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• Setting up and using Bing Translate API Service for Machine Translation

  - by Rick Strahl

  Last week I spent quite a bit of time trying to set up the Bing Translate API service. I can honestly say this was one of the most screwed up developer experiences I've had in a long while - specifically related to the byzantine sign up process that Microsoft has in place. Not only is it nearly impossible to find decent documentation on the required signup process, some of the links in the docs are just plain wrong, and some of the account pages you need to access the actual account information once signed up are not linked anywhere from the administration UI. To make things even harder is the fact that the APIs changed a while back, with a completely new authentication scheme that's described and not directly linked documentation topic also made for a very frustrating search experience. It's a bummer that this is the case too, because the actual API itself is easy to use and works very well - fast and reasonably accurate (as accurate as you can expect machine translation to be). But the sign up process is a pain in the ass doubtlessly leaving many people giving up in frustration. In this post I'll try to hit all the points needed to set up to use the Bing Translate API in one place since such a document seems to be missing from Microsoft. Hopefully the API folks at Microsoft will get their shit together and actually provide this sort of info on their site… Signing Up The first step required is to create a Windows Azure MarketPlace account. Go to: https://datamarket.azure.com/ Sign in with your Windows Live Id If you don't have an account you will be taken to a registration page which you have to fill out. Follow the links and complete the registration. Once you're signed in you can start adding services. Click on the Data Link on the main page Select Microsoft Translator from the list This adds the Microsoft Bing Translator to your services. Pricing The page shows the pricing matrix and the free service which provides 2 megabytes for translations a month for free. Prices go up steeply from there. Pricing is determined by actual bytes of the result translations used. Max translations are 1000 characters so at minimum this means you get around 2000 translations a month for free. However most translations are probable much less so you can expect larger number of translations to go through. For testing or low volume translations this should be just fine. Once signed up there are no further instructions and you're left in limbo on the MS site. Register your Application Once you've created the Data association with Translator the next step is registering your application. To do this you need to access your developer account. Go to https://datamarket.azure.com/developer/applications/register Provide a ClientId, which is effectively the unique string identifier for your application (not your customer id!) Provide your name The client secret was auto-created and this becomes your 'password' For the redirect url provide any https url: https://microsoft.com works Give this application a description of your choice so you can identify it in the list of apps Now, once you've registered your application, keep track of the ClientId and ClientSecret - those are the two keys you need to authenticate before you can call the Translate API. Oddly the applications page is hidden from the Azure Portal UI. I couldn't find a direct link from anywhere on the site back to this page where I can examine my developer application keys. To find them you can go to: https://datamarket.azure.com/developer/applications You can come back here to look at your registered applications and pick up the ClientID and ClientSecret. Fun eh? But we're now ready to actually call the API and do some translating. Using the Bing Translate API The good news is that after this signup hell, using the API is pretty straightforward. To use the translation API you'll need to actually use two services: You need to call an authentication API service first, before you can call the actual translator API. These two APIs live on different domains, and the authentication API returns JSON data while the translator service returns XML. So much for consistency. Authentication The first step is authentication. The service uses oAuth authentication with a  bearer token that has to be passed to the translator API. The authentication call retrieves the oAuth token that you can then use with the translate API call. The bearer token has a short 10 minute life time, so while you can cache it for successive calls, the token can't be cached for long periods. This means for Web backend requests you typically will have to authenticate each time unless you build a more elaborate caching scheme that takes the timeout into account (perhaps using the ASP.NET Cache object). For low volume operations you can probably get away with simply calling the auth API for every translation you do. To call the Authentication API use code like this:/// /// Retrieves an oAuth authentication token to be used on the translate /// API request. The result string needs to be passed as a bearer token /// to the translate API. /// /// You can find client ID and Secret (or register a new one) at: /// https://datamarket.azure.com/developer/applications/ /// /// The client ID of your application /// The client secret or password /// public string GetBingAuthToken(string clientId = null, string clientSecret = null) { string authBaseUrl = https://datamarket.accesscontrol.windows.net/v2/OAuth2-13; if (string.IsNullOrEmpty(clientId) || string.IsNullOrEmpty(clientSecret)) { ErrorMessage = Resources.Resources.Client_Id_and_Client_Secret_must_be_provided; return null; } var postData = string.Format("grant_type=client_credentials&client_id={0}" + "&client_secret={1}" + "&scope=http://api.microsofttranslator.com", HttpUtility.UrlEncode(clientId), HttpUtility.UrlEncode(clientSecret)); // POST Auth data to the oauth API string res, token; try { var web = new WebClient(); web.Encoding = Encoding.UTF8; res = web.UploadString(authBaseUrl, postData); } catch (Exception ex) { ErrorMessage = ex.GetBaseException().Message; return null; } var ser = new JavaScriptSerializer(); var auth = ser.Deserialize<BingAuth>(res); if (auth == null) return null; token = auth.access_token; return token; } private class BingAuth { public string token_type { get; set; } public string access_token { get; set; } } This code basically takes the client id and secret and posts it at the oAuth endpoint which returns a JSON string. Here I use the JavaScript serializer to deserialize the JSON into a custom object I created just for deserialization. You can also use JSON.NET and dynamic deserialization if you are already using JSON.NET in your app in which case you don't need the extra type. In my library that houses this component I don't, so I just rely on the built in serializer. The auth method returns a long base64 encoded string which can be used as a bearer token in the translate API call. Translation Once you have the authentication token you can use it to pass to the translate API. The auth token is passed as an Authorization header and the value is prefixed with a 'Bearer ' prefix for the string. Here's what the simple Translate API call looks like:/// /// Uses the Bing API service to perform translation /// Bing can translate up to 1000 characters. /// /// Requires that you provide a CLientId and ClientSecret /// or set the configuration values for these two. /// /// More info on setup: /// http://www.west-wind.com/weblog/ /// /// Text to translate /// Two letter culture name /// Two letter culture name /// Pass an access token retrieved with GetBingAuthToken. /// If not passed the default keys from .config file are used if any /// public string TranslateBing(string text, string fromCulture, string toCulture, string accessToken = null) { string serviceUrl = "http://api.microsofttranslator.com/V2/Http.svc/Translate"; if (accessToken == null) { accessToken = GetBingAuthToken(); if (accessToken == null) return null; } string res; try { var web = new WebClient(); web.Headers.Add("Authorization", "Bearer " + accessToken); string ct = "text/plain"; string postData = string.Format("?text={0}&from={1}&to={2}&contentType={3}", HttpUtility.UrlEncode(text), fromCulture, toCulture, HttpUtility.UrlEncode(ct)); web.Encoding = Encoding.UTF8; res = web.DownloadString(serviceUrl + postData); } catch (Exception e) { ErrorMessage = e.GetBaseException().Message; return null; } // result is a single XML Element fragment var doc = new XmlDocument(); doc.LoadXml(res); return doc.DocumentElement.InnerText; } The first of this code deals with ensuring the auth token exists. You can either pass the token into the method manually or let the method automatically retrieve the auth code on its own. In my case I'm using this inside of a Web application and in that situation I simply need to re-authenticate every time as there's no convenient way to manage the lifetime of the auth cookie. The auth token is added as an Authorization HTTP header prefixed with 'Bearer ' and attached to the request. The text to translate, the from and to language codes and a result format are passed on the query string of this HTTP GET request against the Translate API. The translate API returns an XML string which contains a single element with the translated string. Using the Wrapper Methods It should be pretty obvious how to use these two methods but here are a couple of test methods that demonstrate the two usage scenarios:[TestMethod] public void TranslateBingWithAuthTest() { var translate = new TranslationServices(); string clientId = DbResourceConfiguration.Current.BingClientId; string clientSecret = DbResourceConfiguration.Current.BingClientSecret; string auth = translate.GetBingAuthToken(clientId, clientSecret); Assert.IsNotNull(auth); string text = translate.TranslateBing("Hello World we're back home!", "en", "de",auth); Assert.IsNotNull(text, translate.ErrorMessage); Console.WriteLine(text); } [TestMethod] public void TranslateBingIntegratedTest() { var translate = new TranslationServices(); string text = translate.TranslateBing("Hello World we're back home!","en","de"); Assert.IsNotNull(text, translate.ErrorMessage); Console.WriteLine(text); } Other API Methods The Translate API has a number of methods available and this one is the simplest one but probably also the most common one that translates a single string. You can find additional methods for this API here: http://msdn.microsoft.com/en-us/library/ff512419.aspx Soap and AJAX APIs are also available and documented on MSDN: http://msdn.microsoft.com/en-us/library/dd576287.aspx These links will be your starting points for calling other methods in this API. Dual Interface I've talked about my database driven localization provider here in the past, and it's for this tool that I added the Bing localization support. Basically I have a localization administration form that allows me to translate individual strings right out of the UI, using both Google and Bing APIs: As you can see in this example, the results from Google and Bing can vary quite a bit - in this case Google is stumped while Bing actually generated a valid translation. At other times it's the other way around - it's pretty useful to see multiple translations at the same time. Here I can choose from one of the values and driectly embed them into the translated text field. Lost in Translation There you have it. As I mentioned using the API once you have all the bureaucratic crap out of the way calling the APIs is fairly straight forward and reasonably fast, even if you have to call the Auth API for every call. Hopefully this post will help out a few of you trying to navigate the Microsoft bureaucracy, at least until next time Microsoft upends everything and introduces new ways to sign up again. Until then - happy translating… Related Posts Translation method Source on Github Translating with Google Translate without Google API Keys Creating a data-driven ASP.NET Resource Provider© Rick Strahl, West Wind Technologies, 2005-2013Posted in Localization  ASP.NET  .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (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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• Inside the Concurrent Collections: ConcurrentDictionary

  - by Simon Cooper

  Using locks to implement a thread-safe collection is rather like using a sledgehammer - unsubtle, easy to understand, and tends to make any other tool redundant. Unlike the previous two collections I looked at, ConcurrentStack and ConcurrentQueue, ConcurrentDictionary uses locks quite heavily. However, it is careful to wield locks only where necessary to ensure that concurrency is maximised. This will, by necessity, be a higher-level look than my other posts in this series, as there is quite a lot of code and logic in ConcurrentDictionary. Therefore, I do recommend that you have ConcurrentDictionary open in a decompiler to have a look at all the details that I skip over. The problem with locks There's several things to bear in mind when using locks, as encapsulated by the lock keyword in C# and the System.Threading.Monitor class in .NET (if you're unsure as to what lock does in C#, I briefly covered it in my first post in the series): Locks block threads The most obvious problem is that threads waiting on a lock can't do any work at all. No preparatory work, no 'optimistic' work like in ConcurrentQueue and ConcurrentStack, nothing. It sits there, waiting to be unblocked. This is bad if you're trying to maximise concurrency. Locks are slow Whereas most of the methods on the Interlocked class can be compiled down to a single CPU instruction, ensuring atomicity at the hardware level, taking out a lock requires some heavy lifting by the CLR and the operating system. There's quite a bit of work required to take out a lock, block other threads, and wake them up again. If locks are used heavily, this impacts performance. Deadlocks When using locks there's always the possibility of a deadlock - two threads, each holding a lock, each trying to aquire the other's lock. Fortunately, this can be avoided with careful programming and structured lock-taking, as we'll see. So, it's important to minimise where locks are used to maximise the concurrency and performance of the collection. Implementation As you might expect, ConcurrentDictionary is similar in basic implementation to the non-concurrent Dictionary, which I studied in a previous post. I'll be using some concepts introduced there, so I recommend you have a quick read of it. So, if you were implementing a thread-safe dictionary, what would you do? The naive implementation is to simply have a single lock around all methods accessing the dictionary. This would work, but doesn't allow much concurrency. Fortunately, the bucketing used by Dictionary allows a simple but effective improvement to this - one lock per bucket. This allows different threads modifying different buckets to do so in parallel. Any thread making changes to the contents of a bucket takes the lock for that bucket, ensuring those changes are thread-safe. The method that maps each bucket to a lock is the GetBucketAndLockNo method: private void GetBucketAndLockNo( int hashcode, out int bucketNo, out int lockNo, int bucketCount) { // the bucket number is the hashcode (without the initial sign bit) // modulo the number of buckets bucketNo = (hashcode & 0x7fffffff) % bucketCount; // and the lock number is the bucket number modulo the number of locks lockNo = bucketNo % m_locks.Length; } However, this does require some changes to how the buckets are implemented. The 'implicit' linked list within a single backing array used by the non-concurrent Dictionary adds a dependency between separate buckets, as every bucket uses the same backing array. Instead, ConcurrentDictionary uses a strict linked list on each bucket: This ensures that each bucket is entirely separate from all other buckets; adding or removing an item from a bucket is independent to any changes to other buckets. Modifying the dictionary All the operations on the dictionary follow the same basic pattern: void AlterBucket(TKey key, ...) { int bucketNo, lockNo; 1: GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, m_buckets.Length); 2: lock (m_locks[lockNo]) { 3: Node headNode = m_buckets[bucketNo]; 4: Mutate the node linked list as appropriate } } For example, when adding another entry to the dictionary, you would iterate through the linked list to check whether the key exists already, and add the new entry as the head node. When removing items, you would find the entry to remove (if it exists), and remove the node from the linked list. Adding, updating, and removing items all follow this pattern. Performance issues There is a problem we have to address at this point. If the number of buckets in the dictionary is fixed in the constructor, then the performance will degrade from O(1) to O(n) when a large number of items are added to the dictionary. As more and more items get added to the linked lists in each bucket, the lookup operations will spend most of their time traversing a linear linked list. To fix this, the buckets array has to be resized once the number of items in each bucket has gone over a certain limit. (In ConcurrentDictionary this limit is when the size of the largest bucket is greater than the number of buckets for each lock. This check is done at the end of the TryAddInternal method.) Resizing the bucket array and re-hashing everything affects every bucket in the collection. Therefore, this operation needs to take out every lock in the collection. Taking out mutiple locks at once inevitably summons the spectre of the deadlock; two threads each hold a lock, and each trying to acquire the other lock. How can we eliminate this? Simple - ensure that threads never try to 'swap' locks in this fashion. When taking out multiple locks, always take them out in the same order, and always take out all the locks you need before starting to release them. In ConcurrentDictionary, this is controlled by the AcquireLocks, AcquireAllLocks and ReleaseLocks methods. Locks are always taken out and released in the order they are in the m_locks array, and locks are all released right at the end of the method in a finally block. At this point, it's worth pointing out that the locks array is never re-assigned, even when the buckets array is increased in size. The number of locks is fixed in the constructor by the concurrencyLevel parameter. This simplifies programming the locks; you don't have to check if the locks array has changed or been re-assigned before taking out a lock object. And you can be sure that when a thread takes out a lock, another thread isn't going to re-assign the lock array. This would create a new series of lock objects, thus allowing another thread to ignore the existing locks (and any threads controlling them), breaking thread-safety. Consequences of growing the array Just because we're using locks doesn't mean that race conditions aren't a problem. We can see this by looking at the GrowTable method. The operation of this method can be boiled down to: private void GrowTable(Node[] buckets) { try { 1: Acquire first lock in the locks array // this causes any other thread trying to take out // all the locks to block because the first lock in the array // is always the one taken out first // check if another thread has already resized the buckets array // while we were waiting to acquire the first lock 2: if (buckets != m_buckets) return; 3: Calculate the new size of the backing array 4: Node[] array = new array[size]; 5: Acquire all the remaining locks 6: Re-hash the contents of the existing buckets into array 7: m_buckets = array; } finally { 8: Release all locks } } As you can see, there's already a check for a race condition at step 2, for the case when the GrowTable method is called twice in quick succession on two separate threads. One will successfully resize the buckets array (blocking the second in the meantime), when the second thread is unblocked it'll see that the array has already been resized & exit without doing anything. There is another case we need to consider; looking back at the AlterBucket method above, consider the following situation: Thread 1 calls AlterBucket; step 1 is executed to get the bucket and lock numbers. Thread 2 calls GrowTable and executes steps 1-5; thread 1 is blocked when it tries to take out the lock in step 2. Thread 2 re-hashes everything, re-assigns the buckets array, and releases all the locks (steps 6-8). Thread 1 is unblocked and continues executing, but the calculated bucket and lock numbers are no longer valid. Between calculating the correct bucket and lock number and taking out the lock, another thread has changed where everything is. Not exactly thread-safe. Well, a similar problem was solved in ConcurrentStack and ConcurrentQueue by storing a local copy of the state, doing the necessary calculations, then checking if that state is still valid. We can use a similar idea here: void AlterBucket(TKey key, ...) { while (true) { Node[] buckets = m_buckets; int bucketNo, lockNo; GetBucketAndLockNo( key.GetHashCode(), out bucketNo, out lockNo, buckets.Length); lock (m_locks[lockNo]) { // if the state has changed, go back to the start if (buckets != m_buckets) continue; Node headNode = m_buckets[bucketNo]; Mutate the node linked list as appropriate } break; } } TryGetValue and GetEnumerator And so, finally, we get onto TryGetValue and GetEnumerator. I've left these to the end because, well, they don't actually use any locks. How can this be? Whenever you change a bucket, you need to take out the corresponding lock, yes? Indeed you do. However, it is important to note that TryGetValue and GetEnumerator don't actually change anything. Just as immutable objects are, by definition, thread-safe, read-only operations don't need to take out a lock because they don't change anything. All lockless methods can happily iterate through the buckets and linked lists without worrying about locking anything. However, this does put restrictions on how the other methods operate. Because there could be another thread in the middle of reading the dictionary at any time (even if a lock is taken out), the dictionary has to be in a valid state at all times. Every change to state has to be made visible to other threads in a single atomic operation (all relevant variables are marked volatile to help with this). This restriction ensures that whatever the reading threads are doing, they never read the dictionary in an invalid state (eg items that should be in the collection temporarily removed from the linked list, or reading a node that has had it's key & value removed before the node itself has been removed from the linked list). Fortunately, all the operations needed to change the dictionary can be done in that way. Bucket resizes are made visible when the new array is assigned back to the m_buckets variable. Any additions or modifications to a node are done by creating a new node, then splicing it into the existing list using a single variable assignment. Node removals are simply done by re-assigning the node's m_next pointer. Because the dictionary can be changed by another thread during execution of the lockless methods, the GetEnumerator method is liable to return dirty reads - changes made to the dictionary after GetEnumerator was called, but before the enumeration got to that point in the dictionary. It's worth listing at this point which methods are lockless, and which take out all the locks in the dictionary to ensure they get a consistent view of the dictionary: Lockless: TryGetValue GetEnumerator The indexer getter ContainsKey Takes out every lock (lockfull?): Count IsEmpty Keys Values CopyTo ToArray Concurrent principles That covers the overall implementation of ConcurrentDictionary. I haven't even begun to scratch the surface of this sophisticated collection. That I leave to you. However, we've looked at enough to be able to extract some useful principles for concurrent programming: Partitioning When using locks, the work is partitioned into independant chunks, each with its own lock. Each partition can then be modified concurrently to other partitions. Ordered lock-taking When a method does need to control the entire collection, locks are taken and released in a fixed order to prevent deadlocks. Lockless reads Read operations that don't care about dirty reads don't take out any lock; the rest of the collection is implemented so that any reading thread always has a consistent view of the collection. That leads us to the final collection in this little series - ConcurrentBag. Lacking a non-concurrent analogy, it is quite different to any other collection in the class libraries. Prepare your thinking hats!

