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  • Ninject.ActivationException: Error activating IMainLicense

    - by Stefan Karlsson
    Im don't know fully how Ninject works thats wye i ask this question here to figure out whats wrong. If i create a empty constructor in ClaimsSecurityService it gets hit. This is my error: Error activating IMainLicense No matching bindings are available, and the type is not self-bindable. Activation path: 3) Injection of dependency IMainLicense into parameter mainLicenses of constructor of type ClaimsSecurityService 2) Injection of dependency ISecurityService into parameter securityService of constructor of type AccountController 1) Request for AccountController Stack: Ninject.KernelBase.Resolve(IRequest request) +474 Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) +153 Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) +747 Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) +269 Ninject.Activation.Providers.<>c__DisplayClass4.<Create>b__2(ITarget target) +69 System.Linq.WhereSelectArrayIterator`2.MoveNext() +66 System.Linq.Buffer`1..ctor(IEnumerable`1 source) +216 System.Linq.Enumerable.ToArray(IEnumerable`1 source) +77 Ninject.Activation.Providers.StandardProvider.Create(IContext context) +847 Ninject.Activation.Context.ResolveInternal(Object scope) +218 Ninject.Activation.Context.Resolve() +277 Ninject.<>c__DisplayClass15.<Resolve>b__f(IBinding binding) +86 System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145 System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +4059897 Ninject.Planning.Targets.Target`1.GetValue(Type service, IContext parent) +169 Ninject.Planning.Targets.Target`1.ResolveWithin(IContext parent) +747 Ninject.Activation.Providers.StandardProvider.GetValue(IContext context, ITarget target) +269 Ninject.Activation.Providers.<>c__DisplayClass4.<Create>b__2(ITarget target) +69 System.Linq.WhereSelectArrayIterator`2.MoveNext() +66 System.Linq.Buffer`1..ctor(IEnumerable`1 source) +216 System.Linq.Enumerable.ToArray(IEnumerable`1 source) +77 Ninject.Activation.Providers.StandardProvider.Create(IContext context) +847 Ninject.Activation.Context.ResolveInternal(Object scope) +218 Ninject.Activation.Context.Resolve() +277 Ninject.<>c__DisplayClass15.<Resolve>b__f(IBinding binding) +86 System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145 System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +4059897 Ninject.Web.Mvc.NinjectDependencyResolver.GetService(Type serviceType) +145 System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +87 [InvalidOperationException: An error occurred when trying to create a controller of type 'Successful.Struct.Web.Controllers.AccountController'. Make sure that the controller has a parameterless public constructor.] System.Web.Mvc.DefaultControllerActivator.Create(RequestContext requestContext, Type controllerType) +247 System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType) +438 System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName) +257 System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory) +326 System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state) +157 System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContext httpContext, AsyncCallback callback, Object state) +88 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) +50 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +301 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155 Account controller: public class AccountController : Controller { private readonly ISecurityService _securityService; public AccountController(ISecurityService securityService) { _securityService = securityService; } // // GET: /Account/Login [AllowAnonymous] public ActionResult Login(string returnUrl) { ViewBag.ReturnUrl = returnUrl; return View(); } } NinjectWebCommon: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Http; using System.Web.Http.Dependencies; using Microsoft.Web.Infrastructure.DynamicModuleHelper; using Ninject; using Ninject.Extensions.Conventions; using Ninject.Parameters; using Ninject.Syntax; using Ninject.Web.Common; using Successful.Struct.Web; [assembly: WebActivator.PreApplicationStartMethod(typeof(NinjectWebCommon), "Start")] [assembly: WebActivator.ApplicationShutdownMethodAttribute(typeof(NinjectWebCommon), "Stop")] namespace Successful.Struct.Web { public static class NinjectWebCommon { private static readonly Bootstrapper Bootstrapper = new Bootstrapper(); /// <summary> /// Starts the application /// </summary> public static void Start() { DynamicModuleUtility.RegisterModule(typeof(OnePerRequestHttpModule)); DynamicModuleUtility.RegisterModule(typeof(NinjectHttpModule)); Bootstrapper.Initialize(CreateKernel); } /// <summary> /// Stops the application. /// </summary> public static void Stop() { Bootstrapper.ShutDown(); } /// <summary> /// Creates the kernel that will manage your application. /// </summary> /// <returns>The created kernel.</returns> private static IKernel CreateKernel() { var kernel = new StandardKernel(); kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel); kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>(); kernel.Load("Successful*.dll"); kernel.Bind(x => x.FromAssembliesMatching("Successful*.dll") .SelectAllClasses() .BindAllInterfaces() ); GlobalConfiguration.Configuration.DependencyResolver = new NinjectResolver(kernel); RegisterServices(kernel); return kernel; } /// <summary> /// Load your modules or register your services here! /// </summary> /// <param name="kernel">The kernel.</param> private static void RegisterServices(IKernel kernel) { } } public class NinjectResolver : NinjectScope, IDependencyResolver { private readonly IKernel _kernel; public NinjectResolver(IKernel kernel) : base(kernel) { _kernel = kernel; } public IDependencyScope BeginScope() { return new NinjectScope(_kernel.BeginBlock()); } } public class NinjectScope : IDependencyScope { protected IResolutionRoot ResolutionRoot; public NinjectScope(IResolutionRoot kernel) { ResolutionRoot = kernel; } public object GetService(Type serviceType) { var request = ResolutionRoot.CreateRequest(serviceType, null, new Parameter[0], true, true); return ResolutionRoot.Resolve(request).SingleOrDefault(); } public IEnumerable<object> GetServices(Type serviceType) { var request = ResolutionRoot.CreateRequest(serviceType, null, new Parameter[0], true, true); return ResolutionRoot.Resolve(request).ToList(); } public void Dispose() { var disposable = (IDisposable)ResolutionRoot; if (disposable != null) disposable.Dispose(); ResolutionRoot = null; } } } ClaimsSecurityService: public class ClaimsSecurityService : ISecurityService { private const string AscClaimsIdType = "http://schemas.microsoft.com/accesscontrolservice/2010/07/claims/identityprovider"; private const string SuccessfulStructWebNamespace = "Successful.Struct.Web"; private readonly IMainLicense _mainLicenses; private readonly ICompany _companys; private readonly IAuthTokenService _authService; [Inject] public IApplicationContext ApplicationContext { get; set; } [Inject] public ILogger<LocationService> Logger { get; set; } public ClaimsSecurityService(IMainLicense mainLicenses, ICompany companys, IAuthTokenService authService) { _mainLicenses = mainLicenses; _companys = companys; _authService = authService; } }

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  • Trouble linking libboost libraries to compile sslsniff on RHEL

    - by rwong48
    Trying to build sslsniff on a RHEL 5.2 system here. When compiling sslsniff on RHEL I hit the same errors when using libboost packages (from repositories like rpmforge) and compiling libboost from source (which appeared to be successful.) I tried this on a fresh system as well (no previous/failed/garbage installs of libboost etc.) # make g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT SSLConnectionManager.o -MD -MP -MF .deps/SSLConnectionManager.Tpo -c -o SSLConnectionManager.o SSLConnectionManager.cpp mv -f .deps/SSLConnectionManager.Tpo .deps/SSLConnectionManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT FirefoxUpdater.o -MD -MP -MF .deps/FirefoxUpdater.Tpo -c -o FirefoxUpdater.o FirefoxUpdater.cpp mv -f .deps/FirefoxUpdater.Tpo .deps/FirefoxUpdater.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT Logger.o -MD -MP -MF .deps/Logger.Tpo -c -o Logger.o Logger.cpp mv -f .deps/Logger.Tpo .deps/Logger.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT SessionCache.o -MD -MP -MF .deps/SessionCache.Tpo -c -o SessionCache.o SessionCache.cpp mv -f .deps/SessionCache.Tpo .deps/SessionCache.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT SSLBridge.o -MD -MP -MF .deps/SSLBridge.Tpo -c -o SSLBridge.o SSLBridge.cpp mv -f .deps/SSLBridge.Tpo .deps/SSLBridge.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT HTTPSBridge.o -MD -MP -MF .deps/HTTPSBridge.Tpo -c -o HTTPSBridge.o HTTPSBridge.cpp mv -f .deps/HTTPSBridge.Tpo .deps/HTTPSBridge.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT sslsniff.o -MD -MP -MF .deps/sslsniff.Tpo -c -o sslsniff.o sslsniff.cpp mv -f .deps/sslsniff.Tpo .deps/sslsniff.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT FingerprintManager.o -MD -MP -MF .deps/FingerprintManager.Tpo -c -o FingerprintManager.o FingerprintManager.cpp mv -f .deps/FingerprintManager.Tpo .deps/FingerprintManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT AuthorityCertificateManager.o -MD -MP -MF .deps/AuthorityCertificateManager.Tpo -c -o AuthorityCertificateManager.o `test -f 'certificate/AuthorityCertificateManager.cpp' || echo './'`certificate/AuthorityCertificateManager.cpp mv -f .deps/AuthorityCertificateManager.Tpo .deps/AuthorityCertificateManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT TargetedCertificateManager.o -MD -MP -MF .deps/TargetedCertificateManager.Tpo -c -o TargetedCertificateManager.o `test -f 'certificate/TargetedCertificateManager.cpp' || echo './'`certificate/TargetedCertificateManager.cpp mv -f .deps/TargetedCertificateManager.Tpo .deps/TargetedCertificateManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT CertificateManager.o -MD -MP -MF .deps/CertificateManager.Tpo -c -o CertificateManager.o `test -f 'certificate/CertificateManager.cpp' || echo './'`certificate/CertificateManager.cpp mv -f .deps/CertificateManager.Tpo .deps/CertificateManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT HttpBridge.o -MD -MP -MF .deps/HttpBridge.Tpo -c -o HttpBridge.o `test -f 'http/HttpBridge.cpp' || echo './'`http/HttpBridge.cpp mv -f .deps/HttpBridge.Tpo .deps/HttpBridge.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT HttpConnectionManager.o -MD -MP -MF .deps/HttpConnectionManager.Tpo -c -o HttpConnectionManager.o `test -f 'http/HttpConnectionManager.cpp' || echo './'`http/HttpConnectionManager.cpp mv -f .deps/HttpConnectionManager.Tpo .deps/HttpConnectionManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT HttpHeaders.o -MD -MP -MF .deps/HttpHeaders.Tpo -c -o HttpHeaders.o `test -f 'http/HttpHeaders.cpp' || echo './'`http/HttpHeaders.cpp mv -f .deps/HttpHeaders.Tpo .deps/HttpHeaders.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT UpdateManager.o -MD -MP -MF .deps/UpdateManager.Tpo -c -o UpdateManager.o UpdateManager.cpp mv -f .deps/UpdateManager.Tpo .deps/UpdateManager.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT OCSPDenier.o -MD -MP -MF .deps/OCSPDenier.Tpo -c -o OCSPDenier.o `test -f 'http/OCSPDenier.cpp' || echo './'`http/OCSPDenier.cpp mv -f .deps/OCSPDenier.Tpo .deps/OCSPDenier.Po g++ -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE=\"sslsniff\" -DVERSION=\"0.6\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -I. -ggdb -g -O2 -MT FirefoxAddonUpdater.o -MD -MP -MF .deps/FirefoxAddonUpdater.Tpo -c -o FirefoxAddonUpdater.o FirefoxAddonUpdater.cpp mv -f .deps/FirefoxAddonUpdater.Tpo .deps/FirefoxAddonUpdater.Po g++ -ggdb -g -O2 -lssl -lboost_filesystem -lpthread -lboost_thread -llog4cpp -o sslsniff SSLConnectionManager.o FirefoxUpdater.o Logger.o SessionCache.o SSLBridge.o HTTPSBridge.o sslsniff.o FingerprintManager.o AuthorityCertificateManager.o TargetedCertificateManager.o CertificateManager.o HttpBridge.o HttpConnectionManager.o HttpHeaders.o UpdateManager.o OCSPDenier.o FirefoxAddonUpdater.o SSLConnectionManager.o: In function `__static_initialization_and_destruction_0': /usr/local/include/boost/system/error_code.hpp:208: undefined reference to `boost::system::get_system_category()' /usr/local/include/boost/system/error_code.hpp:209: undefined reference to `boost::system::get_generic_category()' /usr/local/include/boost/system/error_code.hpp:214: undefined reference to `boost::system::get_generic_category()' /usr/local/include/boost/system/error_code.hpp:215: undefined reference to `boost::system::get_generic_category()' /usr/local/include/boost/system/error_code.hpp:216: undefined reference to `boost::system::get_system_category()' There's more, but I guess there's a post length limit.. Most of them appear related to boost::system so I added -lboost_system to the linker command and got farther: # g++ -ggdb -g -O2 -lssl -lboost_filesystem -lpthread -lboost_thread -llog4cpp -o sslsniff SSLConnectionManager.o FirefoxUpdater.o Logger.o SessionCache.o SSLBridge.o HTTPSBridge.o sslsniff.o FingerprintManager.o AuthorityCertificateManager.o TargetedCertificateManager.o CertificateManager.o HttpBridge.o HttpConnectionManager.o HttpHeaders.o UpdateManager.o OCSPDenier.o FirefoxAddonUpdater.o -lboost_system SSLConnectionManager.o: In function `thread<boost::_bi::bind_t<void, boost::_mfi::mf3<void, SSLConnectionManager, boost::shared_ptr<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> > >, boost::asio::ip::basic_endpoint<boost::asio::ip::tcp>, bool>, boost::_bi::list4<boost::_bi::value<SSLConnectionManager*>, boost::_bi::value<boost::shared_ptr<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> > > >, boost::_bi::value<boost::asio::ip::basic_endpoint<boost::asio::ip::tcp> >, boost::_bi::value<bool> > > >': /usr/local/include/boost/thread/detail/thread.hpp:191: undefined reference to `boost::thread::start_thread()' SSLConnectionManager.o: In function `~thread_data': /usr/local/include/boost/thread/detail/thread.hpp:40: undefined reference to `boost::detail::thread_data_base::~thread_data_base()' /usr/local/include/boost/thread/detail/thread.hpp:40: undefined reference to `boost::detail::thread_data_base::~thread_data_base()' /usr/local/include/boost/thread/detail/thread.hpp:40: undefined reference to `boost::detail::thread_data_base::~thread_data_base()' /usr/local/include/boost/thread/detail/thread.hpp:40: undefined reference to `boost::detail::thread_data_base::~thread_data_base()' Now the errors are related to boost::detail and boost::filesystem::detail. I've tried using boost 1.35 and 1.42 (latest). On my own Ubuntu system, I installed the libraries from Ubuntu repositories and I was able to compile+link sslsniff just fine. Thanks in advance.

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  • Implementing an async "read all currently available data from stream" operation

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a console's standard output Stream. Console output streams are of type FileStream; the implementation can cast to that, if needed. There is also an associated StreamReader already present to leverage. There is only one thing I need to implement in this class to achieve my desired functionality: an async "read all the data available this moment" operation. Reading to the end of the stream is not viable because the stream will not end unless the process closes the console output handle, and it will not do that because it is interactive and expecting input before continuing. I will be using that hypothetical async operation to implement event-based notification, which will be more convenient for my callers. The public interface of the class is this: public class ConsoleAutomator { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Remember that the goal here is to read all of the chunk and call event subscribers exactly once for each chunk. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream. private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer (in which case we know that there was no more data to be read during the last read operation), all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Never more than one event for each time data is available to be read Is almost agnostic to the buffer size The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this. Update: I definitely did not communicate the scenario well in my initial writeup. I have since revised the writeup quite a bit, but to be extra sure: The question is about how to implement an async "read all the data available this moment" operation. My apologies to the people who took the time to read and answer without me making my intent clear enough.

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  • How to Configure Parameter Interceptors ?

