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• GKTank example is not working.

  - by david

  Hello, I'm trying to get the GKTank example working with 2 iPhones. Both have bluetooth enabled. I start the app on both devices and tap the screen. The Peer Picker comes up and the devices find each other. If I select one device in the list it says "Waiting for {other iPhone}..." forever. On the {other iPhone} the waiting phone gets grayed out. If I select the device to connect to from both devices at the same time both go into waiting state forever... The debug log says this if I select the other iPhone on the debugged device: 2010-05-30 23:20:24.331 GKTank[2433:4e03] handleEvents started (2) 2010-05-30 23:20:25.269 GKTank[2433:4e03] ~ DNSServiceRegister callback: Ref=135f70, Flags=2, ErrorType=0 name=00oRWv-0A..David’s iPhone regtype=_gktank._udp. domain=local. 2010-05-30 23:20:25.375 GKTank[2433:4e03] ~ DNSServiceBrowse callback: Ref=134f30, Flags=2, IFIndex=8 (name=[en2]), ErrorType=0 name=00oRWv-0A..David’s iPhone regtype=_gktank._udp. domain=local. 2010-05-30 23:20:30.691 GKTank[2433:4e03] ~ DNSServiceBrowse callback: Ref=134f30, Flags=2, IFIndex=-3 (name=[]), ErrorType=0 name=00K83eS0A..iPhone von Tamara regtype=_gktank._udp. domain=local. 2010-05-30 23:20:30.855 GKTank[2433:4e03] ~ DNSServiceQueryRecord callback: Ref=13a320, Flags=2, IFIndex=-3 (name=[]), ErrorType=0 fullname=00k83es0a..iphone\032von\032tamara._gktank._udp.local. rrtype=16 rrclass=1 rdlen=18 ttl=7200 2010-05-30 23:20:30.872 GKTank[2433:4e03] ** peer 480260628: oldbusy=0, newbusy=0 2010-05-30 23:20:35.215 GKTank[2433:207] ** Stop resolving? potentially previous resolves 2010-05-30 23:20:35.226 GKTank[2433:207] **** BEGIN RESOLVE: 480260628 and it stays that way. On the second iPhone the device is listed as not available and grayed out. If I select each other at the same time it says this: 2010-05-30 23:24:31.416 GKTank[2442:4e03] handleEvents started (2) 2010-05-30 23:24:32.321 GKTank[2442:4e03] ~ DNSServiceRegister callback: Ref=135120, Flags=2, ErrorType=0 name=006JiAZ0A..David’s iPhone regtype=_gktank._udp. domain=local. 2010-05-30 23:24:32.419 GKTank[2442:4e03] ~ DNSServiceBrowse callback: Ref=134f30, Flags=2, IFIndex=8 (name=[en2]), ErrorType=0 name=006JiAZ0A..David’s iPhone regtype=_gktank._udp. domain=local. 2010-05-30 23:24:57.156 GKTank[2442:4e03] ~ DNSServiceBrowse callback: Ref=134f30, Flags=2, IFIndex=-3 (name=[]), ErrorType=0 name=004_n6C0A..iPhone von Tamara regtype=_gktank._udp. domain=local. 2010-05-30 23:24:57.308 GKTank[2442:4e03] ~ DNSServiceQueryRecord callback: Ref=13a320, Flags=2, IFIndex=-3 (name=[]), ErrorType=0 fullname=004_n6c0a..iphone\032von\032tamara._gktank._udp.local. rrtype=16 rrclass=1 rdlen=18 ttl=7200 2010-05-30 23:24:57.314 GKTank[2442:4e03] ** peer 203104196: oldbusy=0, newbusy=0 2010-05-30 23:25:02.383 GKTank[2442:207] ** Stop resolving? potentially previous resolves 2010-05-30 23:25:02.425 GKTank[2442:207] **** BEGIN RESOLVE: 203104196 2010-05-30 23:25:13.562 GKTank[2442:4e03] ~ DNSServiceQueryRecord callback: Ref=13a320, Flags=2, IFIndex=-3 (name=[]), ErrorType=0 fullname=004_n6c0a..iphone\032von\032tamara._gktank._udp.local. rrtype=16 rrclass=1 rdlen=18 ttl=7200 2010-05-30 23:25:13.569 GKTank[2442:4e03] ** peer 203104196: oldbusy=0, newbusy=1 2010-05-30 23:25:33.660 GKTank[2442:4e03] ~ DNSServiceBrowse callback: Ref=134f30, Flags=0, IFIndex=-3 (name=[]), ErrorType=0 name=004_n6C0A..iPhone von Tamara regtype=_gktank._udp. domain=local. 2010-05-30 23:25:33.671 GKTank[2442:4e03] Peer [203104196] removed? (0). 2010-05-30 23:25:33.683 GKTank[2442:4e03] GKPeer[139f10] 203104196 service count old=1 new=0 2010-05-30 23:25:37.786 GKTank[2442:4e03] ~ DNSServiceBrowse callback: Ref=134f30, Flags=2, IFIndex=-3 (name=[]), ErrorType=0 name=004_n6C0A..iPhone von Tamara regtype=_gktank._udp. domain=local. 2010-05-30 23:25:37.816 GKTank[2442:4e03] GKPeer[139f10] 203104196 service count old=0 new=1 ... and waits forever. Does anybody know whats wrong with this sample??

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• How to use delegate to perform callback between caller and web service helper class?

  - by codemonkie

  I have 2 classes A and B, where they belongs to the same namespace but resides in seperate files namely a.cs and b.cs, where class B essentially is a helper wrapping a web service call as follow: public class A { public A() // constructor { protected static B b = new B(); } private void processResult1(string result) { // come here when result is successful } private void processResult2(string result) { // come here when result is failed } static void main() { b.DoJobHelper(...); } } public class B { private com.nowhere.somewebservice ws; public B() { this.ws = new com.nowhere.somewebservice(); ws.JobCompleted += new JobCompletedEventHandler(OnCompleted); } void OnCompleted(object sender, JobCompletedEventArgs e) { string s = e.Result; Guid taskID = (Guid)e.UserState; switch (s) { case "Success": // Call processResult1(); break; case "Failed": // Call processResult2(); break; default: break; } } public void DoJobHelper() { Object userState = Guid.NewGuid(); ws.DoJob(..., userState); } } (1) I have seen texts on the net on using delegates for callbacks but failed to apply that to my case. All I want to do is to call the appropriate processResult() method upon OnCompleted() event, but dunno how to and where to declare the delegate: public delegate void CallBack(string s); (2) There is a sender object passed in to OnCompleted() but never used, did I miss anything there? Or how can I make good use of sender? Any helps appreciated.

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• [C#] How to use delegate to perform callback between caller and web service helper class?

  - by codemonkie

  I have 2 classes A and B, where they belongs to the same namespace but resides in seperate files namely a.cs and b.cs, where class B essentially is a helper wrapping a web service call as follow: public class A { public A() // constructor { protected static B b = new B(); } private void processResult1(string result) { // come here when result is successful } private void processResult2(string result) { // come here when result is failed } static void main() { b.DoJobHelper(...); } } public class B { private com.nowhere.somewebservice ws; public B() { this.ws = new com.nowhere.somewebservice(); ws.JobCompleted += new JobCompletedEventHandler(OnCompleted); } void OnCompleted(object sender, JobCompletedEventArgs e) { string s; Guid taskID = (Guid)e.UserState; switch (s) { case "Success": // Call processResult1(); break; case "Failed": // Call processResult2(); break; default: break; } } public void DoJobHelper() { Object userState = Guid.NewGuid(); ws.DoJob(..., userState); } } (1) I have seen texts on the net on using delegates for callbacks but failed to apply that to my case. All I want to do is to call the appropriate processResult() method upon OnCompleted() event, but dunno how to and where to declare the delegate: public delegate void CallBack(string s); (2) There is a sender object passed in to OnCompleted() but never used, did I miss anything there? Or how can I make good use of sender? Any helps appreciated.

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• How do I reset a form in an ajax callback?

  - by B.Gordon

  I am sending a form using simple ajax and returning the results in a div above the form. The problem is that after the form is submitted and validated, I display a thank you and want to reset the form so they don't just press the submit button again... Can't seem to find the right code to do this... <form id="myForm" target="sendemail.php" method="post"> <div id="results"></div> <input type="text" name="value1"> <input type="text" name="value2"> <input type="submit" name="submit"> </form> So, my sendemail.php validation errors and success messages appear in #results without problems. But... when I try to send back a javascript form reset command, it does not work. Naturally I cannot see it in the source code since it is an AJAX callback so I don't know if that is the issue or if I am just using the wrong syntax. echo "<p>Thank you. Your message has been accepted for delivery.</p>"; echo "<script type=\"text/javascript\">setTimeout('document.getElementById('myForm').reset();',1000);</script>"; Any ideas gurus?

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• passing callback function accross windows causing error with ie ...

  - by krul

  I have a problem with IE causing two errors: 1. Object doesn't support this property or method 2. Call was rejected by callee. My Intention: To call window.opener.myObject method that is going to retrieve some data using ajax and pass in callback function that live as nested function in popup window that initiated call that is going to handle response data and modify popup window html accordingly. Here is a scenario: I pull up popup window that handles some specific operation. This popup window calling window.opener.myObject method that using ajax call. I'm passing in popup window function that is going to handle response and it works with ff and safari but not with ie. Here is code sample //RELEVANT SCRIPT ON POPUP WINDOW $('#myButton').live('click', function() { var h = window.opener.myObject, p = { 'p1': 1 }; var responseHandler = function(responseObj) { //in IE we never got here if (!responseObj) { alert('Unexpected error!! No response from server'); return false; } //..handle response }; p.p1 = $('#control').val(); h.executeMethod(p, responseHandler); }); //RELEVANT SCRIPT ON WINDOW OPENER MYOBJECT try { $.ajax({ type: 'POST', async: true, url: url, data: postData, dataType: "json", contentType: 'application/x-www-form-urlencoded; charset=utf-8', success: r, // r here is reference to my responseHandler popup window function error: handleError }); } catch (ex) { alert(ex.message); } Any tips?

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• Matlab GUI - How to get the previous value entered from a callback function?

  - by Graham

  Hi, I know that this is probably a simple problem but I am new to Matlab GUI's and basically want to get the old value which used to be stored in the text box to replace the value which has just been entered. E.g. Text box contains a valid string, User enters invalid string, Callback func, validates input and realises new input is an error and reverts to the old previous value. How should this be implemented or done? Atm I am just using the get and set property values. Below is some sample code: function sampledist_Callback(hObject, eventdata, handles) % hObject handle to sampledist (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) % Hints: get(hObject,'String') returns contents of sampledist as text % str2double(get(hObject,'String')) returns contents of sampledist as a double input = str2double(get(hObject,'String')); if(input < 0 || input > 500) errordlg('Sampled Dist. must be > 0 and < 500','Sample Dist - Input Error'); set(handles.sampledist,'String',['10']); %<--- I would like this value 10 to be the previous entry! guidata(hObject,handles); else set(handles.sampledist,'String',['',input]); guidata(hObject,handles); end

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• Is there a Symfony callback at the termination of a session?

