysql.allow_local_infile On On mysql.allow_persistent On On mysql.connect_timeout 60 60 mysql.default_host no value no value mysql.default_password no value no value mysql.default_port 3306 3306 mysql.default_socket MySQL MySQL mysql.default_user no value no value mysql.max_links Unlimited Unlimited mysql.max_persistent Unlimited Unlimited mysql.trace_mode Off Off mysqli MysqlI Support enabled Client API library version 5.1.41 Active Persistent Links 0 Inactive Persistent Links 0 Active Links 0 Client API header version 5.1.41 MYSQLI_SOCKET MySQL Directive Local Value Master Value mysqli.allow_local_infile On On mysqli.allow_persistent On On mysqli.default_host no value no value mysqli.default_port 3306 3306 mysqli.default_pw no value no value mysqli.default_socket MySQL MySQL mysqli.default_user no value no value mysqli.max_links Unlimited Unlimited mysqli.max_persistent Unlimited Unlimited mysqli.reconnect Off Off mysqlnd mysqlnd enabled Version mysqlnd 5.0.5-dev - 081106 - $Revision: 289630 $ Command buffer size 4096 Read buffer size 32768 Read timeout 31536000 Collecting statistics Yes Collecting memory statistics No Client statistics bytes_sent 0 bytes_received 0 packets_sent 0 packets_received 0 protocol_overhead_in 0 protocol_overhead_out 0 bytes_received_ok_packet 0 bytes_received_eof_packet 0 bytes_received_rset_header_packet 0 bytes_received_rset_field_meta_packet 0 bytes_received_rset_row_packet 0 bytes_received_prepare_response_packet 0 bytes_received_change_user_packet 0 packets_sent_command 0 packets_received_ok 0 packets_received_eof 0 packets_received_rset_header 0 packets_received_rset_field_meta 0 packets_received_rset_row 0 packets_received_prepare_response 0 packets_received_change_user 0 result_set_queries 0 non_result_set_queries 0 no_index_used 0 bad_index_used 0 slow_queries 0 buffered_sets 0 unbuffered_sets 0 ps_buffered_sets 0 ps_unbuffered_sets 0 flushed_normal_sets 0 flushed_ps_sets 0 ps_prepared_never_executed 0 ps_prepared_once_executed 0 rows_fetched_from_server_normal 0 rows_fetched_from_server_ps 0 rows_buffered_from_client_normal 0 rows_buffered_from_client_ps 0 rows_fetched_from_client_normal_buffered 0 rows_fetched_from_client_normal_unbuffered 0 rows_fetched_from_client_ps_buffered 0 rows_fetched_from_client_ps_unbuffered 0 rows_fetched_from_client_ps_cursor 0 rows_skipped_normal 0 rows_skipped_ps 0 copy_on_write_saved 0 copy_on_write_performed 0 command_buffer_too_small 0 connect_success 0 connect_failure 0 connection_reused 0 reconnect 0 pconnect_success 0 active_connections 0 active_persistent_connections 0 explicit_close 0 implicit_close 0 disconnect_close 0 in_middle_of_command_close 0 explicit_free_result 0 implicit_free_result 0 explicit_stmt_close 0 implicit_stmt_close 0 mem_emalloc_count 0 mem_emalloc_ammount 0 mem_ecalloc_count 0 mem_ecalloc_ammount 0 mem_erealloc_count 0 mem_erealloc_ammount 0 mem_efree_count 0 mem_malloc_count 0 mem_malloc_ammount 0 mem_calloc_count 0 mem_calloc_ammount 0 mem_realloc_count 0 mem_realloc_ammount 0 mem_free_count 0 proto_text_fetched_null 0 proto_text_fetched_bit 0 proto_text_fetched_tinyint 0 proto_text_fetched_short 0 proto_text_fetched_int24 0 proto_text_fetched_int 0 proto_text_fetched_bigint 0 proto_text_fetched_decimal 0 proto_text_fetched_float 0 proto_text_fetched_double 0 proto_text_fetched_date 0 proto_text_fetched_year 0 proto_text_fetched_time 0 proto_text_fetched_datetime 0 proto_text_fetched_timestamp 0 proto_text_fetched_string 0 proto_text_fetched_blob 0 proto_text_fetched_enum 0 proto_text_fetched_set 0 proto_text_fetched_geometry 0 proto_text_fetched_other 0 