    - by jyo
    Hi In my Struts2 applicaion I have a Jsp page with some feilds , like this <s:form action="customer.action" method="post" validate="false"> <s:textfield name="cust.fname" key="fname" size="20" /> <s:textfield name="cust.lname" key="lname" size="20" /> <s:textfield name="cust.title" key="title" size="20" /> <s:submit method="addCustomer" key="label.submit" align="center" /> </s:form> I have created a Bean Class For that public class Customer { private String fname; private String lname; private String title; public String getFname() { return fname; } public void setFname(String fname) { this.fname = fname; } public String getLname() { return lname; } public void setLname(String lname) { this.lname = lname; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } } an Action Class public class CustomerAction extends ActionSupport { private Customer cust; public Customer getCust() { return cust; } public void setCust(Customer cust) { this.cust = cust; } public String addCustomer() { return "success"; } } When i hit the submit button i m getting exception like this com.opensymphony.xwork2.interceptor.ParametersInterceptor setParameters SEVERE: ParametersInterceptor - [setParameters]: Unexpected Exception catched: Error setting expression 'cust.address' with value '[Ljava.lang.String;@153113d' SEVERE: ParametersInterceptor - [setParameters]: Unexpected Exception catched: Error setting expression 'cust.fname' with value '[Ljava.lang.String;@18c8aea' 17 Jun, 2010 3:37:36 PM com.opensymphony.xwork2.interceptor.ParametersInterceptor setParameters SEVERE: ParametersInterceptor - [setParameters]: Unexpected Exception catched: Error setting expression 'cust.lname' with value '[Ljava.lang.String;@1f42731' 17 Jun, 2010 3:37:36 PM com.opensymphony.xwork2.interceptor.ParametersInterceptor setParameters WARNING: Caught an exception while evaluating expression 'cust.lname' against value stack Caught an Ognl exception while getting property cust - Class: ognl.OgnlRuntime File: OgnlRuntime.java Method: getMethodValue Line: 935 - ognl/OgnlRuntime.java:935:-1 at com.opensymphony.xwork2.util.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:106) at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1643) at ognl.ASTProperty.getValueBody(ASTProperty.java:92) at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170) at ognl.SimpleNode.getValue(SimpleNode.java:210) at ognl.ASTChain.getValueBody(ASTChain.java:109) at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170) at ognl.SimpleNode.getValue(SimpleNode.java:210) at ognl.Ognl.getValue(Ognl.java:333) at com.opensymphony.xwork2.util.OgnlUtil.getValue(OgnlUtil.java:194) at com.opensymphony.xwork2.util.OgnlValueStack.findValue(OgnlValueStack.java:238) at org.apache.struts2.components.Property.start(Property.java:136) at org.apache.struts2.views.jsp.ComponentTagSupport.doStartTag(ComponentTagSupport.java:54) at org.apache.jsp.pages.SuccessCustomer_jsp._jspx_meth_s_005fproperty_005f1(SuccessCustomer_jsp.java:139) at org.apache.jsp.pages.SuccessCustomer_jsp._jspService(SuccessCustomer_jsp.java:72) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302) at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:139) at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:178) at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:343) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248) at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:213) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:150) at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:48) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:86) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:123) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ParametersInterceptor.intercept(ParametersInterceptor.java:161) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:105) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:83) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:207) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:74) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:127) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:107) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:206) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:115) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:143) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.PrepareInterceptor.intercept(PrepareInterceptor.java:115) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:170) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:123) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at com.opensymphony.xwork2.interceptor.ParametersInterceptor.intercept(ParametersInterceptor.java:161) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:83) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:219) at com.opensymphony.xwork2.DefaultActionInvocation$2.doProfiling(DefaultActionInvocation.java:218) at com.opensymphony.xwork2.util.profiling.UtilTimerStack.profile(UtilTimerStack.java:455) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:216) at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:50) at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:507) at org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:421) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) at java.lang.Thread.run(Thread.java:636) Caused by: ognl.OgnlException: cust [java.lang.NullPointerException] at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:935) at ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:53) at ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:121) at com.opensymphony.xwork2.util.OgnlValueStack$ObjectAccessor.getProperty(OgnlValueStack.java:58) at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1643) at com.opensymphony.xwork2.util.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:101) ... 143 more 17 Jun, 2010 3:48:55 PM com.opensymphony.xwork2.util.OgnlValueStack logLookupFailure WARNING: NOTE: Previous warning message was issued due to devMode set to true. How do i resolve this ? Thnks

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  • Append/Add Child Div (jQuery) for Messaging System

    - by Lord Varlin
    So, I'm having difficulty trying to append/add a child div to the parent div, and thought someone out here may know the best way for me to go about this. I have attached my code (without PHP right now, just hard coding text and stuff). But here is what I am trying to do: When a message is posted, you hit the "Reply Button" and a new div will appear underneath containing the reply form. Right now, here are the issues I know about and can't get around: The DIV is a class, so when I use jQuery to try to target the DIV it targets everything since it's no unique. The Reply Button is also a class, so it's not unique. Here is a video of it in action: http://tinypic.com/r/2luxwnr/7 HTML <body> <div id="content-container"> <div id="message-viewer"> <div class="roar"> <div class="roaractionpanel"> <div id="msg-business2"></div> <div class="roartime"><p class="roartime-text">3:26PM</p></div> </div> <div class="roarcontent"> <button type="submit" class="btn-reply"></button> <h5>Test Post</h5><br> <h6>Lord Varlin</h6><br> <h2>Test post... let's see.</h2> </div> </div> <div class="newreply"> <div class="newreplycontent"> <h1>This is where the fields for a new reply will go.</h1> </div> </div> <div class="roar"> <div class="roaractionpanel"> <div id="msg-business2"></div> <div class="roartime"><p class="roartime-text">3:26PM</p></div> </div> <div class="roarcontent"> <button type="submit" class="btn-reply"></button> <h5>Testing another</h5><br> <h6>Lord Varlin</h6><br> <h2>Hmm dee dumm...</h2> </div> </div> <div class="roarreply"> <div class="roarreply-marker"> <p class="roarreplytime-text">June 26th @ 4:42AM</p> </div> <div class="roarreplycontent"> <h9>Testing a reply. Hmmmm.</h9><br> <h8>Lord Varlin</h8> </div> </div> <div class="newreply"> <div class="newreplycontent"> <h1>This is where the fields for a new reply will go.</h1> </div> </div> <div class="roar"> <div class="roaractionpanel"> <div id="msg-business2"></div> <div class="roartime"><p class="roartime- text">3:26PM</p></div> </div> <div class="roarcontent"> <button type="submit" class="btn-reply"></button> <h5>Testing another</h5><br> <h6>Lord Varlin</h6><br> <h2>jQuery, work with me please.</h2> </div> </div> <div class="roarreply"> <div class="roarreply-marker"> <p class="roarreplytime-text">June 26th @ 4:42AM</p> </div> <div class="roarreplycontent"> <h9>Testing a reply. Hmmmm.</h9><br> <h8>Lord Varlin</h8> </div> </div> <div class="roarreply"> <div class="roarreply-marker"> <p class="roarreplytime-text">June 26th @ 4:42AM</p> </div> <div class="roarreplycontent"> <h9>Testing a reply. Hmmmm.</h9><br> <h8>Lord Varlin</h8> </div> </div> <div class="newreply"> <div class="newreplycontent"> <h1>This is where the fields for a new reply will go.</h1> </div> </div> </div> </div> </body> JQUERY $(".btn-reply").click(function() { $(".newreply").toggleClass("show"); return false; }); So, I see the flaws, but I just can't wrap my head around how to pull this off! Any guidance would be awesome! :)

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  • Implementing a robust async stream reader

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output, but that is a detail and does not play an important role. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • UITableview has problem reloading

    - by seelani
    Hi guys, I've kinda finished my application for a school project but have run into a major "bug". It's a account management application. I'm unable to insert a picture here so here's a link: http://i232.photobucket.com/albums/ee112/seelani/Screenshot2010-12-22atPM075512.png Here's the problem when i click on the plus sign, i push a nav controller to load another view to handle the adding and deleting of categories. When i add and return back to the view above, it doesn't update. It only updates after i hit the button on the right which is another view used to change some settings, and return back to the page. I did some research on viewWillAppear and such but I'm still confused to why it doesn't work properly. This problem is also affecting my program when i delete a category, and return back to this view it crashes cos the view has not reloaded successfully. I will get this error when deleting and returning to the view. "* Terminating app due to uncaught exception 'NSRangeException', reason: '* -[NSMutableArray objectAtIndex:]: index 4 beyond bounds [0 .. 3]'". [EDIT] Table View Code: @class LoginViewController; @implementation CategoryTableViewController @synthesize categoryTableViewController; @synthesize categoryArray; @synthesize accountsTableViewController; @synthesize editAccountTable; @synthesize window; CategoryMgmtTableController *categoryMgmtTableController; ChangePasswordView *changePasswordView; - (void) save_Clicked:(id)sender { /* UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Category Management" message:@"Load category management table view" delegate:self cancelButtonTitle: @"OK" otherButtonTitles:nil]; [alert show]; [alert release]; */ KeyCryptAppAppDelegate *appDelegate = (KeyCryptAppAppDelegate *)[[UIApplication sharedApplication] delegate]; categoryMgmtTableController = [[CategoryMgmtTableController alloc]initWithNibName:@"CategoryMgmtTable" bundle:nil]; [appDelegate.categoryNavController pushViewController:categoryMgmtTableController animated:YES]; } - (void) change_Clicked:(id)sender { UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Change Password" message:@"Change password View" delegate:self cancelButtonTitle: @"OK" otherButtonTitles:nil]; [alert show]; [alert release]; KeyCryptAppAppDelegate *appDelegate = (KeyCryptAppAppDelegate *)[[UIApplication sharedApplication] delegate]; changePasswordView = [[ChangePasswordView alloc]initWithNibName:@"ChangePasswordView" bundle:nil]; [appDelegate.categoryNavController pushViewController:changePasswordView animated:YES]; /* KeyCryptAppAppDelegate *appDelegate = (KeyCryptAppAppDelegate *)[[UIApplication sharedApplication] delegate]; categoryMgmtTableController = [[CategoryMgmtTableController alloc]initWithNibName:@"CategoryMgmtTable" bundle:nil]; [appDelegate.categoryNavController pushViewController:categoryMgmtTableController animated:YES]; */ } #pragma mark - #pragma mark Initialization /* - (id)initWithStyle:(UITableViewStyle)style { // Override initWithStyle: if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad. if ((self = [super initWithStyle:style])) { } return self; } */ -(void) initializeCategoryArray { sqlite3 *db= [KeyCryptAppAppDelegate getNewDBConnection]; KeyCryptAppAppDelegate *appDelegate = (KeyCryptAppAppDelegate *)[[UIApplication sharedApplication] delegate]; const char *sql = [[NSString stringWithFormat:(@"Select Category from Categories;")]cString]; const char *cmd = [[NSString stringWithFormat:@"pragma key = '%@' ", appDelegate.pragmaKey]cString]; sqlite3_stmt *compiledStatement; sqlite3_exec(db, cmd, NULL, NULL, NULL); if (sqlite3_prepare_v2(db, sql, -1, &compiledStatement, NULL)==SQLITE_OK) { while(sqlite3_step(compiledStatement) == SQLITE_ROW) [categoryArray addObject:[NSString stringWithUTF8String:(char*) sqlite3_column_text(compiledStatement, 0)]]; } else { NSAssert1(0,@"Error preparing statement", sqlite3_errmsg(db)); } sqlite3_finalize(compiledStatement); } #pragma mark - #pragma mark View lifecycle - (void)viewDidLoad { // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem; [super viewDidLoad]; } - (void)viewWillAppear:(BOOL)animated { self.title = NSLocalizedString(@"Categories",@"Types of Categories"); categoryArray = [[NSMutableArray alloc]init]; [self initializeCategoryArray]; self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(save_Clicked:)] autorelease]; self.navigationItem.leftBarButtonItem = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:@selector(change_Clicked:)] autorelease]; [super viewWillAppear:animated]; } - (void)viewDidAppear:(BOOL)animated { NSLog (@"view did appear"); [super viewDidAppear:animated]; } - (void)viewWillDisappear:(BOOL)animated { NSLog (@"view will disappear"); [super viewWillDisappear:animated]; } - (void)viewDidDisappear:(BOOL)animated { [categoryTableView reloadData]; NSLog (@"view did disappear"); [super viewDidDisappear:animated]; } /* // Override to allow orientations other than the default portrait orientation. - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { // Return YES for supported orientations return (interfaceOrientation == UIInterfaceOrientationPortrait); } */ #pragma mark - #pragma mark Table view data source - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { // Return the number of sections. return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { // Return the number of rows in the section. return [self.categoryArray count]; } // Customize the appearance of table view cells. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } // Configure the cell... NSUInteger row = [indexPath row]; cell.text = [categoryArray objectAtIndex:row]; cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; return cell; } /* // Override to support conditional editing of the table view. - (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the specified item to be editable. return YES; } */ /* // Override to support editing the table view. - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { // Delete the row from the data source [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES]; } else if (editingStyle == UITableViewCellEditingStyleInsert) { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } } */ /* // Override to support rearranging the table view. - (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath { } */ /* // Override to support conditional rearranging of the table view. - (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the item to be re-orderable. return YES; } */ #pragma mark - #pragma mark Table view delegate - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { NSString *selectedCategory = [categoryArray objectAtIndex:[indexPath row]]; NSLog (@"AccountsTableView.xib is called."); if ([categoryArray containsObject: selectedCategory]) { if (self.accountsTableViewController == nil) { AccountsTableViewController *aAccountsView = [[AccountsTableViewController alloc]initWithNibName:@"AccountsTableView"bundle:nil]; self.accountsTableViewController =aAccountsView; [aAccountsView release]; } NSInteger row =[indexPath row]; accountsTableViewController.title = [NSString stringWithFormat:@"%@", [categoryArray objectAtIndex:row]]; // This portion pushes the categoryNavController. KeyCryptAppAppDelegate *delegate = [[UIApplication sharedApplication] delegate]; [self.accountsTableViewController initWithTextSelected:selectedCategory]; KeyCryptAppAppDelegate *appDelegate = (KeyCryptAppAppDelegate *)[[UIApplication sharedApplication] delegate]; appDelegate.pickedCategory = selectedCategory; [delegate.categoryNavController pushViewController:accountsTableViewController animated:YES]; } } #pragma mark - #pragma mark Memory management - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Relinquish ownership any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand. // For example: self.myOutlet = nil; } - (void)dealloc { [accountsTableViewController release]; [super dealloc]; } @end And the code that i used to delete rows(this is in a totally different tableview): - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { // Delete the row from the data source NSString *selectedCategory = [categoryArray objectAtIndex:indexPath.row]; [categoryArray removeObjectAtIndex:indexPath.row]; [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES]; [deleteCategoryTable reloadData]; //NSString *selectedCategory = [categoryArray objectAtIndex:indexPath.row]; sqlite3 *db= [KeyCryptAppAppDelegate getNewDBConnection]; KeyCryptAppAppDelegate *appDelegate = (KeyCryptAppAppDelegate *)[[UIApplication sharedApplication] delegate]; const char *sql = [[NSString stringWithFormat:@"Delete from Categories where Category = '%@';", selectedCategory]cString]; const char *cmd = [[NSString stringWithFormat:@"pragma key = '%@' ", appDelegate.pragmaKey]cString]; sqlite3_stmt *compiledStatement; sqlite3_exec(db, cmd, NULL, NULL, NULL); if (sqlite3_prepare_v2(db, sql, -1, &compiledStatement, NULL)==SQLITE_OK) { sqlite3_exec(db,sql,NULL,NULL,NULL); } else { NSAssert1(0,@"Error preparing statement", sqlite3_errmsg(db)); } sqlite3_finalize(compiledStatement); } else if (editingStyle == UITableViewCellEditingStyleInsert) { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } }

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  • Will these optimizations to my Ruby implementation of diff improve performance in a Rails app?