  - by Rob Wilkerson

  I have an application that is authenticating against an external server in a filter. In that filter, I'm trying to set a couple of session attributes on the user by using Symfony's setAttribute() method: $this->getContext()->getUser()->setAttribute( 'myAttribute', 'myValue' ); What I'm finding is that, if I dump $_SESSION immediately after setting the attribute. On the other hand, if I call getAttribute( 'myAttribute' ), I get back exactly what I put in. All along, I've assumed that reading/writing to user attributes was synonymous with reading/writing to the session, but that seems to be an incorrect assumption. Is there a timing issue? I'm not getting any non-object errors, so it seems that the user is fully initialized. Where is the disconnect here? Thanks. UPDATE The reason this was happening is because I had some code in myUser::shutdown() that cleared out a bunch of stuff. Because myUser is loosely equivalent to $_SESSION (at least with respect to attributes), I assumed that the shutdown() method would be called at the end of each session. It's not. It seems to get called at the close of each request which is why my attributes never seemed to get set. Now, though, I'm left wondering whether there's a session closing callback. Anyone know?

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• Any reason why my $.ajax success callback is not executed in Jquery?

  - by arma

  Hello, Today i discovered that my dev version of my website do not execute success callback, but all other javascript and jquery code is running good. Even my ajax request is performed and i can see response in firebug. $('#login').submit(function(){ var email = $('#l_email').val(); var pass = $('#l_pass').val(); if(email && pass != ''){ var str = decodeURIComponent($(this).serialize()); $.ajax({ type: "POST", url: "login.php", data: str, success: function(msg){ if(msg == 'OK'){ window.location = 'index.php' }else if (msg == 'NOT_OK'){ if(lang == 'lv'){ alert(message); }else if(lang == 'ru'){ alert(message); } }else if (msg == 'EMAIL_NOT_VALID'){ if(lang == 'lv'){ alert(message); }else if(lang == 'ru'){ alert(message); } } } }); }else{ alert('That form is empty.'); } return false; }); The thing is $.ajax part executes fine and i can see response in firebug "OK". But redirect is not happening and even if i replace that redirect with something like alert or console.log nothing comes up. What could cause this? It's really hard to track since firebug gives no errors.

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• How to show useful error messages from a database error callback in Phonegap?

  - by Magnus Smith

  Using Phonegap you can set a function to be called back if the whole database transaction or the individual SQL statement errors. I'd like to know how to get more information about the error. I have one generic error-handling function, and lots of different SELECTs or INSERTs that may trigger it. How can I tell which one was at fault? It is not always obvious from the error message. My code so far is... function get_rows(tx) { tx.executeSql("SELECT * FROM Blah", [], lovely_success, statement_error); } function add_row(tx) { tx.executeSql("INSERT INTO Blah (1, 2, 3)", [], carry_on, statement_error); } function statement_error(tx, error) { alert(error.code + ' / ' + error.message); } From various examples I see the error callback will be passed a transaction object and an error object. I read that .code can have the following values: UNKNOWN_ERR = 0 DATABASE_ERR = 1 VERSION_ERR = 2 TOO_LARGE_ERR = 3 QUOTA_ERR = 4 SYNTAX_ERR = 5 CONSTRAINT_ERR = 6 TIMEOUT_ERR = 7 Are there any other properties/methods of the error object? What are the properties/methods of the transaction object at this point? I can't seem to find a good online reference for this. Certainly not on the Phonegap website!

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• Syncing Data with a Server using Silverlight and HTTP Polling Duplex