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• Loosely coupled .NET Cache Provider using Dependency Injection

  - by Rhames

  I have recently been reading the excellent book “Dependency Injection in .NET”, written by Mark Seemann. I do not generally buy software development related books, as I never seem to have the time to read them, but I have found the time to read Mark’s book, and it was time well spent I think. Reading the ideas around Dependency Injection made me realise that the Cache Provider code I wrote about earlier (see http://geekswithblogs.net/Rhames/archive/2011/01/10/using-the-asp.net-cache-to-cache-data-in-a-model.aspx) could be refactored to use Dependency Injection, which should produce cleaner code. The goals are to: Separate the cache provider implementation (using the ASP.NET data cache) from the consumers (loose coupling). This will also mean that the dependency on System.Web for the cache provider does not ripple down into the layers where it is being consumed (such as the domain layer). Provide a decorator pattern to allow a consumer of the cache provider to be implemented separately from the base consumer (i.e. if we have a base repository, we can decorate this with a caching version). Although I used the term repository, in reality the cache consumer could be just about anything. Use constructor injection to provide the Dependency Injection, with a suitable DI container (I use Castle Windsor). The sample code for this post is available on github, https://github.com/RobinHames/CacheProvider.git ICacheProvider In the sample code, the key interface is ICacheProvider, which is in the domain layer. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace CacheDiSample.Domain 5: { 6: public interface ICacheProvider<T> 7: { 8: T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 9: IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 10: } 11: }   This interface contains two methods to retrieve data from the cache, either as a single instance or as an IEnumerable. the second paramerter is of type Func<T>. This is the method used to retrieve data if nothing is found in the cache. The ASP.NET implementation of the ICacheProvider interface needs to live in a project that has a reference to system.web, typically this will be the root UI project, or it could be a separate project. The key thing is that the domain or data access layers do not need system.web references adding to them. In my sample MVC application, the CacheProvider is implemented in the UI project, in a folder called “CacheProviders”: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Caching; 6: using CacheDiSample.Domain; 7:   8: namespace CacheDiSample.CacheProvider 9: { 10: public class CacheProvider<T> : ICacheProvider<T> 11: { 12: public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 13: { 14: return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); 15: } 16:   17: public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 18: { 19: return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); 20: } 21:   22: #region Helper Methods 23:   24: private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 25: { 26: U value; 27: if (!TryGetValue<U>(key, out value)) 28: { 29: value = retrieveData(); 30: if (!absoluteExpiry.HasValue) 31: absoluteExpiry = Cache.NoAbsoluteExpiration; 32:   33: if (!relativeExpiry.HasValue) 34: relativeExpiry = Cache.NoSlidingExpiration; 35:   36: HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); 37: } 38: return value; 39: } 40:   41: private bool TryGetValue<U>(string key, out U value) 42: { 43: object cachedValue = HttpContext.Current.Cache.Get(key); 44: if (cachedValue == null) 45: { 46: value = default(U); 47: return false; 48: } 49: else 50: { 51: try 52: { 53: value = (U)cachedValue; 54: return true; 55: } 56: catch 57: { 58: value = default(U); 59: return false; 60: } 61: } 62: } 63:   64: #endregion 65:   66: } 67: }   The FetchAndCache helper method checks if the specified cache key exists, if it does not, the Func<U> retrieveData method is called, and the results are added to the cache. Using Castle Windsor to register the cache provider In the MVC UI project (my application root), Castle Windsor is used to register the CacheProvider implementation, using a Windsor Installer: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain; 6: using CacheDiSample.CacheProvider; 7:   8: namespace CacheDiSample.WindsorInstallers 9: { 10: public class CacheInstaller : IWindsorInstaller 11: { 12: public void Install(IWindsorContainer container, IConfigurationStore store) 13: { 14: container.Register( 15: Component.For(typeof(ICacheProvider<>)) 16: .ImplementedBy(typeof(CacheProvider<>)) 17: .LifestyleTransient()); 18: } 19: } 20: }   Note that the cache provider is registered as a open generic type. Consuming a Repository I have an existing couple of repository interfaces defined in my domain layer: IRepository.cs 1: using System; 2: using System.Collections.Generic; 3:   4: using CacheDiSample.Domain.Model; 5:   6: namespace CacheDiSample.Domain.Repositories 7: { 8: public interface IRepository<T> 9: where T : EntityBase 10: { 11: T GetById(int id); 12: IList<T> GetAll(); 13: } 14: }   IBlogRepository.cs 1: using System; 2: using CacheDiSample.Domain.Model; 3:   4: namespace CacheDiSample.Domain.Repositories 5: { 6: public interface IBlogRepository : IRepository<Blog> 7: { 8: Blog GetByName(string name); 9: } 10: }   These two repositories are implemented in the DataAccess layer, using Entity Framework to retrieve data (this is not important though). One important point is that in the BaseRepository implementation of IRepository, the methods are virtual. This will allow the decorator to override them. The BlogRepository is registered in a RepositoriesInstaller, again in the MVC UI project. 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15: container.Register(Component.For<IBlogRepository>() 16: .ImplementedBy<BlogRepository>() 17: .LifestyleTransient() 18: .DependsOn(new 19: { 20: nameOrConnectionString = "BloggingContext" 21: })); 22: } 23: } 24: }   Now I can inject a dependency on the IBlogRepository into a consumer, such as a controller in my sample code: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:   7: using CacheDiSample.Domain.Repositories; 8: using CacheDiSample.Domain.Model; 9:   10: namespace CacheDiSample.Controllers 11: { 12: public class HomeController : Controller 13: { 14: private readonly IBlogRepository blogRepository; 15:   16: public HomeController(IBlogRepository blogRepository) 17: { 18: if (blogRepository == null) 19: throw new ArgumentNullException("blogRepository"); 20:   21: this.blogRepository = blogRepository; 22: } 23:   24: public ActionResult Index() 25: { 26: ViewBag.Message = "Welcome to ASP.NET MVC!"; 27:   28: var blogs = blogRepository.GetAll(); 29:   30: return View(new Models.HomeModel { Blogs = blogs }); 31: } 32:   33: public ActionResult About() 34: { 35: return View(); 36: } 37: } 38: }   Consuming the Cache Provider via a Decorator I used a Decorator pattern to consume the cache provider, this means my repositories follow the open/closed principle, as they do not require any modifications to implement the caching. It also means that my controllers do not have any knowledge of the caching taking place, as the DI container will simply inject the decorator instead of the root implementation of the repository. The first step is to implement a BlogRepository decorator, with the caching logic in it. Note that this can reside in the domain layer, as it does not require any knowledge of the data access methods. BlogRepositoryWithCaching.cs 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5:   6: using CacheDiSample.Domain.Model; 7: using CacheDiSample.Domain; 8: using CacheDiSample.Domain.Repositories; 9:   10: namespace CacheDiSample.Domain.CacheDecorators 11: { 12: public class BlogRepositoryWithCaching : IBlogRepository 13: { 14: // The generic cache provider, injected by DI 15: private ICacheProvider<Blog> cacheProvider; 16: // The decorated blog repository, injected by DI 17: private IBlogRepository parentBlogRepository; 18:   19: public BlogRepositoryWithCaching(IBlogRepository parentBlogRepository, ICacheProvider<Blog> cacheProvider) 20: { 21: if (parentBlogRepository == null) 22: throw new ArgumentNullException("parentBlogRepository"); 23:   24: this.parentBlogRepository = parentBlogRepository; 25:   26: if (cacheProvider == null) 27: throw new ArgumentNullException("cacheProvider"); 28:   29: this.cacheProvider = cacheProvider; 30: } 31:   32: public Blog GetByName(string name) 33: { 34: string key = string.Format("CacheDiSample.DataAccess.GetByName.{0}", name); 35: // hard code 5 minute expiry! 36: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 37: return cacheProvider.Fetch(key, () => 38: { 39: return parentBlogRepository.GetByName(name); 40: }, 41: null, relativeCacheExpiry); 42: } 43:   44: public Blog GetById(int id) 45: { 46: string key = string.Format("CacheDiSample.DataAccess.GetById.{0}", id); 47:   48: // hard code 5 minute expiry! 49: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 50: return cacheProvider.Fetch(key, () => 51: { 52: return parentBlogRepository.GetById(id); 53: }, 54: null, relativeCacheExpiry); 55: } 56:   57: public IList<Blog> GetAll() 58: { 59: string key = string.Format("CacheDiSample.DataAccess.GetAll"); 60:   61: // hard code 5 minute expiry! 62: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 63: return cacheProvider.Fetch(key, () => 64: { 65: return parentBlogRepository.GetAll(); 66: }, 67: null, relativeCacheExpiry) 68: .ToList(); 69: } 70: } 71: }   The key things in this caching repository are: I inject into the repository the ICacheProvider<Blog> implementation, via the constructor. This will make the cache provider functionality available to the repository. I inject the parent IBlogRepository implementation (which has the actual data access code), via the constructor. This will allow the methods implemented in the parent to be called if nothing is found in the cache. I override each of the methods implemented in the repository, including those implemented in the generic BaseRepository. Each override of these methods follows the same pattern. It makes a call to the CacheProvider.Fetch method, and passes in the parentBlogRepository implementation of the method as the retrieval method, to be used if nothing is present in the cache. Configuring the Caching Repository in the DI Container The final piece of the jigsaw is to tell Castle Windsor to use the BlogRepositoryWithCaching implementation of IBlogRepository, but to inject the actual Data Access implementation into this decorator. This is easily achieved by modifying the RepositoriesInstaller to use Windsor’s implicit decorator wiring: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15:   16: // Use Castle Windsor implicit wiring for the block repository decorator 17: // Register the outermost decorator first 18: container.Register(Component.For<IBlogRepository>() 19: .ImplementedBy<BlogRepositoryWithCaching>() 20: .LifestyleTransient()); 21: // Next register the IBlogRepository inmplementation to inject into the outer decorator 22: container.Register(Component.For<IBlogRepository>() 23: .ImplementedBy<BlogRepository>() 24: .LifestyleTransient() 25: .DependsOn(new 26: { 27: nameOrConnectionString = "BloggingContext" 28: })); 29: } 30: } 31: }   This is all that is needed. Now if the consumer of the repository makes a call to the repositories method, it will be routed via the caching mechanism. You can test this by stepping through the code, and seeing that the DataAccess.BlogRepository code is only called if there is no data in the cache, or this has expired. The next step is to add the SQL Cache Dependency support into this pattern, this will be a future post.

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• Get data from MySQL to Android application