proto_binary_fetched_null 0 proto_binary_fetched_bit 0 proto_binary_fetched_tinyint 0 proto_binary_fetched_short 0 proto_binary_fetched_int24 0 proto_binary_fetched_int 0 proto_binary_fetched_bigint 0 proto_binary_fetched_decimal 0 proto_binary_fetched_float 0 proto_binary_fetched_double 0 proto_binary_fetched_date 0 proto_binary_fetched_year 0 proto_binary_fetched_time 0 proto_binary_fetched_datetime 0 proto_binary_fetched_timestamp 0 proto_binary_fetched_string 0 proto_binary_fetched_blob 0 proto_binary_fetched_enum 0 proto_binary_fetched_set 0 proto_binary_fetched_geometry 0 proto_binary_fetched_other 0 init_command_executed_count 0 init_command_failed_count 0 odbc ODBC Support enabled Active Persistent Links 0 Active Links 0 ODBC library Win32 Directive Local Value Master Value odbc.allow_persistent On On odbc.check_persistent On On odbc.default_cursortype Static cursor Static cursor odbc.default_db no value no value odbc.default_pw no value no value odbc.default_user no value no value odbc.defaultbinmode return as is return as is odbc.defaultlrl return up to 4096 bytes return up to 4096 bytes odbc.max_links Unlimited Unlimited odbc.max_persistent Unlimited Unlimited openssl OpenSSL support enabled OpenSSL Library Version OpenSSL 0.9.8l 5 Nov 2009 OpenSSL Header Version OpenSSL 0.9.8l 5 Nov 2009 pcre PCRE (Perl Compatible Regular Expressions) Support enabled PCRE Library Version 8.00 2009-10-19 Directive Local Value Master Value pcre.backtrack_limit 100000 100000 pcre.recursion_limit 100000 100000 pdf PDF Support enabled PDFlib GmbH Version 7.0.4p4 PECL Version 2.1.6 Revision $Revision: 277110 $ PDO PDO support enabled PDO drivers mysql, odbc, sqlite, sqlite2 pdo_mysql PDO Driver for MySQL enabled Client API version 5.1.41 PDO_ODBC PDO Driver for ODBC (Win32) enabled ODBC Connection Pooling Enabled, strict matching pdo_sqlite PDO Driver for SQLite 3.x enabled SQLite Library 3.6.20 Phar Phar: PHP Archive support enabled Phar EXT version 2.0.1 Phar API version 1.1.1 CVS revision $Revision: 286338 $ Phar-based phar archives enabled Tar-based phar archives enabled ZIP-based phar archives enabled gzip compression enabled bzip2 compression enabled Native OpenSSL support enabled Phar based on pear/PHP_Archive, original concept by Davey Shafik. Phar fully realized by Gregory Beaver and Marcus Boerger. Portions of tar implementation Copyright (c) 2003-2009 Tim Kientzle. Directive Local Value Master Value phar.cache_list no value no value phar.readonly On On phar.require_hash On On Reflection Reflection enabled Version $Revision: 287991 $ session Session Support enabled Registered save handlers files user sqlite Registered serializer handlers php php_binary wddx Directive Local Value Master Value session.auto_start Off Off session.bug_compat_42 On On session.bug_compat_warn On On session.cache_expire 180 180 session.cache_limiter nocache nocache session.cookie_domain no value no value session.cookie_httponly Off Off session.cookie_lifetime 0 0 session.cookie_path / / session.cookie_secure Off Off session.entropy_file no value no value session.entropy_length 0 0 session.gc_divisor 100 100 session.gc_maxlifetime 1440 1440 session.gc_probability 1 1 session.hash_bits_per_character 5 5 session.hash_function 0 0 session.name PHPSESSID PHPSESSID session.referer_check no value no value session.save_handler files files session.save_path C:\xampp\tmp C:\xampp\tmp session.serialize_handler php php session.use_cookies On On session.use_only_cookies Off Off session.use_trans_sid 0 0 SimpleXML Simplexml support enabled Revision $Revision: 281953 $ Schema support enabled soap Soap Client