  - by dwahlin

  Many applications have the need to stay in-sync with data provided by a service. Although web applications typically rely on standard polling techniques to check if data has changed, Silverlight provides several interesting options for keeping an application in-sync that rely on server “push” technologies. A few years back I wrote several blog posts covering different “push” technologies available in Silverlight that rely on sockets or HTTP Polling Duplex. We recently had a project that looked like it could benefit from pushing data from a server to one or more clients so I thought I’d revisit the subject and provide some updates to the original code posted. If you’ve worked with AJAX before in Web applications then you know that until browsers fully support web sockets or other duplex (bi-directional communication) technologies that it’s difficult to keep applications in-sync with a server without relying on polling. The problem with polling is that you have to check for changes on the server on a timed-basis which can often be wasteful and take up unnecessary resources. With server “push” technologies, data can be pushed from the server to the client as it changes. Once the data is received, the client can update the user interface as appropriate. Using “push” technologies allows the client to listen for changes from the data but stay 100% focused on client activities as opposed to worrying about polling and asking the server if anything has changed. Silverlight provides several options for pushing data from a server to a client including sockets, TCP bindings and HTTP Polling Duplex.  Each has its own strengths and weaknesses as far as performance and setup work with HTTP Polling Duplex arguably being the easiest to setup and get going.  In this article I’ll demonstrate how HTTP Polling Duplex can be used in Silverlight 4 applications to push data and show how you can create a WCF server that provides an HTTP Polling Duplex binding that a Silverlight client can consume.   What is HTTP Polling Duplex? Technologies that allow data to be pushed from a server to a client rely on duplex functionality. Duplex (or bi-directional) communication allows data to be passed in both directions.  A client can call a service and the server can call the client. HTTP Polling Duplex (as its name implies) allows a server to communicate with a client without forcing the client to constantly poll the server. It has the benefit of being able to run on port 80 making setup a breeze compared to the other options which require specific ports to be used and cross-domain policy files to be exposed on port 943 (as with sockets and TCP bindings). Having said that, if you’re looking for the best speed possible then sockets and TCP bindings are the way to go. But, they’re not the only game in town when it comes to duplex communication. The first time I heard about HTTP Polling Duplex (initially available in Silverlight 2) I wasn’t exactly sure how it was any better than standard polling used in AJAX applications. I read the Silverlight SDK, looked at various resources and generally found the following definition unhelpful as far as understanding the actual benefits that HTTP Polling Duplex provided: "The Silverlight client periodically polls the service on the network layer, and checks for any new messages that the service wants to send on the callback channel. The service queues all messages sent on the client callback channel and delivers them to the client when the client polls the service." Although the previous definition explained the overall process, it sounded as if standard polling was used. Fortunately, Microsoft’s Scott Guthrie provided me with a more clear definition several years back that explains the benefits provided by HTTP Polling Duplex quite well (used with his permission): "The [HTTP Polling Duplex] duplex support does use polling in the background to implement notifications – although the way it does it is different than manual polling. It initiates a network request, and then the request is effectively “put to sleep” waiting for the server to respond (it doesn’t come back immediately). The server then keeps the connection open but not active until it has something to send back (or the connection times out after 90 seconds – at which point the duplex client will connect again and wait). This way you are avoiding hitting the server repeatedly – but still get an immediate response when there is data to send." After hearing Scott’s definition the light bulb went on and it all made sense. A client makes a request to a server to check for changes, but instead of the request returning immediately, it parks itself on the server and waits for data. It’s kind of like waiting to pick up a pizza at the store. Instead of calling the store over and over to check the status, you sit in the store and wait until the pizza (the request data) is ready. Once it’s ready you take it back home (to the client). This technique provides a lot of efficiency gains over standard polling techniques even though it does use some polling of its own as a request is initially made from a client to a server. So how do you implement HTTP Polling Duplex in your Silverlight applications? Let’s take a look at the process by starting with the server. Creating an HTTP Polling Duplex WCF Service Creating a WCF service that exposes an HTTP Polling Duplex binding is straightforward as far as coding goes. Add some one way operations into an interface, create a client callback interface and you’re ready to go. The most challenging part comes into play when configuring the service to properly support the necessary binding and that’s more of a cut and paste operation once you know the configuration code to use. To create an HTTP Polling Duplex service you’ll need to expose server-side and client-side interfaces and reference the System.ServiceModel.PollingDuplex assembly (located at C:\Program Files (x86)\Microsoft SDKs\Silverlight\v4.0\Libraries\Server on my machine) in the server project. For the demo application I upgraded a basketball simulation service to support the latest polling duplex assemblies. The service simulates a simple basketball game using a Game class and pushes information about the game such as score, fouls, shots and more to the client as the game changes over time. Before jumping too far into the game push service, it’s important to discuss two interfaces used by the service to communicate in a bi-directional manner. The first is called IGameStreamService and defines the methods/operations that the client can call on the server (see Listing 1). The second is IGameStreamClient which defines the callback methods that a server can use to communicate with a client (see Listing 2).   [ServiceContract(Namespace = "Silverlight", CallbackContract = typeof(IGameStreamClient))] public interface IGameStreamService { [OperationContract(IsOneWay = true)] void GetTeamData(); } Listing 1. The IGameStreamService interface defines server operations that can be called on the server.   [ServiceContract] public interface IGameStreamClient { [OperationContract(IsOneWay = true)] void ReceiveTeamData(List<Team> teamData); [OperationContract(IsOneWay = true, AsyncPattern=true)] IAsyncResult BeginReceiveGameData(GameData gameData, AsyncCallback callback, object state); void EndReceiveGameData(IAsyncResult result); } Listing 2. The IGameStreamClient interfaces defines client operations that a server can call.   The IGameStreamService interface is decorated with the standard ServiceContract attribute but also contains a value for the CallbackContract property.  This property is used to define the interface that the client will expose (IGameStreamClient in this example) and use to receive data pushed from the service. Notice that each OperationContract attribute in both interfaces sets the IsOneWay property to true. This means that the operation can be called and passed data as appropriate, however, no data will be passed back. Instead, data will be pushed back to the client as it’s available.  Looking through the IGameStreamService interface you can see that the client can request team data whereas the IGameStreamClient interface allows team and game data to be received by the client. One interesting point about the IGameStreamClient interface is the inclusion of the AsyncPattern property on the BeginReceiveGameData operation. I initially created this operation as a standard one way operation and it worked most of the time. However, as I disconnected clients and reconnected new ones game data wasn’t being passed properly. After researching the problem more I realized that because the service could take up to 7 seconds to return game data, things were getting hung up. By setting the AsyncPattern property to true on the BeginReceivedGameData operation and providing a corresponding EndReceiveGameData operation I was able to get around this problem and get everything running properly. I’ll provide more details on the implementation of these two methods later in this post. Once the interfaces were created I moved on to the game service class. The first order of business was to create a class that implemented the IGameStreamService interface. Since the service can be used by multiple clients wanting game data I added the ServiceBehavior attribute to the class definition so that I could set its InstanceContextMode to InstanceContextMode.Single (in effect creating a Singleton service object). Listing 3 shows the game service class as well as its fields and constructor.   [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.Single)] public class GameStreamService : IGameStreamService { object _Key = new object(); Game _Game = null; Timer _Timer = null; Random _Random = null; Dictionary<string, IGameStreamClient> _ClientCallbacks = new Dictionary<string, IGameStreamClient>(); static AsyncCallback _ReceiveGameDataCompleted = new AsyncCallback(ReceiveGameDataCompleted); public GameStreamService() { _Game = new Game(); _Timer = new Timer { Enabled = false, Interval = 2000, AutoReset = true }; _Timer.Elapsed += new ElapsedEventHandler(_Timer_Elapsed); _Timer.Start(); _Random = new Random(); }} Listing 3. The GameStreamService implements the IGameStreamService interface which defines a callback contract that allows the service class to push data back to the client. By implementing the IGameStreamService interface, GameStreamService must supply a GetTeamData() method which is responsible for supplying information about the teams that are playing as well as individual players.  GetTeamData() also acts as a client subscription method that tracks clients wanting to receive game data.  Listing 4 shows the GetTeamData() method. public void GetTeamData() { //Get client callback channel var context = OperationContext.Current; var sessionID = context.SessionId; var currClient = context.GetCallbackChannel<IGameStreamClient>(); context.Channel.Faulted += Disconnect; context.Channel.Closed += Disconnect; IGameStreamClient client; if (!_ClientCallbacks.TryGetValue(sessionID, out client)) { lock (_Key) { _ClientCallbacks[sessionID] = currClient; } } currClient.ReceiveTeamData(_Game.GetTeamData()); //Start timer which when fired sends updated score information to client if (!_Timer.Enabled) { _Timer.Enabled = true; } } Listing 4. The GetTeamData() method subscribes a given client to the game service and returns. The key the line of code in the GetTeamData() method is the call to GetCallbackChannel<IGameStreamClient>().  This method is responsible for accessing the calling client’s callback channel. The callback channel is defined by the IGameStreamClient interface shown earlier in Listing 2 and used by the server to communicate with the client. Before passing team data back to the client, GetTeamData() grabs the client’s session ID and checks if it already exists in the _ClientCallbacks dictionary object used to track clients wanting callbacks from the server. If the client doesn’t exist it adds it into the collection. It then pushes team data from the Game class back to the client by calling ReceiveTeamData().  Since the service simulates a basketball game, a timer is then started if it’s not already enabled which is then used to randomly send data to the client. When the timer fires, game data is pushed down to the client. Listing 5 shows the _Timer_Elapsed() method that is called when the timer fires as well as the SendGameData() method used to send data to the client. void _Timer_Elapsed(object sender, ElapsedEventArgs e) { int interval = _Random.Next(3000, 7000); lock (_Key) { _Timer.Interval = interval; _Timer.Enabled = false; } SendGameData(_Game.GetGameData()); } private void SendGameData(GameData gameData) { var cbs = _ClientCallbacks.Where(cb => ((IContextChannel)cb.Value).State == CommunicationState.Opened); for (int i = 0; i < cbs.Count(); i++) { var cb = cbs.ElementAt(i).Value; try { cb.BeginReceiveGameData(gameData, _ReceiveGameDataCompleted, cb); } catch (TimeoutException texp) { //Log timeout error } catch (CommunicationException cexp) { //Log communication error } } lock (_Key) _Timer.Enabled = true; } private static void ReceiveGameDataCompleted(IAsyncResult result) { try { ((IGameStreamClient)(result.AsyncState)).EndReceiveGameData(result); } catch (CommunicationException) { // empty } catch (TimeoutException) { // empty } } LIsting 5. _Timer_Elapsed is used to simulate time in a basketball game. When _Timer_Elapsed() fires the SendGameData() method is called which iterates through the clients wanting to be notified of changes. As each client is identified, their respective BeginReceiveGameData() method is called which ultimately pushes game data down to the client. Recall that this method was defined in the client callback interface named IGameStreamClient shown earlier in Listing 2. Notice that BeginReceiveGameData() accepts _ReceiveGameDataCompleted as its second parameter (an AsyncCallback delegate defined in the service class) and passes the client callback as the third parameter. The initial version of the sample application had a standard ReceiveGameData() method in the client callback interface. However, sometimes the client callbacks would work properly and sometimes they wouldn’t which was a little baffling at first glance. After some investigation I realized that I needed to implement an asynchronous pattern for client callbacks to work properly since 3 – 7 second delays are occurring as a result of the timer. Once I added the BeginReceiveGameData() and ReceiveGameDataCompleted() methods everything worked properly since each call was handled in an asynchronous manner. The final task that had to be completed to get the server working properly with HTTP Polling Duplex was adding configuration code into web.config. In the interest of brevity I won’t post all of the code here since the sample application includes everything you need. However, Listing 6 shows the key configuration code to handle creating a custom binding named pollingDuplexBinding and associate it with the service’s endpoint.   <bindings> <customBinding> <binding name="pollingDuplexBinding"> <binaryMessageEncoding /> <pollingDuplex maxPendingSessions="2147483647" maxPendingMessagesPerSession="2147483647" inactivityTimeout="02:00:00" serverPollTimeout="00:05:00"/> <httpTransport /> </binding> </customBinding> </bindings> <services> <service name="GameService.GameStreamService" behaviorConfiguration="GameStreamServiceBehavior"> <endpoint address="" binding="customBinding" bindingConfiguration="pollingDuplexBinding" contract="GameService.IGameStreamService"/> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services>   Listing 6. Configuring an HTTP Polling Duplex binding in web.config and associating an endpoint with it. Calling the Service and Receiving “Pushed” Data Calling the service and handling data that is pushed from the server is a simple and straightforward process in Silverlight. Since the service is configured with a MEX endpoint and exposes a WSDL file, you can right-click on the Silverlight project and select the standard Add Service Reference item. After the web service proxy is created you may notice that the ServiceReferences.ClientConfig file only contains an empty configuration element instead of the normal configuration elements created when creating a standard WCF proxy. You can certainly update the file if you want to read from it at runtime but for the sample application I fed the service URI directly to the service proxy as shown next: var address = new EndpointAddress("http://localhost.:5661/GameStreamService.svc"); var binding = new PollingDuplexHttpBinding(); _Proxy = new GameStreamServiceClient(binding, address); _Proxy.ReceiveTeamDataReceived += _Proxy_ReceiveTeamDataReceived; _Proxy.ReceiveGameDataReceived += _Proxy_ReceiveGameDataReceived; _Proxy.GetTeamDataAsync(); This code creates the proxy and passes the endpoint address and binding to use to its constructor. It then wires the different receive events to callback methods and calls GetTeamDataAsync().  Calling GetTeamDataAsync() causes the server to store the client in the server-side dictionary collection mentioned earlier so that it can receive data that is pushed.  As the server-side timer fires and game data is pushed to the client, the user interface is updated as shown in Listing 7. Listing 8 shows the _Proxy_ReceiveGameDataReceived() method responsible for handling the data and calling UpdateGameData() to process it.   Listing 7. The Silverlight interface. Game data is pushed from the server to the client using HTTP Polling Duplex. void _Proxy_ReceiveGameDataReceived(object sender, ReceiveGameDataReceivedEventArgs e) { UpdateGameData(e.gameData); } private void UpdateGameData(GameData gameData) { //Update Score this.tbTeam1Score.Text = gameData.Team1Score.ToString(); this.tbTeam2Score.Text = gameData.Team2Score.ToString(); //Update ball visibility if (gameData.Action != ActionsEnum.Foul) { if (tbTeam1.Text == gameData.TeamOnOffense) { AnimateBall(this.BB1, this.BB2); } else //Team 2 { AnimateBall(this.BB2, this.BB1); } } if (this.lbActions.Items.Count > 9) this.lbActions.Items.Clear(); this.lbActions.Items.Add(gameData.LastAction); if (this.lbActions.Visibility == Visibility.Collapsed) this.lbActions.Visibility = Visibility.Visible; } private void AnimateBall(Image onBall, Image offBall) { this.FadeIn.Stop(); Storyboard.SetTarget(this.FadeInAnimation, onBall); Storyboard.SetTarget(this.FadeOutAnimation, offBall); this.FadeIn.Begin(); } Listing 8. As the server pushes game data, the client’s _Proxy_ReceiveGameDataReceived() method is called to process the data. In a real-life application I’d go with a ViewModel class to handle retrieving team data, setup data bindings and handle data that is pushed from the server. However, for the sample application I wanted to focus on HTTP Polling Duplex and keep things as simple as possible.   Summary Silverlight supports three options when duplex communication is required in an application including TCP bindins, sockets and HTTP Polling Duplex. In this post you’ve seen how HTTP Polling Duplex interfaces can be created and implemented on the server as well as how they can be consumed by a Silverlight client. HTTP Polling Duplex provides a nice way to “push” data from a server while still allowing the data to flow over port 80 or another port of your choice.   Sample Application Download

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• How to know the source of certain TCP traffic on AIX

  - by A.Rashad

  We have two AIX boxes, one for production system and another for testing. both systems are running ATM machine switches, where the ATM device is connected via TCP socket. we had an issue on production system where the machine would power off or get disconnected but the netstat -na | grep <IP of machine > would still mention that the socket is up when simulated that case on the UAT environment, the problem did not happen, where the socket would terminate in 3 to 5 minutes. when sniffed on the traffic between the machine and ATM we found that no traffic takes place on production while there is some sort of heartbeat on UAT. but it is not initiated by the application. $>tcpdump | grep -v "10.2.2.71" | grep -v "HSRP" | grep "10.3.1.30" tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on en6, link-type 1, capture size 96 bytes 09:08:13.323421 IP server073.afs3-callback > 10.3.1.30.impera: . 278204201:278204202(1) ack 3307884029 win 164 09:08:13.335334 IP 10.3.1.30.impera > server073.afs3-callback: . ack 1 win 64180 09:08:23.425771 IP 10.3.1.30.impera > server073.afs3-callback: . 1:2(1) ack 1 win 64180 09:08:23.425789 IP server073.afs3-callback > 10.3.1.30.impera: . ack 2 win 65535 09:09:13.628985 IP server073.afs3-callback > 10.3.1.30.impera: . 0:1(1) ack 1 win 164 09:09:13.633900 IP 10.3.1.30.impera > server073.afs3-callback: . ack 1 win 64180 09:09:23.373634 IP 10.3.1.30.impera > server073.afs3-callback: . 1:2(1) ack 1 win 64180 09:09:23.373647 IP server073.afs3-callback > 10.3.1.30.impera: . ack 2 win 65535 while on production, that traffic is not there. we want to know where this traffic is initiated from to implement on production to sense disconnection our comms parameters are: tcp_keepcnt = 2 tcp_keepidle = 100 tcp_keepinit = 150 tcp_keepintvl = 150 tcp_finwait2 = 1200 can anyone help? Editing Question: One point I missed because I was rushing to a meeting. the difference between the Production and UAT in setup is that in Production we have an application called F5 working as load balancer between the ATMs and the AIX box, while it is a direct connection through MPLS in case of UAT. note: we had one MPLS and one GPRS connected ATMs on UAT, and both connections terminated when unplugged in about 4 minutes Edit 2 the no -o tcp_timewait command returns 1 in both Production and UAT