  - by Mona

  I want to get data from MySQL database using PHP and display it in Android activity. I code it and pass JSON Array but there is a problem i dont know how to connect to server and my all database is on local server. I code it Kindly tell me where i go wrong so I can get exact results. I'll be very thankful to you. My PHP code is: <?php $response = array(); require_once __DIR__ . '/db_connect.php'; $db = new DB_CONNECT(); if (isset($_GET["cid"])) { $cid = $_GET['cid']; // get a product from products table $result = mysql_query("SELECT *FROM my_task WHERE cid = $cid"); if (!empty($result)) { // check for empty result if (mysql_num_rows($result) > 0) { $result = mysql_fetch_array($result); $task = array(); $task["cid"] = $result["cid"]; $task["cus_name"] = $result["cus_name"]; $task["contact_number"] = $result["contact_number"]; $task["ticket_no"] = $result["ticket_no"]; $task["task_detail"] = $result["task_detail"]; // success $response["success"] = 1; // user node $response["task"] = array(); array_push($response["my_task"], $task); // echoing JSON response echo json_encode($response); } else { // no task found $response["success"] = 0; $response["message"] = "No product found"; // echo no users JSON echo json_encode($response); } } else { // no task found $response["success"] = 0; $response["message"] = "No product found"; echo json_encode($response); } } else { $response["success"] = 0; $response["message"] = "Required field(s) is missing"; // echoing JSON response echo json_encode($response);} ?> My Android code is: public class My_Task extends Activity { TextView cus_name_txt, contact_no_txt, ticket_no_txt, task_detail_txt; EditText attend_by_txtbx, cus_name_txtbx, contact_no_txtbx, ticket_no_txtbx, task_detail_txtbx; Button btnSave; Button btnDelete; String cid; // Progress Dialog private ProgressDialog tDialog; // Creating JSON Parser object JSONParser jParser = new JSONParser(); ArrayList<HashMap<String, String>> my_taskList; // single task url private static final String url_read_mytask = "http://198.168.0.29/mobile/read_My_Task.php"; // url to update product private static final String url_update_mytask = "http://198.168.0.29/mobile/update_mytask.php"; // url to delete product private static final String url_delete_mytask = "http://198.168.0.29/mobile/delete_mytask.php"; // JSON Node names private static String TAG_SUCCESS = "success"; private static String TAG_MYTASK = "my_task"; private static String TAG_CID = "cid"; private static String TAG_NAME = "cus_name"; private static String TAG_CONTACT = "contact_number"; private static String TAG_TICKET = "ticket_no"; private static String TAG_TASKDETAIL = "task_detail"; private static String attend_by_txt; // task JSONArray JSONArray my_task = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.my_task); cus_name_txt = (TextView) findViewById(R.id.cus_name_txt); contact_no_txt = (TextView)findViewById(R.id.contact_no_txt); ticket_no_txt = (TextView)findViewById(R.id.ticket_no_txt); task_detail_txt = (TextView)findViewById(R.id.task_detail_txt); attend_by_txtbx = (EditText)findViewById(R.id.attend_by_txt); attend_by_txtbx.setText(My_Task.attend_by_txt); Spinner severity = (Spinner) findViewById(R.id.severity_spinner); // Create an ArrayAdapter using the string array and a default spinner layout ArrayAdapter<CharSequence> adapter3 = ArrayAdapter.createFromResource(this, R.array.Severity_array, android.R.layout.simple_dropdown_item_1line); // Specify the layout to use when the list of choices appears adapter3.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); // Apply the adapter to the spinner severity.setAdapter(adapter3); // save button btnSave = (Button) findViewById(R.id.btnSave); btnDelete = (Button) findViewById(R.id.btnDelete); // getting product details from intent Intent i = getIntent(); // getting product id (pid) from intent cid = i.getStringExtra(TAG_CID); // Getting complete product details in background thread new GetProductDetails().execute(); // save button click event btnSave.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { // starting background task to update product new SaveProductDetails().execute(); } }); // Delete button click event btnDelete.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { // deleting product in background thread new DeleteProduct().execute(); } }); } /** * Background Async Task to Get complete product details * */ class GetProductDetails extends AsyncTask<String, String, String> { /** * Before starting background thread Show Progress Dialog * */ @Override protected void onPreExecute() { super.onPreExecute(); tDialog = new ProgressDialog(My_Task.this); tDialog.setMessage("Loading task details. Please wait..."); tDialog.setIndeterminate(false); tDialog.setCancelable(true); tDialog.show(); } /** * Getting product details in background thread * */ protected String doInBackground(String... params) { // updating UI from Background Thread runOnUiThread(new Runnable() { public void run() { // Check for success tag int success; try { // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("cid", cid)); // getting product details by making HTTP request // Note that product details url will use GET request JSONObject json = JSONParser.makeHttpRequest( url_read_mytask, "GET", params); // check your log for json response Log.d("Single Task Details", json.toString()); // json success tag success = json.getInt(TAG_SUCCESS); if (success == 1) { // successfully received product details JSONArray my_taskObj = json .getJSONArray(TAG_MYTASK); // JSON Array // get first product object from JSON Array JSONObject my_task = my_taskObj.getJSONObject(0); // task with this cid found // Edit Text // display task data in EditText cus_name_txtbx = (EditText) findViewById(R.id.cus_name_txt); cus_name_txtbx.setText(my_task.getString(TAG_NAME)); contact_no_txtbx = (EditText) findViewById(R.id.contact_no_txt); contact_no_txtbx.setText(my_task.getString(TAG_CONTACT)); ticket_no_txtbx = (EditText) findViewById(R.id.ticket_no_txt); ticket_no_txtbx.setText(my_task.getString(TAG_TICKET)); task_detail_txtbx = (EditText) findViewById(R.id.task_detail_txt); task_detail_txtbx.setText(my_task.getString(TAG_TASKDETAIL)); } else { // task with cid not found } } catch (JSONException e) { e.printStackTrace(); } } }); return null; } /** * After completing background task Dismiss the progress dialog * **/ protected void onPostExecute(String file_url) { // dismiss the dialog once got all details tDialog.dismiss(); } } /** * Background Async Task to Save product Details * */ class SaveProductDetails extends AsyncTask<String, String, String> { /** * Before starting background thread Show Progress Dialog * */ @Override protected void onPreExecute() { super.onPreExecute(); tDialog = new ProgressDialog(My_Task.this); tDialog.setMessage("Saving task ..."); tDialog.setIndeterminate(false); tDialog.setCancelable(true); tDialog.show(); } /** * Saving product * */ protected String doInBackground(String... args) { // getting updated data from EditTexts String cus_name = cus_name_txt.getText().toString(); String contact_no = contact_no_txt.getText().toString(); String ticket_no = ticket_no_txt.getText().toString(); String task_detail = task_detail_txt.getText().toString(); // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair(TAG_CID, cid)); params.add(new BasicNameValuePair(TAG_NAME, cus_name)); params.add(new BasicNameValuePair(TAG_CONTACT, contact_no)); params.add(new BasicNameValuePair(TAG_TICKET, ticket_no)); params.add(new BasicNameValuePair(TAG_TASKDETAIL, task_detail)); // sending modified data through http request // Notice that update product url accepts POST method JSONObject json = JSONParser.makeHttpRequest(url_update_mytask, "POST", params); // check json success tag try { int success = json.getInt(TAG_SUCCESS); if (success == 1) { // successfully updated Intent i = getIntent(); // send result code 100 to notify about product update setResult(100, i); finish(); } else { // failed to update product } } catch (JSONException e) { e.printStackTrace(); } return null; } /** * After completing background task Dismiss the progress dialog * **/ protected void onPostExecute(String file_url) { // dismiss the dialog once product uupdated tDialog.dismiss(); } } /***************************************************************** * Background Async Task to Delete Product * */ class DeleteProduct extends AsyncTask<String, String, String> { /** * Before starting background thread Show Progress Dialog * */ @Override protected void onPreExecute() { super.onPreExecute(); tDialog = new ProgressDialog(My_Task.this); tDialog.setMessage("Deleting Product..."); tDialog.setIndeterminate(false); tDialog.setCancelable(true); tDialog.show(); } /** * Deleting product * */ protected String doInBackground(String... args) { // Check for success tag int success; try { // Building Parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("cid", cid)); // getting product details by making HTTP request JSONObject json = JSONParser.makeHttpRequest( url_delete_mytask, "POST", params); // check your log for json response Log.d("Delete Task", json.toString()); // json success tag success = json.getInt(TAG_SUCCESS); if (success == 1) { // product successfully deleted // notify previous activity by sending code 100 Intent i = getIntent(); // send result code 100 to notify about product deletion setResult(100, i); finish(); } } catch (JSONException e) { e.printStackTrace(); } return null; } /** * After completing background task Dismiss the progress dialog * **/ protected void onPostExecute(String file_url) { // dismiss the dialog once product deleted tDialog.dismiss(); } } public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) { // An item was selected. You can retrieve the selected item using // parent.getItemAtPosition(pos) } public void onNothingSelected(AdapterView<?> parent) { // Another interface callback } } My JSONParser code is: public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } // function get json from url // by making HTTP POST or GET mehtod public static JSONObject makeHttpRequest(String url, String method, List<NameValuePair> params) { // Making HTTP request try { // check for request method if(method == "POST"){ // request method is POST // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); }else if(method == "GET"){ // request method is GET DefaultHttpClient httpClient = new DefaultHttpClient(); String paramString = URLEncodedUtils.format(params, "utf-8"); url += "?" + paramString; HttpGet httpGet = new HttpGet(url); HttpResponse httpResponse = httpClient.execute(httpGet); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; my all database is in localhost and it is not opening an activity. displays an error "Stopped unexpectedly":( How can i get exact results. Kindly guide me

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• LiteSpeed enable Access-Control-Allow-Origin (no response header on CORS request)

  - by Joe Coder Guy

  Seriously, I can't find a single page discussing this for litespeed. Using this format in the htaccess "Header set Access-Control-Allow-Origin http://aSite.com" (and https) sends the setting in the http response header, but I still get the "XMLHttpRequest cannot load https://aSite.com/aFile.php. Origin aSite.com is not allowed by Access-Control-Allow-Origin" error when trying to access https from http origin. Also, I receive no response header for https, only that message shows up in Chrome. Is the server still blocking it even though I've sent the proper headers? I read elsewhere that it helps to add these terms Access-Control-Allow-Headers X-Requested-With Access-Control-Allow-Methods OPTIONS, GET, POST Access-Control-Allow-Headers Content-Type, Depth, User-Agent, X-File-Size, X-Requested-With, If-Modified-Since, X-File-Name, Cache-Control but I don't see these in my headers. Using these, my PHP files aren't even reached (because they register no errors or anything), so it looks like it comes from the server only, but what do I know. Thanks in advance! Update Since no response header, Prashant seems to suggest it's a server issue in his error since it worked on another server. http://stackoverflow.com/questions/11953132/no-response-obtained-while-implementing-cors Anyone know how to flip this switch? Headers work now Bad litespeed format. Should look like this. Still being denied though. Header set Access-Control-Allow-Headers X-Requested-With Header set Access-Control-Allow-Methods OPTIONS Header set Access-Control-Allow-Methods GET Header set Access-Control-Allow-Methods POST Header set Access-Control-Allow-Headers Content-Type Header set Access-Control-Allow-Headers Depth Header set Access-Control-Allow-Headers User-Agent Header set Access-Control-Allow-Headers X-File-Size Header set Access-Control-Allow-Headers X-Requested-With Header set Access-Control-Allow-Headers If-Modified-Since Header set Access-Control-Allow-Headers X-File-Name Header set Access-Control-Allow-Headers Cache-Control

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• postfix: Temporary lookup failure