enabled Soap Server enabled Directive Local Value Master Value soap.wsdl_cache 1 1 soap.wsdl_cache_dir /tmp /tmp soap.wsdl_cache_enabled 1 1 soap.wsdl_cache_limit 5 5 soap.wsdl_cache_ttl 86400 86400 sockets Sockets Support enabled SPL SPL support enabled Interfaces Countable, OuterIterator, RecursiveIterator, SeekableIterator, SplObserver, SplSubject Classes AppendIterator, ArrayIterator, ArrayObject, BadFunctionCallException, BadMethodCallException, CachingIterator, DirectoryIterator, DomainException, EmptyIterator, FilesystemIterator, FilterIterator, GlobIterator, InfiniteIterator, InvalidArgumentException, IteratorIterator, LengthException, LimitIterator, LogicException, MultipleIterator, NoRewindIterator, OutOfBoundsException, OutOfRangeException, OverflowException, ParentIterator, RangeException, RecursiveArrayIterator, RecursiveCachingIterator, RecursiveDirectoryIterator, RecursiveFilterIterator, RecursiveIteratorIterator, RecursiveRegexIterator, RecursiveTreeIterator, RegexIterator, RuntimeException, SplDoublyLinkedList, SplFileInfo, SplFileObject, SplFixedArray, SplHeap, SplMinHeap, SplMaxHeap, SplObjectStorage, SplPriorityQueue, SplQueue, SplStack, SplTempFileObject, UnderflowException, UnexpectedValueException SQLite SQLite support enabled PECL Module version 2.0-dev $Id: sqlite.c 289598 2009-10-12 22:37:52Z pajoye $ SQLite Library 2.8.17 SQLite Encoding iso8859 Directive Local Value Master Value sqlite.assoc_case 0 0 sqlite3 SQLite3 support enabled SQLite3 module version 0.7-dev SQLite Library 3.6.20 Directive Local Value Master Value sqlite3.extension_dir no value no value standard Dynamic Library Support enabled Internal Sendmail Support for Windows enabled Directive Local Value Master Value assert.active 1 1 assert.bail 0 0 assert.callback no value no value assert.quiet_eval 0 0 assert.warning 1 1 auto_detect_line_endings 0 0 default_socket_timeout 60 60 safe_mode_allowed_env_vars PHP_ PHP_ safe_mode_protected_env_vars LD_LIBRARY_PATH LD_LIBRARY_PATH url_rewriter.tags a=href,area=href,frame=src,input=src,form=,fieldset= a=href,area=href,frame=src,input=src,form=,fieldset= user_agent no value no value tokenizer Tokenizer Support enabled wddx WDDX Support enabled WDDX Session Serializer enabled xml XML Support active XML Namespace Support active libxml2 Version 2.7.6 xmlreader XMLReader enabled xmlrpc core library version xmlrpc-epi v. 0.54 php extension version 0.51 author Dan Libby homepage http://xmlrpc-epi.sourceforge.net open sourced by Epinions.com xmlwriter XMLWriter enabled xsl XSL enabled libxslt Version 1.1.26 libxslt compiled against libxml Version 2.7.6 EXSLT enabled libexslt Version 1.1.26 zip Zip enabled Extension Version $Id: php_zip.c 276389 2009-02-24 23:55:14Z iliaa $ Zip version 1.9.1 Libzip version 0.9.0 zlib ZLib Support enabled Stream Wrapper support compress.zlib:// Stream Filter support zlib.inflate, zlib.deflate Compiled Version 1.2.3 Linked Version 1.2.3 Directive Local Value Master Value zlib.output_compression Off Off zlib.output_compression_level -1 -1 zlib.output_handler no value no value Additional Modules Module Name Environment Variable Value no value ::=::\ no value C:=C:\xampp ALLUSERSPROFILE C:\Documents and Settings\All Users APPDATA C:\Documents and Settings\Andrew\Application Data CHROME_RESTART Google Chrome|Whoa! Google Chrome has crashed. Restart now?