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• How to know the source of certain TCP traffic on AIX

  - by A.Rashad

  We have two AIX boxes, one for production system and another for testing. both systems are running ATM machine switches, where the ATM device is connected via TCP socket. we had an issue on production system where the machine would power off or get disconnected but the netstat -na | grep <IP of machine > would still mention that the socket is up when simulated that case on the UAT environment, the problem did not happen, where the socket would terminate in 3 to 5 minutes. when sniffed on the traffic between the machine and ATM we found that no traffic takes place on production while there is some sort of heartbeat on UAT. but it is not initiated by the application. $>tcpdump | grep -v "10.2.2.71" | grep -v "HSRP" | grep "10.3.1.30" tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on en6, link-type 1, capture size 96 bytes 09:08:13.323421 IP server073.afs3-callback > 10.3.1.30.impera: . 278204201:278204202(1) ack 3307884029 win 164 09:08:13.335334 IP 10.3.1.30.impera > server073.afs3-callback: . ack 1 win 64180 09:08:23.425771 IP 10.3.1.30.impera > server073.afs3-callback: . 1:2(1) ack 1 win 64180 09:08:23.425789 IP server073.afs3-callback > 10.3.1.30.impera: . ack 2 win 65535 09:09:13.628985 IP server073.afs3-callback > 10.3.1.30.impera: . 0:1(1) ack 1 win 164 09:09:13.633900 IP 10.3.1.30.impera > server073.afs3-callback: . ack 1 win 64180 09:09:23.373634 IP 10.3.1.30.impera > server073.afs3-callback: . 1:2(1) ack 1 win 64180 09:09:23.373647 IP server073.afs3-callback > 10.3.1.30.impera: . ack 2 win 65535 while on production, that traffic is not there. we want to know where this traffic is initiated from to implement on production to sense disconnection our comms parameters are: tcp_keepcnt = 2 tcp_keepidle = 100 tcp_keepinit = 150 tcp_keepintvl = 150 tcp_finwait2 = 1200 can anyone help?

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• Why does @PostConstruct callback fire every time even though bean is @ViewScoped? JSF

  - by Nitesh Panchal

  Hello, I am using datatable on page and using binding attribute to bind it to my backing bean. This is my code :- <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:p="http://primefaces.prime.com.tr/ui"> <h:head> <title>Facelet Title</title> </h:head> <h:body> <h:form prependId="false"> <h:dataTable var="item" value="#{testBean.stringCollection}" binding="#{testBean.dataTable}"> <h:column> <h:outputText value="#{item}"/> </h:column> <h:column> <h:commandButton value="Click" actionListener="#{testBean.action}"/> </h:column> </h:dataTable> </h:form> </h:body> </html> This is my bean :- package managedBeans; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.annotation.PostConstruct; import javax.faces.bean.ManagedBean; import javax.faces.bean.ViewScoped; import javax.faces.component.html.HtmlDataTable; @ManagedBean(name="testBean") @ViewScoped public class testBean implements Serializable { private List<String> stringCollection; public List<String> getStringCollection() { return stringCollection; } public void setStringCollection(List<String> stringCollection) { this.stringCollection = stringCollection; } private HtmlDataTable dataTable; public HtmlDataTable getDataTable() { return dataTable; } public void setDataTable(HtmlDataTable dataTable) { this.dataTable = dataTable; } @PostConstruct public void init(){ System.out.println("Post Construct fired!!"); stringCollection = new ArrayList<String>(); stringCollection.add("a"); stringCollection.add("b"); stringCollection.add("c"); } public void action(){ System.out.println("Clicked!!"); } } Please tell me why is the @PostConstruct firing each and every time i click on button? It should fire only once as long as i am on same page beacause my bean is @ViewScoped. Further, if i remove the binding attribute then everything works fine and @PostConstruct callback fires only once. Then why every time when i use binding attribute? I need binding attribute and want to perform initialisation tasks like fetching data from webservice, etc only once. What should i do? Where should i write my initialisation task?

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• TypeInitializeException on MVVM pattern

  - by Mohit Deshpande

  System.TypeInitializationException was unhandled Message=The type initializer for 'SmartHomeworkOrganizer.ViewModels.MainViewModel' threw an exception. Source=SmartHomeworkOrganizer TypeName=SmartHomeworkOrganizer.ViewModels.MainViewModel StackTrace: at SmartHomeworkOrganizer.ViewModels.MainViewModel..ctor() at SmartHomeworkOrganizer.App.OnStartup(Object sender, StartupEventArgs e) in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\SmartHomeworkOrganizer\SmartHomeworkOrganizer\App.xaml.cs:line 21 at System.Windows.Application.OnStartup(StartupEventArgs e) at System.Windows.Application.<.ctor>b__0(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.DispatcherOperation.InvokeImpl() at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Threading.DispatcherOperation.Invoke() at System.Windows.Threading.Dispatcher.ProcessQueue() at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter) at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg) at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam) at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.Run() at System.Windows.Application.RunDispatcher(Object ignore) at System.Windows.Application.RunInternal(Window window) at System.Windows.Application.Run(Window window) at System.Windows.Application.Run() at SmartHomeworkOrganizer.App.Main() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\SmartHomeworkOrganizer\SmartHomeworkOrganizer\obj\Debug\App.g.cs:line 0 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: System.ArgumentException Message=Default value type does not match type of property 'Score'. Source=WindowsBase StackTrace: at System.Windows.DependencyProperty.ValidateDefaultValueCommon(Object defaultValue, Type propertyType, String propertyName, ValidateValueCallback validateValueCallback, Boolean checkThreadAffinity) at System.Windows.DependencyProperty.ValidateMetadataDefaultValue(PropertyMetadata defaultMetadata, Type propertyType, String propertyName, ValidateValueCallback validateValueCallback) at System.Windows.DependencyProperty.RegisterCommon(String name, Type propertyType, Type ownerType, PropertyMetadata defaultMetadata, ValidateValueCallback validateValueCallback) at System.Windows.DependencyProperty.Register(String name, Type propertyType, Type ownerType, PropertyMetadata typeMetadata, ValidateValueCallback validateValueCallback) at System.Windows.DependencyProperty.Register(String name, Type propertyType, Type ownerType, PropertyMetadata typeMetadata) at SmartHomeworkOrganizer.ViewModels.MainViewModel..cctor() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\SmartHomeworkOrganizer\SmartHomeworkOrganizer\ViewModels\MainViewModel.cs:line 72 InnerException: This bit of code throws a System.ArgumentException before the TypeInitializeException. It says: "Default value type does not match type of property Score": public static readonly DependencyProperty ScoreProperty = DependencyProperty.Register("Score", typeof(float), typeof(MainViewModel), new UIPropertyMetadata(0.0)); Here is the .NET property: public float Score { get { return (float) GetValue(ScoreProperty); } set { SetValue(ScoreProperty, value); } }

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• Codeigniter Twitter Library : What is my Callback URL. Where can i find it?

  - by Tapha

  I would like to know where i can find my callback url in ci? Im quite new to it so not really sure. Here is the lib im using. <?php class Home extends Controller { function Home() { parent::Controller(); } public function index() { // This is how we do a basic auth: // $this->twitter->auth('user', 'password'); // Fill in your twitter oauth client keys here $consumer_key = ''; $consumer_key_secret = ''; // For this example, we're going to get and save our access_token and access_token_secret // in session data, but you might want to use a database instead :) $this->load->library('session'); $tokens['access_token'] = NULL; $tokens['access_token_secret'] = NULL; // GET THE ACCESS TOKENS $oauth_tokens = $this->session->userdata('twitter_oauth_tokens'); if ( $oauth_tokens !== FALSE ) $tokens = $oauth_tokens; $this->load->library('twitter'); $auth = $this->twitter->oauth($consumer_key, $consumer_key_secret, $tokens['access_token'], $tokens['access_token_secret']); if ( isset($auth['access_token']) && isset($auth['access_token_secret']) ) { // SAVE THE ACCESS TOKENS $this->session->set_userdata('twitter_oauth_tokens', $auth); if ( isset($_GET['oauth_token']) ) { $uri = $_SERVER['REQUEST_URI']; $parts = explode('?', $uri); // Now we redirect the user since we've saved their stuff! header('Location: '.$parts[0]); return; } } // This is where you can call a method. $this->twitter->call('statuses/update', array('status' => 'Testing CI Twitter oAuth sexyness by @elliothaughin')); // Here's the calls you can make now. // Sexy! /* $this->twitter->call('statuses/friends_timeline'); $this->twitter->search('search', array('q' => 'elliot')); $this->twitter->search('trends'); $this->twitter->search('trends/current'); $this->twitter->search('trends/daily'); $this->twitter->search('trends/weekly'); $this->twitter->call('statuses/public_timeline'); $this->twitter->call('statuses/friends_timeline'); $this->twitter->call('statuses/user_timeline'); $this->twitter->call('statuses/show', array('id' => 1234)); $this->twitter->call('direct_messages'); $this->twitter->call('statuses/update', array('status' => 'If this tweet appears, oAuth is working!')); $this->twitter->call('statuses/destroy', array('id' => 1234)); $this->twitter->call('users/show', array('id' => 'elliothaughin')); $this->twitter->call('statuses/friends', array('id' => 'elliothaughin')); $this->twitter->call('statuses/followers', array('id' => 'elliothaughin')); $this->twitter->call('direct_messages'); $this->twitter->call('direct_messages/sent'); $this->twitter->call('direct_messages/new', array('user' => 'jamierumbelow', 'text' => 'This is a library test. Ignore')); $this->twitter->call('direct_messages/destroy', array('id' => 123)); $this->twitter->call('friendships/create', array('id' => 'elliothaughin')); $this->twitter->call('friendships/destroy', array('id' => 123)); $this->twitter->call('friendships/exists', array('user_a' => 'elliothaughin', 'user_b' => 'jamierumbelow')); $this->twitter->call('account/verify_credentials'); $this->twitter->call('account/rate_limit_status'); $this->twitter->call('account/rate_limit_status'); $this->twitter->call('account/update_delivery_device', array('device' => 'none')); $this->twitter->call('account/update_profile_colors', array('profile_text_color' => '666666')); $this->twitter->call('help/test'); */ } } /* End of file welcome.php */ /* Location: ./system/application/controllers/home.php */ Thank you all