    - by grg-n-sox
    <tl;dr> In source version control diff patch generation, would it be worth it to use the optimizations listed at the very bottom of this writing (see <optimizations>) in my Ruby implementation of diff for making diff patches? </tl;dr> <introduction> I am programming something I have never done before and there might already be tools out there to do the exact thing I am programming but at this point I am having too much fun to care so I am still going to do it from scratch, even if there is a tool for this. So anyways, I am working on a Ruby on Rails app and need a certain feature. Basically I want each entry in a table of mine, let's say for example a table of video games, to have a stored chunk of text that represents a review or something of the sort for that table entry. However, I want this text to be both editable by any registered user and also keep track of different submissions in a version control system. The simplest solution I could think of is just implement a solution that keeps track of the text body and the diff patch history of different versions of the text body as objects in Ruby and then serialize it, preferably in human readable form (so I'll most likely use YAML for this) for editing if needed due to corruption by a software bug or a mistake is made by an admin doing some version editing. So at first I just tried to dive in head first into this feature to find that the problem of generating a diff patch is more difficult that I thought to do efficiently. So I did some research and came across some ideas. Some I have implemented already and some I have not. However, it all pretty much revolves around the longest common subsequence problem, as you would already know if you have already done anything with diff or diff-like features, and optimization the function that solves it. Currently I have it so it truncates the compared versions of the text body from the beginning and end until non-matching lines are found. Then it solves the problem using a comparison matrix, but instead of incrementing the value stored in a cell when it finds a matching line like in most longest common subsequence algorithms I have seen examples of, I increment when I have a non-matching line so as to calculate edit distance instead of longest common subsequence. Although as far as I can tell between the two approaches, they are essentially two sides of the same coin so either could be used to derive an answer. It then back-traces through the comparison matrix and notes when there was an incrementation and in which adjacent cell (West, Northwest, or North) to determine that line's diff entry and assumes all other lines to be unchanged. Normally I would leave it at that, but since this is going into a Rails environment and not just some stand-alone Ruby script, I started getting worried about needing to optimize at least enough so if a spammer that somehow knew how I implemented the version control system and knew my worst case scenario entry still wouldn't be able to hit the server that bad. After some searching and reading of research papers and articles through the internet, I've come across several that seem decent but all seem to have pros and cons and I am having a hard time deciding how well in this situation that the pros and cons balance out. So are the ones listed here worth it? I have listed them with known pros and cons. </introduction> <optimizations> Chop the compared sequences into multiple chucks of subsequences by splitting where lines are unchanged, and then truncating each section of unchanged lines at the beginning and end of each section. Then solve the edit distance of each subsequence. Pro: Changes the time increase as the changed area gets bigger from a quadratic increase to something more similar to a linear increase. Con: Figuring out where to split already seems like you have to solve edit distance except now you don't care how it is changed. Would be fine if this was solvable by a process closer to solving hamming distance but a single insertion would throw this off. Use a cryptographic hash function to both convert all sequence elements into integers and ensure uniqueness. Then solve the edit distance comparing the hash integers instead of the sequence elements themselves. Pro: The operation of comparing two integers is faster than the operation of comparing two strings, so a slight performance gain is received after every comparison, which can be a lot overall. Con: Using a cryptographic hash function takes time to convert all the sequence elements and may end up costing more time to do the conversion that you gain back from the integer comparisons. You could use the built in hash function for a string but that will not guarantee uniqueness. Use lazy evaluation to only calculate the three center-most diagonals of the comparison matrix and then only calculate additional diagonals as needed. And then also use this approach to possibly remove the need on some comparisons to compare all three adjacent cells as desribed here. Pro: Can turn an algorithm that always takes O(n * m) time and make it so only worst case scenario is that time, best case becomes practically linear, and average case is somewhere between the two. Con: It is an algorithm I've only seen implemented in functional programming languages and I am having a difficult time comprehending how to convert this into Ruby based on how it is described at the site linked to above. Make a C module and do the hard work at the native level in C and just make a Ruby wrapper for it so Ruby can make all the calls to it that it needs. Pro: I have to imagine that evaluating something like this in could be a LOT faster. Con: I have no idea how Rails handles apps with ruby code that has C extensions and it hurts the portability of the app. This is an optimization for after the solving of edit distance, but idea is to store additional combined diffs with the ones produced by each version to make a delta-tree data structure with the most recently made diff as the root node of the tree so getting to any version takes worst case time of O(log n) instead of O(n). Pro: Would make going back to an old version a lot faster. Con: It would mean every new commit, the delta-tree would get a new root node that will cost time to reorganize the delta-tree for an operation that will be carried out a lot more often than going back a version, not to mention the unlikelihood it will be an old version. </optimizations> So are these things worth the effort?

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  • Authoritative sources about Database vs. Flatfile decision

    - by FastAl
    <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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  • Validating textboxes and checkboxes then add the values of those checkboxes

    - by TiTi Nguyen
    I am very new to Javascript. I am running to a problem and don't know how to solve it. Could you please help? Basically, I want to create some textboxes and checkboxes in a form. Then I have to validate those fields, and add the values of the checkboxes if they are selected. One of the textboxes asking for how many semesters attended, and 3 checkboxes with value of 100, 1000, and 750. Whichever checkbox is selected, it should multiply its value to the number of semesters attended. For example if the first two checkboxes are selected then totalCost = (100+1000)* semester. Here is my code: User Name: <label>User Address: <input type = "text" id ="address" size = "30"/></label> <br/><br/> <label> User E-mail address: <input type = "text" id ="email" size = "30"/></label> <br/><br/> <label> User Phone number: <input type = "text" id ="phone" size = "30"/></label> <br/><br/> <label> User area code: <input type = "text" id ="area" size = "30"/></label> <br/><br/> <label> User SSN: <input type = "text" id ="ssn" size = "30"/></label> <br/><br/> <label> User Birthday: <input type = "text" id ="birthday" size = "30"/></label> <br/><br/> <label> Number of semester attended: <input type = "text" id ="semester" size = "3"/></label> <br/><br/> <label><input type="checkbox" id="box_book" value="100"/>Books $100 per semester</label> <br/> <label><input type="checkbox" id="box_tuition" value="1000"/>Tuition $1000 per semester</label> <br/> <label><input type="checkbox" id="box_room" value="750"/>Room and Board $750 per semester</label> <br/> <input type="reset" id="reset"/> <input type="submit" id="submit" onclick="checking()"/> <p/> </form> function checking() { var name=document.forms["myForm"]["name"].value; var address=document.forms["myForm"]["address"].value; var email=document.forms["myForm"]["email"].value; var atpos=email.indexOf("@"); var dotpos=email.lastIndexOf("."); var phone=document.forms["myForm"]["phone"].value; var area=document.forms["myForm"]["area"].value; var ssn=document.forms["myForm"]["ssn"].value; var birth=document.forms["myForm"]["birthday"].value; var semester=document.forms["myForm"]["semester"].value; var boxBook = document.forms["myForm"]["box_book"].value; var boxTuition = document.forms["myForm"]["box_tuition"].value; var boxRoom = document.forms["myForm"]["box_room"].value; if (name==null || name=="") { alert("Please fill in your name."); return false; } if (address==null || address=="") { alert("Please fill in your address."); return false; } if (atpos<1 || dotpos<atpos+2 || dotpos+2>=email.length) { alert("The email (" + email + ") is not a valid e-mail address. Please reenter your email address."); return false; } if(phone.length!=10) { alert("Phone number entered in incorrect form. Please reenter phone number in the correct form which contains 10 numbers."); return false; } if (area==null || area=="") { alert("Please fill in the area code"); return false; } if(ssn.length!=9) { alert("SSN entered in incorrect form. Please reenter SSN."); return false; } if (birth==null || birth=="") { alert("Please fill in your date of birth."); return false; } if (semester==null || semester=="") { alert("How many semester have you attended?"); return false; } if (document.getElementById("box_book").checked == false && document.getElementById("box_tuition").checked == false && document.getElementById("box_room").checked == false) { alert("You must select one of the checkboxes"); return false; } if (document.getElementById("box_book").checked ==true) { var subcost = boxBook; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } if (document.getElementById("box_book").checked == true && document.getElementById("box_tuition").checked == true) { var subcost = boxBook + boxTuition; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } if (document.getElementById("box_book").checked == true && document.getElementById("box_tuition").checked == true && document.getElementById("box_room").checked == true) { var subcost = boxBook + boxTuition + boxRoom; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } if (document.getElementById("box_tuition").checked ==true) { var subcost = boxTuition; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } if (document.getElementById("box_tuition").checked == true && document.getElementById("box_room").checked == true) { var subcost = boxTuition + boxRoom; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } if (document.getElementById("box_room").checked ==true) { var subcost = boxRoom; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } if (document.getElementById("box_book").checked == true && document.getElementById("box_room").checked == true) { var subcost = boxBook + boxRoom; var totalcost = subcost * semester; alert ("Your total cost is: $" + totalcost); } else return false; } When I hit the submit button, nothing happens!! Please help.

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  • Edit Contact code worked in 1.6 but doesn't work on Droid 2.1?

    - by user225405
    Hi All, I had some fairly simple code in my app to invoke Edit Contact activity on a known good contact index that worked in Android 1.6 but is broken for me now in Android 2.1 on the Droid. I built a sample activity/app 'EdCon' to show this: package com.jbh; import android.app.Activity; import android.content.Intent; import android.net.Uri; import android.os.Bundle; public class EdCon extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Build an intent to edit a known good contact index Intent i; i = new Intent(Intent.ACTION_EDIT); i.setData(Uri.parse("content://contacts/people/10")); startActivity(i); } } When I run this on my G1 running 1.6 it works as expected i.e. brings up the Edit Contact screen for the known index and then I can hit BACK to return to "Hello World, EdCon". When I run this on the Droid under 2.1 I get the following: 05-07 15:35:57.787: INFO/ActivityManager(1013): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.jbh/.EdCon } 05-07 15:35:57.826: DEBUG/AndroidRuntime(13780): Shutting down VM 05-07 15:35:57.826: DEBUG/dalvikvm(13780): DestroyJavaVM waiting for non-daemon threads to exit 05-07 15:35:57.928: DEBUG/dalvikvm(13780): DestroyJavaVM shutting VM down 05-07 15:35:57.928: DEBUG/dalvikvm(13780): HeapWorker thread shutting down 05-07 15:35:57.928: DEBUG/dalvikvm(13780): HeapWorker thread has shut down 05-07 15:35:57.928: DEBUG/jdwp(13780): JDWP shutting down net... 05-07 15:35:57.928: DEBUG/jdwp(13780): Got wake-up signal, bailing out of select 05-07 15:35:57.928: INFO/dalvikvm(13780): Debugger has detached; object registry had 1 entries 05-07 15:35:57.928: DEBUG/dalvikvm(13780): VM cleaning up 05-07 15:35:57.935: INFO/ActivityManager(1013): Start proc com.jbh for activity com.jbh/.EdCon: pid=13802 uid=10052 gids={1015} 05-07 15:35:57.967: ERROR/AndroidRuntime(13780): ERROR: thread attach failed 05-07 15:35:58.053: INFO/ActivityThread(13792): Publishing provider com.android.vending.SuggestionsProvider: com.android.vending.SuggestionsProvider 05-07 15:35:58.154: INFO/dalvikvm(13802): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=38) 05-07 15:35:58.209: DEBUG/dalvikvm(13780): LinearAlloc 0x0 used 639500 of 5242880 (12%) 05-07 15:35:58.365: INFO/dalvikvm(13802): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=18) 05-07 15:35:58.639: INFO/ActivityManager(1013): Starting activity: Intent { act=android.intent.action.EDIT dat=content://contacts/people/10 cmp=com.android.contacts/.ui.EditContactActivity } 05-07 15:35:58.975: DEBUG/dalvikvm(13137): GC freed 2902 objects / 166768 bytes in 61ms 05-07 15:35:59.100: DEBUG/vending(13792): com.android.vending.LocalDbSyncService.run(): Syncing local DB with package manager... 05-07 15:35:59.100: DEBUG/vending(13792): com.android.vending.LocalDbSyncService.syncLocalDbWithPackageManager(): No INSTALLING or UNINSTALLING assets. 05-07 15:35:59.115: INFO/ActivityManager(1013): Displayed activity com.android.contacts/.ui.EditContactActivity: 387 ms (total 1296 ms) 05-07 15:35:59.185: DEBUG/Sources(13137): Creating external source for type=com.facebook.auth.login, packageName=com.facebook.katana 05-07 15:35:59.225: DEBUG/vending(13792): com.android.vending.LocalDbSyncService.run(): Syncing done. 05-07 15:35:59.232: WARN/dalvikvm(13137): threadid=27: thread exiting with uncaught exception (group=0x4001b180) 05-07 15:35:59.232: ERROR/AndroidRuntime(13137): Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): java.lang.RuntimeException: An error occured while executing doInBackground() 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.os.AsyncTask$3.done(AsyncTask.java:200) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.lang.Thread.run(Thread.java:1096) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): Caused by: android.database.sqlite.SQLiteException: no such column: raw_contact_id: , while compiling: SELECT account_name, account_type, sourceid, version, dirty, data_id, res_package, mimetype, data1, data2, data3, data4, data5, data6, data7, data8, data9, data10, data11, data12, data13, data14, data15, data_sync1, data_sync2, data_sync3, data_sync4, _id, is_primary, is_super_primary, data_version, group_sourceid, sync1, sync2, sync3, sync4, deleted, contact_id, starred, is_restricted FROM contact_entities_view WHERE (1) AND (raw_contact_id=10) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteProgram.native_compile(Native Method) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteProgram.compile(SQLiteProgram.java:110) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:59) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteQuery.(SQLiteQuery.java:49) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:49) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1221) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java:316) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:3850) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:3840) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2$RawContactsEntityIterator.(ContactsProvider2.java:4498) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2.queryEntities(ContactsProvider2.java:4751) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.content.ContentProvider$Transport.queryEntities(ContentProvider.java:140) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.content.ContentProviderClient.queryEntities(ContentProviderClient.java:98) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.content.ContentResolver.queryEntities(ContentResolver.java:296) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.model.EntitySet.fromQuery(EntitySet.java:72) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.ui.EditContactActivity$QueryEntitiesTask.doInBackground(EditContactActivity.java:191) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.ui.EditContactActivity$QueryEntitiesTask.doInBackground(EditContactActivity.java:154) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.util.WeakAsyncTask.doInBackground(WeakAsyncTask.java:45) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.os.AsyncTask$2.call(AsyncTask.java:185) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): ... 4 more 05-07 15:35:59.303: INFO/Process(1013): Sending signal. PID: 13137 SIG: 3 05-07 15:35:59.303: INFO/dalvikvm(13137): threadid=7: reacting to signal 3 05-07 15:35:59.303: ERROR/dalvikvm(13137): Unable to open stack trace file '/data/anr/traces.txt': Permission denied 05-07 15:35:59.506: INFO/DumpStateReceiver(1013): Added state dump to 1 crashes 05-07 15:36:07.053: DEBUG/dalvikvm(12901): GC freed 389 objects / 25056 bytes in 145ms 05-07 15:36:17.287: DEBUG/dalvikvm(11649): GC freed 154 objects / 6816 bytes in 136ms 05-07 15:36:22.365: DEBUG/dalvikvm(13574): GC freed 348 objects / 67848 bytes in 112ms 05-07 15:36:27.451: DEBUG/dalvikvm(11836): GC freed 267 objects / 17432 bytes in 65ms 05-07 15:36:32.553: DEBUG/dalvikvm(12757): GC freed 1888 objects / 92440 bytes in 67ms 05-07 15:36:38.803: INFO/power(1013): * set_screen_state 0 05-07 15:36:38.813: DEBUG/SurfaceFlinger(1013): About to give-up screen, flinger = 0x114c30 05-07 15:36:38.826: DEBUG/Sensors(1013): using accelerometer (name=accelerometer) 05-07 15:36:38.834: DEBUG/PhoneWindow(13137): couldn't save which view has focus because the focused view android.widget.ScrollView@44883558 has no id. 05-07 15:36:38.865: DEBUG/WifiService(1013): ACTION_SCREEN_OFF 05-07 15:36:38.889: DEBUG/WifiService(1013): setting ACTION_DEVICE_IDLE timer for 900000ms 05-07 15:36:44.107: DEBUG/dalvikvm(1013): GC freed 7351 objects / 521440 bytes in 130ms 05-07 15:36:49.373: DEBUG/dalvikvm(13553): GC freed 321 objects / 12056 bytes in 102ms The no such column: raw_contact_id: looks like the issue but I'm not sure how or why that would happen or what it means. Any help appreciated! [email protected]

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  • How do I prove I should put a table of values in source code instead of a database table?