|LEFT_TO_RIGHT CHROME_VERSION 5.0.342.8 CLASSPATH .;C:\Program Files\QuickTime\QTSystem\QTJava.zip CommonProgramFiles C:\Program Files\Common Files COMPUTERNAME ANDREW_LAPTOP ComSpec C:\WINDOWS\system32\cmd.exe FP_NO_HOST_CHECK NO HOMEDRIVE C: HOMEPATH \Documents and Settings\Andrew LOGONSERVER \\ANDREW_LAPTOP NUMBER_OF_PROCESSORS 2 OS Windows_NT PATH C:\Documents and Settings\Andrew\Local Settings\Application Data\Google\Chrome\Application;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\Common Files\DivX Shared\;C:\Program Files\WiTopia.Net\bin PATHEXT .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH PROCESSOR_ARCHITECTURE x86 PROCESSOR_IDENTIFIER x86 Family 6 Model 15 Stepping 10, GenuineIntel PROCESSOR_LEVEL 6 PROCESSOR_REVISION 0f0a ProgramFiles C:\Program Files PROMPT $P$G QTJAVA C:\Program Files\QuickTime\QTSystem\QTJava.zip SESSIONNAME Console sfxcmd "C:\Documents and Settings\Andrew\My Documents\Downloads\xampp-win32-1.7.3.exe" sfxname C:\Documents and Settings\Andrew\My Documents\Downloads\xampp-win32-1.7.3.exe SystemDrive C: SystemRoot C:\WINDOWS TEMP C:\DOCUME~1\Andrew\LOCALS~1\Temp TMP C:\DOCUME~1\Andrew\LOCALS~1\Temp USERDOMAIN ANDREW_LAPTOP USERNAME Andrew USERPROFILE C:\Documents and Settings\Andrew VS100COMNTOOLS C:\Program Files\Microsoft Visual Studio 10.0\Common7\Tools\ windir C:\WINDOWS AP_PARENT_PID 2216 PHP Variables Variable Value _SERVER["MIBDIRS"] C:/xampp/php/extras/mibs _SERVER["MYSQL_HOME"] C:\xampp\mysql\bin _SERVER["OPENSSL_CONF"] C:/xampp/apache/bin/openssl.cnf _SERVER["PHP_PEAR_SYSCONF_DIR"] C:\xampp\php _SERVER["PHPRC"] C:\xampp\php _SERVER["TMP"] C:\xampp\tmp _SERVER["HTTP_HOST"] localhost _SERVER["HTTP_CONNECTION"] keep-alive _SERVER["HTTP_USER_AGENT"] Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/533.2 (KHTML, like Gecko) Chrome/5.0.342.8 Safari/533.2 _SERVER["HTTP_CACHE_CONTROL"] max-age=0 _SERVER["HTTP_ACCEPT"] application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 _SERVER["HTTP_ACCEPT_ENCODING"] gzip,deflate,sdch _SERVER["HTTP_ACCEPT_LANGUAGE"] en-US,en;q=0.8 _SERVER["HTTP_ACCEPT_CHARSET"] ISO-8859-1,utf-8;q=0.7,*;q=0.3 _SERVER["PATH"] C:\Documents and Settings\Andrew\Local Settings\Application Data\Google\Chrome\Application;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;c:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\Common Files\DivX Shared\;C:\Program Files\WiTopia.Net\bin _SERVER["SystemRoot"] C:\WINDOWS _SERVER["COMSPEC"] C:\WINDOWS\system32\cmd.exe _SERVER["PATHEXT"] .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH _SERVER["WINDIR"] C:\WINDOWS _SERVER["SERVER_SIGNATURE"] <address>Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 Server at localhost Port 80</address> _SERVER["SERVER_SOFTWARE"] Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1 _SERVER["SERVER_NAME"] localhost _SERVER["SERVER_ADDR"] 127.0.0.1 _SERVER["SERVER_PORT"] 80 _SERVER["REMOTE_ADDR"] 127.0.0.1 _SERVER["DOCUMENT_ROOT"] C:/xampp/htdocs _SERVER["SERVER_ADMIN"] postmaster@localhost _SERVER["SCRIPT_FILENAME"] C:/xampp/htdocs/test.php _SERVER["REMOTE_PORT"] 3275 _SERVER["GATEWAY_INTERFACE"] CGI/1.1 _SERVER["SERVER_PROTOCOL"] HTTP/1.1 _SERVER["REQUEST_METHOD"] GET _SERVER["QUERY_STRING"] no value _SERVER["REQUEST_URI"] /test.php _SERVER["SCRIPT_NAME"] /test.php _SERVER["PHP_SELF"] /test.php _SERVER["REQUEST_TIME"] 1270600868 _SERVER["argv"] Array ( ) _SERVER["argc"] 0 PHP License This program is free software; you can redistribute it and/or modify it under the terms of the PHP License as published by the PHP Group and included in the distribution in the file: LICENSE This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. If you did not receive a copy of the PHP license, or have any questions about PHP licensing, please contact [email protected].

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• Why does this PHP script interfere with my CSS layout?