  - by mk_89

  I have followed the tutorials step by step for installing and configuring postfix https://help.ubuntu.com/community/Postfix https://help.ubuntu.com/community/PostfixBasicSetupHowto I am trying to test the services to whether Temporary lookup failure error telnet localhost 25 250 2.1.0 Ok rcpt to: fmaster@localhost 451 4.3.0 <fmaster@localhost>: Temporary lookup failure rcpt to: info@localhost 451 4.3.0 <info@localhost>: Temporary lookup failure I have tried searching the web but I have found no solutions, why am I getting this problem? mail.log Sep 24 01:03:05 bookcdb postfix/smtpd[21055]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <info@localhost>: Temporary lookup failure; from=<root@localhost> to=<info@localhost> proto=ESMTP helo=<localhost> Sep 24 01:03:19 bookcdb postfix/smtpd[21055]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <root@localhost>: Temporary lookup failure; from=<root@localhost> to=<root@localhost> proto=ESMTP helo=<localhost> Sep 24 01:08:19 bookcdb postfix/smtpd[21055]: timeout after RCPT from unknown[::1] Sep 24 01:08:19 bookcdb postfix/smtpd[21055]: disconnect from unknown[::1] Sep 24 01:10:49 bookcdb postfix/anvil[21059]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:00:49 Sep 24 01:10:49 bookcdb postfix/anvil[21059]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:00:49 Sep 24 01:10:49 bookcdb postfix/anvil[21059]: statistics: max cache size 1 at Sep 24 01:00:49 Sep 24 01:15:36 bookcdb postfix/smtpd[22175]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory Sep 24 01:15:36 bookcdb postfix/smtpd[22175]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:15:36 bookcdb postfix/smtpd[22175]: connect from unknown[::1] Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: error: open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "root@localhost" Sep 24 01:15:55 bookcdb postfix/trivial-rewrite[22195]: warning: transport_maps lookup failure Sep 24 01:15:59 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:15:59 bookcdb postfix/trivial-rewrite[22195]: warning: hash:/etc/postfix/transport lookup error for "fmaster@localhost" Sep 24 01:15:59 bookcdb postfix/trivial-rewrite[22195]: warning: transport_maps lookup failure Sep 24 01:15:59 bookcdb postfix/smtpd[22175]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<root@localhost> to=<fmaster@localhost> proto=ESMTP helo=<localhost> Sep 24 01:16:30 postfix/smtpd[22175]: last message repeated 5 times Sep 24 01:16:30 bookcdb postfix/smtpd[22175]: disconnect from unknown[::1] Sep 24 01:19:50 bookcdb postfix/anvil[22177]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:15:36 Sep 24 01:19:50 bookcdb postfix/anvil[22177]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:15:36 Sep 24 01:19:50 bookcdb postfix/anvil[22177]: statistics: max cache size 1 at Sep 24 01:15:36 Sep 24 01:20:32 bookcdb postfix/qmgr[21039]: D0C596E0B34: from=<[email protected]>, size=442, nrcpt=1 (queue active) Sep 24 01:20:32 bookcdb postfix/qmgr[21039]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 01:20:32 bookcdb postfix/error[22402]: D0C596E0B34: to=<[email protected]>, relay=none, delay=5369, delays=5369/0.01/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 01:24:16 bookcdb postfix/smtpd[22573]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory Sep 24 01:24:16 bookcdb postfix/smtpd[22573]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:24:16 bookcdb postfix/smtpd[22573]: connect from unknown[::1] Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: error: open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "root@localhost" Sep 24 01:24:43 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:25:14 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:25:14 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "[email protected]" Sep 24 01:25:14 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:25:14 bookcdb postfix/smtpd[22573]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <[email protected]>: Temporary lookup failure; from=<root@localhost> to=<[email protected]> proto=ESMTP helo=<localhost> Sep 24 01:25:32 bookcdb postfix/qmgr[21039]: 2E5C36E0A07: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 01:25:32 bookcdb postfix/qmgr[21039]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 01:25:32 bookcdb postfix/qmgr[21039]: 0EA3A6E0ACC: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 01:25:32 bookcdb postfix/error[22631]: 2E5C36E0A07: to=<[email protected]>, orig_to=<root>, relay=none, delay=30203, delays=30203/0.01/0/0.1, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 01:25:32 bookcdb postfix/error[22632]: 0EA3A6E0ACC: to=<[email protected]>, orig_to=<root>, relay=none, delay=30115, delays=30115/0.01/0/0.11, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 01:25:58 bookcdb postfix/smtpd[22573]: warning: non-SMTP command from unknown[::1]: subject: fdf Sep 24 01:25:58 bookcdb postfix/smtpd[22573]: disconnect from unknown[::1] Sep 24 01:26:01 bookcdb postfix/smtpd[22573]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:26:01 bookcdb postfix/smtpd[22573]: connect from unknown[::1] Sep 24 01:26:10 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:26:10 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "root@locahost" Sep 24 01:26:10 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:26:37 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:26:37 bookcdb postfix/trivial-rewrite[22594]: warning: hash:/etc/postfix/transport lookup error for "fmaster@localhost" Sep 24 01:26:37 bookcdb postfix/trivial-rewrite[22594]: warning: transport_maps lookup failure Sep 24 01:26:37 bookcdb postfix/smtpd[22573]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<root@locahost> to=<fmaster@localhost> proto=SMTP Sep 24 01:26:45 bookcdb postfix/smtpd[22573]: disconnect from unknown[::1] Sep 24 01:30:05 bookcdb postfix/anvil[22575]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:24:16 Sep 24 01:30:05 bookcdb postfix/anvil[22575]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:24:16 Sep 24 01:30:05 bookcdb postfix/anvil[22575]: statistics: max cache size 1 at Sep 24 01:24:16 Sep 24 01:34:57 bookcdb dovecot: master: Dovecot v2.0.19 starting up (core dumps disabled) Sep 24 01:35:02 bookcdb amavis[1009]: starting. /usr/sbin/amavisd-new at mail.bookcdb.com amavisd-new-2.6.5 (20110407), Unicode aware Sep 24 01:35:02 bookcdb amavis[1009]: Perl version 5.014002 Sep 24 01:35:05 bookcdb amavis[1155]: Net::Server: Group Not Defined. Defaulting to EGID '114 114' Sep 24 01:35:05 bookcdb amavis[1155]: Net::Server: User Not Defined. Defaulting to EUID '108' Sep 24 01:35:05 bookcdb amavis[1155]: Module Amavis::Conf 2.208 Sep 24 01:35:05 bookcdb amavis[1155]: Module Archive::Zip 1.30 Sep 24 01:35:05 bookcdb amavis[1155]: Module BerkeleyDB 0.49 Sep 24 01:35:05 bookcdb amavis[1155]: Module Compress::Zlib 2.033 Sep 24 01:35:05 bookcdb amavis[1155]: Module Convert::TNEF 0.17 Sep 24 01:35:05 bookcdb amavis[1155]: Module Convert::UUlib 1.4 Sep 24 01:35:05 bookcdb amavis[1155]: Module Crypt::OpenSSL::RSA 0.27 Sep 24 01:35:05 bookcdb amavis[1155]: Module DB_File 1.821 Sep 24 01:35:05 bookcdb amavis[1155]: Module Digest::MD5 2.51 Sep 24 01:35:05 bookcdb amavis[1155]: Module Digest::SHA 5.61 Sep 24 01:35:05 bookcdb amavis[1155]: Module IO::Socket::INET6 2.69 Sep 24 01:35:05 bookcdb amavis[1155]: Module MIME::Entity 5.502 Sep 24 01:35:05 bookcdb amavis[1155]: Module MIME::Parser 5.502 Sep 24 01:35:05 bookcdb amavis[1155]: Module MIME::Tools 5.502 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::DKIM::Signer 0.39 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::DKIM::Verifier 0.39 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::Header 2.08 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::Internet 2.08 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::SPF v2.008 Sep 24 01:35:05 bookcdb amavis[1155]: Module Mail::SpamAssassin 3.003002 Sep 24 01:35:05 bookcdb amavis[1155]: Module Net::DNS 0.66 Sep 24 01:35:05 bookcdb amavis[1155]: Module Net::Server 0.99 Sep 24 01:35:05 bookcdb amavis[1155]: Module NetAddr::IP 4.058 Sep 24 01:35:05 bookcdb amavis[1155]: Module Socket6 0.23 Sep 24 01:35:05 bookcdb amavis[1155]: Module Time::HiRes 1.972101 Sep 24 01:35:05 bookcdb amavis[1155]: Module URI 1.59 Sep 24 01:35:05 bookcdb amavis[1155]: Module Unix::Syslog 1.1 Sep 24 01:35:05 bookcdb amavis[1155]: Amavis::DB code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Amavis::Cache code loaded Sep 24 01:35:05 bookcdb amavis[1155]: SQL base code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: SQL::Log code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: SQL::Quarantine NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Lookup::SQL code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Lookup::LDAP code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: AM.PDP-in proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: SMTP-in proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Courier proto code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: SMTP-out proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Pipe-out proto code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: BSMTP-out proto code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Local-out proto code loaded Sep 24 01:35:05 bookcdb amavis[1155]: OS_Fingerprint code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-VIRUS code loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM code loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM-EXT code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM-C code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: ANTI-SPAM-SA code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Unpackers code loaded Sep 24 01:35:05 bookcdb amavis[1155]: DKIM code loaded Sep 24 01:35:05 bookcdb amavis[1155]: Tools code NOT loaded Sep 24 01:35:05 bookcdb amavis[1155]: Found $file at /usr/bin/file Sep 24 01:35:05 bookcdb amavis[1155]: No $altermime, not using it Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .mail Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .F Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .Z at /bin/uncompress Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .gz Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .bz2 at /bin/bzip2 -d Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .lzo tried: lzop -d Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .rpm tried: rpm2cpio.pl, rpm2cpio Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .cpio at /bin/pax Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .tar at /bin/pax Sep 24 01:35:05 bookcdb amavis[1155]: Found decoder for .deb at /usr/bin/ar Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .zip Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .7z tried: 7zr, 7za, 7z Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .rar tried: unrar-free Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .arj tried: arj, unarj Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .arc tried: nomarch, arc Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .zoo tried: zoo Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .lha Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .doc tried: ripole Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .cab tried: cabextract Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .tnef Sep 24 01:35:05 bookcdb amavis[1155]: Internal decoder for .tnef Sep 24 01:35:05 bookcdb amavis[1155]: No decoder for .exe tried: unrar-free; arj, unarj Sep 24 01:35:05 bookcdb amavis[1155]: Using primary internal av scanner code for ClamAV-clamd Sep 24 01:35:05 bookcdb amavis[1155]: Found secondary av scanner ClamAV-clamscan at /usr/bin/clamscan Sep 24 01:35:05 bookcdb amavis[1155]: Creating db in /var/lib/amavis/db/; BerkeleyDB 0.49, libdb 5.1 Sep 24 01:35:05 bookcdb postgrey[1219]: Process Backgrounded Sep 24 01:35:05 bookcdb postgrey[1219]: 2012/09/24-01:35:05 postgrey (type Net::Server::Multiplex) starting! pid(1219) Sep 24 01:35:05 bookcdb postgrey[1219]: Using default listen value of 128 Sep 24 01:35:05 bookcdb postgrey[1219]: Binding to TCP port 10023 on host localhost#012 Sep 24 01:35:05 bookcdb postgrey[1219]: Setting gid to "116 116" Sep 24 01:35:05 bookcdb postgrey[1219]: Setting uid to "110" Sep 24 01:35:06 bookcdb spamd[1231]: logger: removing stderr method Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server started on port 783/tcp (running version 3.3.2) Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server pid: 1233 Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server successfully spawned child process, pid 1238 Sep 24 01:35:08 bookcdb spamd[1233]: spamd: server successfully spawned child process, pid 1240 Sep 24 01:35:08 bookcdb spamd[1233]: prefork: child states: SI Sep 24 01:35:08 bookcdb spamd[1233]: prefork: child states: II Sep 24 01:35:15 bookcdb postfix/master[1729]: daemon started -- version 2.9.3, configuration /etc/postfix Sep 24 01:36:08 bookcdb postfix/smtpd[1995]: error: open database /var/lib/mailman/data/aliases.db: No such file or directory Sep 24 01:36:08 bookcdb postfix/smtpd[1995]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:36:08 bookcdb postfix/smtpd[1995]: connect from unknown[::1] Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: error: open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "*" Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "root@localhost" Sep 24 01:36:51 bookcdb postfix/trivial-rewrite[1999]: warning: transport_maps lookup failure Sep 24 01:37:00 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:37:00 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "fmaster@localhost" Sep 24 01:37:00 bookcdb postfix/trivial-rewrite[1999]: warning: transport_maps lookup failure Sep 24 01:37:00 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<root@localhost> to=<fmaster@localhost> proto=SMTP Sep 24 01:37:28 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2730, secured Sep 24 01:37:28 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=44/697 Sep 24 01:37:29 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2732, secured Sep 24 01:37:29 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=464/1303 Sep 24 01:37:29 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2734, secured Sep 24 01:37:29 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=117/1395 Sep 24 01:37:31 bookcdb dovecot: imap-login: Login: user=<mkadiri89>, method=PLAIN, rip=::1, lip=::1, mpid=2737, secured Sep 24 01:37:31 bookcdb dovecot: imap(mkadiri89): Disconnected: Logged out bytes=117/1395 Sep 24 01:37:49 bookcdb dovecot: imap-login: Login: user=<root>, method=PLAIN, rip=::1, lip=::1, mpid=2739, secured Sep 24 01:37:49 bookcdb dovecot: imap: Error: user root: Invalid settings in userdb: userdb returned 0 as uid Sep 24 01:37:49 bookcdb dovecot: imap: Error: Invalid user settings. Refer to server log for more information. Sep 24 01:37:54 bookcdb dovecot: imap-login: Login: user=<root>, method=PLAIN, rip=::1, lip=::1, mpid=2741, secured Sep 24 01:37:54 bookcdb dovecot: imap: Error: user root: Invalid settings in userdb: userdb returned 0 as uid Sep 24 01:37:54 bookcdb dovecot: imap: Error: Invalid user settings. Refer to server log for more information. Sep 24 01:38:04 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2743, secured Sep 24 01:38:04 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=44/697 Sep 24 01:38:04 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2745, secured Sep 24 01:38:04 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=464/1303 Sep 24 01:38:04 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2747, secured Sep 24 01:38:04 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=117/1395 Sep 24 01:38:55 bookcdb postfix/smtpd[1995]: disconnect from unknown[::1] Sep 24 01:38:58 bookcdb postfix/smtpd[1995]: warning: hostname localhost does not resolve to address ::1: No address associated with hostname Sep 24 01:38:58 bookcdb postfix/smtpd[1995]: connect from unknown[::1] Sep 24 01:39:11 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport is unavailable. open database /etc/postfix/transport.db: No such file or directory Sep 24 01:39:11 bookcdb postfix/trivial-rewrite[1999]: warning: hash:/etc/postfix/transport lookup error for "info@localhost" Sep 24 01:39:11 bookcdb postfix/trivial-rewrite[1999]: warning: transport_maps lookup failure Sep 24 01:39:37 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<info@localhost> to=<fmaster@localhost> proto=SMTP Sep 24 01:39:47 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <fmaster@localhost>: Temporary lookup failure; from=<info@localhost> to=<fmaster@localhost> proto=SMTP Sep 24 01:40:13 bookcdb postfix/smtpd[1995]: NOQUEUE: reject: RCPT from unknown[::1]: 451 4.3.0 <info@localhost>: Temporary lookup failure; from=<info@localhost> to=<info@localhost> proto=SMTP Sep 24 01:43:08 bookcdb postfix/smtpd[1995]: disconnect from unknown[::1] Sep 24 01:46:08 bookcdb postfix/anvil[1998]: statistics: max connection rate 1/60s for (smtp:::1) at Sep 24 01:36:08 Sep 24 01:46:08 bookcdb postfix/anvil[1998]: statistics: max connection count 1 for (smtp:::1) at Sep 24 01:36:08 Sep 24 01:46:08 bookcdb postfix/anvil[1998]: statistics: max cache size 1 at Sep 24 01:36:08 Sep 24 01:48:05 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2805, secured Sep 24 01:48:05 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=85/681 Sep 24 01:51:30 bookcdb dovecot: imap-login: Login: user=<info>, method=PLAIN, rip=::1, lip=::1, mpid=2815, secured Sep 24 01:51:30 bookcdb dovecot: imap(info): Disconnected: Logged out bytes=117/1395 Sep 24 02:05:15 bookcdb postfix/qmgr[1745]: 2EA006E0B32: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 02:05:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 02:05:15 bookcdb postfix/qmgr[1745]: E76996E09B2: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 02:05:15 bookcdb postfix/error[2842]: 2EA006E0B32: to=<[email protected]>, relay=none, delay=8391, delays=8391/0.05/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:05:16 bookcdb postfix/error[2843]: E76996E09B2: to=<[email protected]>, relay=none, delay=8416, delays=8416/0.03/0/0.11, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:30:15 bookcdb postfix/qmgr[1745]: D0C596E0B34: from=<[email protected]>, size=442, nrcpt=1 (queue active) Sep 24 02:30:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 02:30:15 bookcdb postfix/error[2914]: D0C596E0B34: to=<[email protected]>, relay=none, delay=9551, delays=9551/0.01/0/0.08, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:35:15 bookcdb postfix/qmgr[1745]: 2E5C36E0A07: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 02:35:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 02:35:15 bookcdb postfix/qmgr[1745]: 0EA3A6E0ACC: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 02:35:15 bookcdb postfix/error[2926]: 2E5C36E0A07: to=<[email protected]>, orig_to=<root>, relay=none, delay=34386, delays=34386/0.03/0/0.1, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 02:35:15 bookcdb postfix/error[2927]: 0EA3A6E0ACC: to=<[email protected]>, orig_to=<root>, relay=none, delay=34299, delays=34298/0.02/0/0.12, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:15:15 bookcdb postfix/qmgr[1745]: 2EA006E0B32: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 03:15:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 03:15:15 bookcdb postfix/qmgr[1745]: E76996E09B2: from=<[email protected]>, size=439, nrcpt=1 (queue active) Sep 24 03:15:15 bookcdb postfix/error[3025]: 2EA006E0B32: to=<[email protected]>, relay=none, delay=12590, delays=12590/0.01/0/0.07, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:15:15 bookcdb postfix/error[3026]: E76996E09B2: to=<[email protected]>, relay=none, delay=12616, delays=12616/0.01/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:40:15 bookcdb postfix/qmgr[1745]: D0C596E0B34: from=<[email protected]>, size=442, nrcpt=1 (queue active) Sep 24 03:40:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 03:40:15 bookcdb postfix/error[3097]: D0C596E0B34: to=<[email protected]>, relay=none, delay=13752, delays=13752/0.01/0/0.07, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:45:15 bookcdb postfix/qmgr[1745]: 2E5C36E0A07: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 03:45:15 bookcdb postfix/qmgr[1745]: warning: connect to transport private/smtp-amavis: No such file or directory Sep 24 03:45:15 bookcdb postfix/qmgr[1745]: 0EA3A6E0ACC: from=<[email protected]>, size=438, nrcpt=1 (queue active) Sep 24 03:45:15 bookcdb postfix/error[3129]: 2E5C36E0A07: to=<[email protected]>, orig_to=<root>, relay=none, delay=38586, delays=38586/0.01/0/0.09, dsn=4.3.0, status=deferred (mail transport unavailable) Sep 24 03:45:15 bookcdb postfix/error[3130]: 0EA3A6E0ACC: to=<[email protected]>, orig_to=<root>, relay=none, delay=38498, delays=38498/0.01/0/0.08, dsn=4.3.0, status=deferred (mail transport unavailable) postconf -n alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases, hash:/var/lib/mailman/data/aliases append_dot_mydomain = no biff = no broken_sasl_auth_clients = yes config_directory = /etc/postfix content_filter = smtp-amavis:[127.0.0.1]:10024 home_mailbox = Maildir/ inet_interfaces = all inet_protocols = all mailbox_command = mailbox_size_limit = 0 mailman_destination_recipient_limit = 1 mydestination = server1.bookcdb.com, bookcdb.com, localhost.bookcdb.com, localho st, bookcdb.com myhostname = server1.bookcdb.com mynetworks = 127.0.0.0/8 myorigin = /etc/mailname readme_directory = no recipient_delimiter = + relay_domains = lists.bookcdb.com relayhost = smtp_tls_note_starttls_offer = yes smtp_tls_security_level = may smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) smtpd_recipient_restrictions = permit_sasl_authenticated,permit_mynetworks,rejec t_unauth_destination smtpd_sasl_auth_enable = yes smtpd_sasl_local_domain = smtpd_sasl_security_options = noanonymous smtpd_tls_CAfile = /etc/ssl/certs/cacert.pem smtpd_tls_auth_only = no smtpd_tls_cert_file = /etc/ssl/certs/smtpd.crt smtpd_tls_key_file = /etc/ssl/private/smtpd.key smtpd_tls_loglevel = 1 smtpd_tls_received_header = yes smtpd_tls_security_level = may smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtpd_tls_session_cache_timeout = 3600s smtpd_use_tls = yes tls_random_source = dev:/dev/urandom transport_maps = hash:/etc/postfix/transport

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• Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 1