    - by FastAl
    <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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  • Android: restful API service

    - by Martyn
    Hey, I'm looking to make a service which I can use to make calls to a web based rest api. I've spent a couple of days looking through stackoverflow.com, reading books and looking at articles whilst playing about with some code and I can't get anything which I'm happy with. Basically I want to start a service on app init then I want to be able to ask that service to request a url and return the results. In the meantime I want to be able to display a progress window or something similar. I've created a service currently which uses IDL, I've read somewhere that you only really need this for cross app communication, so think these needs stripping out but unsure how to do callbacks without it. Also when I hit the post(Config.getURL("login"), values) the app seems to pause for a while (seems weird - thought the idea behind a service was that it runs on a different thread!) Currently I have a service with post and get http methods inside, a couple of AIDL files (for two way communication), a ServiceManager which deals with starting, stopping, binding etc to the service and I'm dynamically creating a Handler with specific code for the callbacks as needed. I don't want anyone to give me a complete code base to work on, but some pointers would be greatly appreciated; even if it's to say I'm doing it completely wrong. I'm pretty new to Android and Java dev so if there are any blindingly obvious mistakes here - please don't think I'm a rubbish developer, I'm just wet behind the ears and would appreciate being told exactly where I'm going wrong. Anyway, code in (mostly) full (really didn't want to put this much code here, but I don't know where I'm going wrong - apologies in advance): public class RestfulAPIService extends Service { final RemoteCallbackList<IRemoteServiceCallback> mCallbacks = new RemoteCallbackList<IRemoteServiceCallback>(); public void onStart(Intent intent, int startId) { super.onStart(intent, startId); } public IBinder onBind(Intent intent) { return binder; } public void onCreate() { super.onCreate(); } public void onDestroy() { super.onDestroy(); mCallbacks.kill(); } private final IRestfulService.Stub binder = new IRestfulService.Stub() { public void doLogin(String username, String password) { Message msg = new Message(); Bundle data = new Bundle(); HashMap<String, String> values = new HashMap<String, String>(); values.put("username", username); values.put("password", password); String result = post(Config.getURL("login"), values); data.putString("response", result); msg.setData(data); msg.what = Config.ACTION_LOGIN; mHandler.sendMessage(msg); } public void registerCallback(IRemoteServiceCallback cb) { if (cb != null) mCallbacks.register(cb); } }; private final Handler mHandler = new Handler() { public void handleMessage(Message msg) { // Broadcast to all clients the new value. final int N = mCallbacks.beginBroadcast(); for (int i = 0; i < N; i++) { try { switch (msg.what) { case Config.ACTION_LOGIN: mCallbacks.getBroadcastItem(i).userLogIn( msg.getData().getString("response")); break; default: super.handleMessage(msg); return; } } catch (RemoteException e) { } } mCallbacks.finishBroadcast(); } public String post(String url, HashMap<String, String> namePairs) {...} public String get(String url) {...} }; A couple of AIDL files: package com.something.android oneway interface IRemoteServiceCallback { void userLogIn(String result); } and package com.something.android import com.something.android.IRemoteServiceCallback; interface IRestfulService { void doLogin(in String username, in String password); void registerCallback(IRemoteServiceCallback cb); } and the service manager: public class ServiceManager { final RemoteCallbackList<IRemoteServiceCallback> mCallbacks = new RemoteCallbackList<IRemoteServiceCallback>(); public IRestfulService restfulService; private RestfulServiceConnection conn; private boolean started = false; private Context context; public ServiceManager(Context context) { this.context = context; } public void startService() { if (started) { Toast.makeText(context, "Service already started", Toast.LENGTH_SHORT).show(); } else { Intent i = new Intent(); i.setClassName("com.something.android", "com.something.android.RestfulAPIService"); context.startService(i); started = true; } } public void stopService() { if (!started) { Toast.makeText(context, "Service not yet started", Toast.LENGTH_SHORT).show(); } else { Intent i = new Intent(); i.setClassName("com.something.android", "com.something.android.RestfulAPIService"); context.stopService(i); started = false; } } public void bindService() { if (conn == null) { conn = new RestfulServiceConnection(); Intent i = new Intent(); i.setClassName("com.something.android", "com.something.android.RestfulAPIService"); context.bindService(i, conn, Context.BIND_AUTO_CREATE); } else { Toast.makeText(context, "Cannot bind - service already bound", Toast.LENGTH_SHORT).show(); } } protected void destroy() { releaseService(); } private void releaseService() { if (conn != null) { context.unbindService(conn); conn = null; Log.d(LOG_TAG, "unbindService()"); } else { Toast.makeText(context, "Cannot unbind - service not bound", Toast.LENGTH_SHORT).show(); } } class RestfulServiceConnection implements ServiceConnection { public void onServiceConnected(ComponentName className, IBinder boundService) { restfulService = IRestfulService.Stub.asInterface((IBinder) boundService); try { restfulService.registerCallback(mCallback); } catch (RemoteException e) {} } public void onServiceDisconnected(ComponentName className) { restfulService = null; } }; private IRemoteServiceCallback mCallback = new IRemoteServiceCallback.Stub() { public void userLogIn(String result) throws RemoteException { mHandler.sendMessage(mHandler.obtainMessage(Config.ACTION_LOGIN, result)); } }; private Handler mHandler; public void setHandler(Handler handler) { mHandler = handler; } } Service init and bind: // this I'm calling on app onCreate servicemanager = new ServiceManager(this); servicemanager.startService(); servicemanager.bindService(); application = (ApplicationState)this.getApplication(); application.setServiceManager(servicemanager); service function call: // this lot i'm calling as required - in this example for login progressDialog = new ProgressDialog(Login.this); progressDialog.setMessage("Logging you in..."); progressDialog.show(); application = (ApplicationState) getApplication(); servicemanager = application.getServiceManager(); servicemanager.setHandler(mHandler); try { servicemanager.restfulService.doLogin(args[0], args[1]); } catch (RemoteException e) { e.printStackTrace(); } ...later in the same file... Handler mHandler = new Handler() { public void handleMessage(Message msg) { switch (msg.what) { case Config.ACTION_LOGIN: if (progressDialog.isShowing()) { progressDialog.dismiss(); } try { ...process login results... } } catch (JSONException e) { Log.e("JSON", "There was an error parsing the JSON", e); } break; default: super.handleMessage(msg); } } }; Any and all help is greatly appreciated and I'll even buy you a coffee or a beer if you fancy :D Martyn

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  • Implementing a robust async stream reader for a console

    - by Jon
    I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

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  • Creating a grid overlay over image.

    - by neteus
    Hi everybody, I made a script (using mootools library) that is supposed to overlay an image with a table grid and when each grid cell is clicked/dragged over its background color changes 'highlighting' the cell. Current code creates a table and positions it over the element (el, image in this case). Table was used since I am planning to add rectangle select tool later on, and it seemed easiest way to do it. <html> <head> <title></title> <script type="text/javascript" src="mootools.js"></script> <script type="text/javascript"> var SetGrid = function(el, sz, nr, nc){ //get number of rows/columns according to the 'grid' size numcols = el.getSize().x/sz; numrows = el.getSize().y/sz; //create table element for injecting cols/rows var gridTable = new Element('table', { 'id' : 'gridTable', 'styles' : { 'width' : el.getSize().x, 'height' : el.getSize().y, 'top' : el.getCoordinates().top, 'left' : el.getCoordinates().left } }); //inject rows/cols into gridTable for (row = 1; row<=numrows; row++){ thisRow = new Element('tr', { 'id' : row, 'class' : 'gridRow' }); for(col = 1; col<=numcols; col++){ thisCol = new Element('td', { 'id' : col, 'class' : 'gridCol0' }); //each cell gets down/up over event... down starts dragging|up stops|over draws area if down was fired thisCol.addEvents({ 'mousedown' : function(){ dragFlag = true; startRow = this.getParent().get('id'); startCol = this.get('id'); }, 'mouseup' : function(){ dragFlag = false; }, 'mouseover' : function(){ if (dragFlag==true){ this.set('class', 'gridCol'+$$('#lvlSelect .on').get('value')); } }, 'click' : function(){ //this.set('class', 'gridCol'+$$('#lvlSelect .on').get('id').substr(3, 1) ); str = $$('#lvlSelect .on').get('id'); alert(str.substr(2, 3)); } }); thisCol.inject(thisRow, 'bottom'); }; thisRow.inject(gridTable, 'bottom'); }; gridTable.inject(el.getParent()); } //sens level selector func var SetSensitivitySelector = function(el, sz, nr, nc){ $$('#lvlSelect ul li').each(function(el){ el.addEvents({ 'click' : function(){ $$('#lvlSelect ul li').set('class', ''); this.set('class', 'on'); }, 'mouseover' : function(){ el.setStyle('cursor','pointer'); }, 'mouseout' : function(){ el.setStyle('cursor',''); } }); }); } //execute window.addEvent('load', function(){ SetGrid($('imagetomap'), 32); SetSensitivitySelector(); }); </script> <style> #imagetomapdiv { float:left; display: block; } #gridTable { border:1px solid red; border-collapse:collapse; position:absolute; z-index:5; } #gridTable td { opacity:0.2; filter:alpha(opacity=20); } #gridTable .gridCol0 { border:1px solid gray; background-color: none; } #gridTable .gridCol1 { border:1px solid gray; background-color: green; } #gridTable .gridCol2 { border:1px solid gray; background-color: blue; } #gridTable .gridCol3 { border:1px solid gray; background-color: yellow; } #gridTable .gridCol4 { border:1px solid gray; background-color: orange; } #gridTable .gridCol5 { border:1px solid gray; background-color: red; } #lvlSelect ul {float: left; display:block; position:relative; margin-left: 20px; padding: 10px; } #lvlSelect ul li { width:40px; text-align:center; display:block; border:1px solid black; position:relative; padding: 10px; list-style:none; opacity:0.2; filter:alpha(opacity=20); } #lvlSelect ul li.on { opacity:1; filter:alpha(opacity=100); } #lvlSelect ul #li0 { background-color: none; } #lvlSelect ul #li1 { background-color: green; } #lvlSelect ul #li2 { background-color: blue; } #lvlSelect ul #li3 { background-color: yellow; } #lvlSelect ul #li4 { background-color: orange; } #lvlSelect ul #li5 { background-color: red; } </style> </head> <body> <div id="imagetomapdiv"> <img id="imagetomap" src="1.png"> </div> <div id="lvlSelect"> <ul> <li value="0" id="li0">0</li> <li value="1" id="li1">1</li> <li value="2" id="li2">2</li> <li value="3" id="li3">3</li> <li value="4" id="li4">4</li> <li value="5" id="li5" class="on">5</li> </ul> </div> </body> </html> A 'working' example: http://72.14.186.218/~alex/motion.php There are two problems: while it works just fine in FF, IE and Chrome do not create the table if the page is refreshed. If you go back to directory root and click on the link to the file the grid table is displayed, if you hit 'refresh' button -- the script runs but the table is not injected. Secondly, although the table HTML is injected in IE, it does not display it. I tried adding nbsp's to make sure its not ignored -- to no avail. Any suggestions on improving code or help with the issues is appreciated. Thanks!

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  • Backbone events not firing (this.el undefined) & general feedback on use of the framework

    - by Leo
    I am very new to backbone.js and I am struggling a little. I figured out a way to get data from the server (in json) onto the screen successfully but am I doing it the right/best way? I know there is something wrong because the only view which contains a valid this.el is the parent view. I suspect that because of this, the events of the view are not firing ()... What is the best way forward? Here is the code: var surveyUrl = "/api/Survey?format=json&callback=?"; $(function () { AnswerOption = Backbone.Model.extend({}); AnswerOptionList = Backbone.Collection.extend({ initialize: function (models, options) { this.bind("add", options.view.render); } }); AnswerOptionView = Backbone.View.extend({ initialize: function () { this.answerOptionList = new AnswerOptionList(null, { view: this }); _.bindAll(this, 'render'); }, events: { "click .answerOptionControl": "updateCheckedState" //does not fire because there is no this.el }, render: function (model) { // Compile the template using underscore var template = _.template($("#questionAnswerOptionTemplate").html(), model.answerOption); $('#answerOptions' + model.answerOption.questionId + '>fieldset').append(template); return this; }, updateCheckedState: function (data) { //never hit... } }); Question = Backbone.Model.extend({}); QuestionList = Backbone.Collection.extend({ initialize: function (models, options) { this.bind("add", options.view.render); } }); QuestionView = Backbone.View.extend({ initialize: function () { this.questionlist = new QuestionList(null, { view: this }); _.bindAll(this, 'render'); }, render: function (model) { // Compile the template using underscore var template = _.template($("#questionTemplate").html(), model.question); $("#questions").append(template); //append answers using AnswerOptionView var view = new AnswerOptionView(); for (var i = 0; i < model.question.answerOptions.length; i++) { var qModel = new AnswerOption(); qModel.answerOption = model.question.answerOptions[i]; qModel.questionChoiceType = ChoiceType(); view.answerOptionList.add(qModel); } $('#questions').trigger('create'); return this; } }); Survey = Backbone.Model.extend({ url: function () { return this.get("id") ? surveyUrl + '/' + this.get("id") : surveyUrl; } }); SurveyList = Backbone.Collection.extend({ model: Survey, url: surveyUrl }); aSurvey = new Survey({ Id: 1 }); SurveyView = Backbone.View.extend({ model: aSurvey, initialize: function () { _.bindAll(this, 'render'); this.model.bind('refresh', this.render); this.model.bind('change', this.render); this.model.view = this; }, // Re-render the contents render: function () { var view = new QuestionView(); //{el:this.el}); for (var i = 0; i < this.model.attributes[0].questions.length; i++) { var qModel = new Question(); qModel.question = this.model.attributes[0].questions[i]; view.questionlist.add(qModel); } } }); window.App = new SurveyView(aSurvey); aSurvey.fetch(); }); -html <body> <div id="questions"></div> <!-- Templates --> <script type="text/template" id="questionAnswerOptionTemplate"> <input name="answerOptionGroup<%= questionId %>" id="answerOptionInput<%= id %>" type="checkbox" class="answerOptionControl"/> <label for="answerOptionInput<%= id %>"><%= text %></label> </script> <script type="text/template" id="questionTemplate"> <div id="question<%=id %>" class="questionWithCurve"> <h1><%= headerText %></h1> <h2><%= subText %></h2> <div data-role="fieldcontain" id="answerOptions<%= id %>" > <fieldset data-role="controlgroup" data-type="vertical"> <legend> </legend> </fieldset> </div> </div> </script> </body> And the JSON from the server: ? ({ "name": "Survey", "questions": [{ "surveyId": 1, "headerText": "Question 1", "subText": "subtext", "type": "Choice", "positionOrder": 1, "answerOptions": [{ "questionId": 1, "text": "Question 1 - Option 1", "positionOrder": 1, "id": 1, "createdOn": "\/Date(1333666034297+0100)\/" }, { "questionId": 1, "text": "Question 1 - Option 2", "positionOrder": 2, "id": 2, "createdOn": "\/Date(1333666034340+0100)\/" }, { "questionId": 1, "text": "Question 1 - Option 3", "positionOrder": 3, "id": 3, "createdOn": "\/Date(1333666034350+0100)\/" }], "questionValidators": [{ "questionId": 1, "value": "3", "type": "MaxAnswers", "id": 1, "createdOn": "\/Date(1333666034267+0100)\/" }, { "questionId": 1, "value": "1", "type": "MinAnswers", "id": 2, "createdOn": "\/Date(1333666034283+0100)\/" }], "id": 1, "createdOn": "\/Date(1333666034257+0100)\/" }, { "surveyId": 1, "headerText": "Question 2", "subText": "subtext", "type": "Choice", "positionOrder": 2, "answerOptions": [{ "questionId": 2, "text": "Question 2 - Option 1", "positionOrder": 1, "id": 4, "createdOn": "\/Date(1333666034427+0100)\/" }, { "questionId": 2, "text": "Question 2 - Option 2", "positionOrder": 2, "id": 5, "createdOn": "\/Date(1333666034440+0100)\/" }, { "questionId": 2, "text": "Question 2 - Option 3", "positionOrder": 3, "id": 6, "createdOn": "\/Date(1333666034447+0100)\/" }], "questionValidators": [{ "questionId": 2, "value": "3", "type": "MaxAnswers", "id": 3, "createdOn": "\/Date(1333666034407+0100)\/" }, { "questionId": 2, "value": "1", "type": "MinAnswers", "id": 4, "createdOn": "\/Date(1333666034417+0100)\/" }], "id": 2, "createdOn": "\/Date(1333666034377+0100)\/" }, { "surveyId": 1, "headerText": "Question 3", "subText": "subtext", "type": "Choice", "positionOrder": 3, "answerOptions": [{ "questionId": 3, "text": "Question 3 - Option 1", "positionOrder": 1, "id": 7, "createdOn": "\/Date(1333666034477+0100)\/" }, { "questionId": 3, "text": "Question 3 - Option 2", "positionOrder": 2, "id": 8, "createdOn": "\/Date(1333666034483+0100)\/" }, { "questionId": 3, "text": "Question 3 - Option 3", "positionOrder": 3, "id": 9, "createdOn": "\/Date(1333666034487+0100)\/" }], "questionValidators": [{ "questionId": 3, "value": "3", "type": "MaxAnswers", "id": 5, "createdOn": "\/Date(1333666034463+0100)\/" }, { "questionId": 3, "value": "1", "type": "MinAnswers", "id": 6, "createdOn": "\/Date(1333666034470+0100)\/" }], "id": 3, "createdOn": "\/Date(1333666034457+0100)\/" }, { "surveyId": 1, "headerText": "Question 4", "subText": "subtext", "type": "Choice", "positionOrder": 4, "answerOptions": [{ "questionId": 4, "text": "Question 4 - Option 1", "positionOrder": 1, "id": 10, "createdOn": "\/Date(1333666034500+0100)\/" }, { "questionId": 4, "text": "Question 4 - Option 2", "positionOrder": 2, "id": 11, "createdOn": "\/Date(1333666034507+0100)\/" }, { "questionId": 4, "text": "Question 4 - Option 3", "positionOrder": 3, "id": 12, "createdOn": "\/Date(1333666034507+0100)\/" }], "questionValidators": [{ "questionId": 4, "value": "3", "type": "MaxAnswers", "id": 7, "createdOn": "\/Date(1333666034493+0100)\/" }, { "questionId": 4, "value": "1", "type": "MinAnswers", "id": 8, "createdOn": "\/Date(1333666034497+0100)\/" }], "id": 4, "createdOn": "\/Date(1333666034490+0100)\/" }], "id": 1, "createdOn": "\/Date(1333666034243+0100)\/" })