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• Tkinter Packing Strangeness: Buttons packed above others

  - by Parand

  I'm sure I'm doing something obvious wrong here, but I can't see it. I end up with the "Should be on top" label packed at the bottom instead of at the top. What am I doing wrong? from Tkinter import * class SelectAction(Frame): buttons = {} def callback(self): print "Callback" def createWidgets(self): logo_label = Label(text="Should be on top").pack(fill=X) for name, text, callback in ( ('setup_account', 'Account Settings', self.callback), ('do_action', 'Do Something', self.callback), ): self.buttons[name] = Button(self, text=text, command=callback).pack(fill=X) def __init__(self, master=None): Frame.__init__(self, master) self.pack() self.createWidgets() if __name__ == "__main__": root = Tk() app = SelectAction(master=root) app.mainloop() root.destroy()

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• Jsonp request using jquery to fetch bing web results

  - by Blankman

  using this as a guide: http://msdn.microsoft.com/en-us/library/dd250846.aspx can someone help me with the jquery call? Do I actually pass in the javascript code for the callback, or just the name of the function? BingSearch = function($bingUrl, $bingAppID, $keyword, $callBack) { $bingUrl = $bingUrl + "?JsonType=callback&JsonCallback=" + $callBack + "&Appid=" + $bingAppID + "&query=" + encodeURI($keyword) + "&sources=web"; $.ajax({ dataType: 'jsonp', jsonp: $callBack, url: $bingUrl, success: function(data) { alert('success'); $callBack(data); }, error: function(XMLHttpRequest, textStatus, errorThrown) { alert("error: " + textStatus); } }); };

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• Executing functions parallelly in PHP

  - by binaryLV

  Hi! Can PHP call a function and don't wait for it to return? So something like this: function callback($pause, $arg) { sleep($pause); echo $arg, "\n"; } header('Content-Type: text/plain'); fast_call_user_func_array('callback', array(3, 'three')); fast_call_user_func_array('callback', array(2, 'two')); fast_call_user_func_array('callback', array(1, 'one')); would output one (after 1 second) two (after 2 seconds) three (after 3 seconds) rather than three (after 3 seconds) two (after 3 + 2 = 5 seconds) one (after 3 + 2 + 1 = 6 seconds) Main script is intended to be run as a permanent process (TCP server). callback() function would receive data from client, execute external PHP script and then do something based on other arguments that are passed to callback(). The problem is that main script must not wait for external PHP script to finish. Result of external script is important, so exec('php -f file.php &') is not an option.

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• what does calling ´this´ outside of a jquery plugin refer to

  - by Richard

  Hi, I am using the liveTwitter plugin The problem is that I need to stop the plugin from hitting the Twitter api. According to the documentation I need to do this $("#tab1 .container_twitter_status").each(function(){ this.twitter.stop(); }); Already, the each does not make sense on an id and what does this refer to? Anyway, I get an undefined error. I will paste the plugin code and hope it makes sense to somebody MY only problem thusfar with this plugin is that I need to be able to stop it. thanks in advance, Richard /* * jQuery LiveTwitter 1.5.0 * - Live updating Twitter plugin for jQuery * * Copyright (c) 2009-2010 Inge Jørgensen (elektronaut.no) * Licensed under the MIT license (MIT-LICENSE.txt) * * $Date: 2010/05/30$ */ /* * Usage example: * $("#twitterSearch").liveTwitter('bacon', {limit: 10, rate: 15000}); */ (function($){ if(!$.fn.reverse){ $.fn.reverse = function() { return this.pushStack(this.get().reverse(), arguments); }; } $.fn.liveTwitter = function(query, options, callback){ var domNode = this; $(this).each(function(){ var settings = {}; // Handle changing of options if(this.twitter) { settings = jQuery.extend(this.twitter.settings, options); this.twitter.settings = settings; if(query) { this.twitter.query = query; } this.twitter.limit = settings.limit; this.twitter.mode = settings.mode; if(this.twitter.interval){ this.twitter.refresh(); } if(callback){ this.twitter.callback = callback; } // ..or create a new twitter object } else { // Extend settings with the defaults settings = jQuery.extend({ mode: 'search', // Mode, valid options are: 'search', 'user_timeline' rate: 15000, // Refresh rate in ms limit: 10, // Limit number of results refresh: true }, options); // Default setting for showAuthor if not provided if(typeof settings.showAuthor == "undefined"){ settings.showAuthor = (settings.mode == 'user_timeline') ? false : true; } // Set up a dummy function for the Twitter API callback if(!window.twitter_callback){ window.twitter_callback = function(){return true;}; } this.twitter = { settings: settings, query: query, limit: settings.limit, mode: settings.mode, interval: false, container: this, lastTimeStamp: 0, callback: callback, // Convert the time stamp to a more human readable format relativeTime: function(timeString){ var parsedDate = Date.parse(timeString); var delta = (Date.parse(Date()) - parsedDate) / 1000; var r = ''; if (delta < 60) { r = delta + ' seconds ago'; } else if(delta < 120) { r = 'a minute ago'; } else if(delta < (45*60)) { r = (parseInt(delta / 60, 10)).toString() + ' minutes ago'; } else if(delta < (90*60)) { r = 'an hour ago'; } else if(delta < (24*60*60)) { r = '' + (parseInt(delta / 3600, 10)).toString() + ' hours ago'; } else if(delta < (48*60*60)) { r = 'a day ago'; } else { r = (parseInt(delta / 86400, 10)).toString() + ' days ago'; } return r; }, // Update the timestamps in realtime refreshTime: function() { var twitter = this; $(twitter.container).find('span.time').each(function(){ $(this).html(twitter.relativeTime(this.timeStamp)); }); }, // Handle reloading refresh: function(initialize){ var twitter = this; if(this.settings.refresh || initialize) { var url = ''; var params = {}; if(twitter.mode == 'search'){ params.q = this.query; if(this.settings.geocode){ params.geocode = this.settings.geocode; } if(this.settings.lang){ params.lang = this.settings.lang; } if(this.settings.rpp){ params.rpp = this.settings.rpp; } else { params.rpp = this.settings.limit; } // Convert params to string var paramsString = []; for(var param in params){ if(params.hasOwnProperty(param)){ paramsString[paramsString.length] = param + '=' + encodeURIComponent(params[param]); } } paramsString = paramsString.join("&"); url = "http://search.twitter.com/search.json?"+paramsString+"&callback=?"; } else if(twitter.mode == 'user_timeline') { url = "http://api.twitter.com/1/statuses/user_timeline/"+encodeURIComponent(this.query)+".json?count="+twitter.limit+"&callback=?"; } else if(twitter.mode == 'list') { var username = encodeURIComponent(this.query.user); var listname = encodeURIComponent(this.query.list); url = "http://api.twitter.com/1/"+username+"/lists/"+listname+"/statuses.json?per_page="+twitter.limit+"&callback=?"; } $.getJSON(url, function(json) { var results = null; if(twitter.mode == 'search'){ results = json.results; } else { results = json; } var newTweets = 0; $(results).reverse().each(function(){ var screen_name = ''; var profile_image_url = ''; if(twitter.mode == 'search') { screen_name = this.from_user; profile_image_url = this.profile_image_url; created_at_date = this.created_at; } else { screen_name = this.user.screen_name; profile_image_url = this.user.profile_image_url; // Fix for IE created_at_date = this.created_at.replace(/^(\w+)\s(\w+)\s(\d+)(.*)(\s\d+)$/, "$1, $3 $2$5$4"); } var userInfo = this.user; var linkified_text = this.text.replace(/[A-Za-z]+:\/\/[A-Za-z0-9-_]+\.[A-Za-z0-9-_:%&\?\/.=]+/, function(m) { return m.link(m); }); linkified_text = linkified_text.replace(/@[A-Za-z0-9_]+/g, function(u){return u.link('http://twitter.com/'+u.replace(/^@/,''));}); linkified_text = linkified_text.replace(/#[A-Za-z0-9_\-]+/g, function(u){return u.link('http://search.twitter.com/search?q='+u.replace(/^#/,'%23'));}); if(!twitter.settings.filter || twitter.settings.filter(this)) { if(Date.parse(created_at_date) > twitter.lastTimeStamp) { newTweets += 1; var tweetHTML = '<div class="tweet tweet-'+this.id+'">'; if(twitter.settings.showAuthor) { tweetHTML += '<img width="24" height="24" src="'+profile_image_url+'" />' + '<p class="text"><span class="username"><a href="http://twitter.com/'+screen_name+'">'+screen_name+'</a>:</span> '; } else { tweetHTML += '<p class="text"> '; } tweetHTML += linkified_text + ' <span class="time">'+twitter.relativeTime(created_at_date)+'</span>' + '</p>' + '</div>'; $(twitter.container).prepend(tweetHTML); var timeStamp = created_at_date; $(twitter.container).find('span.time:first').each(function(){ this.timeStamp = timeStamp; }); if(!initialize) { $(twitter.container).find('.tweet-'+this.id).hide().fadeIn(); } twitter.lastTimeStamp = Date.parse(created_at_date); } } }); if(newTweets > 0) { // Limit number of entries $(twitter.container).find('div.tweet:gt('+(twitter.limit-1)+')').remove(); // Run callback if(twitter.callback){ twitter.callback(domNode, newTweets); } // Trigger event $(domNode).trigger('tweets'); } }); } }, start: function(){ var twitter = this; if(!this.interval){ this.interval = setInterval(function(){twitter.refresh();}, twitter.settings.rate); this.refresh(true); } }, stop: function(){ if(this.interval){ clearInterval(this.interval); this.interval = false; } } }; var twitter = this.twitter; this.timeInterval = setInterval(function(){twitter.refreshTime();}, 5000); this.twitter.start(); } }); return this; }; })(jQuery);

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• jQuery Time Entry with Time Navigation Keys