  - by shiju

  In this post, I will demonstrate web application development using ASP. NET MVC 3, Razor and EF code First. This post will also cover Dependency Injection using Unity 2.0 and generic Repository and Unit of Work for EF Code First. The following frameworks will be used for this step by step tutorial. ASP.NET MVC 3 EF Code First CTP 5 Unity 2.0 Define Domain Model Let’s create domain model for our simple web application Category class public class Category {     public int CategoryId { get; set; }     [Required(ErrorMessage = "Name Required")]     [StringLength(25, ErrorMessage = "Must be less than 25 characters")]     public string Name { get; set;}     public string Description { get; set; }     public virtual ICollection<Expense> Expenses { get; set; } }   Expense class public class Expense {             public int ExpenseId { get; set; }            public string  Transaction { get; set; }     public DateTime Date { get; set; }     public double Amount { get; set; }     public int CategoryId { get; set; }     public virtual Category Category { get; set; } } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. In this post, we will be focusing on CRUD operations for the entity Category and will be working on the Expense entity with a View Model object in the later post. And the source code for this application will be refactored over time. The above entities are very simple POCO (Plain Old CLR Object) classes and the entity Category is decorated with validation attributes in the System.ComponentModel.DataAnnotations namespace. Now we want to use these entities for defining model objects for the Entity Framework 4. Using the Code First approach of Entity Framework, we can first define the entities by simply writing POCO classes without any coupling with any API or database library. This approach lets you focus on domain model which will enable Domain-Driven Development for applications. EF code first support is currently enabled with a separate API that is runs on top of the Entity Framework 4. EF Code First is reached CTP 5 when I am writing this article. Creating Context Class for Entity Framework We have created our domain model and let’s create a class in order to working with Entity Framework Code First. For this, you have to download EF Code First CTP 5 and add reference to the assembly EntitFramework.dll. You can also use NuGet to download add reference to EEF Code First.    public class MyFinanceContext : DbContext {     public MyFinanceContext() : base("MyFinance") { }     public DbSet<Category> Categories { get; set; }     public DbSet<Expense> Expenses { get; set; }         }   The above class MyFinanceContext is derived from DbContext that can connect your model classes to a database. The MyFinanceContext class is mapping our Category and Expense class into database tables Categories and Expenses using DbSet<TEntity> where TEntity is any POCO class. When we are running the application at first time, it will automatically create the database. EF code-first look for a connection string in web.config or app.config that has the same name as the dbcontext class. If it is not find any connection string with the convention, it will automatically create database in local SQL Express database by default and the name of the database will be same name as the dbcontext class. You can also define the name of database in constructor of the the dbcontext class. Unlike NHibernate, we don’t have to use any XML based mapping files or Fluent interface for mapping between our model and database. The model classes of Code First are working on the basis of conventions and we can also use a fluent API to refine our model. The convention for primary key is ‘Id’ or ‘<class name>Id’.  If primary key properties are detected with type ‘int’, ‘long’ or ‘short’, they will automatically registered as identity columns in the database by default. Primary key detection is not case sensitive. We can define our model classes with validation attributes in the System.ComponentModel.DataAnnotations namespace and it automatically enforces validation rules when a model object is updated or saved. Generic Repository for EF Code First We have created model classes and dbcontext class. Now we have to create generic repository pattern for data persistence with EF code first. If you don’t know about the repository pattern, checkout Martin Fowler’s article on Repository Let’s create a generic repository to working with DbContext and DbSet generics. public interface IRepository<T> where T : class     {         void Add(T entity);         void Delete(T entity);         T GetById(long Id);         IEnumerable<T> All();     }   RepositoryBasse – Generic Repository class public abstract class RepositoryBase<T> where T : class { private MyFinanceContext database; private readonly IDbSet<T> dbset; protected RepositoryBase(IDatabaseFactory databaseFactory) {     DatabaseFactory = databaseFactory;     dbset = Database.Set<T>(); }   protected IDatabaseFactory DatabaseFactory {     get; private set; }   protected MyFinanceContext Database {     get { return database ?? (database = DatabaseFactory.Get()); } } public virtual void Add(T entity) {     dbset.Add(entity);            }        public virtual void Delete(T entity) {     dbset.Remove(entity); }   public virtual T GetById(long id) {     return dbset.Find(id); }   public virtual IEnumerable<T> All() {     return dbset.ToList(); } }   DatabaseFactory class public class DatabaseFactory : Disposable, IDatabaseFactory {     private MyFinanceContext database;     public MyFinanceContext Get()     {         return database ?? (database = new MyFinanceContext());     }     protected override void DisposeCore()     {         if (database != null)             database.Dispose();     } } Unit of Work If you are new to Unit of Work pattern, checkout Fowler’s article on Unit of Work . According to Martin Fowler, the Unit of Work pattern "maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency problems." Let’s create a class for handling Unit of Work   public interface IUnitOfWork {     void Commit(); }   UniOfWork class public class UnitOfWork : IUnitOfWork {     private readonly IDatabaseFactory databaseFactory;     private MyFinanceContext dataContext;       public UnitOfWork(IDatabaseFactory databaseFactory)     {         this.databaseFactory = databaseFactory;     }       protected MyFinanceContext DataContext     {         get { return dataContext ?? (dataContext = databaseFactory.Get()); }     }       public void Commit()     {         DataContext.Commit();     } }   The Commit method of the UnitOfWork will call the commit method of MyFinanceContext class and it will execute the SaveChanges method of DbContext class.   Repository class for Category In this post, we will be focusing on the persistence against Category entity and will working on other entities in later post. Let’s create a repository for handling CRUD operations for Category using derive from a generic Repository RepositoryBase<T>.   public class CategoryRepository: RepositoryBase<Category>, ICategoryRepository     {     public CategoryRepository(IDatabaseFactory databaseFactory)         : base(databaseFactory)         {         }                } public interface ICategoryRepository : IRepository<Category> { } If we need additional methods than generic repository for the Category, we can define in the CategoryRepository. Dependency Injection using Unity 2.0 If you are new to Inversion of Control/ Dependency Injection or Unity, please have a look on my articles at http://weblogs.asp.net/shijuvarghese/archive/tags/IoC/default.aspx. I want to create a custom lifetime manager for Unity to store container in the current HttpContext.   public class HttpContextLifetimeManager<T> : LifetimeManager, IDisposable {     public override object GetValue()     {         return HttpContext.Current.Items[typeof(T).AssemblyQualifiedName];     }     public override void RemoveValue()     {         HttpContext.Current.Items.Remove(typeof(T).AssemblyQualifiedName);     }     public override void SetValue(object newValue)     {         HttpContext.Current.Items[typeof(T).AssemblyQualifiedName] = newValue;     }     public void Dispose()     {         RemoveValue();     } }   Let’s create controller factory for Unity in the ASP.NET MVC 3 application. public class UnityControllerFactory : DefaultControllerFactory { IUnityContainer container; public UnityControllerFactory(IUnityContainer container) {     this.container = container; } protected override IController GetControllerInstance(RequestContext reqContext, Type controllerType) {     IController controller;     if (controllerType == null)         throw new HttpException(                 404, String.Format(                     "The controller for path '{0}' could not be found" +     "or it does not implement IController.",                 reqContext.HttpContext.Request.Path));       if (!typeof(IController).IsAssignableFrom(controllerType))         throw new ArgumentException(                 string.Format(                     "Type requested is not a controller: {0}",                     controllerType.Name),                     "controllerType");     try     {         controller= container.Resolve(controllerType) as IController;     }     catch (Exception ex)     {         throw new InvalidOperationException(String.Format(                                 "Error resolving controller {0}",                                 controllerType.Name), ex);     }     return controller; }   }   Configure contract and concrete types in Unity Let’s configure our contract and concrete types in Unity for resolving our dependencies.   private void ConfigureUnity() {     //Create UnityContainer               IUnityContainer container = new UnityContainer()                 .RegisterType<IDatabaseFactory, DatabaseFactory>(new HttpContextLifetimeManager<IDatabaseFactory>())     .RegisterType<IUnitOfWork, UnitOfWork>(new HttpContextLifetimeManager<IUnitOfWork>())     .RegisterType<ICategoryRepository, CategoryRepository>(new HttpContextLifetimeManager<ICategoryRepository>());                 //Set container for Controller Factory                ControllerBuilder.Current.SetControllerFactory(             new UnityControllerFactory(container)); }   In the above ConfigureUnity method, we are registering our types onto Unity container with custom lifetime manager HttpContextLifetimeManager. Let’s call ConfigureUnity method in the Global.asax.cs for set controller factory for Unity and configuring the types with Unity.   protected void Application_Start() {     AreaRegistration.RegisterAllAreas();     RegisterGlobalFilters(GlobalFilters.Filters);     RegisterRoutes(RouteTable.Routes);     ConfigureUnity(); }   Developing web application using ASP.NET MVC 3 We have created our domain model for our web application and also have created repositories and configured dependencies with Unity container. Now we have to create controller classes and views for doing CRUD operations against the Category entity. Let’s create controller class for Category Category Controller   public class CategoryController : Controller {     private readonly ICategoryRepository categoryRepository;     private readonly IUnitOfWork unitOfWork;           public CategoryController(ICategoryRepository categoryRepository, IUnitOfWork unitOfWork)     {         this.categoryRepository = categoryRepository;         this.unitOfWork = unitOfWork;     }       public ActionResult Index()     {         var categories = categoryRepository.All();         return View(categories);     }     [HttpGet]     public ActionResult Edit(int id)     {         var category = categoryRepository.GetById(id);         return View(category);     }       [HttpPost]     public ActionResult Edit(int id, FormCollection collection)     {         var category = categoryRepository.GetById(id);         if (TryUpdateModel(category))         {             unitOfWork.Commit();             return RedirectToAction("Index");         }         else return View(category);                 }       [HttpGet]     public ActionResult Create()     {         var category = new Category();         return View(category);     }           [HttpPost]     public ActionResult Create(Category category)     {         if (!ModelState.IsValid)         {             return View("Create", category);         }                     categoryRepository.Add(category);         unitOfWork.Commit();         return RedirectToAction("Index");     }       [HttpPost]     public ActionResult Delete(int  id)     {         var category = categoryRepository.GetById(id);         categoryRepository.Delete(category);         unitOfWork.Commit();         var categories = categoryRepository.All();         return PartialView("CategoryList", categories);       }        }   Creating Views in Razor Now we are going to create views in Razor for our ASP.NET MVC 3 application.  Let’s create a partial view CategoryList.cshtml for listing category information and providing link for Edit and Delete operations. CategoryList.cshtml @using MyFinance.Helpers; @using MyFinance.Domain; @model IEnumerable<Category>      <table>         <tr>         <th>Actions</th>         <th>Name</th>          <th>Description</th>         </tr>     @foreach (var item in Model) {             <tr>             <td>                 @Html.ActionLink("Edit", "Edit",new { id = item.CategoryId })                 @Ajax.ActionLink("Delete", "Delete", new { id = item.CategoryId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divCategoryList" })                           </td>             <td>                 @item.Name             </td>             <td>                 @item.Description             </td>         </tr>          }       </table>     <p>         @Html.ActionLink("Create New", "Create")     </p> The delete link is providing Ajax functionality using the Ajax.ActionLink. This will call an Ajax request for Delete action method in the CategoryCotroller class. In the Delete action method, it will return Partial View CategoryList after deleting the record. We are using CategoryList view for the Ajax functionality and also for Index view using for displaying list of category information. Let’s create Index view using partial view CategoryList  Index.chtml @model IEnumerable<MyFinance.Domain.Category> @{     ViewBag.Title = "Index"; }    <h2>Category List</h2>    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script>    <div id="divCategoryList">               @Html.Partial("CategoryList", Model) </div>   We can call the partial views using Html.Partial helper method. Now we are going to create View pages for insert and update functionality for the Category. Both view pages are sharing common user interface for entering the category information. So I want to create an EditorTemplate for the Category information. We have to create the EditorTemplate with the same name of entity object so that we can refer it on view pages using @Html.EditorFor(model => model) . So let’s create template with name Category. Let’s create view page for insert Category information   @model MyFinance.Domain.Category   @{     ViewBag.Title = "Save"; }   <h2>Create</h2>   <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>   @using (Html.BeginForm()) {     @Html.ValidationSummary(true)     <fieldset>         <legend>Category</legend>                @Html.EditorFor(model => model)               <p>             <input type="submit" value="Create" />         </p>     </fieldset> }   <div>     @Html.ActionLink("Back to List", "Index") </div> ViewStart file In Razor views, we can add a file named _viewstart.cshtml in the views directory  and this will be shared among the all views with in the Views directory. The below code in the _viewstart.cshtml, sets the Layout page for every Views in the Views folder.      @{     Layout = "~/Views/Shared/_Layout.cshtml"; }   Source Code You can download the source code from http://efmvc.codeplex.com/ . The source will be refactored on over time.   Summary In this post, we have created a simple web application using ASP.NET MVC 3 and EF Code First. We have discussed on technologies and practices such as ASP.NET MVC 3, Razor, EF Code First, Unity 2, generic Repository and Unit of Work. In my later posts, I will modify the application and will be discussed on more things. Stay tuned to my blog  for more posts on step by step application building.

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• JPA - insert and retrieve clob and blob types

  - by pachunoori.vinay.kumar(at)oracle.com

  This article describes about the JPA feature for handling clob and blob data types.You will learn the following in this article. @Lob annotation Client code to insert and retrieve the clob/blob types End to End ADFaces application to retrieve the image from database table and display it in web page. Use Case Description Persisting and reading the image from database using JPA clob/blob type. @Lob annotation By default, TopLink JPA assumes that all persistent data can be represented as typical database data types. Use the @Lob annotation with a basic mapping to specify that a persistent property or field should be persisted as a large object to a database-supported large object type. A Lob may be either a binary or character type. TopLink JPA infers the Lob type from the type of the persistent field or property. For string and character-based types, the default is Clob. In all other cases, the default is Blob. Example Below code shows how to use this annotation to specify that persistent field picture should be persisted as a Blob. public class Person implements Serializable {    @Id    @Column(nullable = false, length = 20)    private String name;    @Column(nullable = false)    @Lob    private byte[] picture;    @Column(nullable = false, length = 20) } Client code to insert and retrieve the clob/blob types Reading a image file and inserting to Database table Below client code will read the image from a file and persist to Person table in database.                       Person p=new Person();                      p.setName("Tom");                      p.setSex("male");                      p.setPicture(writtingImage("Image location"));// - c:\images\test.jpg                       sessionEJB.persistPerson(p); //Retrieving the image from Database table and writing to a file                       List<Person> plist=sessionEJB.getPersonFindAll();//                      Person person=(Person)plist.get(0);//get a person object                      retrieveImage(person.getPicture());   //get picture retrieved from Table //Private method to create byte[] from image file  private static byte[] writtingImage(String fileLocation) {      System.out.println("file lication is"+fileLocation);     IOManager manager=new IOManager();        try {           return manager.getBytesFromFile(fileLocation);                    } catch (IOException e) {        }        return null;    } //Private method to read byte[] from database and write to a image file    private static void retrieveImage(byte[] b) {    IOManager manager=new IOManager();        try {            manager.putBytesInFile("c:\\webtest.jpg",b);        } catch (IOException e) {        }    } End to End ADFaces application to retrieve the image from database table and display it in web page. Please find the application in this link. Following are the j2ee components used in the sample application. ADFFaces(jspx page) HttpServlet Class - Will make a call to EJB and retrieve the person object from person table.Read the byte[] and write to response using Outputstream. SessionEJBBean - This is a session facade to make a local call to JPA entities JPA Entity(Person.java) - Person java class with setter and getter method annotated with @Lob representing the clob/blob types for picture field.

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• Invariant code contracts – using class-wide contracts

  - by DigiMortal

  It is possible to define invariant code contracts for classes. Invariant contracts should always hold true whatever member of class is called. In this posting I will show you how to use invariant code contracts so you understand how they work and how they should be tested. This is my randomizer class I am using to demonstrate code contracts. I added one method for invariant code contracts. Currently there is one contract that makes sure that random number generator is not null. public class Randomizer {     private IRandomGenerator _generator;       private Randomizer() { }       public Randomizer(IRandomGenerator generator)     {         _generator = generator;     }       public int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(             min < max,             "Min must be less than max"         );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           return _generator.Next(min, max);     }       [ContractInvariantMethod]     private void ObjectInvariant()     {         Contract.Invariant(_generator != null);     } } Invariant code contracts are define in methods that have ContractInvariantMethod attribute. Some notes: It is good idea to define invariant methods as private. Don’t call invariant methods from your code because code contracts system does not allow it. Invariant methods are defined only as place where you can keep invariant contracts. Invariant methods are called only when call to some class member is made! The last note means that having invariant method and creating Randomizer object with null as argument does not automatically generate exception. We have to call at least one method from Randomizer class. Here is the test for generator. You can find more about contracted code testing from my posting Code Contracts: Unit testing contracted code. There is also explained why the exception handling in test is like it is. [TestMethod] [ExpectedException(typeof(Exception))] public void Should_fail_if_generator_is_null() {     try     {         var randomizer = new Randomizer(null);         randomizer.GetRandomFromRangeContracted(1, 4);     }     catch (Exception ex)     {         throw new Exception(ex.Message, ex);     } } Try out this code – with unit tests or with test application to see that invariant contracts are checked as soon as you call some member of Randomizer class.

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• Use Extension method to write cleaner code

  - by Fredrik N

  This blog post will show you step by step to refactoring some code to be more readable (at least what I think). Patrik Löwnedahl gave me some of the ideas when we where talking about making code much cleaner. The following is an simple application that will have a list of movies (Normal and Transfer). The task of the application is to calculate the total sum of each movie and also display the price of each movie. class Program { enum MovieType { Normal, Transfer } static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies) { if (movie == MovieType.Normal) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } else if (movie == MovieType.Transfer) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } } } private static IEnumerable<MovieType> GetMovies() { return new List<MovieType>() { MovieType.Normal, MovieType.Transfer, MovieType.Normal }; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } In the code above I’m using an enum, a good way to add types (isn’t it ;)). I also use one foreach loop to calculate the price, the loop has a condition statement to check what kind of movie is added to the list of movies. I want to reuse the foreach only to increase performance and let it do two things (isn’t that smart of me?! ;)). First of all I can admit, I’m not a big fan of enum. Enum often results in ugly condition statements and can be hard to maintain (if a new type is added we need to check all the code in our app to see if we use the enum somewhere else). I don’t often care about pre-optimizations when it comes to write code (of course I have performance in mind). I rather prefer to use two foreach to let them do one things instead of two. So based on what I don’t like and Martin Fowler’s Refactoring catalog, I’m going to refactoring this code to what I will call a more elegant and cleaner code. First of all I’m going to use Split Loop to make sure the foreach will do one thing not two, it will results in two foreach (Don’t care about performance here, if the results will results in bad performance, you can refactoring later, but computers are so fast to day, so iterating through a list is not often so time consuming.) Note: The foreach actually do four things, will come to is later. var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies) { if (movie == MovieType.Normal) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } } foreach (var movie in movies) { if (movie == MovieType.Transfer) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To remove the condition statement we can use the Where extension method added to the IEnumerable<T> and is located in the System.Linq namespace: foreach (var movie in movies.Where( m => m == MovieType.Normal)) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } foreach (var movie in movies.Where( m => m == MovieType.Transfer)) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The above code will still do two things, calculate the total price, and display the price of the movie. I will not take care of it at the moment, instead I will focus on the enum and try to remove them. One way to remove enum is by using the Replace Conditional with Polymorphism. So I will create two classes, one base class called Movie, and one called MovieTransfer. The Movie class will have a property called Price, the Movie will now hold the price:   public class Movie { public virtual int Price { get { return 2; } } } public class MovieTransfer : Movie { public override int Price { get { return 3; } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The following code has no enum and will use the new Movie classes instead: class Program { static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies.Where( m => m is Movie)) { totalPriceOfNormalMovie += movie.Price; Console.WriteLine(movie.Price); } foreach (var movie in movies.Where( m => m is MovieTransfer)) { totalPriceOfTransferMovie += movie.Price; Console.WriteLine(movie.Price); } } private static IEnumerable<Movie> GetMovies() { return new List<Movie>() { new Movie(), new MovieTransfer(), new Movie() }; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   If you take a look at the foreach now, you can see it still actually do two things, calculate the price and display the price. We can do some more refactoring here by using the Sum extension method to calculate the total price of the movies:   static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = movies.Where(m => m is Movie) .Sum(m => m.Price); int totalPriceOfTransferMovie = movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); foreach (var movie in movies.Where( m => m is Movie)) Console.WriteLine(movie.Price); foreach (var movie in movies.Where( m => m is MovieTransfer)) Console.WriteLine(movie.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now when the Movie object will hold the price, there is no need to use two separate foreach to display the price of the movies in the list, so we can use only one instead: foreach (var movie in movies) Console.WriteLine(movie.Price); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If we want to increase the Maintainability index we can use the Extract Method to move the Sum of the prices into two separate methods. The name of the method will explain what we are doing: static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); foreach (var movie in movies) Console.WriteLine(movie.Price); } private static int TotalPriceOfMovieTransfer(IEnumerable<Movie> movies) { return movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); } private static int TotalPriceOfMovie(IEnumerable<Movie> movies) { return movies.Where(m => m is Movie) .Sum(m => m.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now to the last thing, I love the ForEach method of the List<T>, but the IEnumerable<T> doesn’t have it, so I created my own ForEach extension, here is the code of the ForEach extension method: public static class LoopExtensions { public static void ForEach<T>(this IEnumerable<T> values, Action<T> action) { Contract.Requires(values != null); Contract.Requires(action != null); foreach (var v in values) action(v); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I will now replace the foreach by using this ForEach method: static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); movies.ForEach(m => Console.WriteLine(m.Price)); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The ForEach on the movies will now display the price of the movie, but maybe we want to display the name of the movie etc, so we can use Extract Method by moving the lamdba expression into a method instead, and let the method explains what we are displaying: movies.ForEach(DisplayMovieInfo); private static void DisplayMovieInfo(Movie movie) { Console.WriteLine(movie.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now the refactoring is done! Here is the complete code:   class Program { static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); movies.ForEach(DisplayMovieInfo); } private static void DisplayMovieInfo(Movie movie) { Console.WriteLine(movie.Price); } private static int TotalPriceOfMovieTransfer(IEnumerable<Movie> movies) { return movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); } private static int TotalPriceOfMovie(IEnumerable<Movie> movies) { return movies.Where(m => m is Movie) .Sum(m => m.Price); } private static IEnumerable<Movie> GetMovies() { return new List<Movie>() { new Movie(), new MovieTransfer(), new Movie() }; } } public class Movie { public virtual int Price { get { return 2; } } } public class MovieTransfer : Movie { public override int Price { get { return 3; } } } pulbic static class LoopExtensions { public static void ForEach<T>(this IEnumerable<T> values, Action<T> action) { Contract.Requires(values != null); Contract.Requires(action != null); foreach (var v in values) action(v); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I think the new code is much cleaner than the first one, and I love the ForEach extension on the IEnumerable<T>, I can use it for different kind of things, for example: movies.Where(m => m is Movie) .ForEach(DoSomething); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } By using the Where and ForEach extension method, some if statements can be removed and will make the code much cleaner. But the beauty is in the eye of the beholder. What would you have done different, what do you think will make the first example in the blog post look much cleaner than my results, comments are welcome! If you want to know when I will publish a new blog post, you can follow me on twitter: http://www.twitter.com/fredrikn