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  • a value that shows in select mode disappears in edit mode from a gridview column

    - by Jbob Johan
    i have a gridview(GridView1) with a few Bound Fields first one is Date (ActivityDate) from a table named "tblTime" i have managed to add one extra colum (manually), that is not bound that shows dayInWeek value according to the "ActivityDate" field programtically in CodeBehind but when i enter into Edit Mode , all Bound fields are showing their values correctly but the one column i have added manually will not show the value as it did in "select mode"(first mode b4 trying to edit) while im not a great dibbagger i have manged to view the cell's value (GridView1.Rows[e.NewEditIndex].Cells[1].Text) which does hold on to the day in week value but it does not appear in gridview edit mode only this is some of the code protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.Header) { e.Row.Cells[0].Text = "?????"; //Activity Date (in hebrew) e.Row.Cells[1].Text = "??? ?????"; //DayinWeek e.Row.Cells[2].Text = "??????"; //ActivityType (work seek vacation) named Reason e.Row.Cells[3].Text = "??? ?????"; //time finish (to Work) e.Row.Cells[4].Text = "??? ?????"; //Time out (of work) } if (e.Row.RowType == DataControlRowType.DataRow) { if (Convert.ToBoolean(ViewState["theSubIsclckd"]) == true) //if submit button clicked { try { string twekday1 = Convert.ToString(DataBinder.Eval(e.Row.DataItem, "ActiveDate")); twekday1 = twekday1.Remove(9, 11); //geting date only without the time- portion string[] arymd = twekday1.Split('/'); // spliting [d m y] in order to make int day = Convert.ToInt32(arymd[1]); // it into [m d y] ...also requierd int month = Convert.ToInt32(arymd[0]); // when i update the table int year = Convert.ToInt32(arymd[2]); DateTime ILDateInit = new DateTime(year, month, day); //finally extracting Day CultureInfo ILci = CultureInfo.CreateSpecificCulture("he-IL"); // in week //from the converted activity date string MyIL_DayInWeek = ILDateInit.ToString("dddd", ILci); ViewState["MyIL_DayInWeek"] = MyIL_DayInWeek; e.Row.Cells[1].Text = MyIL_DayInWeek; string displayReason = DataBinder.Eval(e.Row.DataItem, "Reason").ToString(); e.Row.Cells[2].Text = displayReason; } catch (System.Exception excep) { Js.functions.but bb = new Js.functions.but(); bb.buttonName = "rex"; bb.documentwrite = true; bb.testCsVar = excep.ToString(); bb.f1(bb); // this was supposed to throw exep in javaScript injected from code behid - alert } // just in case.. } } so that works for the non edit period of time then when i hit the edit ... no day in week shows THE aspX - after selcting date... name etc' , click on button to display gridview: <asp:Button ID="TheSubB" runat="server" Text="???" onclick="TheSubB_Click" /> <asp:GridView ID="GridView1" runat="server" OnRowDataBound="GridView1_RowDataBound" onrowediting="GridView1_RowEditing" onrowcancelingedit="GridView1_RowCancelingEdit" OnRowUpdating="GridView1_RowUpdating" BackColor="LightGoldenrodYellow" BorderColor="Tan" BorderWidth="1px" CellPadding="2" ForeColor="Black" GridLines="None" AutoGenerateColumns="False" DataKeyNames="tId" DataSourceID="SqlDataSource1" style="z-index: 1; left: 0%; top: 0%; position: relative; width: 812px; height: 59px; font-family:Arial; text-align: center;" AllowSorting="True" > <AlternatingRowStyle BackColor="PaleGoldenrod" /> <Columns> <asp:BoundField DataField="ActiveDate" HeaderText="ActiveDate" SortExpression="ActiveDate" ControlStyle-Width="70" DataFormatString="{0:dd/MM/yyyy}" > <ControlStyle Width="70px" /> </asp:BoundField> <asp:TemplateField HeaderText="???.???.??"> <EditItemTemplate> <asp:TextBox ID="dayinW_EditTB" runat="server"></asp:TextBox> </EditItemTemplate> <ItemTemplate> <asp:Label ID="dayInW_editLabel" runat="server"></asp:Label> </ItemTemplate> </asp:TemplateField> <asp:BoundField DataField="Reason" HeaderText="???? ?????" SortExpression="Reason" ControlStyle-Width="50"> <ControlStyle Width="50px" /> </asp:BoundField> <asp:BoundField DataField="TimeOut" HeaderText="TimeOut" SortExpression="TimeOut" ControlStyle-Width="50" DataFormatString="{0:HH:mm}" > <ControlStyle Width="50px"></ControlStyle> </asp:BoundField> <asp:BoundField DataField="TimeIn" HeaderText="TimeIn" SortExpression="TimeIn" ControlStyle-Width="50" DataFormatString="{0:HH:mm}" > <ControlStyle Width="50px"></ControlStyle> </asp:BoundField> <asp:TemplateField HeaderText="????" > <EditItemTemplate> <asp:ImageButton width="15" Height="15" ImageUrl="~/images/edit.png" runat="server" CausesValidation="True" CommandName="Update" Text="Update"> </asp:ImageButton> <asp:ImageButton Width="15" Height="15" ImageUrl="images/cancel.png" runat="server" CausesValidation="False" CommandName="Cancel" Text="Cancel"> </asp:ImageButton> </EditItemTemplate> <ItemTemplate> <asp:ImageButton width="25" Height="15" ImageUrl="images/edit.png" ID="EditIB" runat="server" CausesValidation="False" CommandName="Edit" AlternateText="????"></asp:ImageButton> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="???"> <ItemTemplate> <asp:ImageButton width="15" Height="15" ImageUrl="images/Delete.png" ID="DeleteIB" runat="server" CommandName="Delete" AlternateText="???" /> </ItemTemplate> </asp:TemplateField> </Columns> <FooterStyle BackColor="Tan" /> <HeaderStyle BackColor="Tan" Font-Bold="True" /> <PagerStyle BackColor="PaleGoldenrod" ForeColor="DarkSlateBlue" HorizontalAlign="Center" /> <SelectedRowStyle BackColor="DarkSlateBlue" ForeColor="GhostWhite" /> <SortedAscendingCellStyle BackColor="#FAFAE7" /> <SortedAscendingHeaderStyle BackColor="#DAC09E" /> <SortedDescendingCellStyle BackColor="#E1DB9C" /> <SortedDescendingHeaderStyle BackColor="#C2A47B" /> </asp:GridView>

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  • Committed JDO writes do not apply on local GAE HRD, or possibly reused transaction

    - by eeeeaaii
    I'm using JDO 2.3 on app engine. I was using the Master/Slave datastore for local testing and recently switched over to using the HRD datastore for local testing, and parts of my app are breaking (which is to be expected). One part of the app that's breaking is where it sends a lot of writes quickly - that is because of the 1-second limit thing, it's failing with a concurrent modification exception. Okay, so that's also to be expected, so I have the browser retry the writes again later when they fail (maybe not the best hack but I'm just trying to get it working quickly). But a weird thing is happening. Some of the writes which should be succeeding (the ones that DON'T get the concurrent modification exception) are also failing, even though the commit phase completes and the request returns my success code. I can see from the log that the retried requests are working okay, but these other requests that seem to have committed on the first try are, I guess, never "applied." But from what I read about the Apply phase, writing again to that same entity should force the apply... but it doesn't. Code follows. Some things to note: I am attempting to use automatic JDO caching. So this is where JDO uses memcache under the covers. This doesn't actually work unless you wrap everything in a transaction. all the requests are doing is reading a string out of an entity, modifying part of the string, and saving that string back to the entity. If these requests weren't in transactions, you'd of course have the "dirty read" problem. But with transactions, isolation is supposed to be at the level of "serializable" so I don't see what's happening here. the entity being modified is a root entity (not in a group) I have cross-group transactions enabled Another weird thing is happening. If the concurrent modification thing happens, and I subsequently edit more than 5 more entities (this is the max for cross-group transactions), then nothing happens right away, but when I stop and restart the server I get "IllegalArgumentException: operating on too many entity groups in a single transaction". Could it be possible that the PMF is returning the same PersistenceManager every time, or the PM is reusing the same transaction every time? I don't see how I could possibly get the above error otherwise. The code inside the transaction just edits one root entity. I can't think of any other way that GAE would give me the "too many entity groups" error. The relevant code (this is a simplified version) PersistenceManager pm = PMF.getManager(); Transaction tx = pm.currentTransaction(); String responsetext = ""; try { tx.begin(); // I have extra calls to "makePersistent" because I found that relying // on pm.close didn't always write the objects to cache, maybe that // was only a DataNucleus 1.x issue though Key userkey = obtainUserKeyFromCookie(); User u = pm.getObjectById(User.class, userkey); pm.makePersistent(u); // to make sure it gets cached for next time Key mapkey = obtainMapKeyFromQueryString(); // this is NOT a java.util.Map, just FYI Map currentmap = pm.getObjectById(Map.class, mapkey); Text mapData = currentmap.getMapData(); // mapData is JSON stored in the entity Text newMapData = parseModifyAndReturn(mapData); // transform the map currentmap.setMapData(newMapData); // mutate the Map object pm.makePersistent(currentmap); // make sure to persist so there is a cache hit tx.commit(); responsetext = "OK"; } catch (JDOCanRetryException jdoe) { // log jdoe responsetext = "RETRY"; } catch (Exception e) { // log e responsetext = "ERROR"; } finally { if (tx.isActive()) { tx.rollback(); } pm.close(); } resp.getWriter().println(responsetext); EDIT: so I have verified that it fails after exactly 5 transactions. Here's what I do: I create a Foo (root entity), do a bunch of concurrent operations on that Foo, and some fail and get retried, and some commit but don't apply (as described above). Then, I start creating more Foos, and do a few operations on those new Foos. If I only create four Foos, stopping and restarting app engine does NOT give me the IllegalArgumentException. However if I create five Foos (which is the limit for cross-group transactions), then when I stop and restart app engine, I do get the exception. So it seems that somehow these new Foos I am creating are counting toward the limit of 5 max entities per transaction, even though they are supposed to be handled by separate transactions. It's as if a transaction is still open and is being reused by the servlet when it handles the new requests for the 2nd through 5th Foos. EDIT2: it looks like the IllegalArgument thing is independent of the other bug. In other words, it always happens when I create five Foos, even if I don't get the concurrent modification exception. I don't know if it's a symptom of the same problem or if it's unrelated. EDIT3: I found out what was causing the (unrelated) IllegalArgumentException, it was a dumb mistake on my part. But the other issue is still happening. EDIT4: added pseudocode for the datastore access EDIT5: I am pretty sure I know why this is happening, but I will still award the bounty to anyone who can confirm it. Basically, I think the problem is that transactions are not really implemented in the local version of the datastore. References: https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/gVMS1dFSpcU https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/deGasFdIO-M https://groups.google.com/forum/?hl=en&fromgroups=#!msg/google-appengine-java/4YuNb6TVD6I/gSttMmHYwo0J Because transactions are not implemented, rollback is essentially a no-op. Therefore, I get a dirty read when two transactions try to modify the record at the same time. In other words, A reads the data and B reads the data at the same time. A attempts to modify the data, and B attempts to modify a different part of the data. A writes to the datastore, then B writes, obliterating A's changes. Then B is "rolled back" by app engine, but since rollbacks are a no-op when running on the local datastore, B's changes stay, and A's do not. Meanwhile, since B is the thread that threw the exception, the client retries B, but does not retry A (since A was supposedly the transaction that succeeded).

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  • Databinding, using formulas for unusual binding possible?

    - by Rattenmann
    Edit: added Info for WPF being used I am trying to bind a list of custom objects to a DataGrid. Straight binding seems easy enough, but i need to specify some complex formulas for some extra fields that do not directly show up in my class. Also i want to be able to EDIT the data in the Grid and get updates on related fields. Let me show you an example, because it is really hard to explain. I will simplify it to rooms with items. Each item can be red and blue. My Class looks like this: public class room { public string strRoomName { set; get; } public string strItemname { set; get; } public int intRedItem { set; get; } public int intBlueItem { set; get; } } Now if i use dataTable.ItemSource = myList; i get something like this: nr. | room | name | red | blue 1. living room, ball, 2, 1 2. sleeping room, bunny, 4, 1 3. living room, chair, 3, 2 4. kitchen, ball, 4, 7 5. garage, chair, 1, 4 Now for the complex part i need help with. I want every item to be the same number, red and blue. And because this does not hold true i want to see the "inbalance" per room AND globally like this: nr. | room | name | red | blue | missing | global red | global blue | global missing 1. living room, ball, 2, 1, 1 blue, 6, 7, 1 red 2. sleeping room, bunny, 4, 1, 3 blue, 4, 1, 3 blue 3. living room, chair, 3, 2, 1 blue, 4, 6, 2 red 4. kitchen, ball, 4, 7, 3 red, 6, 7, 1 red 5. garage, chair, 1, 4, 3 red, 4, 6, 2 red As you can see this smeels like excel formulas, i am unsure how to handle this in c# code however. You can also see i need to use data in the same row, but also get data from other rows that match one propertiy (the items name). Also if i change the blue value=1 in line 1 to value=2, i want line 1 to read like this: 1. living room, ball, 2, 2, even, 6, 8, 2 red and of corse line 4 needs to change to: 4. kitchen, ball, 4, 7, 3 red, 6, 8, 2 red As i said, this smells like excel, that's why i am really upset about myself not finding an easy solution. Surely enough c# offers some way to handle this stuff, right? Disclaimer: It is totally possible that i need a complete differend approach, pointing that out ot me is perfectly fine. Be it other ways to handle this, or a better way to structure my class. I am ok with every way to handle this as it is for learning purposes. I am simply doing programms for fun next to my college and just so happen to hit these kinda things that bug me out because i don't find a clean solution. And then i neglect my studies because i want to solve my (unreleated to studys,...) issue. Just can't stand having unsolved coding stuff around, don't judge me! ;-) And big thanks in advance if you have gotten this far in my post. It sure must be confusing with all those reds and blues. Edit: After reading trough your answers and testing my skills to implement your hints, i now have the following code as my class: public class RoomList : ObservableCollection<room> { public RoomList() : base() { Add(new room() { strRoomName = "living room", strItemname = "ball", intRedItem = 2, intBlueItem = 1 }); Add(new room() { strRoomName = "sleeping room", strItemname = "bunny", intRedItem = 4, intBlueItem = 1 }); Add(new room() { strRoomName = "living room", strItemname = "chair", intRedItem = 3, intBlueItem = 2 }); Add(new room() { strRoomName = "kitchen", strItemname = "ball", intRedItem = 4, intBlueItem = 7 }); Add(new room() { strRoomName = "garage", strItemname = "chair", intRedItem = 1, intBlueItem = 4 }); } } //rooms public class room : INotifyPropertyChanged { public string strRoomName { set; get; } public string strItemname { set; get; } public int intRedItem { get { return intRedItem; } set { intRedItem = value; NotifyPropertyChanged("intRedItem", "strMissing"); } } public int intBlueItem { get { return intBlueItem; } set { intBlueItem = value; NotifyPropertyChanged("intBlueItem", "strMissing"); } } public string strMissing { get { int missingCount = intRedItem - intBlueItem; return missingCount == 0 ? "Even" : missingCount.ToString(); } } public event PropertyChangedEventHandler PropertyChanged; public void NotifyPropertyChanged(params string[] propertyNames) { if (PropertyChanged != null) { foreach (string propertyName in propertyNames) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } } } I got the "missing" field working right away, thanks alot for that tip. It really was as easy as i imagined and will be of great use for future projects. Still two (three maybe....) things i am missing tho. The above code terminates with a "System.StackOverflowException" in the setter of intRedItem and intBlueItem. I fail to see the error, that could be due to being 4:30am here, or my lack of understanding. Second issue: I followed the link to ObservableCollections as you can see from my code above. Yet i am unsure how to actually use that collection. Putting it as DataContent like suggested on that page shows a missing ressource. Adding it as a ressource like listed there crashes my VSExpress designer and leads to the programm not starting. So for now i am still using my old approach of a list like this: listRooms.Add(new room() { strRoomName = "living room", strItemname = "ball", intRedItem = 2, intBlueItem = 1 }); listRooms.Add(new room() { strRoomName = "sleeping room", strItemname = "bunny", intRedItem = 4, intBlueItem = 1 }); listRooms.Add(new room() { strRoomName = "living room", strItemname = "chair", intRedItem = 3, intBlueItem = 2 }); listRooms.Add(new room() { strRoomName = "kitchen", strItemname = "ball", intRedItem = 4, intBlueItem = 7 }); listRooms.Add(new room() { strRoomName = "garage", strItemname = "chair", intRedItem = 1, intBlueItem = 4 }); datagridRooms.ItemsSource = listRooms; And lastly: When testing before adding the notifyevents i tried to implement a proterty that looped trough the other objects, without any luck. The "missingItem" property worked so easy, yet it only tries to access "it's own" properties kind of. I need to access other objects, like "all objects that have the same room value". The idea behind this is that i am trying to calculate a value from other objects without even having those objects yet, at least in my logic. Where is the flaw in my thinking? Those 5 objects are added and created (?) one after another. So if the first tries to set it's "all red balls in my room AND all other rooms" value,.. how could it know about the balls in the kitchen, that get added as 4th object? So far so good tho, got on the right track i think. Just need some sleep first.