  - by CT

  This page uses $_GET to grab an asset id and query a mysql database and return some information. If 'id' does not match anything, no results are displayed but the page looks fine. If 'id' is null an error would occur at $id = $_GET["id"] or die(mysql_error()); When this occurs, they page layout is not displayed correctly. How do I fix this? Bonus question: How would I get a message like "No matching results found" or something when the id does not match any id in the database or is null. Thank you. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="style.css" /> <title>Wagman IT Asset</title> </head> <body> <div id="page"> <div id="header"> <img src="images/logo.png" /> </div> </div> <div id="content"> <div id="container"> <div id="main"> <div id="menu"> <ul> <table width="100%" border="0"> <tr> <td><li><a href="index.php">Search Assets</a></li></td> <td><li><a href="browse.php">Browse Assets</a></li></td> <td><li><a href="add_asset.php">Add Asset</a></li></td> <td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td> </tr> </table> </ul> </div> <div id="text"> <ul> <li> <h1>View Asset</h1> </li> </ul> <table width="100%" border="0" cellpadding="2"> <?php //make database connect mysql_connect("localhost", "asset_db", "asset_db") or die(mysql_error()); mysql_select_db("asset_db") or die(mysql_error()); //get asset $id = $_GET["id"] or die(mysql_error()); //get type of asset $sql = "SELECT asset.type From asset WHERE asset.id = $id"; $result = mysql_query($sql) or die(mysql_error()); $row = mysql_fetch_assoc($result); $type = $row['type']; switch ($type){ case "Server": $sql = " SELECT asset.id ,asset.company ,asset.location ,asset.purchase_date ,asset.purchase_order ,asset.value ,asset.type ,asset.notes ,server.manufacturer ,server.model ,server.serial_number ,server.esc ,server.user ,server.prev_user ,server.warranty FROM asset LEFT JOIN server ON server.id = asset.id WHERE asset.id = $id "; $result = mysql_query($sql); while($row = mysql_fetch_assoc($result)) { echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Asset ID:</td><td>"; $id = $row['id']; setcookie('id', $id); echo "$id</td></tr>"; echo "<tr<td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Company:</td><td>"; $company = $row['company']; setcookie('company', $company); echo "$company</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Location:</td><td>"; $location = $row['location']; setcookie('location', $location); echo "$location</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Purchase Date:</td><td>"; $purchase_date = $row['purchase_date']; setcookie('purchase_date', $purchase_date); echo "$purchase_date</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Purchase Order:</td><td>"; $purchase_order = $row['purchase_order']; setcookie('purchase_order', $purchase_order); echo "$purchase_order</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Value:</td><td>"; $value = $row['value']; setcookie('value', $value); echo "$value</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Type:</td><td>"; $type = $row['type']; setcookie('type', $type); echo "$type</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Notes:</td><td>"; $notes = $row['notes']; setcookie('notes', $notes); echo "$notes</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Manufacturer:</td><td>"; $manufacturer = $row['manufacturer']; setcookie('manufacturer', $manufacturer); echo "$manufacturer</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Model / Description:</td><td>"; $model = $row['model']; setcookie('model', $model); echo "$model</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Serial Number / Service Tag:</td><td>"; $serial_number = $row['serial_number']; setcookie('serial_number', $serial_number); echo "$serial_number</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Express Service Code:</td><td>"; $esc = $row['esc']; setcookie('esc', $esc); echo "$esc</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>User:</td><td>"; $user = $row['user']; setcookie('user', $user); echo "$user</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Previous User:</td><td>"; $prev_user = $row['prev_user']; setcookie('prev_user', $prev_user); echo "$prev_user</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Warranty:</td><td>"; $warranty = $row['warranty']; setcookie('warranty', $warranty); echo "$warranty</td></tr>"; } break; case "Laptop": $sql = " SELECT asset.id ,asset.company ,asset.location ,asset.purchase_date ,asset.purchase_order ,asset.value ,asset.type ,asset.notes ,laptop.manufacturer ,laptop.model ,laptop.serial_number ,laptop.esc ,laptop.user ,laptop.prev_user ,laptop.warranty FROM asset LEFT JOIN laptop ON laptop.id = asset.id WHERE asset.id = $id "; $result = mysql_query($sql); while($row = mysql_fetch_assoc($result)) { echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Asset ID:</td><td>"; $id = $row['id']; setcookie('id', $id); echo "$id</td></tr>"; echo "<tr<td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Company:</td><td>"; $company = $row['company']; setcookie('company', $company); echo "$company</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Location:</td><td>"; $location = $row['location']; setcookie('location', $location); echo "$location</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Purchase Date:</td><td>"; $purchase_date = $row['purchase_date']; setcookie('purchase_date', $purchase_date); echo "$purchase_date</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Purchase Order:</td><td>"; $purchase_order = $row['purchase_order']; setcookie('purchase_order', $purchase_order); echo "$purchase_order</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Value:</td><td>"; $value = $row['value']; setcookie('value', $value); echo "$value</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Type:</td><td>"; $type = $row['type']; setcookie('type', $type); echo "$type</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Notes:</td><td>"; $notes = $row['notes']; setcookie('notes', $notes); echo "$notes</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Manufacturer:</td><td>"; $manufacturer = $row['manufacturer']; setcookie('manufacturer', $manufacturer); echo "$manufacturer</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Model / Description:</td><td>"; $model = $row['model']; setcookie('model', $model); echo "$model</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Serial Number / Service Tag:</td><td>"; $serial_number = $row['serial_number']; setcookie('serial_number', $serial_number); echo "$serial_number</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Express Service Code:</td><td>"; $esc = $row['esc']; setcookie('esc', $esc); echo "$esc</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>User:</td><td>"; $user = $row['user']; setcookie('user', $user); echo "$user</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Previous User:</td><td>"; $prev_user = $row['prev_user']; setcookie('prev_user', $prev_user); echo "$prev_user</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Warranty:</td><td>"; $warranty = $row['warranty']; setcookie('warranty', $warranty); echo "$warranty</td></tr>"; } break; case "Desktop": $sql = " SELECT asset.id ,asset.company ,asset.location ,asset.purchase_date ,asset.purchase_order ,asset.value ,asset.type ,asset.notes ,desktop.manufacturer ,desktop.model ,desktop.serial_number ,desktop.esc ,desktop.user ,desktop.prev_user ,desktop.warranty FROM asset LEFT JOIN desktop ON desktop.id = asset.id WHERE asset.id = $id "; $result = mysql_query($sql); while($row = mysql_fetch_assoc($result)) { echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Asset ID:</td><td>"; $id = $row['id']; setcookie('id', $id); echo "$id</td></tr>"; echo "<tr<td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Company:</td><td>"; $company = $row['company']; setcookie('company', $company); echo "$company</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Location:</td><td>"; $location = $row['location']; setcookie('location', $location); echo "$location</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Purchase Date:</td><td>"; $purchase_date = $row['purchase_date']; setcookie('purchase_date', $purchase_date); echo "$purchase_date</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Purchase Order:</td><td>"; $purchase_order = $row['purchase_order']; setcookie('purchase_order', $purchase_order); echo "$purchase_order</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Value:</td><td>"; $value = $row['value']; setcookie('value', $value); echo "$value</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Type:</td><td>"; $type = $row['type']; setcookie('type', $type); echo "$type</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Notes:</td><td>"; $notes = $row['notes']; setcookie('notes', $notes); echo "$notes</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Manufacturer:</td><td>"; $manufacturer = $row['manufacturer']; setcookie('manufacturer', $manufacturer); echo "$manufacturer</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Model / Description:</td><td>"; $model = $row['model']; setcookie('model', $model); echo "$model</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Serial Number / Service Tag:</td><td>"; $serial_number = $row['serial_number']; setcookie('serial_number', $serial_number); echo "$serial_number</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Express Service Code:</td><td>"; $esc = $row['esc']; setcookie('esc', $esc); echo "$esc</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>User:</td><td>"; $user = $row['user']; setcookie('user', $user); echo "$user</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Previous User:</td><td>"; $prev_user = $row['prev_user']; setcookie('prev_user', $prev_user); echo "$prev_user</td></tr>"; echo "<tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td><td>Warranty:</td><td>"; $warranty = $row['warranty']; setcookie('warranty', $warranty); echo "$warranty</td></tr>"; } break; } ?> </table> <br /> <br /> <table width="100%" border="0"> <tr> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td><a href="#">Add Software</a></td> <td><a href="#">Edit Asset</a></td> <td><a href="#">Delete Asset</a></td> </tr> </table> </div> </div> </div> <div class="clear"></div> <div id="footer" align="center"> <p>&nbsp;</p> </div> </div> <div id="tagline"> Wagman Construction - Bridging Generations since 1902 </div> </body> </html>

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