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• ASP.NET Web API - Screencast series Part 3: Delete and Update

  - by Jon Galloway

  We're continuing a six part series on ASP.NET Web API that accompanies the getting started screencast series. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. In Part 1 we looked at what ASP.NET Web API is, why you'd care, did the File / New Project thing, and did some basic HTTP testing using browser F12 developer tools. In Part 2 we started to build up a sample that returns data from a repository in JSON format via GET methods. In Part 3, we'll start to modify data on the server using DELETE and POST methods. So far we've been looking at GET requests, and the difference between standard browsing in a web browser and navigating an HTTP API isn't quite as clear. Delete is where the difference becomes more obvious. With a "traditional" web page, to delete something'd probably have a form that POSTs a request back to a controller that needs to know that it's really supposed to be deleting something even though POST was really designed to create things, so it does the work and then returns some HTML back to the client that says whether or not the delete succeeded. There's a good amount of plumbing involved in communicating between client and server. That gets a lot easier when we just work with the standard HTTP DELETE verb. Here's how the server side code works: public Comment DeleteComment(int id) { Comment comment; if (!repository.TryGet(id, out comment)) throw new HttpResponseException(HttpStatusCode.NotFound); repository.Delete(id); return comment; } If you look back at the GET /api/comments code in Part 2, you'll see that they start the exact same because the use cases are kind of similar - we're looking up an item by id and either displaying it or deleting it. So the only difference is that this method deletes the comment once it finds it. We don't need to do anything special to handle cases where the id isn't found, as the same HTTP 404 handling works fine here, too. Pretty much all "traditional" browsing uses just two HTTP verbs: GET and POST, so you might not be all that used to DELETE requests and think they're hard. Not so! Here's the jQuery method that calls the /api/comments with the DELETE verb: $(function() { $("a.delete").live('click', function () { var id = $(this).data('comment-id'); $.ajax({ url: "/api/comments/" + id, type: 'DELETE', cache: false, statusCode: { 200: function(data) { viewModel.comments.remove( function(comment) { return comment.ID == data.ID; } ); } } }); return false; }); }); So in order to use the DELETE verb instead of GET, we're just using $.ajax() and setting the type to DELETE. Not hard. But what's that statusCode business? Well, an HTTP status code of 200 is an OK response. Unless our Web API method sets another status (such as by throwing the Not Found exception we saw earlier), the default response status code is HTTP 200 - OK. That makes the jQuery code pretty simple - it calls the Delete action, and if it gets back an HTTP 200, the server-side delete was successful so the comment can be deleted. Adding a new comment uses the POST verb. It starts out looking like an MVC controller action, using model binding to get the new comment from JSON data into a c# model object to add to repository, but there are some interesting differences. public HttpResponseMessage<Comment> PostComment(Comment comment) { comment = repository.Add(comment); var response = new HttpResponseMessage<Comment>(comment, HttpStatusCode.Created); response.Headers.Location = new Uri(Request.RequestUri, "/api/comments/" + comment.ID.ToString()); return response; } First off, the POST method is returning an HttpResponseMessage<Comment>. In the GET methods earlier, we were just returning a JSON payload with an HTTP 200 OK, so we could just return the  model object and Web API would wrap it up in an HttpResponseMessage with that HTTP 200 for us (much as ASP.NET MVC controller actions can return strings, and they'll be automatically wrapped in a ContentResult). When we're creating a new comment, though, we want to follow standard REST practices and return the URL that points to the newly created comment in the Location header, and we can do that by explicitly creating that HttpResposeMessage and then setting the header information. And here's a key point - by using HTTP standard status codes and headers, our response payload doesn't need to explain any context - the client can see from the status code that the POST succeeded, the location header tells it where to get it, and all it needs in the JSON payload is the actual content. Note: This is a simplified sample. Among other things, you'll need to consider security and authorization in your Web API's, and especially in methods that allow creating or deleting data. We'll look at authorization in Part 6. As for security, you'll want to consider things like mass assignment if binding directly to model objects, etc. In Part 4, we'll extend on our simple querying methods form Part 2, adding in support for paging and querying.

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• Big Data – Role of Cloud Computing in Big Data – Day 11 of 21

  - by Pinal Dave

  In yesterday’s blog post we learned the importance of the NewSQL. In this article we will understand the role of Cloud in Big Data Story What is Cloud? Cloud is the biggest buzzword around from last few years. Everyone knows about the Cloud and it is extremely well defined online. In this article we will discuss cloud in the context of the Big Data. Cloud computing is a method of providing a shared computing resources to the application which requires dynamic resources. These resources include applications, computing, storage, networking, development and various deployment platforms. The fundamentals of the cloud computing are that it shares pretty much share all the resources and deliver to end users as a service.  Examples of the Cloud Computing and Big Data are Google and Amazon.com. Both have fantastic Big Data offering with the help of the cloud. We will discuss this later in this blog post. There are two different Cloud Deployment Models: 1) The Public Cloud and 2) The Private Cloud Public Cloud Public Cloud is the cloud infrastructure build by commercial providers (Amazon, Rackspace etc.) creates a highly scalable data center that hides the complex infrastructure from the consumer and provides various services. Private Cloud Private Cloud is the cloud infrastructure build by a single organization where they are managing highly scalable data center internally. Here is the quick comparison between Public Cloud and Private Cloud from Wikipedia:   Public Cloud Private Cloud Initial cost Typically zero Typically high Running cost Unpredictable Unpredictable Customization Impossible Possible Privacy No (Host has access to the data Yes Single sign-on Impossible Possible Scaling up Easy while within defined limits Laborious but no limits Hybrid Cloud Hybrid Cloud is the cloud infrastructure build with the composition of two or more clouds like public and private cloud. Hybrid cloud gives best of the both the world as it combines multiple cloud deployment models together. Cloud and Big Data – Common Characteristics There are many characteristics of the Cloud Architecture and Cloud Computing which are also essentially important for Big Data as well. They highly overlap and at many places it just makes sense to use the power of both the architecture and build a highly scalable framework. Here is the list of all the characteristics of cloud computing important in Big Data Scalability Elasticity Ad-hoc Resource Pooling Low Cost to Setup Infastructure Pay on Use or Pay as you Go Highly Available Leading Big Data Cloud Providers There are many players in Big Data Cloud but we will list a few of the known players in this list. Amazon Amazon is arguably the most popular Infrastructure as a Service (IaaS) provider. The history of how Amazon started in this business is very interesting. They started out with a massive infrastructure to support their own business. Gradually they figured out that their own resources are underutilized most of the time. They decided to get the maximum out of the resources they have and hence  they launched their Amazon Elastic Compute Cloud (Amazon EC2) service in 2006. Their products have evolved a lot recently and now it is one of their primary business besides their retail selling. Amazon also offers Big Data services understand Amazon Web Services. Here is the list of the included services: Amazon Elastic MapReduce – It processes very high volumes of data Amazon DynammoDB – It is fully managed NoSQL (Not Only SQL) database service Amazon Simple Storage Services (S3) – A web-scale service designed to store and accommodate any amount of data Amazon High Performance Computing – It provides low-tenancy tuned high performance computing cluster Amazon RedShift – It is petabyte scale data warehousing service Google Though Google is known for Search Engine, we all know that it is much more than that. Google Compute Engine – It offers secure, flexible computing from energy efficient data centers Google Big Query – It allows SQL-like queries to run against large datasets Google Prediction API – It is a cloud based machine learning tool Other Players Besides Amazon and Google we also have other players in the Big Data market as well. Microsoft is also attempting Big Data with the Cloud with Microsoft Azure. Additionally Rackspace and NASA together have initiated OpenStack. The goal of Openstack is to provide a massively scaled, multitenant cloud that can run on any hardware. Thing to Watch The cloud based solutions provides a great integration with the Big Data’s story as well it is very economical to implement as well. However, there are few things one should be very careful when deploying Big Data on cloud solutions. Here is a list of a few things to watch: Data Integrity Initial Cost Recurring Cost Performance Data Access Security Location Compliance Every company have different approaches to Big Data and have different rules and regulations. Based on various factors, one can implement their own custom Big Data solution on a cloud. Tomorrow In tomorrow’s blog post we will discuss about various Operational Databases supporting Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• To ref or not to ref

  - by nmarun

  So the question is what is the point of passing a reference type along with the ref keyword? I have an Employee class as below: 1: public class Employee 2: { 3: public string FirstName { get; set; } 4: public string LastName { get; set; } 5:  6: public override string ToString() 7: { 8: return string.Format("{0}-{1}", FirstName, LastName); 9: } 10: } In my calling class, I say: 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(Employee employee) 16: { 17: employee.FirstName = "Smith"; 18: employee.LastName = "Doe"; 19: } 20: }   After having a look at the code, you’ll probably say, Well, an instance of a class gets passed as a reference, so any changes to the instance inside the CallSomeMethod, actually modifies the original object. Hence the output will be ‘John-Doe’ on the first call and ‘Smith-Doe’ on the second. And you’re right: So the question is what’s the use of passing this Employee parameter as a ref? 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(ref employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(ref Employee employee) 16: { 17: employee.FirstName = "Smith"; 18: employee.LastName = "Doe"; 19: } 20: } The output is still the same: Ok, so is there really a need to pass a reference type using the ref keyword? I’ll remove the ‘ref’ keyword and make one more change to the CallSomeMethod method. 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(Employee employee) 16: { 17: employee = new Employee 18: { 19: FirstName = "Smith", 20: LastName = "John" 21: }; 22: } 23: } In line 17 you’ll see I’ve ‘new’d up the incoming Employee parameter and then set its properties to new values. The output tells me that the original instance of the Employee class does not change. Huh? But an instance of a class gets passed by reference, so why did the values not change on the original instance or how do I keep the two instances in-sync all the times? Aah, now here’s the answer. In order to keep the objects in sync, you pass them using the ‘ref’ keyword. 1: class Program 2: { 3: static void Main() 4: { 5: Employee employee = new Employee 6: { 7: FirstName = "John", 8: LastName = "Doe" 9: }; 10: Console.WriteLine(employee); 11: CallSomeMethod(ref employee); 12: Console.WriteLine(employee); 13: } 14:  15: private static void CallSomeMethod(ref Employee employee) 16: { 17: employee = new Employee 18: { 19: FirstName = "Smith", 20: LastName = "John" 21: }; 22: } 23: } Viola! Now, to prove it beyond doubt, I said, let me try with another reference type: string. 1: class Program 2: { 3: static void Main() 4: { 5: string name = "abc"; 6: Console.WriteLine(name); 7: CallSomeMethod(ref name); 8: Console.WriteLine(name); 9: } 10:  11: private static void CallSomeMethod(ref string name) 12: { 13: name = "def"; 14: } 15: } The output was as expected, first ‘abc’ and then ‘def’ - proves the 'ref' keyword works here as well. Now, what if I remove the ‘ref’ keyword? The output should still be the same as the above right, since string is a reference type? 1: class Program 2: { 3: static void Main() 4: { 5: string name = "abc"; 6: Console.WriteLine(name); 7: CallSomeMethod(name); 8: Console.WriteLine(name); 9: } 10:  11: private static void CallSomeMethod(string name) 12: { 13: name = "def"; 14: } 15: } Wrong, the output shows ‘abc’ printed twice. Wait a minute… now how could this be? This is because string is an immutable type. This means that any time you modify an instance of string, new memory address is allocated to the instance. The effect is similar to ‘new’ing up the Employee instance inside the CallSomeMethod in the absence of the ‘ref’ keyword. Verdict: ref key came to the rescue and saved the planet… again!

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• Analysing and measuring the performance of a .NET application (survey results)

  - by Laila

  Back in December last year, I asked myself: could it be that .NET developers think that you need three days and a PhD to do performance profiling on their code? What if developers are shunning profilers because they perceive them as too complex to use? If so, then what method do they use to measure and analyse the performance of their .NET applications? Do they even care about performance? So, a few weeks ago, I decided to get a 1-minute survey up and running in the hopes that some good, hard data would clear the matter up once and for all. I posted the survey on Simple Talk and got help from a few people to promote it. The survey consisted of 3 simple questions: Amazingly, 533 developers took the time to respond - which means I had enough data to get representative results! So before I go any further, I would like to thank all of you who contributed, because I now have some pretty good answers to the troubling questions I was asking myself. To thank you properly, I thought I would share some of the results with you. First of all, application performance is indeed important to most of you. In fact, performance is an intrinsic part of the development cycle for a good 40% of you, which is much higher than I had anticipated, I have to admit. (I know, "Have a little faith Laila!") When asked what tool you use to measure and analyse application performance, I found that nearly half of the respondents use logging statements, a third use performance counters, and 70% of respondents use a profiler of some sort (a 3rd party performance profilers, the CLR profiler or the Visual Studio profiler). The importance attributed to logging statements did surprise me a little. I am still not sure why somebody would go to the trouble of manually instrumenting code in order to measure its performance, instead of just using a profiler. I personally find the process of annotating code, calculating times from log files, and relating it all back to your source terrifyingly laborious. Not to mention that you then need to remember to turn it all off later! Even when you have logging in place throughout all your code anyway, you still have a fair amount of potentially error-prone calculation to sift through the results; in addition, you'll only get method-level rather than line-level timings, and you won't get timings from any framework or library methods you don't have source for. To top it all, we all know that bottlenecks are rarely where you would expect them to be, so you could be wasting time looking for a performance problem in the wrong place. On the other hand, profilers do all the work for you: they automatically collect the CPU and wall-clock timings, and present the results from method timing all the way down to individual lines of code. Maybe I'm missing a trick. I would love to know about the types of scenarios where you actively prefer to use logging statements. Finally, while a third of the respondents didn't have a strong opinion about code performance profilers, those who had an opinion thought that they were mainly complex to use and time consuming. Three respondents in particular summarised this perfectly: "sometimes, they are rather complex to use, adding an additional time-sink to the process of trying to resolve the existing problem". "they are simple to use, but the results are hard to understand" "Complex to find the more advanced things, easy to find some low hanging fruit". These results confirmed my suspicions: Profilers are seen to be designed for more advanced users who can use them effectively and make sense of the results. I found yet more interesting information when I started comparing samples of "developers for whom performance is an important part of the dev cycle", with those "to whom performance is only looked at in times of crisis", and "developers to whom performance is not important, as long as the app works". See the three graphs below. Sample of developers to whom performance is an important part of the dev cycle: Sample of developers to whom performance is important only in times of crisis: Sample of developers to whom performance is not important, as long as the app works: As you can see, there is a strong correlation between the usage of a profiler and the importance attributed to performance: indeed, the more important performance is to a development team, the more likely they are to use a profiler. In addition, developers to whom performance is an important part of the dev cycle have a higher tendency to use a much wider range of methods for performance measurement and analysis. And, unsurprisingly, the less important performance is, the less varied the methods of measurement are. So all in all, to come back to my random questions: .NET developers do care about performance. Those who care the most use a wider range of performance measurement methods than those who care less. But overall, logging statements, performance counters and third party performance profilers are the performance measurement methods of choice for most developers. Finally, although most of you find code profilers complex to use, those of you who care the most about performance tend to use profilers more than those of you to whom performance is not so important.