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  • NetBeans Development 7 - Windows 7 64-bit … JNI native calls ... a how to guide

    - by CirrusFlyer
    I provide this for you to hopefully save you some time and pain. As part of my expereince in getting to know NB Development v7 on my Windows 64-bit workstation I found another frustrating adventure in trying to get the JNI (Java Native Interface) abilities up and working in my project. As such, I am including a brief summary of steps required (as all the documentation I found was completely incorrect for these versions of Windows and NetBeans on how to do JNI). It took a couple of days of experimentation and reviewing every webpage I could find that included these technologies as keyword searches. Yuk!! Not fun. To begin, as NetBeans Development is "all about modules" if you are reading this you probably have a need for one, or more, of your modules to perform JNI calls. Most of what is available on this site or the Internet in general (not to mention the help file in NB7) is either completely wrong for these versions, or so sparse as to be essentially unuseful to anyone other than a JNI expert. Here is what you are looking for ... the "cut to the chase" - "how to guide" to get a JNI call up and working on your NB7 / Windows 64-bit box. 1) From within your NetBeans Module (not the host appliation) declair your native method(s) and make sure you can compile the Java source without errors. Example: package org.mycompanyname.nativelogic; public class NativeInterfaceTest { static { try { if (System.getProperty( "os.arch" ).toLowerCase().equals( "amd64" ) ) System.loadLibrary( <64-bit_folder_name_on_file_system>/<file_name.dll> ); else System.loadLibrary( <32-bit_folder_name_on_file_system>/<file_name.dll> ); } catch (SecurityException se) {} catch (UnsatisfieldLinkError ule) {} catch (NullPointerException npe) {} } public NativeInterfaceTest() {} native String echoString(String s); } Take notice to the fact that we only load the Assembly once (as it's in a static block), because othersise you will throw exceptions if attempting to load it again. Also take note of our single (in this example) native method titled "echoString". This is the method that our C / C++ application is going to implement, then via the majic of JNI we'll call from our Java code. 2) If using a 64-bit version of Windows (which we are here) we need to open a 64-bit Visual Studio Command Prompt (versus the standard 32-bit version), and execute the "vcvarsall" BAT file, along with an "amd64" command line argument, to set the environment up for 64-bit tools. Example: <path_to_Microsoft_Visual_Studio_10.0>/VC/vcvarsall.bat amd64 Take note that you can use any version of the C / C++ compiler from Microsoft you wish. I happen to have Visual Studio 2005, 2008, and 2010 installed on my box so I chose to use "v10.0" but any that support 64-bit development will work fine. The other important aspect here is the "amd64" param. 3) In the Command Prompt change drives \ directories on your computer so that you are at the root of the fully qualified Class location on the file system that contains your native method declairation. Example: The fully qualified class name for my natively declair method is "org.mycompanyname.nativelogic.NativeInterfaceTest". As we successfully compiled our Java in Step 1 above, we should find it contained in our NetBeans Module something similar to the following: "/build/classes/org/mycompanyname/nativelogic/NativeInterfaceTest.class" We need to make sure our Command Prompt sets, as the current directly, "/build/classes" because of our next step. 4) In this step we'll create our C / C++ Header file that contains the JNI required statments. Type the following in the Command Prompt: javah -jni org.mycompanyname.nativelogic.NativeInterfaceTest and hit enter. If you receive any kind of error that states this is an unrecognized command that simply means your Windows computer does not know the PATH to that command (it's in your /bin folder). Either run the command from there, or include the fully qualified path name when invoking this application, or set your computer's PATH environmental variable to include that path in its search. This should produce a file called "org_mycompanyname_nativelogic_NativeInterfaceTest.h" ... a C Header file. I'd make a copy of this in case you need a backup later. 5) Edit the NativeInterfaceTest.h header file and include an implementation for the echoString() method. Example: JNIEXPORT jstring JNICALL Java_org_mycompanyname_nativelogic_NativeInterfaceTest_echoString (JNIEnv *env, jobject jobj, jstring js) { return((*env)->NewStringUTF(env, "My JNI is up and working after lots of research")); } Notice how you can't simply return a normal Java String (because you're in C at the moment). You have to tell the passed in JVM variable to create a Java String for you that will be returned back. Check out the following Oracle web page for other data types and how to create them for JNI purposes. 6) Close and Save your changes to the Header file. Now that you've added an implementation to the Header change the file extention from ".h" to ".c" as it's now a C source code file that properly implements the JNI required interface. Example: NativeInterfaceTest.c 7) We need to compile the newly created source code file and Link it too. From within the Command Prompt type the following: cl /I"path_to_my_jdks_include_folder" /I"path_to_my_jdks_include_win32_folder" /D:AMD64=1 /LD NativeInterfaceTest.c /FeNativeInterfaceTest.dll /link /machine:x64 Example: cl /I"D:/Program Files/Java/jdk1.6.0_21/include" /I"D:/Program Files/java/jdk1.6.0_21/include/win32" /D:AMD64=1 /LD NativeInterfaceTest.c /FeNativeInterfaceTest.dll /link /machine:x64 Notice the quotes around the paths to the 'include" and 'include/win32' folders is required because I have spaces in my folder names ... 'Program Files'. You can include them if you have no spaces without problems, but they are mandatory if you have spaces when using a command prompt. This will generate serveral files, but it's the DLL we're interested in. This is what the System.loadLirbary() java method is looking for. 8) Congratuations! You're at the last step. Simply take the DLL Assembly and paste it at the following location: <path_of_NetBeansProjects_folder>/<project_name>/<module_name>/build/cluster/modules/lib/x64 Note that you'll probably have to create the "lib" and "x64" folders. Example: C:\Users\<user_name>\Documents\NetBeansProjects\<application_name>\<module_name>\build\cluster\modules\lib\x64\NativeInterfaceTest.dll Java code ... notice how we don't inlude the ".dll" file extension in the loadLibrary() call? System.loadLibrary( "/x64/NativeInterfaceTest" ); Now, in your Java code you can create a NativeInterfaceTest object and call the echoString() method and it will return the String value you typed in the NativeInterfaceTest.c source code file. Hopefully this will save you the brain damage I endured trying to figure all this out on my own. Good luck and happy coding!

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  • Introduction to the ASP.NET Web API

    - by Stephen.Walther
    I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html>     Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "\n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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  • Introduction to the ASP.NET Web API