  - by Rick Strahl

  So, how do you display time values in your Web applications? Displaying date AND time values in applications is lot less standardized than date display only. While date input has become fairly universal with various date picker controls available, time entry continues to be a bit of a non-standardized. In my own applications I tend to use the jQuery UI DatePicker control for date entries and it works well for that. Here's an example: The date entry portion is well defined and it makes perfect sense to have a calendar pop up so you can pick a date from a rich UI when necessary. However, time values are much less obvious when it comes to displaying a UI or even just making time entries more useful. There are a slew of time picker controls available but other than adding some visual glitz, they are not really making time entry any easier. Part of the reason for this is that time entry is usually pretty simple. Clicking on a dropdown of any sort and selecting a value from a long scrolling list tends to take more user interaction than just typing 5 characters (7 if am/pm is used). Keystrokes can make Time Entry easier Time entry maybe pretty simple, but I find that adding a few hotkeys to handle date navigation can make it much easier. Specifically it'd be nice to have keys to: Jump to the current time (Now) Increase/decrease minutes Increase/decrease hours The timeKeys jQuery PlugIn Some time ago I created a small plugin to handle this scenario. It's non-visual other than tooltip that pops up when you press ? to display the hotkeys that are available: Try it Online The keys loosely follow the ancient Quicken convention of using the first and last letters of what you're increasing decreasing (ie. H to decrease, R to increase hours and + and - for the base unit or minutes here). All navigation happens via the keystrokes shown above, so it's all non-visual, which I think is the most efficient way to deal with dates. To hook up the plug-in, start with the textbox:<input type="text" id="txtTime" name="txtTime" value="12:05 pm" title="press ? for time options" /> Note the title which might be useful to alert people using the field that additional functionality is available. To hook up the plugin code is as simple as:$("#txtTime").timeKeys(); You essentially tie the plugin to any text box control. OptionsThe syntax for timeKeys allows for an options map parameter:$(selector).timeKeys(options); Options are passed as a parameter map object which can have the following properties: timeFormatYou can pass in a format string that allows you to format the date. The default is "hh:mm t" which is US time format that shows a 12 hour clock with am/pm. Alternately you can pass in "HH:mm" which uses 24 hour time. HH, hh, mm and t are translated in the format string - you can arrange the format as you see fit. callbackYou can also specify a callback function that is called when the date value has been set. This allows you to either re-format the date or perform post processing (such as displaying highlight if it's after a certain hour for example). Here's another example that uses both options:$("#txtTime").timeKeys({ timeFormat: "HH:mm", callback: function (time) { showStatus("new time is: " + time.toString() + " " + $(this).val() ); } }); The plugin code itself is fairly simple. It hooks the keydown event and checks for the various keys that affect time navigation which is straight forward. The bulk of the code however deals with parsing the time value and formatting the output using a Time class that implements parsing, formatting and time navigation methods. Here's the code for the timeKeys jQuery plug-in:/// <reference path="jquery.js" /> /// <reference path="ww.jquery.js" /> (function ($) { $.fn.timeKeys = function (options) { /// <summary> /// Attaches a set of hotkeys to time fields /// + Add minute - subtract minute /// H Subtract Hour R Add houR /// ? Show keys /// </summary> /// <param name="options" type="object"> /// Options: /// timeFormat: "hh:mm t" by default HH:mm alternate /// callback: callback handler after time assignment /// </param> /// <example> /// var proxy = new ServiceProxy("JsonStockService.svc/"); /// proxy.invoke("GetStockQuote",{symbol:"msft"},function(quote) { alert(result.LastPrice); },onPageError); ///</example> if (this.length < 1) return this; var opt = { timeFormat: "hh:mm t", callback: null } $.extend(opt, options); return this.keydown(function (e) { var $el = $(this); var time = new Time($el.val()); //alert($(this).val() + " " + time.toString() + " " + time.date.toString()); switch (e.keyCode) { case 78: // [N]ow time = new Time(new Date()); break; case 109: case 189: // - time.addMinutes(-1); break; case 107: case 187: // + time.addMinutes(1); break; case 72: //H time.addHours(-1); break; case 82: //R time.addHours(1); break; case 191: // ? if (e.shiftKey) $(this).tooltip("<b>N</b> Now<br/><b>+</b> add minute<br /><b>-</b> subtract minute<br /><b>H</b> Subtract Hour<br /><b>R</b> add hour", 4000, { isHtml: true }); return false; default: return true; } $el.val(time.toString(opt.timeFormat)); if (opt.callback) { // call async and set context in this element setTimeout(function () { opt.callback.call($el.get(0), time) }, 1); } return false; }); } Time = function (time, format) { /// <summary> /// Time object that can parse and format /// a time values. /// </summary> /// <param name="time" type="object"> /// A time value as a string (12:15pm or 23:01), a Date object /// or time value. /// /// </param> /// <param name="format" type="string"> /// Time format string: /// HH:mm (23:01) /// hh:mm t (11:01 pm) /// </param> /// <example> /// var time = new Time( new Date()); /// time.addHours(5); /// time.addMinutes(10); /// var s = time.toString(); /// /// var time2 = new Time(s); // parse with constructor /// var t = time2.parse("10:15 pm"); // parse with .parse() method /// alert( t.hours + " " + t.mins + " " + t.ampm + " " + t.hours25) ///</example> var _I = this; this.date = new Date(); this.timeFormat = "hh:mm t"; if (format) this.timeFormat = format; this.parse = function (time) { /// <summary> /// Parses time value from a Date object, or string in format of: /// 12:12pm or 23:01 /// </summary> /// <param name="time" type="any"> /// A time value as a string (12:15pm or 23:01), a Date object /// or time value. /// /// </param> if (!time) return null; // Date if (time.getDate) { var t = {}; var d = time; t.hours24 = d.getHours(); t.mins = d.getMinutes(); t.ampm = "am"; if (t.hours24 > 11) { t.ampm = "pm"; if (t.hours24 > 12) t.hours = t.hours24 - 12; } time = t; } if (typeof (time) == "string") { var parts = time.split(":"); if (parts < 2) return null; var time = {}; time.hours = parts[0] * 1; time.hours24 = time.hours; time.mins = parts[1].toLowerCase(); if (time.mins.indexOf("am") > -1) { time.ampm = "am"; time.mins = time.mins.replace("am", ""); if (time.hours == 12) time.hours24 = 0; } else if (time.mins.indexOf("pm") > -1) { time.ampm = "pm"; time.mins = time.mins.replace("pm", ""); if (time.hours < 12) time.hours24 = time.hours + 12; } time.mins = time.mins * 1; } _I.date.setMinutes(time.mins); _I.date.setHours(time.hours24); return time; }; this.addMinutes = function (mins) { /// <summary> /// adds minutes to the internally stored time value. /// </summary> /// <param name="mins" type="number"> /// number of minutes to add to the date /// </param> _I.date.setMinutes(_I.date.getMinutes() + mins); } this.addHours = function (hours) { /// <summary> /// adds hours the internally stored time value. /// </summary> /// <param name="hours" type="number"> /// number of hours to add to the date /// </param> _I.date.setHours(_I.date.getHours() + hours); } this.getTime = function () { /// <summary> /// returns a time structure from the currently /// stored time value. /// Properties: hours, hours24, mins, ampm /// </summary> return new Time(new Date()); h } this.toString = function (format) { /// <summary> /// returns a short time string for the internal date /// formats: 12:12 pm or 23:12 /// </summary> /// <param name="format" type="string"> /// optional format string for date /// HH:mm, hh:mm t /// </param> if (!format) format = _I.timeFormat; var hours = _I.date.getHours(); if (format.indexOf("t") > -1) { if (hours > 11) format = format.replace("t", "pm") else format = format.replace("t", "am") } if (format.indexOf("HH") > -1) format = format.replace("HH", hours.toString().padL(2, "0")); if (format.indexOf("hh") > -1) { if (hours > 12) hours -= 12; if (hours == 0) hours = 12; format = format.replace("hh", hours.toString().padL(2, "0")); } if (format.indexOf("mm") > -1) format = format.replace("mm", _I.date.getMinutes().toString().padL(2, "0")); return format; } // construction if (time) this.time = this.parse(time); } String.prototype.padL = function (width, pad) { if (!width || width < 1) return this; if (!pad) pad = " "; var length = width - this.length if (length < 1) return this.substr(0, width); return (String.repeat(pad, length) + this).substr(0, width); } String.repeat = function (chr, count) { var str = ""; for (var x = 0; x < count; x++) { str += chr }; return str; } })(jQuery); The plugin consists of the actual plugin and the Time class which handles parsing and formatting of the time value via the .parse() and .toString() methods. Code like this always ends up taking up more effort than the actual logic unfortunately. There are libraries out there that can handle this like datejs or even ww.jquery.js (which is what I use) but to keep the code self contained for this post the plugin doesn't rely on external code. There's one optional exception: The code as is has one dependency on ww.jquery.js  for the tooltip plugin that provides the small popup for all the hotkeys available. You can replace that code with some other mechanism to display hotkeys or simply remove it since that behavior is optional. While we're at it: A jQuery dateKeys plugIn Although date entry tends to be much better served with drop down calendars to pick dates from, often it's also easier to pick dates using a few simple hotkeys. Navigation that uses + - for days and M and H for MontH navigation, Y and R for YeaR navigation are a quick way to enter dates without having to resort to using a mouse and clicking around to what you want to find. Note that this plugin does have a dependency on ww.jquery.js for the date formatting functionality.$.fn.dateKeys = function (options) { /// <summary> /// Attaches a set of hotkeys to date 'fields' /// + Add day - subtract day /// M Subtract Month H Add montH /// Y Subtract Year R Add yeaR /// ? Show keys /// </summary> /// <param name="options" type="object"> /// Options: /// dateFormat: "MM/dd/yyyy" by default "MMM dd, yyyy /// callback: callback handler after date assignment /// </param> /// <example> /// var proxy = new ServiceProxy("JsonStockService.svc/"); /// proxy.invoke("GetStockQuote",{symbol:"msft"},function(quote) { alert(result.LastPrice); },onPageError); ///</example> if (this.length < 1) return this; var opt = { dateFormat: "MM/dd/yyyy", callback: null }; $.extend(opt, options); return this.keydown(function (e) { var $el = $(this); var d = new Date($el.val()); if (!d) d = new Date(1900, 0, 1, 1, 1); var month = d.getMonth(); var year = d.getFullYear(); var day = d.getDate(); switch (e.keyCode) { case 84: // [T]oday d = new Date(); break; case 109: case 189: d = new Date(year, month, day - 1); break; case 107: case 187: d = new Date(year, month, day + 1); break; case 77: //M d = new Date(year, month - 1, day); break; case 72: //H d = new Date(year, month + 1, day); break; case 191: // ? if (e.shiftKey) $el.tooltip("<b>T</b> Today<br/><b>+</b> add day<br /><b>-</b> subtract day<br /><b>M</b> subtract Month<br /><b>H</b> add montH<br/><b>Y</b> subtract Year<br/><b>R</b> add yeaR", 5000, { isHtml: true }); return false; default: return true; } $el.val(d.formatDate(opt.dateFormat)); if (opt.callback) // call async setTimeout(function () { opt.callback.call($el.get(0),d); }, 10); return false; }); } The logic for this plugin is similar to the timeKeys plugin, but it's a little simpler as it tries to directly parse the date value from a string via new Date(inputString). As mentioned it also uses a helper function from ww.jquery.js to format dates which removes the logic to perform date formatting manually which again reduces the size of the code. And the Key is… I've been using both of these plugins in combination with the jQuery UI datepicker for datetime values and I've found that I rarely actually pop up the date picker any more. It's just so much more efficient to use the hotkeys to navigate dates. It's still nice to have the picker around though - it provides the expected behavior for date entry. For time values however I can't justify the UI overhead of a picker that doesn't make it any easier to pick a time. Most people know how to type in a time value and if they want shortcuts keystrokes easily beat out any pop up UI. Hopefully you'll find this as useful as I have found it for my code. Resources Online Sample Download Sample Project © Rick Strahl, West Wind Technologies, 2005-2011Posted in jQuery  HTML   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• WCF RIA Services DomainContext Abstraction Strategies–Say That 10 Times!