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• Join us for Live Oracle Linux and Oracle VM Cloud Events in Europe

  - by Monica Kumar

  Join us for a series of live events and discover how Oracle VM and Oracle Linux offer an integrated and optimized infrastructure for quickly deploying a private cloud environment at lower cost. As one of the most widely deployed operating systems today, Oracle Linux delivers higher performance, better reliability, and stability, at a lower cost for your cloud environments. Oracle VM is an application-driven server virtualization solution fully integrated and certified with Oracle applications to deliver rapid application deployment and simplified management. With Oracle VM, you have peace of mind that the entire Oracle stack deployed is fully certified by Oracle. Register now for any of the upcoming events, and meet with Oracle experts to discuss how we can help in enabling your private cloud. Nov 20: Foundation for the Cloud: Oracle Linux and Oracle VM (Belgium) Nov 21: Oracle Linux & Oracle VM Enabling Private Cloud (Germany) Nov 28: Realize Substantial Savings and Increased Efficiency with Oracle Linux and Oracle VM (Luxembourg) Nov 29: Foundation for the Cloud: Oracle Linux and Oracle VM (Netherlands) Dec 5: MySQL Tech Tour, including Oracle Linux and Oracle VM (France) Hope to see you at one of these events!

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• Cross-language Extension Method Calling

  - by Tom Hines

  Extension methods are a concise way of binding functions to particular types. In my last post, I showed how Extension methods can be created in the .NET 2.0 environment. In this post, I discuss calling the extensions from other languages. Most of the differences I find between the Dot Net languages are mainly syntax.  The declaration of Extensions is no exception.  There is, however, a distinct difference with the framework accepting excensions made with C++ that differs from C# and VB.  When calling the C++ extension from C#, the compiler will SOMETIMES say there is no definition for DoCPP with the error: 'string' does not contain a definition for 'DoCPP' and no extension method 'DoCPP' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?) If I recompile, the error goes away. The strangest problem with calling the C++ extension from C# is that I first must make SOME type of reference to the class BEFORE using the extension or it will not be recognized at all.  So, if I first call the DoCPP() as a static method, the extension works fine later.  If I make a dummy instantiation of the class, it works.  If I have no forward reference of the class, I get the same error as before and recompiling does not fix it.  It seems as if this none of this is supposed to work across the languages. I have made a few work-arounds to get the examples to compile and run. Note the following examples: Extension in C# using System; namespace Extension_CS {    public static class CExtension_CS    {  //in C#, the "this" keyword is the key.       public static void DoCS(this string str)       {          Console.WriteLine("CS\t{0:G}\tCS", str);       }    } } Extension in C++ /****************************************************************************\  * Here is the C++ implementation.  It is the least elegant and most quirky,  * but it works. \****************************************************************************/ #pragma once using namespace System; using namespace System::Runtime::CompilerServices;     //<-Essential // Reference: System.Core.dll //<- Essential namespace Extension_CPP {        public ref class CExtension_CPP        {        public:               [Extension] // or [ExtensionAttribute] /* either works */               static void DoCPP(String^ str)               {                      Console::WriteLine("C++\t{0:G}\tC++", str);               }        }; } Extension in VB ' Here is the VB implementation.  This is not as elegant as the C#, but it's ' functional. Imports System.Runtime.CompilerServices ' Public Module modExtension_VB 'Extension methods can be defined only in modules.    <Extension()> _       Public Sub DoVB(ByVal str As String)       Console.WriteLine("VB" & Chr(9) & "{0:G}" & Chr(9) & "VB", str)    End Sub End Module   Calling program in C# /******************************************************************************\  * Main calling program  * Intellisense and VS2008 complain about the CPP implementation, but with a  * little duct-tape, it works just fine. \******************************************************************************/ using System; using Extension_CPP; using Extension_CS; using Extension_VB; // vitual namespace namespace TestExtensions {    public static class CTestExtensions    {       /**********************************************************************\        * For some reason, this needs a direct reference into the C++ version        * even though it does nothing than add a null reference.        * The constructor provides the fake usage to please the compiler.       \**********************************************************************/       private static CExtension_CPP x = null;   // <-DUCT_TAPE!       static CTestExtensions()       {          // Fake usage to stop compiler from complaining          if (null != x) {} // <-DUCT_TAPE       }       static void Main(string[] args)       {          string strData = "from C#";          strData.DoCPP();          strData.DoCS();          strData.DoVB();       }    } }   Calling program in VB  Imports Extension_CPP Imports Extension_CS Imports Extension_VB Imports System.Runtime.CompilerServices Module TestExtensions_VB    <Extension()> _       Public Sub DoCPP(ByVal str As String)       'Framework does not treat this as an extension, so use the static       CExtension_CPP.DoCPP(str)    End Sub    Sub Main()       Dim strData As String = "from VB"       strData.DoCS()       strData.DoVB()       strData.DoCPP() 'fake    End Sub End Module  Calling program in C++ // TestExtensions_CPP.cpp : main project file. #include "stdafx.h" using namespace System; using namespace Extension_CPP; using namespace Extension_CS; using namespace Extension_VB; void main(void) {        /*******************************************************\         * Extension methods are called like static methods         * when called from C++.  There may be a difference in         * syntax when calling the VB extension as VB Extensions         * are embedded in Modules instead of classes        \*******************************************************/     String^ strData = "from C++";     CExtension_CPP::DoCPP(strData);     CExtension_CS::DoCS(strData);     modExtension_VB::DoVB(strData); //since Extensions go in Modules }

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• Can find any /.ecryptfs dir to retrieve my encrypted home dir

  - by Roberto de Armas

  At firs sorry for my english, it isn't my native languaje. I've readed some questions similar but no the exactly whith the same problem. I've moved my home directory to a separated partitión (Ubuntu 11.10) following this tutorial http://www.ubuntu-es.org/node/58233 After checking that they were all my files and folders (forgetting that one of dirs was encrypted by ecryptfs) i've installed fedora 16. Well, suprised when in my home folder was an Readme.txt advising me that my folder was unmounted for security reasons and proposing to type in comand line "ecryptfs-mount-Private" (din't work) or make click on labeled icon "acces your private data desktop" (neither din't work). After three days reading all i could find on the internet, i follow The Dustin Kirkland tutorial in http://blog.dustinkirkland.com/2011/04/introducing-ecryptfs-recover-private.html, but any /.ecryptfs was found. I'm sure that the data are somewere (the size of the moved dir is identical to the original one). Any help would by greatly appreciated. Thaks a lot.

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• Ingame menu is not working correctly

  - by Johnny

  The ingame menu opens when the player presses Escape during the main game. If the player presses Y in the ingame menu, the game switches to the main menu. Up to here, everything works. But: On the other hand, if the player presses N in the ingame menu, the game should switch back to the main game(should resume the main game). But that doesn't work. The game just rests in the ingame menu if the player presses N. I set a breakpoint in this line of the Ingamemenu class: KeyboardState kbState = Keyboard.GetState(); CurrentSate/currentGameState and LastState/lastGameState have the same state: IngamemenuState. But LastState/lastGameState should not have the same state than CurrentSate/currentGameState. What is wrong? Why is the ingame menu not working correctly? public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; IState lastState, currentState; public enum GameStates { IntroState = 0, MenuState = 1, MaingameState = 2, IngamemenuState = 3 } public void ChangeGameState(GameStates newState) { lastGameState = currentGameState; lastState = currentState; switch (newState) { case GameStates.IntroState: currentState = new Intro(this); currentGameState = GameStates.IntroState; break; case GameStates.MenuState: currentState = new Menu(this); currentGameState = GameStates.MenuState; break; case GameStates.MaingameState: currentState = new Maingame(this); currentGameState = GameStates.MaingameState; break; case GameStates.IngamemenuState: currentState = new Ingamemenu(this); currentGameState = GameStates.IngamemenuState; break; } currentState.Load(Content); } public void ChangeCurrentToLastGameState() { currentGameState = lastGameState; currentState = lastState; } public GameStates CurrentState { get { return currentGameState; } set { currentGameState = value; } } public GameStates LastState { get { return lastGameState; } set { lastGameState = value; } } private GameStates currentGameState = GameStates.IntroState; private GameStates lastGameState; public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; } protected override void Initialize() { ChangeGameState(GameStates.IntroState); base.Initialize(); } protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); currentState.Load(Content); } protected override void Update(GameTime gameTime) { currentState.Update(gameTime); if ((lastGameState == GameStates.MaingameState) && (currentGameState == GameStates.IngamemenuState)) { lastState.Update(gameTime); } base.Update(gameTime); } protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); spriteBatch.Begin(); if ((lastGameState == GameStates.MaingameState) && (currentGameState == GameStates.IngamemenuState)) { lastState.Render(spriteBatch); } currentState.Render(spriteBatch); spriteBatch.End(); base.Draw(gameTime); } } public interface IState { void Load(ContentManager content); void Update(GameTime gametime); void Render(SpriteBatch batch); } public class Intro : IState { Texture2D Titelbildschirm; private Game1 game1; public Intro(Game1 game) { game1 = game; } public void Load(ContentManager content) { Titelbildschirm = content.Load<Texture2D>("gruft"); } public void Update(GameTime gametime) { KeyboardState kbState = Keyboard.GetState(); if (kbState.IsKeyDown(Keys.Space)) game1.ChangeGameState(Game1.GameStates.MenuState); } public void Render(SpriteBatch batch) { batch.Draw(Titelbildschirm, new Rectangle(0, 0, 1280, 720), Color.White); } } public class Menu:IState { Texture2D Choosescreen; private Game1 game1; public Menu(Game1 game) { game1 = game; } public void Load(ContentManager content) { Choosescreen = content.Load<Texture2D>("menubild"); } public void Update(GameTime gametime) { KeyboardState kbState = Keyboard.GetState(); if (kbState.IsKeyDown(Keys.Enter)) game1.ChangeGameState(Game1.GameStates.MaingameState); if (kbState.IsKeyDown(Keys.Escape)) game1.Exit(); } public void Render(SpriteBatch batch) { batch.Draw(Choosescreen, new Rectangle(0, 0, 1280, 720), Color.White); } } public class Maingame : IState { Texture2D Spielbildschirm, axe; Vector2 position = new Vector2(100,100); private Game1 game1; public Maingame(Game1 game) { game1 = game; } public void Load(ContentManager content) { Spielbildschirm = content.Load<Texture2D>("hauszombie"); axe = content.Load<Texture2D>("axxx"); } public void Update(GameTime gametime) { KeyboardState keyboardState = Keyboard.GetState(); float delta = (float)gametime.ElapsedGameTime.TotalSeconds; position.X += 5 * delta; position.Y += 3 * delta; if (keyboardState.IsKeyDown(Keys.Escape)) game1.ChangeGameState(Game1.GameStates.IngamemenuState); } public void Render(SpriteBatch batch) { batch.Draw(Spielbildschirm, new Rectangle(0, 0, 1280, 720), Color.White); batch.Draw(axe, position, Color.White); } } public class Ingamemenu : IState { Texture2D Quitscreen; private Game1 game1; public Ingamemenu(Game1 game) { game1 = game; } public void Load(ContentManager content) { Quitscreen = content.Load<Texture2D>("quit"); } public void Update(GameTime gametime) { KeyboardState kbState = Keyboard.GetState(); if (kbState.IsKeyDown(Keys.Y)) game1.ChangeGameState(Game1.GameStates.MenuState); if (kbState.IsKeyDown(Keys.N)) game1.ChangeCurrentToLastGameState(); } public void Render(SpriteBatch batch) { batch.Draw(Quitscreen, new Rectangle(200, 200, 200, 200), Color.White); } }

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• Is this proper OO design for C++?

  - by user121917

  I recently took a software processes course and this is my first time attempting OO design on my own. I am trying to follow OO design principles and C++ conventions. I attempted and gave up on MVC for this application, but I am trying to "decouple" my classes such that they can be easily unit-tested and so that I can easily change the GUI library used and/or the target OS. At this time, I have finished designing classes but have not yet started implementing methods. The function of the software is to log all packets sent and received, and display them on the screen (like WireShark, but for one local process only). The software accomplishes this by hooking the send() and recv() functions in winsock32.dll, or some other pair of analogous functions depending on what the intended Target is. The hooks add packets to SendPacketList/RecvPacketList. The GuiLogic class starts a thread which checks for new packets. When new packets are found, it utilizes the PacketFilter class to determine the formatting for the new packet, and then sends it to MainWindow, a native win32 window (with intent to later port to Qt).1 Full size image of UML class diagram Here are my classes in skeleton/header form (this is my actual code): class PacketModel { protected: std::vector<byte> data; int id; public: PacketModel(); PacketModel(byte* data, unsigned int size); PacketModel(int id, byte* data, unsigned int size); int GetLen(); bool IsValid(); //len >= sizeof(opcode_t) opcode_t GetOpcode(); byte* GetData(); //returns &(data[0]) bool GetData(byte* outdata, int maxlen); void SetData(byte* pdata, int len); int GetId(); void SetId(int id); bool ParseData(char* instr); bool StringRepr(char* outstr); byte& operator[] (const int index); }; class SendPacket : public PacketModel { protected: byte* returnAddy; public: byte* GetReturnAddy(); void SetReturnAddy(byte* addy); }; class RecvPacket : public PacketModel { protected: byte* callAddy; public: byte* GetCallAddy(); void SetCallAddy(byte* addy); }; //problem: packets may be added to list at any time by any number of threads //solution: critical section associated with each packet list class Synch { public: void Enter(); void Leave(); }; template<class PacketType> class PacketList { private: static const int MAX_STORED_PACKETS = 1000; public: static const int DEFAULT_SHOWN_PACKETS = 100; private: vector<PacketType> list; Synch synch; //wrapper for critical section public: void AddPacket(PacketType* packet); PacketType* GetPacket(int id); int TotalPackets(); }; class SendPacketList : PacketList<SendPacket> { }; class RecvPacketList : PacketList<RecvPacket> { }; class Target //one socket { bool Send(SendPacket* packet); bool Inject(RecvPacket* packet); bool InitSendHook(SendPacketList* sendList); bool InitRecvHook(RecvPacketList* recvList); }; class FilterModel { private: opcode_t opcode; int colorID; bool bFilter; char name[41]; }; class FilterFile { private: FilterModel filter; public: void Save(); void Load(); FilterModel* GetFilter(opcode_t opcode); }; class PacketFilter { private: FilterFile filters; public: bool IsFiltered(opcode_t opcode); bool GetName(opcode_t opcode, char* namestr); //return false if name does not exist COLORREF GetColor(opcode_t opcode); //return default color if no custom color }; class GuiLogic { private: SendPacketList sendList; RecvPacketList recvList; PacketFilter packetFilter; void GetPacketRepr(PacketModel* packet); void ReadNew(); void AddToWindow(); public: void Refresh(); //called from thread void GetPacketInfo(int id); //called from MainWindow }; I'm looking for a general review of my OO design, use of UML, and use of C++ features. I especially just want to know if I'm doing anything considerably wrong. From what I've read, design review is on-topic for this site (and off-topic for the Code Review site). Any sort of feedback is greatly appreciated. Thanks for reading this.

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• No space on device

  - by user170810

  Today I tried to move a huge directory to a common directory for 2 users. I first tried to change the permissions of my home directory. So something happened with my ~/.private directory and the disk was full! I have a 2 TB disk. I cannot make a backup, I cannot even enter graphics mode. Please help. Are there a way to restore my contents without making backup? Even creating ~/Private is impossible -- "no space on the device". I have no Private, and don't tell me that I have erased it, because it is not true. Are there some utilities to restore the files and make them not encrypted?

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• .NET 4: &ldquo;Slim&rdquo;-style performance boost!