    - by Stephen.Walther
    I am a huge fan of Ajax. If you want to create a great experience for the users of your website – regardless of whether you are building an ASP.NET MVC or an ASP.NET Web Forms site — then you need to use Ajax. Otherwise, you are just being cruel to your customers. We use Ajax extensively in several of the ASP.NET applications that my company, Superexpert.com, builds. We expose data from the server as JSON and use jQuery to retrieve and update that data from the browser. One challenge, when building an ASP.NET website, is deciding on which technology to use to expose JSON data from the server. For example, how do you expose a list of products from the server as JSON so you can retrieve the list of products with jQuery? You have a number of options (too many options) including ASMX Web services, WCF Web Services, ASHX Generic Handlers, WCF Data Services, and MVC controller actions. Fortunately, the world has just been simplified. With the release of ASP.NET 4 Beta, Microsoft has introduced a new technology for exposing JSON from the server named the ASP.NET Web API. You can use the ASP.NET Web API with both ASP.NET MVC and ASP.NET Web Forms applications. The goal of this blog post is to provide you with a brief overview of the features of the new ASP.NET Web API. You learn how to use the ASP.NET Web API to retrieve, insert, update, and delete database records with jQuery. We also discuss how you can perform form validation when using the Web API and use OData when using the Web API. Creating an ASP.NET Web API Controller The ASP.NET Web API exposes JSON data through a new type of controller called an API controller. You can add an API controller to an existing ASP.NET MVC 4 project through the standard Add Controller dialog box. Right-click your Controllers folder and select Add, Controller. In the dialog box, name your controller MovieController and select the Empty API controller template: A brand new API controller looks like this: using System; using System.Collections.Generic; using System.Linq; using System.Net.Http; using System.Web.Http; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { } } An API controller, unlike a standard MVC controller, derives from the base ApiController class instead of the base Controller class. Using jQuery to Retrieve, Insert, Update, and Delete Data Let’s create an Ajaxified Movie Database application. We’ll retrieve, insert, update, and delete movies using jQuery with the MovieController which we just created. Our Movie model class looks like this: namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } public string Title { get; set; } public string Director { get; set; } } } Our application will consist of a single HTML page named Movies.html. We’ll place all of our jQuery code in the Movies.html page. Getting a Single Record with the ASP.NET Web API To support retrieving a single movie from the server, we need to add a Get method to our API controller: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public Movie GetMovie(int id) { // Return movie by id if (id == 1) { return new Movie { Id = 1, Title = "Star Wars", Director = "Lucas" }; } // Otherwise, movie was not found throw new HttpResponseException(HttpStatusCode.NotFound); } } } In the code above, the GetMovie() method accepts the Id of a movie. If the Id has the value 1 then the method returns the movie Star Wars. Otherwise, the method throws an exception and returns 404 Not Found HTTP status code. After building your project, you can invoke the MovieController.GetMovie() method by entering the following URL in your web browser address bar: http://localhost:[port]/api/movie/1 (You’ll need to enter the correct randomly generated port). In the URL api/movie/1, the first “api” segment indicates that this is a Web API route. The “movie” segment indicates that the MovieController should be invoked. You do not specify the name of the action. Instead, the HTTP method used to make the request – GET, POST, PUT, DELETE — is used to identify the action to invoke. The ASP.NET Web API uses different routing conventions than normal ASP.NET MVC controllers. When you make an HTTP GET request then any API controller method with a name that starts with “GET” is invoked. So, we could have called our API controller action GetPopcorn() instead of GetMovie() and it would still be invoked by the URL api/movie/1. The default route for the Web API is defined in the Global.asax file and it looks like this: routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); We can invoke our GetMovie() controller action with the jQuery code in the following HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Get Movie</title> </head> <body> <div> Title: <span id="title"></span> </div> <div> Director: <span id="director"></span> </div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> getMovie(1, function (movie) { $("#title").html(movie.Title); $("#director").html(movie.Director); }); function getMovie(id, callback) { $.ajax({ url: "/api/Movie", data: { id: id }, type: "GET", contentType: "application/json;charset=utf-8", statusCode: { 200: function (movie) { callback(movie); }, 404: function () { alert("Not Found!"); } } }); } </script> </body> </html> In the code above, the jQuery $.ajax() method is used to invoke the GetMovie() method. Notice that the Ajax call handles two HTTP response codes. When the GetMove() method successfully returns a movie, the method returns a 200 status code. In that case, the details of the movie are displayed in the HTML page. Otherwise, if the movie is not found, the GetMovie() method returns a 404 status code. In that case, the page simply displays an alert box indicating that the movie was not found (hopefully, you would implement something more graceful in an actual application). You can use your browser’s Developer Tools to see what is going on in the background when you open the HTML page (hit F12 in the most recent version of most browsers). For example, you can use the Network tab in Google Chrome to see the Ajax request which invokes the GetMovie() method: Getting a Set of Records with the ASP.NET Web API Let’s modify our Movie API controller so that it returns a collection of movies. The following Movie controller has a new ListMovies() method which returns a (hard-coded) collection of movies: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http; using MyWebAPIApp.Models; namespace MyWebAPIApp.Controllers { public class MovieController : ApiController { public IEnumerable<Movie> ListMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=1, Title="King Kong", Director="Jackson"}, new Movie {Id=1, Title="Memento", Director="Nolan"} }; } } } Because we named our action ListMovies(), the default Web API route will never match it. Therefore, we need to add the following custom route to our Global.asax file (at the top of the RegisterRoutes() method): routes.MapHttpRoute( name: "ActionApi", routeTemplate: "api/{controller}/{action}/{id}", defaults: new { id = RouteParameter.Optional } ); This route enables us to invoke the ListMovies() method with the URL /api/movie/listmovies. Now that we have exposed our collection of movies from the server, we can retrieve and display the list of movies using jQuery in our HTML page: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>List Movies</title> </head> <body> <div id="movies"></div> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> listMovies(function (movies) { var strMovies=""; $.each(movies, function (index, movie) { strMovies += "<div>" + movie.Title + "</div>"; }); $("#movies").html(strMovies); }); function listMovies(callback) { $.ajax({ url: "/api/Movie/ListMovies", data: {}, type: "GET", contentType: "application/json;charset=utf-8", }).then(function(movies){ callback(movies); }); } </script> </body> </html>     Inserting a Record with the ASP.NET Web API Now let’s modify our Movie API controller so it supports creating new records: public HttpResponseMessage<Movie> PostMovie(Movie movieToCreate) { // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } The PostMovie() method in the code above accepts a movieToCreate parameter. We don’t actually store the new movie anywhere. In real life, you will want to call a service method to store the new movie in a database. When you create a new resource, such as a new movie, you should return the location of the new resource. In the code above, the URL where the new movie can be retrieved is assigned to the Location header returned in the PostMovie() response. Because the name of our method starts with “Post”, we don’t need to create a custom route. The PostMovie() method can be invoked with the URL /Movie/PostMovie – just as long as the method is invoked within the context of a HTTP POST request. The following HTML page invokes the PostMovie() method. <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "Jackson" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }); function createMovie(movieToCreate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); } </script> </body> </html> This page creates a new movie (the Hobbit) by calling the createMovie() method. The page simply displays the Id of the new movie: The HTTP Post operation is performed with the following call to the jQuery $.ajax() method: $.ajax({ url: "/api/Movie", data: JSON.stringify( movieToCreate ), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { callback(newMovie); } } }); Notice that the type of Ajax request is a POST request. This is required to match the PostMovie() method. Notice, furthermore, that the new movie is converted into JSON using JSON.stringify(). The JSON.stringify() method takes a JavaScript object and converts it into a JSON string. Finally, notice that success is represented with a 201 status code. The HttpStatusCode.Created value returned from the PostMovie() method returns a 201 status code. Updating a Record with the ASP.NET Web API Here’s how we can modify the Movie API controller to support updating an existing record. In this case, we need to create a PUT method to handle an HTTP PUT request: public void PutMovie(Movie movieToUpdate) { if (movieToUpdate.Id == 1) { // Update the movie in the database return; } // If you can't find the movie to update throw new HttpResponseException(HttpStatusCode.NotFound); } Unlike our PostMovie() method, the PutMovie() method does not return a result. The action either updates the database or, if the movie cannot be found, returns an HTTP Status code of 404. The following HTML page illustrates how you can invoke the PutMovie() method: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Put Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToUpdate = { id: 1, title: "The Hobbit", director: "Jackson" }; updateMovie(movieToUpdate, function () { alert("Movie updated!"); }); function updateMovie(movieToUpdate, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToUpdate), type: "PUT", contentType: "application/json;charset=utf-8", statusCode: { 200: function () { callback(); }, 404: function () { alert("Movie not found!"); } } }); } </script> </body> </html> Deleting a Record with the ASP.NET Web API Here’s the code for deleting a movie: public HttpResponseMessage DeleteMovie(int id) { // Delete the movie from the database // Return status code return new HttpResponseMessage(HttpStatusCode.NoContent); } This method simply deletes the movie (well, not really, but pretend that it does) and returns a No Content status code (204). The following page illustrates how you can invoke the DeleteMovie() action: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Delete Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> deleteMovie(1, function () { alert("Movie deleted!"); }); function deleteMovie(id, callback) { $.ajax({ url: "/api/Movie", data: JSON.stringify({id:id}), type: "DELETE", contentType: "application/json;charset=utf-8", statusCode: { 204: function () { callback(); } } }); } </script> </body> </html> Performing Validation How do you perform form validation when using the ASP.NET Web API? Because validation in ASP.NET MVC is driven by the Default Model Binder, and because the Web API uses the Default Model Binder, you get validation for free. Let’s modify our Movie class so it includes some of the standard validation attributes: using System.ComponentModel.DataAnnotations; namespace MyWebAPIApp.Models { public class Movie { public int Id { get; set; } [Required(ErrorMessage="Title is required!")] [StringLength(5, ErrorMessage="Title cannot be more than 5 characters!")] public string Title { get; set; } [Required(ErrorMessage="Director is required!")] public string Director { get; set; } } } In the code above, the Required validation attribute is used to make both the Title and Director properties required. The StringLength attribute is used to require the length of the movie title to be no more than 5 characters. Now let’s modify our PostMovie() action to validate a movie before adding the movie to the database: public HttpResponseMessage PostMovie(Movie movieToCreate) { // Validate movie if (!ModelState.IsValid) { var errors = new JsonArray(); foreach (var prop in ModelState.Values) { if (prop.Errors.Any()) { errors.Add(prop.Errors.First().ErrorMessage); } } return new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } // Add movieToCreate to the database and update primary key movieToCreate.Id = 23; // Build a response that contains the location of the new movie var response = new HttpResponseMessage<Movie>(movieToCreate, HttpStatusCode.Created); var relativePath = "/api/movie/" + movieToCreate.Id; response.Headers.Location = new Uri(Request.RequestUri, relativePath); return response; } If ModelState.IsValid has the value false then the errors in model state are copied to a new JSON array. Each property – such as the Title and Director property — can have multiple errors. In the code above, only the first error message is copied over. The JSON array is returned with a Bad Request status code (400 status code). The following HTML page illustrates how you can invoke our modified PostMovie() action and display any error messages: <!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Create Movie</title> </head> <body> <script type="text/javascript" src="Scripts/jquery-1.6.2.min.js"></script> <script type="text/javascript"> var movieToCreate = { title: "The Hobbit", director: "" }; createMovie(movieToCreate, function (newMovie) { alert("New movie created with an Id of " + newMovie.Id); }, function (errors) { var strErrors = ""; $.each(errors, function(index, err) { strErrors += "*" + err + "n"; }); alert(strErrors); } ); function createMovie(movieToCreate, success, fail) { $.ajax({ url: "/api/Movie", data: JSON.stringify(movieToCreate), type: "POST", contentType: "application/json;charset=utf-8", statusCode: { 201: function (newMovie) { success(newMovie); }, 400: function (xhr) { var errors = JSON.parse(xhr.responseText); fail(errors); } } }); } </script> </body> </html> The createMovie() function performs an Ajax request and handles either a 201 or a 400 status code from the response. If a 201 status code is returned then there were no validation errors and the new movie was created. If, on the other hand, a 400 status code is returned then there was a validation error. The validation errors are retrieved from the XmlHttpRequest responseText property. The error messages are displayed in an alert: (Please don’t use JavaScript alert dialogs to display validation errors, I just did it this way out of pure laziness) This validation code in our PostMovie() method is pretty generic. There is nothing specific about this code to the PostMovie() method. In the following video, Jon Galloway demonstrates how to create a global Validation filter which can be used with any API controller action: http://www.asp.net/web-api/overview/web-api-routing-and-actions/video-custom-validation His validation filter looks like this: using System.Json; using System.Linq; using System.Net; using System.Net.Http; using System.Web.Http.Controllers; using System.Web.Http.Filters; namespace MyWebAPIApp.Filters { public class ValidationActionFilter:ActionFilterAttribute { public override void OnActionExecuting(HttpActionContext actionContext) { var modelState = actionContext.ModelState; if (!modelState.IsValid) { dynamic errors = new JsonObject(); foreach (var key in modelState.Keys) { var state = modelState[key]; if (state.Errors.Any()) { errors[key] = state.Errors.First().ErrorMessage; } } actionContext.Response = new HttpResponseMessage<JsonValue>(errors, HttpStatusCode.BadRequest); } } } } And you can register the validation filter in the Application_Start() method in the Global.asax file like this: GlobalConfiguration.Configuration.Filters.Add(new ValidationActionFilter()); After you register the Validation filter, validation error messages are returned from any API controller action method automatically when validation fails. You don’t need to add any special logic to any of your API controller actions to take advantage of the filter. Querying using OData The OData protocol is an open protocol created by Microsoft which enables you to perform queries over the web. The official website for OData is located here: http://odata.org For example, here are some of the query options which you can use with OData: · $orderby – Enables you to retrieve results in a certain order. · $top – Enables you to retrieve a certain number of results. · $skip – Enables you to skip over a certain number of results (use with $top for paging). · $filter – Enables you to filter the results returned. The ASP.NET Web API supports a subset of the OData protocol. You can use all of the query options listed above when interacting with an API controller. The only requirement is that the API controller action returns its data as IQueryable. For example, the following Movie controller has an action named GetMovies() which returns an IQueryable of movies: public IQueryable<Movie> GetMovies() { return new List<Movie> { new Movie {Id=1, Title="Star Wars", Director="Lucas"}, new Movie {Id=2, Title="King Kong", Director="Jackson"}, new Movie {Id=3, Title="Willow", Director="Lucas"}, new Movie {Id=4, Title="Shrek", Director="Smith"}, new Movie {Id=5, Title="Memento", Director="Nolan"} }.AsQueryable(); } If you enter the following URL in your browser: /api/movie?$top=2&$orderby=Title Then you will limit the movies returned to the top 2 in order of the movie Title. You will get the following results: By using the $top option in combination with the $skip option, you can enable client-side paging. For example, you can use $top and $skip to page through thousands of products, 10 products at a time. The $filter query option is very powerful. You can use this option to filter the results from a query. Here are some examples: Return every movie directed by Lucas: /api/movie?$filter=Director eq ‘Lucas’ Return every movie which has a title which starts with ‘S’: /api/movie?$filter=startswith(Title,’S') Return every movie which has an Id greater than 2: /api/movie?$filter=Id gt 2 The complete documentation for the $filter option is located here: http://www.odata.org/developers/protocols/uri-conventions#FilterSystemQueryOption Summary The goal of this blog entry was to provide you with an overview of the new ASP.NET Web API introduced with the Beta release of ASP.NET 4. In this post, I discussed how you can retrieve, insert, update, and delete data by using jQuery with the Web API. I also discussed how you can use the standard validation attributes with the Web API. You learned how to return validation error messages to the client and display the error messages using jQuery. Finally, we briefly discussed how the ASP.NET Web API supports the OData protocol. For example, you learned how to filter records returned from an API controller action by using the $filter query option. I’m excited about the new Web API. This is a feature which I expect to use with almost every ASP.NET application which I build in the future.

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  • AngularJS on top of ASP.NET: Moving the MVC framework out to the browser