  - by dwahlin

  The DomainContext available with WCF RIA Services provides a lot of functionality that can help track object state and handle making calls from a Silverlight client to a DomainService. One of the questions I get quite often in our Silverlight training classes (and see often in various forums and other areas) is how the DomainContext can be abstracted out of ViewModel classes when using the MVVM pattern in Silverlight applications. It’s not something that’s super obvious at first especially if you don’t work with delegates a lot, but it can definitely be done. There are various techniques and strategies that can be used but I thought I’d share some of the core techniques I find useful. To start, let’s assume you have the following ViewModel class (this is from my Silverlight Firestarter talk available to watch online here if you’re interested in getting started with WCF RIA Services): public class AdminViewModel : ViewModelBase { BookClubContext _Context = new BookClubContext(); public AdminViewModel() { if (!DesignerProperties.IsInDesignTool) { LoadBooks(); } } private void LoadBooks() { _Context.Load(_Context.GetBooksQuery(), LoadBooksCallback, null); } private void LoadBooksCallback(LoadOperation<Book> books) { Books = new ObservableCollection<Book>(books.Entities); } } Notice that BookClubContext is being used directly in the ViewModel class. There’s nothing wrong with that of course, but if other ViewModel objects need to load books then code would be duplicated across classes. Plus, the ViewModel has direct knowledge of how to load data and I like to make it more loosely-coupled. To do this I create what I call a “Service Agent” class. This class is responsible for getting data from the DomainService and returning it to a ViewModel. It only knows how to get and return data but doesn’t know how data should be stored and isn’t used with data binding operations. An example of a simple ServiceAgent class is shown next. Notice that I’m using the Action<T> delegate to handle callbacks from the ServiceAgent to the ViewModel object. Because LoadBooks accepts an Action<ObservableCollection<Book>>, the callback method in the ViewModel must accept ObservableCollection<Book> as a parameter. The callback is initiated by calling the Invoke method exposed by Action<T>: public class ServiceAgent { BookClubContext _Context = new BookClubContext(); public void LoadBooks(Action<ObservableCollection<Book>> callback) { _Context.Load(_Context.GetBooksQuery(), LoadBooksCallback, callback); } public void LoadBooksCallback(LoadOperation<Book> lo) { //Check for errors of course...keeping this brief var books = new ObservableCollection<Book>(lo.Entities); var action = (Action<ObservableCollection<Book>>)lo.UserState; action.Invoke(books); } } This can be simplified by taking advantage of lambda expressions. Notice that in the following code I don’t have a separate callback method and don’t have to worry about passing any user state or casting any user state (the user state is the 3rd parameter in the _Context.Load method call shown above). public class ServiceAgent { BookClubContext _Context = new BookClubContext(); public void LoadBooks(Action<ObservableCollection<Book>> callback) { _Context.Load(_Context.GetBooksQuery(), (lo) => { var books = new ObservableCollection<Book>(lo.Entities); callback.Invoke(books); }, null); } } A ViewModel class can then call into the ServiceAgent to retrieve books yet never know anything about the DomainContext object or even know how data is loaded behind the scenes: public class AdminViewModel : ViewModelBase { ServiceAgent _ServiceAgent = new ServiceAgent(); public AdminViewModel() { if (!DesignerProperties.IsInDesignTool) { LoadBooks(); } } private void LoadBooks() { _ServiceAgent.LoadBooks(LoadBooksCallback); } private void LoadBooksCallback(ObservableCollection<Book> books) { Books = books } } You could also handle the LoadBooksCallback method using a lambda if you wanted to minimize code just like I did earlier with the LoadBooks method in the ServiceAgent class.  If you’re into Dependency Injection (DI), you could create an interface for the ServiceAgent type, reference it in the ViewModel and then inject in the object to use at runtime. There are certainly other techniques and strategies that can be used, but the code shown here provides an introductory look at the topic that should help get you started abstracting the DomainContext out of your ViewModel classes when using WCF RIA Services in Silverlight applications.

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• How does this game loop actually work?

  - by Nicolai

  I read this playfulJS post, about ray-casting: http://www.playfuljs.com/a-first-person-engine-in-265-lines/ It looks really interested, so I decided to look at his javascript. I am no expert in javascript, so I quickly got lost. It's the game loop "object" that really gets me. I simply don't understand how it works. From the code: function GameLoop() { this.frame = this.frame.bind(this); this.lastTime = 0; this.callback = function() {}; } GameLoop.prototype.start = function(callback) { this.callback = callback; requestAnimationFrame(this.frame); }; GameLoop.prototype.frame = function(time) { var seconds = (time - this.lastTime) / 1000; this.lastTime = time; if (seconds < 0.2) this.callback(seconds); requestAnimationFrame(this.frame); }; var loop = new GameLoop(); loop.start(function frame(seconds) { map.update(seconds); player.update(controls.states, map, seconds); camera.render(player, map); }); Now, what really confuses me here, is this bind stuff and how this actually loops. I am guessing, that if less than 0.2 seconds have passed, since the last time the loop was run, it simply goes back to re-check the time. If more than 0.2 seconds have passed, it leaves the frame function, and executes the 3 lines in the loop. But, if this is true, then how does the loop.start() get called again? And what on earth is the meaning of this.frame = this.frame.bind(this);? I've looked up prototypes bind() but I really don't understand it.

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• Constant game speed independent of variable FPS in OpenGL with GLUT?

  - by Nazgulled

  I've been reading Koen Witters detailed article about different game loop solutions but I'm having some problems implementing the last one with GLUT, which is the recommended one. After reading a couple of articles, tutorials and code from other people on how to achieve a constant game speed, I think that what I currently have implemented (I'll post the code below) is what Koen Witters called Game Speed dependent on Variable FPS, the second on his article. First, through my searching experience, there's a couple of people that probably have the knowledge to help out on this but don't know what GLUT is and I'm going to try and explain (feel free to correct me) the relevant functions for my problem of this OpenGL toolkit. Skip this section if you know what GLUT is and how to play with it. GLUT Toolkit: GLUT is an OpenGL toolkit and helps with common tasks in OpenGL. The glutDisplayFunc(renderScene) takes a pointer to a renderScene() function callback, which will be responsible for rendering everything. The renderScene() function will only be called once after the callback registration. The glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0) takes the number of milliseconds to pass before calling the callback processAnimationTimer(). The last argument is just a value to pass to the timer callback. The processAnimationTimer() will not be called each TIMER_MILLISECONDS but just once. The glutPostRedisplay() function requests GLUT to render a new frame so we need call this every time we change something in the scene. The glutIdleFunc(renderScene) could be used to register a callback to renderScene() (this does not make glutDisplayFunc() irrelevant) but this function should be avoided because the idle callback is continuously called when events are not being received, increasing the CPU load. The glutGet(GLUT_ELAPSED_TIME) function returns the number of milliseconds since glutInit was called (or first call to glutGet(GLUT_ELAPSED_TIME)). That's the timer we have with GLUT. I know there are better alternatives for high resolution timers, but let's keep with this one for now. I think this is enough information on how GLUT renders frames so people that didn't know about it could also pitch in this question to try and help if they fell like it. Current Implementation: Now, I'm not sure I have correctly implemented the second solution proposed by Koen, Game Speed dependent on Variable FPS. The relevant code for that goes like this: #define TICKS_PER_SECOND 30 #define MOVEMENT_SPEED 2.0f const int TIMER_MILLISECONDS = 1000 / TICKS_PER_SECOND; int previousTime; int currentTime; int elapsedTime; void renderScene(void) { (...) // Setup the camera position and looking point SceneCamera.LookAt(); // Do all drawing below... (...) } void processAnimationTimer(int value) { // setups the timer to be called again glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0); // Get the time when the previous frame was rendered previousTime = currentTime; // Get the current time (in milliseconds) and calculate the elapsed time currentTime = glutGet(GLUT_ELAPSED_TIME); elapsedTime = currentTime - previousTime; /* Multiply the camera direction vector by constant speed then by the elapsed time (in seconds) and then move the camera */ SceneCamera.Move(cameraDirection * MOVEMENT_SPEED * (elapsedTime / 1000.0f)); // Requests to render a new frame (this will call my renderScene() once) glutPostRedisplay(); } void main(int argc, char **argv) { glutInit(&argc, argv); (...) glutDisplayFunc(renderScene); (...) // Setup the timer to be called one first time glutTimerFunc(TIMER_MILLISECONDS, processAnimationTimer, 0); // Read the current time since glutInit was called currentTime = glutGet(GLUT_ELAPSED_TIME); glutMainLoop(); } This implementation doesn't fell right. It works in the sense that helps the game speed to be constant dependent on the FPS. So that moving from point A to point B takes the same time no matter the high/low framerate. However, I believe I'm limiting the game framerate with this approach. Each frame will only be rendered when the time callback is called, that means the framerate will be roughly around TICKS_PER_SECOND frames per second. This doesn't feel right, you shouldn't limit your powerful hardware, it's wrong. It's my understanding though, that I still need to calculate the elapsedTime. Just because I'm telling GLUT to call the timer callback every TIMER_MILLISECONDS, it doesn't mean it will always do that on time. I'm not sure how can I fix this and to be completely honest, I have no idea what is the game loop in GLUT, you know, the while( game_is_running ) loop in Koen's article. But it's my understanding that GLUT is event-driven and that game loop starts when I call glutMainLoop() (which never returns), yes? I thought I could register an idle callback with glutIdleFunc() and use that as replacement of glutTimerFunc(), only rendering when necessary (instead of all the time as usual) but when I tested this with an empty callback (like void gameLoop() {}) and it was basically doing nothing, only a black screen, the CPU spiked to 25% and remained there until I killed the game and it went back to normal. So I don't think that's the path to follow. Using glutTimerFunc() is definitely not a good approach to perform all movements/animations based on that, as I'm limiting my game to a constant FPS, not cool. Or maybe I'm using it wrong and my implementation is not right? How exactly can I have a constant game speed with variable FPS? More exactly, how do I correctly implement Koen's Constant Game Speed with Maximum FPS solution (the fourth one on his article) with GLUT? Maybe this is not possible at all with GLUT? If not, what are my alternatives? What is the best approach to this problem (constant game speed) with GLUT? I originally posted this question on Stack Overflow before being pointed out about this site. The following is a different approach I tried after creating the question in SO, so I'm posting it here too. Another Approach: I've been experimenting and here's what I was able to achieve now. Instead of calculating the elapsed time on a timed function (which limits my game's framerate) I'm now doing it in renderScene(). Whenever changes to the scene happen I call glutPostRedisplay() (ie: camera moving, some object animation, etc...) which will make a call to renderScene(). I can use the elapsed time in this function to move my camera for instance. My code has now turned into this: int previousTime; int currentTime; int elapsedTime; void renderScene(void) { (...) // Setup the camera position and looking point SceneCamera.LookAt(); // Do all drawing below... (...) } void renderScene(void) { (...) // Get the time when the previous frame was rendered previousTime = currentTime; // Get the current time (in milliseconds) and calculate the elapsed time currentTime = glutGet(GLUT_ELAPSED_TIME); elapsedTime = currentTime - previousTime; /* Multiply the camera direction vector by constant speed then by the elapsed time (in seconds) and then move the camera */ SceneCamera.Move(cameraDirection * MOVEMENT_SPEED * (elapsedTime / 1000.0f)); // Setup the camera position and looking point SceneCamera.LookAt(); // All drawing code goes inside this function drawCompleteScene(); glutSwapBuffers(); /* Redraw the frame ONLY if the user is moving the camera (similar code will be needed to redraw the frame for other events) */ if(!IsTupleEmpty(cameraDirection)) { glutPostRedisplay(); } } void main(int argc, char **argv) { glutInit(&argc, argv); (...) glutDisplayFunc(renderScene); (...) currentTime = glutGet(GLUT_ELAPSED_TIME); glutMainLoop(); } Conclusion, it's working, or so it seems. If I don't move the camera, the CPU usage is low, nothing is being rendered (for testing purposes I only have a grid extending for 4000.0f, while zFar is set to 1000.0f). When I start moving the camera the scene starts redrawing itself. If I keep pressing the move keys, the CPU usage will increase; this is normal behavior. It drops back when I stop moving. Unless I'm missing something, it seems like a good approach for now. I did find this interesting article on iDevGames and this implementation is probably affected by the problem described on that article. What's your thoughts on that? Please note that I'm just doing this for fun, I have no intentions of creating some game to distribute or something like that, not in the near future at least. If I did, I would probably go with something else besides GLUT. But since I'm using GLUT, and other than the problem described on iDevGames, do you think this latest implementation is sufficient for GLUT? The only real issue I can think of right now is that I'll need to keep calling glutPostRedisplay() every time the scene changes something and keep calling it until there's nothing new to redraw. A little complexity added to the code for a better cause, I think. What do you think?