  - by Vitus

  RTM version of .NET 4 and Visual Studio 2010 is available, and now we can do some test with it. Parallel Extensions is one of the most valuable part of .NET 4.0. It’s a set of good tools for easily consuming multicore hardware power. And it also contains some “upgraded” sync primitives – Slim-version. For example, it include updated variant of widely known ManualResetEvent. For people, who don’t know about it: you can sync concurrency execution of some pieces of code with this sync primitive. Instance of ManualResetEvent can be in 2 states: signaled and non-signaled. Transition between it possible by Set() and Reset() methods call. Some shortly explanation: Thread 1 Thread 2 Time mre.Reset(); mre.WaitOne(); //code execution 0 //wating //code execution 1 //wating //code execution 2 //wating //code execution 3 //wating mre.Set(); 4 //code execution //… 5 Upgraded version of this primitive is ManualResetEventSlim. The idea in decreasing performance cost in case, when only 1 thread use it. Main concept in the “hybrid sync schema”, which can be done as following:   internal sealed class SimpleHybridLock : IDisposable { private Int32 m_waiters = 0; private AutoResetEvent m_waiterLock = new AutoResetEvent(false);   public void Enter() { if (Interlocked.Increment(ref m_waiters) == 1) return; m_waiterLock.WaitOne(); }   public void Leave() { if (Interlocked.Decrement(ref m_waiters) == 0) return; m_waiterLock.Set(); }   public void Dispose() { m_waiterLock.Dispose(); } } It’s a sample from Jeffry Richter’s book “CLR via C#”, 3rd edition. Primitive SimpleHybridLock have two public methods: Enter() and Leave(). You can put your concurrency-critical code between calls of these methods, and it would executed in only one thread at the moment. Code is really simple: first thread, called Enter(), increase counter. Second thread also increase counter, and suspend while m_waiterLock is not signaled. So, if we don’t have concurrent access to our lock, “heavy” methods WaitOne() and Set() will not called. It’s can give some performance bonus. ManualResetEvent use the similar idea. Of course, it have more “smart” technics inside, like a checking of recursive calls, and so on. I want to know a real difference between classic ManualResetEvent realization, and new –Slim. I wrote a simple “benchmark”: class Program { static void Main(string[] args) { ManualResetEventSlim mres = new ManualResetEventSlim(false); ManualResetEventSlim mres2 = new ManualResetEventSlim(false);   ManualResetEvent mre = new ManualResetEvent(false);   long total = 0; int COUNT = 50;   for (int i = 0; i < COUNT; i++) { mres2.Reset(); Stopwatch sw = Stopwatch.StartNew();   ThreadPool.QueueUserWorkItem((obj) => { //Method(mres, true); Method2(mre, true); mres2.Set(); }); //Method(mres, false); Method2(mre, false);   mres2.Wait(); sw.Stop();   Console.WriteLine("Pass {0}: {1} ms", i, sw.ElapsedMilliseconds); total += sw.ElapsedMilliseconds; }   Console.WriteLine(); Console.WriteLine("==============================="); Console.WriteLine("Done in average=" + total / (double)COUNT); Console.ReadLine(); }   private static void Method(ManualResetEventSlim mre, bool value) { for (int i = 0; i < 9000000; i++) { if (value) { mre.Set(); } else { mre.Reset(); } } }   private static void Method2(ManualResetEvent mre, bool value) { for (int i = 0; i < 9000000; i++) { if (value) { mre.Set(); } else { mre.Reset(); } } } } I use 2 concurrent thread (the main thread and one from thread pool) for setting and resetting ManualResetEvents, and try to run test COUNT times, and calculate average execution time. Here is the results (I get it on my dual core notebook with T7250 CPU and Windows 7 x64): ManualResetEvent ManualResetEventSlim Difference is obvious and serious – in 10 times! So, I think preferable way is using ManualResetEventSlim, because not always on calling Set() and Reset() will be called “heavy” methods for working with Windows kernel-mode objects. It’s a small and nice improvement! ;)

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• iPack -The iOS Application Packager

  - by user13277780

  iOS applications are distributed in .ipa archive files. These files are regular zip files which contain application resources and executable-s. To protect them from unauthorized modifications and to provide identification of their sources, the content of the archives is signed. The signature is included in the application executable of an.ipa archive and protects the executable file itself and the associated resource files. Apple provides native Mac OS tools for signing iOS executable-s (which are actually generic Mach-O code signing tools), but these tools are not generally available on other platforms. To provide a multi-platform development environment for JavaFX based iOS applications, we ported iOS signing and packaging to Java and created a dedicated ipack tool for it. The iPack tool can be used as a last step of creating .ipa package on various operating systems. Prototype has been tested by creating a final distributable for JavaFX application that runs on iPad, all done on Windows 7. Source Code The source code of iPac tool is in OpenJFX project repository. You can find it in: <openjfx root>/rt/tools/ios/Maven/ipack To build the iPack tool use: rt/tools/ios/Maven/ipack$ mvn package After building, you can run the tool: java -jar <path to ipack.jar> <arguments>  Signing keystore The tool uses a java key store to read the signing certificate and the associated private key. To prepare such keystore users can use keytool from JDK. One possible scenario is to import an existing private key and the certificate from a key store used on Mac OS: To list the content of an existing key store and identify the source alias: keytool -list -keystore <src keystore>.p12 -storetype pkcs12 -storepass <src keystore password> To create Java key store and import the private key with its certificate to the keys store: keytool -importkeystore \ -destkeystore <dst keystore> -deststorepass <dst keystore password> \ -srckeystore <src keystore>.p12 -srcstorepass <src keystore password> -srcstoretype pkcs12 \ -srcalias <src alias> -destalias <dst alias> -destkeypass <dst key password> Another scenario would be to generate a private / public key pair directly in a Java key store and create a certificate request from it. After sending the request to Apple one can then import the certificate response back to the Java key store and complete the signing certificate entry. In both scenarios the resulting alias in the Java key store will contain only a single (leaf) certificate. This can be verified with the following command: keytool -list -v -keystore <ipack keystore> -storepass <keystore password> When looking at the Certificate chain length entry, the number next to it is 1. When an executable file is signed on Mac OS, the resulting signature (in CMS format) includes the whole certificate chain up to the Apple Root CA. The ipack tool includes only the chain which is stored under the alias specified on the command line. So to have the whole chain in the signature we need to replace the single certificate entry under the alias with the corresponding full certificate chain. To do that we need first to create the chain in a separate file. It is easy to create such chain when working with certificates in Base-64 encoded PEM format. A certificate chain can be created by concatenating PEM certificates, which should form the chain, into a single file. For iOS signing we need the following certificates in our chain: Apple Root CA Apple Worldwide Developer Relations CA Our signing leaf certificate To convert a certificate from the binary DER format (.der, .cer) to PEM format: keytool -importcert -noprompt -keystore temp.ks -storepass temppwd -alias tempcert -file <certificate>.cer keytool -exportcert -keystore temp.ks -storepass temppwd -alias tempcert -rfc -file <certificate>.pem To export the signing certificate into PEM format: keytool -exportcert -keystore <ipack keystore> -storepass <keystore password> -alias <signing alias> -rfc -file SigningCert.pem After constructing a chain from AppleIncRootCertificate.pem, AppleWWDRCA.pem andSigningCert.pem, it can be imported back into the keystore with: keytool -importcert -noprompt -keystore <ipack keystore> -storepass <keystore password> -alias <signing alias> -keypass <key password> -file SigningCertChain.pem To summarize, the following example shows the full certificate chain replacement process: keytool -importcert -noprompt -keystore temp.ks -storepass temppwd -alias tempcert1 -file AppleIncRootCertificate.cer keytool -exportcert -keystore temp.ks -storepass temppwd -alias tempcert1 -rfc -file AppleIncRootCertificate.pem keytool -importcert -noprompt -keystore temp.ks -storepass temppwd -alias tempcert2 -file AppleWWDRCA.cer keytool -exportcert -keystore temp.ks -storepass temppwd -alias tempcert2 -rfc -file AppleWWDRCA.pem keytool -exportcert -keystore ipack.ks -storepass keystorepwd -alias mycert -rfc -file SigningCert.pem cat SigningCert.pem AppleWWDRCA.pem AppleIncRootCertificate.pem >SigningCertChain.pem keytool -importcert -noprompt -keystore ipack.ks -storepass keystorepwd -alias mycert -keypass keypwd -file SigningCertChain.pem keytool -list -v -keystore ipack.ks -storepass keystorepwd Usage When the ipack tool is started with no arguments it prints the following usage information: -appname MyApplication -appid com.myorg.MyApplication     Usage: ipack <archive> <signing opts> <application opts> [ <application opts> ... ] Signing options: -keystore <keystore> keystore to use for signing -storepass <password> keystore password -alias <alias> alias for the signing certificate chain and the associated private key -keypass <password> password for the private key Application options: -basedir <directory> base directory from which to derive relative paths -appdir <directory> directory with the application executable and resources -appname <file> name of the application executable -appid <id> application identifier Example: ipack MyApplication.ipa -keystore ipack.ks -storepass keystorepwd -alias mycert -keypass keypwd -basedir mysources/MyApplication/dist -appdir Payload/MyApplication.app -appname MyApplication -appid com.myorg.MyApplication    

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• Threads are facing deadlock in socket program [migrated]

  - by ankur.trapasiya

  I am developing one program in which a user can download a number of files. Now first I am sending the list of files to the user. So from the list user selects one file at a time and provides path where to store that file. In turn it also gives the server the path of file where does it exist. I am following this approach because I want to give stream like experience without file size limitation. Here is my code.. 1) This is server which gets started each time I start my application public class FileServer extends Thread { private ServerSocket socket = null; public FileServer() { try { socket = new ServerSocket(Utils.tcp_port); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } @Override public void run() { try { System.out.println("request received"); new FileThread(socket.accept()).start(); } catch (IOException ex) { ex.printStackTrace(); } } } 2) This thread runs for each client separately and sends the requested file to the user 8kb data at a time. public class FileThread extends Thread { private Socket socket; private String filePath; public String getFilePath() { return filePath; } public void setFilePath(String filePath) { this.filePath = filePath; } public FileThread(Socket socket) { this.socket = socket; System.out.println("server thread" + this.socket.isConnected()); //this.filePath = filePath; } @Override public void run() { // TODO Auto-generated method stub try { ObjectInputStream ois=new ObjectInputStream(socket.getInputStream()); try { //************NOTE filePath=(String) ois.readObject(); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } File f = new File(this.filePath); byte[] buf = new byte[8192]; InputStream is = new FileInputStream(f); BufferedInputStream bis = new BufferedInputStream(is); ObjectOutputStream oos = new ObjectOutputStream( socket.getOutputStream()); int c = 0; while ((c = bis.read(buf, 0, buf.length)) > 0) { oos.write(buf, 0, c); oos.flush(); // buf=new byte[8192]; } oos.close(); //socket.shutdownOutput(); // client.shutdownOutput(); System.out.println("stop"); // client.shutdownOutput(); ois.close(); // Thread.sleep(500); is.close(); bis.close(); socket.close(); } catch (IOException ex) { ex.printStackTrace(); } } } NOTE: here filePath represents the path of the file where it exists on the server. The client who is connecting to the server provides this path. I am managing this through sockets and I am successfully receiving this path. 3) FileReceiverThread is responsible for receiving the data from the server and constructing file from this buffer data. public class FileReceiveThread extends Thread { private String fileStorePath; private String sourceFile; private Socket socket = null; public FileReceiveThread(String ip, int port, String fileStorePath, String sourceFile) { this.fileStorePath = fileStorePath; this.sourceFile = sourceFile; try { socket = new Socket(ip, port); System.out.println("receive file thread " + socket.isConnected()); } catch (IOException ex) { ex.printStackTrace(); } } @Override public void run() { try { ObjectOutputStream oos = new ObjectOutputStream( socket.getOutputStream()); oos.writeObject(sourceFile); oos.flush(); // oos.close(); File f = new File(fileStorePath); OutputStream os = new FileOutputStream(f); BufferedOutputStream bos = new BufferedOutputStream(os); byte[] buf = new byte[8192]; int c = 0; //************ NOTE ObjectInputStream ois = new ObjectInputStream( socket.getInputStream()); while ((c = ois.read(buf, 0, buf.length)) > 0) { // ois.read(buf); bos.write(buf, 0, c); bos.flush(); // buf = new byte[8192]; } ois.close(); oos.close(); // os.close(); bos.close(); socket.close(); //Thread.sleep(500); } catch (IOException ex) { ex.printStackTrace(); } } } NOTE : Now the problem that I am facing is at the first time when the file is requested the outcome of the program is same as my expectation. I am able to transmit any size of file at first time. Now when the second file is requested (e.g. I have sent file a,b,c,d to the user and user has received file a successfully and now he is requesting file b) the program faces deadlock at this situation. It is waiting for socket's input stream. I put breakpoint and tried to debug it but it is not going in FileThread's run method second time. I could not find out the mistake here. Basically I am making a LAN Messenger which works on LAN. I am using SWT as UI framework.

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• Clean way to use mutable implementation of Immutable interfaces for encapsulation

  - by dsollen

  My code is working on some compost relationship which creates a tree structure, class A has many children of type B, which has many children of type C etc. The lowest level class, call it bar, also points to a connected bar class. This effectively makes nearly every object in my domain inter-connected. Immutable objects would be problematic due to the expense of rebuilding almost all of my domain to make a single change to one class. I chose to go with an interface approach. Every object has an Immutable interface which only publishes the getter methods. I have controller objects which constructs the domain objects and thus has reference to the full objects, thus capable of calling the setter methods; but only ever publishes the immutable interface. Any change requested will go through the controller. So something like this: public interface ImmutableFoo{ public Bar getBar(); public Location getLocation(); } public class Foo implements ImmutableFoo{ private Bar bar; private Location location; @Override public Bar getBar(){ return Bar; } public void setBar(Bar bar){ this.bar=bar; } @Override public Location getLocation(){ return Location; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); if(foo!=null) foo.addBar(bar); return foo; } } I felt the basic approach seems sensible, however, when I speak to others they always seem to have trouble envisioning what I'm describing, which leaves me concerned that I may have a larger design issue then I'm aware of. Is it problematic to have domain objects so tightly coupled, or to use the quasi-mutable approach to modifying them? Assuming that the design approach itself isn't inherently flawed the particular discussion which left me wondering about my approach had to do with the presence of business logic in the domain objects. Currently I have my setter methods in the mutable objects do error checking and all other logic required to verify and make a change to the object. It was suggested that this should be pulled out into a service class, which applies all the business logic, to simplify my domain objects. I understand the advantage in mocking/testing and general separation of logic into two classes. However, with a service method/object It seems I loose some of the advantage of polymorphism, I can't override a base class to add in new error checking or business logic. It seems, if my polymorphic classes were complicated enough, I would end up with a service method that has to check a dozen flags to decide what error checking and business logic applies. So, for example, if I wanted to have a childFoo which also had a size field which should be compared to bar before adding par my current approach would look something like this. public class Foo implements ImmutableFoo{ public void addBar(Bar bar){ if(!getLocation().equals(bar.getLocation()) throw new LocationException(); this.bar=bar; } } public interface ImmutableChildFoo extends ImmutableFoo{ public int getSize(); } public ChildFoo extends Foo implements ImmutableChildFoo{ private int size; @Override public int getSize(){ return size; } @Override public void addBar(Bar bar){ if(getSize()<bar.getSize()){ throw new LocationException(); super.addBar(bar); } My colleague was suggesting instead having a service object that looks something like this (over simplified, the 'service' object would likely be more complex). public interface ImmutableFoo{ ///original interface, presumably used in other methods public Location getLocation(); public boolean isChildFoo(); } public interface ImmutableSizedFoo implements ImmutableFoo{ public int getSize(); } public class Foo implements ImmutableSizedFoo{ public Bar bar; @Override public void addBar(Bar bar){ this.bar=bar; } @Override public int getSize(){ //default size if no size is known return 0; } @Override public boolean isChildFoo return false; } } public ChildFoo extends Foo{ private int size; @Override public int getSize(){ return size; } @Override public boolean isChildFoo(); return true; } } public class Controller{ Private Map<Location, Foo> fooMap; public ImmutableSizedFoo addBar(Bar bar){ Foo foo=fooMap.get(bar.getLocation()); service.addBarToFoo(foo, bar); returned foo; } public class Service{ public static void addBarToFoo(Foo foo, Bar bar){ if(foo==null) return; if(!foo.getLocation().equals(bar.getLocation())) throw new LocationException(); if(foo.isChildFoo() && foo.getSize()<bar.getSize()) throw new LocationException(); foo.setBar(bar); } } } Is the recommended approach of using services and inversion of control inherently superior, or superior in certain cases, to overriding methods directly? If so is there a good way to go with the service approach while not loosing the power of polymorphism to override some of the behavior?

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• MacOSX VirtualHost: "You don't have permission to access / on this server" error

  - by David Casillas

  The Apache instalation of MacOSX is running Ok. I have tried to create a VirtualHost called test.local, but as soon as I uncomment from /private/etc/apache2/httpd.conf the line Include /private/etc/apache2/extra/httpd-vhosts.conf , and try to access test.local virtualhost I get an error "You don't have permission to access / on this server". The VirtualHost configuration in /private/etc/apache2/extra/httpd-vhosts.conf is: <VirtualHost *:80> ServerName test.local DocumentRoot "/Users/username/Sites/Test/public" <Directory "/Users/username/Sites/Test/public"> Options Indexes FollowSymLinks Includes AllowOverride All Order allow,deny Allow from all </Directory> </VirtualHost> I have also include the VirtualHost in hosts file: 127.0.0.1 test.local

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