    - by Varun Chatterji
    Heavily drawing inspiration from Ruby on Rails, MVC4’s convention over configuration model of development soon became the Holy Grail of .NET web development. The MVC model brought with it the goodness of proper separation of concerns between business logic, data, and the presentation logic. However, the MVC paradigm, was still one in which server side .NET code could be mixed with presentation code. The Razor templating engine, though cleaner than its predecessors, still encouraged and allowed you to mix .NET server side code with presentation logic. Thus, for example, if the developer required a certain <div> tag to be shown if a particular variable ShowDiv was true in the View’s model, the code could look like the following: Fig 1: To show a div or not. Server side .NET code is used in the View Mixing .NET code with HTML in views can soon get very messy. Wouldn’t it be nice if the presentation layer (HTML) could be pure HTML? Also, in the ASP.NET MVC model, some of the business logic invariably resides in the controller. It is tempting to use an anti­pattern like the one shown above to control whether a div should be shown or not. However, best practice would indicate that the Controller should not be aware of the div. The ShowDiv variable in the model should not exist. A controller should ideally, only be used to do the plumbing of getting the data populated in the model and nothing else. The view (ideally pure HTML) should render the presentation layer based on the model. In this article we will see how Angular JS, a new JavaScript framework by Google can be used effectively to build web applications where: 1. Views are pure HTML 2. Controllers (in the server sense) are pure REST based API calls 3. The presentation layer is loaded as needed from partial HTML only files. What is MVVM? MVVM short for Model View View Model is a new paradigm in web development. In this paradigm, the Model and View stuff exists on the client side through javascript instead of being processed on the server through postbacks. These frameworks are JavaScript frameworks that facilitate the clear separation of the “frontend” or the data rendering logic from the “backend” which is typically just a REST based API that loads and processes data through a resource model. The frameworks are called MVVM as a change to the Model (through javascript) gets reflected in the view immediately i.e. Model > View. Also, a change on the view (through manual input) gets reflected in the model immediately i.e. View > Model. The following figure shows this conceptually (comments are shown in red): Fig 2: Demonstration of MVVM in action In Fig 2, two text boxes are bound to the same variable model.myInt. Thus, changing the view manually (changing one text box through keyboard input) also changes the other textbox in real time demonstrating V > M property of a MVVM framework. Furthermore, clicking the button adds 1 to the value of model.myInt thus changing the model through JavaScript. This immediately updates the view (the value in the two textboxes) thus demonstrating the M > V property of a MVVM framework. Thus we see that the model in a MVVM JavaScript framework can be regarded as “the single source of truth“. This is an important concept. Angular is one such MVVM framework. We shall use it to build a simple app that sends SMS messages to a particular number. Application, Routes, Views, Controllers, Scope and Models Angular can be used in many ways to construct web applications. For this article, we shall only focus on building Single Page Applications (SPAs). Many of the approaches we will follow in this article have alternatives. It is beyond the scope of this article to explain every nuance in detail but we shall try to touch upon the basic concepts and end up with a working application that can be used to send SMS messages using Sent.ly Plus (a service that is itself built using Angular). Before you read on, we would like to urge you to forget what you know about Models, Views, Controllers and Routes in the ASP.NET MVC4 framework. All these words have different meanings in the Angular world. Whenever these words are used in this article, they will refer to Angular concepts and not ASP.NET MVC4 concepts. The following figure shows the skeleton of the root page of an SPA: Fig 3: The skeleton of a SPA The skeleton of the application is based on the Bootstrap starter template which can be found at: http://getbootstrap.com/examples/starter­template/ Apart from loading the Angular, jQuery and Bootstrap JavaScript libraries, it also loads our custom scripts /app/js/controllers.js /app/js/app.js These scripts define the routes, views and controllers which we shall come to in a moment. Application Notice that the body tag (Fig. 3) has an extra attribute: ng­app=”smsApp” Providing this tag “bootstraps” our single page application. It tells Angular to load a “module” called smsApp. This “module” is defined /app/js/app.js angular.module('smsApp', ['smsApp.controllers', function () {}]) Fig 4: The definition of our application module The line shows above, declares a module called smsApp. It also declares that this module “depends” on another module called “smsApp.controllers”. The smsApp.controllers module will contain all the controllers for our SPA. Routing and Views Notice that in the Navbar (in Fig 3) we have included two hyperlinks to: “#/app” “#/help” This is how Angular handles routing. Since the URLs start with “#”, they are actually just bookmarks (and not server side resources). However, our route definition (in /app/js/app.js) gives these URLs a special meaning within the Angular framework. angular.module('smsApp', ['smsApp.controllers', function () { }]) //Configure the routes .config(['$routeProvider', function ($routeProvider) { $routeProvider.when('/binding', { templateUrl: '/app/partials/bindingexample.html', controller: 'BindingController' }); }]); Fig 5: The definition of a route with an associated partial view and controller As we can see from the previous code sample, we are using the $routeProvider object in the configuration of our smsApp module. Notice how the code “asks for” the $routeProvider object by specifying it as a dependency in the [] braces and then defining a function that accepts it as a parameter. This is known as dependency injection. Please refer to the following link if you want to delve into this topic: http://docs.angularjs.org/guide/di What the above code snippet is doing is that it is telling Angular that when the URL is “#/binding”, then it should load the HTML snippet (“partial view”) found at /app/partials/bindingexample.html. Also, for this URL, Angular should load the controller called “BindingController”. We have also marked the div with the class “container” (in Fig 3) with the ng­view attribute. This attribute tells Angular that views (partial HTML pages) defined in the routes will be loaded within this div. You can see that the Angular JavaScript framework, unlike many other frameworks, works purely by extending HTML tags and attributes. It also allows you to extend HTML with your own tags and attributes (through directives) if you so desire, you can find out more about directives at the following URL: http://www.codeproject.com/Articles/607873/Extending­HTML­with­AngularJS­Directives Controllers and Models We have seen how we define what views and controllers should be loaded for a particular route. Let us now consider how controllers are defined. Our controllers are defined in the file /app/js/controllers.js. The following snippet shows the definition of the “BindingController” which is loaded when we hit the URL http://localhost:port/index.html#/binding (as we have defined in the route earlier as shown in Fig 5). Remember that we had defined that our application module “smsApp” depends on the “smsApp.controllers” module (see Fig 4). The code snippet below shows how the “BindingController” defined in the route shown in Fig 5 is defined in the module smsApp.controllers: angular.module('smsApp.controllers', [function () { }]) .controller('BindingController', ['$scope', function ($scope) { $scope.model = {}; $scope.model.myInt = 6; $scope.addOne = function () { $scope.model.myInt++; } }]); Fig 6: The definition of a controller in the “smsApp.controllers” module. The pieces are falling in place! Remember Fig.2? That was the code of a partial view that was loaded within the container div of the skeleton SPA shown in Fig 3. The route definition shown in Fig 5 also defined that the controller called “BindingController” (shown in Fig 6.) was loaded when we loaded the URL: http://localhost:22544/index.html#/binding The button in Fig 2 was marked with the attribute ng­click=”addOne()” which added 1 to the value of model.myInt. In Fig 6, we can see that this function is actually defined in the “BindingController”. Scope We can see from Fig 6, that in the definition of “BindingController”, we defined a dependency on $scope and then, as usual, defined a function which “asks for” $scope as per the dependency injection pattern. So what is $scope? Any guesses? As you might have guessed a scope is a particular “address space” where variables and functions may be defined. This has a similar meaning to scope in a programming language like C#. Model: The Scope is not the Model It is tempting to assign variables in the scope directly. For example, we could have defined myInt as $scope.myInt = 6 in Fig 6 instead of $scope.model.myInt = 6. The reason why this is a bad idea is that scope in hierarchical in Angular. Thus if we were to define a controller which was defined within the another controller (nested controllers), then the inner controller would inherit the scope of the parent controller. This inheritance would follow JavaScript prototypal inheritance. Let’s say the parent controller defined a variable through $scope.myInt = 6. The child controller would inherit the scope through java prototypical inheritance. This basically means that the child scope has a variable myInt that points to the parent scopes myInt variable. Now if we assigned the value of myInt in the parent, the child scope would be updated with the same value as the child scope’s myInt variable points to the parent scope’s myInt variable. However, if we were to assign the value of the myInt variable in the child scope, then the link of that variable to the parent scope would be broken as the variable myInt in the child scope now points to the value 6 and not to the parent scope’s myInt variable. But, if we defined a variable model in the parent scope, then the child scope will also have a variable model that points to the model variable in the parent scope. Updating the value of $scope.model.myInt in the parent scope would change the model variable in the child scope too as the variable is pointed to the model variable in the parent scope. Now changing the value of $scope.model.myInt in the child scope would ALSO change the value in the parent scope. This is because the model reference in the child scope is pointed to the scope variable in the parent. We did no new assignment to the model variable in the child scope. We only changed an attribute of the model variable. Since the model variable (in the child scope) points to the model variable in the parent scope, we have successfully changed the value of myInt in the parent scope. Thus the value of $scope.model.myInt in the parent scope becomes the “single source of truth“. This is a tricky concept, thus it is considered good practice to NOT use scope inheritance. More info on prototypal inheritance in Angular can be found in the “JavaScript Prototypal Inheritance” section at the following URL: https://github.com/angular/angular.js/wiki/Understanding­Scopes. Building It: An Angular JS application using a .NET Web API Backend Now that we have a perspective on the basic components of an MVVM application built using Angular, let’s build something useful. We will build an application that can be used to send out SMS messages to a given phone number. The following diagram describes the architecture of the application we are going to build: Fig 7: Broad application architecture We are going to add an HTML Partial to our project. This partial will contain the form fields that will accept the phone number and message that needs to be sent as an SMS. It will also display all the messages that have previously been sent. All the executable code that is run on the occurrence of events (button clicks etc.) in the view resides in the controller. The controller interacts with the ASP.NET WebAPI to get a history of SMS messages, add a message etc. through a REST based API. For the purposes of simplicity, we will use an in memory data structure for the purposes of creating this application. Thus, the tasks ahead of us are: Creating the REST WebApi with GET, PUT, POST, DELETE methods. Creating the SmsView.html partial Creating the SmsController controller with methods that are called from the SmsView.html partial Add a new route that loads the controller and the partial. 1. Creating the REST WebAPI This is a simple task that should be quite straightforward to any .NET developer. The following listing shows our ApiController: public class SmsMessage { public string to { get; set; } public string message { get; set; } } public class SmsResource : SmsMessage { public int smsId { get; set; } } public class SmsResourceController : ApiController { public static Dictionary<int, SmsResource> messages = new Dictionary<int, SmsResource>(); public static int currentId = 0; // GET api/<controller> public List<SmsResource> Get() { List<SmsResource> result = new List<SmsResource>(); foreach (int key in messages.Keys) { result.Add(messages[key]); } return result; } // GET api/<controller>/5 public SmsResource Get(int id) { if (messages.ContainsKey(id)) return messages[id]; return null; } // POST api/<controller> public List<SmsResource> Post([FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { SmsResource res = (SmsResource) value; res.smsId = currentId++; messages.Add(res.smsId, res); //SentlyPlusSmsSender.SendMessage(value.to, value.message); return Get(); } } // PUT api/<controller>/5 public List<SmsResource> Put(int id, [FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { if (messages.ContainsKey(id)) { //Update the message messages[id].message = value.message; messages[id].to = value.message; } return Get(); } } // DELETE api/<controller>/5 public List<SmsResource> Delete(int id) { if (messages.ContainsKey(id)) { messages.Remove(id); } return Get(); } } Once this class is defined, we should be able to access the WebAPI by a simple GET request using the browser: http://localhost:port/api/SmsResource Notice the commented line: //SentlyPlusSmsSender.SendMessage The SentlyPlusSmsSender class is defined in the attached solution. We have shown this line as commented as we want to explain the core Angular concepts. If you load the attached solution, this line is uncommented in the source and an actual SMS will be sent! By default, the API returns XML. For consumption of the API in Angular, we would like it to return JSON. To change the default to JSON, we make the following change to WebApiConfig.cs file located in the App_Start folder. public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); var appXmlType = config.Formatters.XmlFormatter. SupportedMediaTypes. FirstOrDefault( t => t.MediaType == "application/xml"); config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType); } } We now have our backend REST Api which we can consume from Angular! 2. Creating the SmsView.html partial This simple partial will define two fields: the destination phone number (international format starting with a +) and the message. These fields will be bound to model.phoneNumber and model.message. We will also add a button that we shall hook up to sendMessage() in the controller. A list of all previously sent messages (bound to model.allMessages) will also be displayed below the form input. The following code shows the code for the partial: <!--­­ If model.errorMessage is defined, then render the error div -­­> <div class="alert alert-­danger alert-­dismissable" style="margin­-top: 30px;" ng­-show="model.errorMessage != undefined"> <button type="button" class="close" data­dismiss="alert" aria­hidden="true">&times;</button> <strong>Error!</strong> <br /> {{ model.errorMessage }} </div> <!--­­ The input fields bound to the model --­­> <div class="well" style="margin-­top: 30px;"> <table style="width: 100%;"> <tr> <td style="width: 45%; text-­align: center;"> <input type="text" placeholder="Phone number (eg; +44 7778 609466)" ng­-model="model.phoneNumber" class="form-­control" style="width: 90%" onkeypress="return checkPhoneInput();" /> </td> <td style="width: 45%; text-­align: center;"> <input type="text" placeholder="Message" ng­-model="model.message" class="form-­control" style="width: 90%" /> </td> <td style="text-­align: center;"> <button class="btn btn-­danger" ng-­click="sendMessage();" ng-­disabled="model.isAjaxInProgress" style="margin­right: 5px;">Send</button> <img src="/Content/ajax-­loader.gif" ng­-show="model.isAjaxInProgress" /> </td> </tr> </table> </div> <!--­­ The past messages ­­--> <div style="margin-­top: 30px;"> <!­­-- The following div is shown if there are no past messages --­­> <div ng­-show="model.allMessages.length == 0"> No messages have been sent yet! </div> <!--­­ The following div is shown if there are some past messages --­­> <div ng-­show="model.allMessages.length == 0"> <table style="width: 100%;" class="table table-­striped"> <tr> <td>Phone Number</td> <td>Message</td> <td></td> </tr> <!--­­ The ng-­repeat directive is line the repeater control in .NET, but as you can see this partial is pure HTML which is much cleaner --> <tr ng-­repeat="message in model.allMessages"> <td>{{ message.to }}</td> <td>{{ message.message }}</td> <td> <button class="btn btn-­danger" ng-­click="delete(message.smsId);" ng­-disabled="model.isAjaxInProgress">Delete</button> </td> </tr> </table> </div> </div> The above code is commented and should be self explanatory. Conditional rendering is achieved through using the ng-­show=”condition” attribute on various div tags. Input fields are bound to the model and the send button is bound to the sendMessage() function in the controller as through the ng­click=”sendMessage()” attribute defined on the button tag. While AJAX calls are taking place, the controller sets model.isAjaxInProgress to true. Based on this variable, buttons are disabled through the ng-­disabled directive which is added as an attribute to the buttons. The ng-­repeat directive added as an attribute to the tr tag causes the table row to be rendered multiple times much like an ASP.NET repeater. 3. Creating the SmsController controller The penultimate piece of our application is the controller which responds to events from our view and interacts with our MVC4 REST WebAPI. The following listing shows the code we need to add to /app/js/controllers.js. Note that controller definitions can be chained. Also note that this controller “asks for” the $http service. The $http service is a simple way in Angular to do AJAX. So far we have only encountered modules, controllers, views and directives in Angular. The $http is new entity in Angular called a service. More information on Angular services can be found at the following URL: http://docs.angularjs.org/guide/dev_guide.services.understanding_services. .controller('SmsController', ['$scope', '$http', function ($scope, $http) { //We define the model $scope.model = {}; //We define the allMessages array in the model //that will contain all the messages sent so far $scope.model.allMessages = []; //The error if any $scope.model.errorMessage = undefined; //We initially load data so set the isAjaxInProgress = true; $scope.model.isAjaxInProgress = true; //Load all the messages $http({ url: '/api/smsresource', method: "GET" }). success(function (data, status, headers, config) { this callback will be called asynchronously //when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { //called asynchronously if an error occurs //or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); $scope.delete = function (id) { //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource/' + id, method: "DELETE" }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } $scope.sendMessage = function () { $scope.model.errorMessage = undefined; var message = ''; if($scope.model.message != undefined) message = $scope.model.message.trim(); if ($scope.model.phoneNumber == undefined || $scope.model.phoneNumber == '' || $scope.model.phoneNumber.length < 10 || $scope.model.phoneNumber[0] != '+') { $scope.model.errorMessage = "You must enter a valid phone number in international format. Eg: +44 7778 609466"; return; } if (message.length == 0) { $scope.model.errorMessage = "You must specify a message!"; return; } //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource', method: "POST", data: { to: $scope.model.phoneNumber, message: $scope.model.message } }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status // We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } }]); We can see from the previous listing how the functions that are called from the view are defined in the controller. It should also be evident how easy it is to make AJAX calls to consume our MVC4 REST WebAPI. Now we are left with the final piece. We need to define a route that associates a particular path with the view we have defined and the controller we have defined. 4. Add a new route that loads the controller and the partial This is the easiest part of the puzzle. We simply define another route in the /app/js/app.js file: $routeProvider.when('/sms', { templateUrl: '/app/partials/smsview.html', controller: 'SmsController' }); Conclusion In this article we have seen how much of the server side functionality in the MVC4 framework can be moved to the browser thus delivering a snappy and fast user interface. We have seen how we can build client side HTML only views that avoid the messy syntax offered by server side Razor views. We have built a functioning app from the ground up. The significant advantage of this approach to building web apps is that the front end can be completely platform independent. Even though we used ASP.NET to create our REST API, we could just easily have used any other language such as Node.js, Ruby etc without changing a single line of our front end code. Angular is a rich framework and we have only touched on basic functionality required to create a SPA. For readers who wish to delve further into the Angular framework, we would recommend the following URL as a starting point: http://docs.angularjs.org/misc/started. To get started with the code for this project: Sign up for an account at http://plus.sent.ly (free) Add your phone number Go to the “My Identies Page” Note Down your Sender ID, Consumer Key and Consumer Secret Download the code for this article at: https://docs.google.com/file/d/0BzjEWqSE31yoZjZlV0d0R2Y3eW8/edit?usp=sharing Change the values of Sender Id, Consumer Key and Consumer Secret in the web.config file Run the project through Visual Studio!

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  • Using HTML 5 SessionState to save rendered Page Content

    - by Rick Strahl
    HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   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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  • car race game collision condition.

    - by ashok patidar
    in this how can rotate car when it goes to collied with the track side. package { import flash.display.MovieClip; import flash.events.Event; import flash.events.KeyboardEvent; import flash.text.TextField; import flash.ui.Keyboard; import Math; /** * ... * @author Ashok */ public class F1race extends MovieClip { public var increment:Number = 0; //amount the car moves each frame public var posNeg:Number = 1; public var acceleration:Number = .05; //acceleration of the car, or the amount increment gets increased by. public var speed:Number = 0; //the speed of the car that will be displayed on screen public var maxSpeed:Number = 100; public var keyLeftPressed:Boolean; public var keyRightPressed:Boolean; public var keyUpPressed:Boolean; public var keyDownPressed:Boolean; public var spedometer:TextField = new TextField(); public var carRotation:Number ; public var txt_hit:TextField = new TextField(); public function F1race() { carRotation = carMC.rotation; trace(carMC.rotation); //addChild(spedometer); //spedometer.x = 0; //spedometer.y = 0; addChild(txt_hit); txt_hit.x = 0; txt_hit.y = 100; //rotation of the car addEventListener(Event.ENTER_FRAME, onEnterFrameFunction); stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed,false); stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased,false); carMC.addEventListener(Event.ENTER_FRAME, carOver_road) } public function carOver_road(event:Event):void { //trace(texture.hitTestPoint(carMC.x,carMC.y,true),"--"); /* if(!texture.hitTestPoint(carMC.x,carMC.y,true)) { txt_hit.text = "WRONG WAY"; if(increment!=0) { increment=1; } } else { txt_hit.text = ""; //increment++; }*/ if (roadless.hitTestPoint(carMC.x - carMC.width / 2, carMC.y,true)) { trace("left Hit" + carMC.rotation); //acceleration = .005; //if(carMC.rotation>90 || carMC.rotation>90 //carMC.rotation += 2; if ((carMC.rotation >= 90) && (carMC.rotation <= 180)) { carMC.rotation += 3; carMC.x += 3; } if ((carMC.rotation <= -90) && (carMC.rotation >= -180)) { carMC.rotation += 3; texture.y -= 3; } if ((carMC.rotation > -90) && (carMC.rotation <= -1)) { carMC.rotation += 3; texture.y -= 3; } if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if (roadless.hitTestPoint(carMC.x + carMC.width / 2, carMC.y,true)) { trace("left right"); //carMC.rotation -= 2; if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if (roadless.hitTestPoint(carMC.x, carMC.y- carMC.height / 2,true)) { trace("left right"); //carMC.rotation -= 2; if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if (roadless.hitTestPoint(carMC.x, carMC.y+ carMC.height / 2,true)) { trace("left right"); //carMC.rotation -= 2; if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if ((!roadless.hitTestPoint(carMC.x - carMC.width / 2, carMC.y, true)) && (!roadless.hitTestPoint(carMC.x, carMC.y- carMC.height / 2,true)) && (!roadless.hitTestPoint(carMC.x, carMC.y+ carMC.height / 2,true)) && (!roadless.hitTestPoint(carMC.x, carMC.y+ carMC.height / 2,true))) { //acceleration = .05; } } public function onEnterFrameFunction(events:Event):void { speed = Math.round((increment) * 5); spedometer.text = String(speed); if ((carMC.rotation < 180)&&(carMC.rotation >= 0)){ carRotation = carMC.rotation; posNeg = 1; } if ((carMC.rotation < 0)&&(carMC.rotation > -180)){ carRotation = -1 * carMC.rotation; posNeg = -1; } if (keyRightPressed) { carMC.rotation += .5 * increment; carMC.LWheel.rotation = 8; carMC.RWheel.rotation = 8; steering.gotoAndStop(2); } if (keyLeftPressed) { carMC.rotation -= .5 * increment; carMC.LWheel.rotation = -8; carMC.RWheel.rotation = -8; steering.gotoAndStop(3); } if (keyDownPressed) { steering.gotoAndStop(1); carMC.LWheel.rotation = 0; carMC.RWheel.rotation = 0; increment -= 0.5 * acceleration; texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } increment -= 1 * acceleration; if ((Math.abs(speed)) < (Math.abs(maxSpeed))) { increment += acceleration; } if ((Math.abs(speed)) == (Math.abs(maxSpeed))) { trace("hello"); } } if (keyUpPressed) { steering.gotoAndStop(1); carMC.LWheel.rotation = 0; carMC.RWheel.rotation = 0; //trace(carMC.rotation); texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } increment += 1 * acceleration; if ((Math.abs(speed)) < (Math.abs(maxSpeed))) { increment += acceleration; } } if ((!keyUpPressed) && (!keyDownPressed)){ /*if (increment > 0 && (!keyUpPressed)&& (!keyDownPressed)) { //texture.y -= ((90-carRotation)/90)*increment; increment -= 1.5 * acceleration; } if((increment==0)&&(!keyUpPressed)&& (!keyDownPressed)) { increment = 0; } if((increment<0)&&(!keyUpPressed)&& (!keyDownPressed)) { increment += 1.5 * acceleration; }*/ if (increment > 0) { increment -= 1.5 * acceleration; texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } } if (increment == 0) { increment = 0; } if (increment < 0) { increment += 1.5 * acceleration; texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } } } } public function keyPressed(event:KeyboardEvent):void { trace("keyPressed"); if (event.keyCode == Keyboard.LEFT) { keyLeftPressed = true; } if (event.keyCode == Keyboard.RIGHT) { keyRightPressed = true; } if (event.keyCode == Keyboard.UP) { keyUpPressed = true; } if (event.keyCode == Keyboard.DOWN) { keyDownPressed = true; } } public function keyReleased(event:KeyboardEvent):void { trace("keyReleased..."); //increment -= 1.5 * acceleration; //increment--; if (event.keyCode == Keyboard.LEFT) { keyLeftPressed = false; } if (event.keyCode == Keyboard.RIGHT) { keyRightPressed = false; } if (event.keyCode == Keyboard.UP) { keyUpPressed = false; } if (event.keyCode == Keyboard.DOWN) { keyDownPressed = false; } } } }

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