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• New EJB with ADF Tutorials and Demo

  Covering callback methods, queries and inheritance

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• option page form in my wordpress theme [migrated]

  - by Templategraphy

  here its is my option page code containing no of fields like logo, slider after filling all the information in option page form i want to things After submitting all the form details save information must retain there. Using get_option() extract each input tag value and show that value in front hand like slider image, slider heading, slider description OPTION PAGE CODE: <?php class MySettingsPage { private $options; public function __construct() { add_action( 'admin_menu', array( $this, 'bguru_register_options_page' ) ); add_action( 'admin_init', array( $this, 'bguru_register_settings' ) ); } public function bguru_register_options_page() { // This page will be under "Settings" add_theme_page('Business Guru Options', 'Theme Customizer', 'edit_theme_options', 'bguru-options', array( $this, 'bguru_options_page') ); } public function bguru_options_page() { // Set class property $this->options = get_option( 'bguru_logo' ); $this->options = get_option( 'bguru_vimeo' ); $this->options = get_option( 'bguru_slide_one_image' ); $this->options = get_option( 'bguru_slide_one_heading' ); $this->options = get_option( 'bguru_slide_one_text' ); $this->options = get_option( 'bguru_slogan_heading' ); $this->options = get_option( 'bguru_slogan_description' ); ?> <div class="wrap"> <?php screen_icon(); ?> <h1>Business Guru Options</h1> <form method="post" action="options.php"> <table class="form-table"> <?php // This prints out all hidden setting fields settings_fields( 'defaultbg' ); do_settings_sections( 'defaultbg' ); submit_button(); ?> </table> </form> </div> <?php } /** * Register and add settings */ public function bguru_register_settings() { register_setting('defaultbg','bguru_logo', array( $this, 'sanitize' ) ); register_setting('defaultbg', 'bguru_vimeo', array( $this, 'sanitize' )); register_setting('defaultbg', 'bguru_slide_one_image', array( $this, 'sanitize' )); register_setting('defaultbg', 'bguru_slide_one_heading', array( $this, 'sanitize' )); register_setting('defaultbg', 'bguru_slide_one_text', array( $this, 'sanitize' )); register_setting('defaultbg', 'bguru_slogan_heading', array( $this, 'sanitize' )); register_setting('defaultbg', 'bguru_slogan_description', array( $this, 'sanitize' )); add_settings_section( 'setting_section_id', // ID '<h2>General</h2>', array( $this, 'print_section_info' ), // Callback 'defaultbg' // Page ); add_settings_field( 'bguru_logo', // ID '<label for="bguru_logo">Logo</label>', // Title array($this,'logo_callback' ), // Callback 'defaultbg', // Page 'setting_section_id'// Section ); add_settings_field( 'bguru_vimeo', // ID 'Vimeo', // Vimeo array( $this, 'socialv_callback' ), // Callback 'defaultbg', // Page 'setting_section_id' // Section ); add_settings_field( 'bguru_slide_one_image', // ID 'Slide 1 Image', // Slide 1 Image array( $this, 'slider1img_callback' ), // Callback 'defaultbg', // Page 'setting_section_id' // Section ); add_settings_field( 'bguru_slide_one_heading', // ID 'Slide 1 Heading', // Slide 1 Heading array( $this, 'slider1head_callback' ), // Callback 'defaultbg', // Page 'setting_section_id' // Section ); add_settings_field( 'bguru_slide_one_text', // ID 'Slide 1 Description', // Slide 1 Description array( $this, 'slider1text_callback' ), // Callback 'defaultbg', // Page 'setting_section_id' // Section ); add_settings_field( 'bguru_slogan_heading', // ID 'Slogan Heading', // Slogan Heading array( $this, 'slogan_head_callback' ), // Callback 'defaultbg', // Page 'setting_section_id' // Section ); add_settings_field( 'bguru_slogan_description', // ID 'Slogan Container', // Slogan Container array( $this, 'slogan_descr_callback' ), // Callback 'defaultbg', // Page 'setting_section_id' // Section ); } public function sanitize( $input ) { $new_input = array(); if( isset( $input['bguru_logo'] ) ) $new_input['bguru_logo'] = sanitize_text_field( $input['bguru_logo'] ); if( isset( $input['bguru_vimeo'] ) ) $new_input['bguru_vimeo'] = sanitize_text_field( $input['bguru_vimeo'] ); if( isset( $input['bguru_slide_one_image'] ) ) $new_input['bguru_slide_one_image'] = sanitize_text_field( $input['bguru_slide_one_image'] ); if( isset( $input['bguru_slide_one_heading'] ) ) $new_input['bguru_slide_one_heading'] = sanitize_text_field( $input['bguru_slide_one_heading'] ); if( isset( $input['bguru_slide_one_text'] ) ) $new_input['bguru_slide_one_text'] = sanitize_text_field( $input['bguru_slide_one_text'] ); if( isset( $input['bguru_slogan_heading'] ) ) $new_input['bguru_slogan_heading'] = sanitize_text_field( $input['bguru_slogan_heading'] ); if( isset( $input['bguru_slogan_description'] ) ) $new_input['bguru_slogan_description'] = sanitize_text_field( $input['bguru_slogan_description'] ); return $new_input; } public function print_section_info() { print 'Enter your settings below:'; } public function logo_callback() { printf( '<input type="text" id="bguru_logo" size="50" name="bguru_logo" value="%s" />', isset( $this->options['bguru_logo'] ) ? esc_attr( $this->options['bguru_logo']) : '' ); } public function socialv_callback() { printf( '<input type="text" id="bguru_vimeo" size="50" name="bguru_vimeo" value="%s" />', isset( $this->options['bguru_vimeo'] ) ? esc_attr( $this->options['bguru_vimeo']) : '' ); } public function slider1img_callback() { printf( '<input type="text" id="bguru_slide_one_image" size="50" name="bguru_slide_one_image" value="%s" />', isset( $this->options['bguru_slide_one_image'] ) ? esc_attr( $this->options['bguru_slide_one_image']) : '' ); } public function slider1head_callback() { printf( '<input type="text" id="bguru_slide_one_heading" size="50" name="bguru_slide_one_heading" value="%s" />', isset( $this->options['bguru_slide_one_heading'] ) ? esc_attr( $this->options['bguru_slide_one_heading']) : '' ); } public function slider1text_callback() { printf( '<input type="text" id="bguru_slide_one_text" size="50" name="bguru_slide_one_text" value="%s" />', isset( $this->options['bguru_slide_one_text'] ) ? esc_attr( $this->options['bguru_slide_one_text']) : '' ); } public function slogan_head_callback() { printf( '<input type="text" id="bguru_slogan_heading" size="50" name="bguru_slogan_heading" value="%s" />', isset( $this->options['bguru_slogan_heading'] ) ? esc_attr( $this->options['bguru_slogan_heading']) : '' ); } public function slogan_descr_callback() { printf( '<input type="text" id="bguru_slogan_description" size="50" name="bguru_slogan_description" value="%s" />', isset( $this->options['bguru_slogan_description'] ) ? esc_attr( $this->options['bguru_slogan_description']) : '' ); } } if( is_admin() ) $my_settings_page = new MySettingsPage(); here its my header.php code where i display all the information of option form $bguru_logo_image = get_option('bguru_logo'); if (!empty($bguru_logo_image)) { echo '<div id="logo"><a href="' . home_url() . '"><img src="' . $bguru_logo_image . '" width="218" alt="logo" /></a></div><!--/ #logo-->'; } else { echo '<div id="logo"><a href="' . home_url() . '"><h1>'. get_bloginfo('name') . '</h1></a></div><!--/ #logo-->'; }?> $bguru_social_vimeo = get_option('bguru_vimeo'); if (!empty($bguru_social_vimeo)) { echo '<li class="vimeo"><a target="_blank" href="'.$bguru_social_vimeo.'">Vimeo</a></li>'; }?> same as for slider image, slider heading, slider description please suggest some solutions

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