/// <summary>
/// Sets up and invokes an entry point on an <see cref="HttpApplication"/> implementer found
/// by probing the given bin path.
/// </summary>
/// <param name="logger">The logger to use when probing.</param>
/// <param name="binPath">The bin path to probe.</param>
private void SetupandInvokeEntryPoint(ILogger logger, string binPath)
{
if (Directory.Exists(binPath))
{
HttpApplicationProbe probe = new HttpApplicationProbe(logger, binPath);
Type type = HttpApplicationProbe.FindApplicationTypes(probe.FindApplicationAssemblies()).FirstOrDefault();
if (type != null)
{
logger.Info("Found an HTTP application requiring startup: {0}.", type.FullName);
HttpApplication httpApplication = null;
try
{
httpApplication = (HttpApplication)Activator.CreateInstance(type);
}
catch (Exception ex)
{
logger.Error(ex, "Failed to create an instance of the HTTP application {0}.", type.FullName);
}
if (httpApplication != null)
{
try
{
MethodInfo entryPoint = HttpApplicationProbe.FindEntryPoint(type);
if (entryPoint != null)
{
logger.Info("Invoking entry point for HTTP application {0}.", type.FullName);
this.InvokeEventHandler(httpApplication, entryPoint);
}
else
{
logger.Info("No entry point found for HTTP application {0}.", type.FullName);
}
this.httpApplication = httpApplication;
httpApplication = null;
}
catch (Exception ex)
{
logger.Error(ex, "Failed to invoke the entry point for HTTP application {0}.", type.FullName);
if (ex.InnerException != null)
{
logger.Error(ex.InnerException);
}
}
finally
{
if (httpApplication != null)
{
httpApplication.Dispose();
}
}
}
}
}
}
/// <summary>
/// Disposes of the HTTP applications that was created as an entry point.
/// </summary>
private void DisposeHttpApplication()
{
HttpApplication httpApplication = this.httpApplication;
this.httpApplication = null;
if (httpApplication != null)
{
try
{
MethodInfo method = HttpApplicationProbe.FindExitPoint(httpApplication.GetType());
if (method != null)
{
this.logger.Info("Invoking exit point for HTTP application {0}.", httpApplication.GetType().FullName);
this.InvokeEventHandler(httpApplication, method);
}
else
{
this.logger.Info("No exit point found for HTTP application {0}.", httpApplication.GetType().FullName);
}
}
finally
{
httpApplication.Dispose();
}
}
}
/// <summary>
/// Finds a method acting as an <see cref="HttpApplication"/> entry point
/// for the given type.
/// </summary>
/// <param name="type">The type to find the entry point for.</param>
/// <returns>An entry point method, or null if none was found.</returns>
public static MethodInfo FindEntryPoint(Type type)
{
if (type == null)
{
throw new ArgumentNullException("type", "type cannot be null.");
}
return(HttpApplicationProbe.FindEventHandler(type, HttpApplicationProbe.EntryPoints));
}
/// <summary>
/// Finds all types in the given assembly collection that implement <see cref="HttpApplication"/>
/// and contain an entry or exit point (or both).
/// </summary>
/// <param name="assemblies">The assemblies to find application types for.</param>
/// <returns>A collection of <see cref="HttpApplication"/> types.</returns>
public static IEnumerable <Type> FindApplicationTypes(IEnumerable <Assembly> assemblies)
{
List <Type> result = new List <Type>();
foreach (Assembly assembly in assemblies ?? new Assembly[0])
{
foreach (Type type in assembly.GetTypes().Where(t => HttpApplicationProbe.IsHttpApplication(t)))
{
if (HttpApplicationProbe.FindEntryPoint(type) != null ||
HttpApplicationProbe.FindExitPoint(type) != null)
{
result.Add(type);
}
}
}
return(result);
}
/// <summary>
/// Sets up and invokes an entry point on an <see cref="HttpApplication"/> implementer found
/// by probing the given bin path.
/// </summary>
/// <param name="logger">The logger to use when probing.</param>
/// <param name="binPath">The bin path to probe.</param>
private void SetupandInvokeEntryPoint(ILogger logger, string binPath)
{
if (Directory.Exists(binPath))
{
HttpApplicationProbe probe = new HttpApplicationProbe(logger, binPath);
Type type = HttpApplicationProbe.FindApplicationTypes(probe.FindApplicationAssemblies()).FirstOrDefault();
if (type != null)
{
logger.Info("Found an HTTP application requiring startup: {0}.", type.FullName);
HttpApplication httpApplication = null;
try
{
httpApplication = (HttpApplication)Activator.CreateInstance(type);
}
catch (Exception ex)
{
logger.Error(ex, "Failed to create an instance of the HTTP application {0}.", type.FullName);
}
if (httpApplication != null)
{
try
{
MethodInfo entryPoint = HttpApplicationProbe.FindEntryPoint(type);
if (entryPoint != null)
{
logger.Info("Invoking entry point for HTTP application {0}.", type.FullName);
this.InvokeEventHandler(httpApplication, entryPoint);
}
else
{
logger.Info("No entry point found for HTTP application {0}.", type.FullName);
}
this.httpApplication = httpApplication;
httpApplication = null;
}
catch (Exception ex)
{
logger.Error(ex, "Failed to invoke the entry point for HTTP application {0}.", type.FullName);
if (ex.InnerException != null)
{
logger.Error(ex.InnerException);
}
}
finally
{
if (httpApplication != null)
{
httpApplication.Dispose();
}
}
}
}
}
}
/// <summary>
/// Finds <see cref="Assembly"/> instances in the current bin path
/// that contain types that implement <see cref="HttpApplication"/>.
/// </summary>
/// <returns>A collection of <see cref="Assembly"/> instances.</returns>
public IEnumerable <Assembly> FindApplicationAssemblies()
{
List <Assembly> result = new List <Assembly>();
string[] assemblyPaths = null;
try
{
assemblyPaths = Directory.GetFiles(this.BinPath, "*.dll");
}
catch (IOException ex)
{
this.Logger.Error(ex);
}
catch (UnauthorizedAccessException ex)
{
this.Logger.Error(ex);
}
if (assemblyPaths != null)
{
foreach (string assemblyPath in assemblyPaths)
{
AssemblyName assemblyName = null;
Assembly assembly = null;
try
{
assemblyName = AssemblyName.GetAssemblyName(assemblyPath);
}
catch (Exception ex)
{
this.Logger.Error(ex);
}
if (assemblyName != null &&
!assemblyName.FullName.StartsWith("System.", StringComparison.OrdinalIgnoreCase) &&
!assemblyName.FullName.StartsWith("Microsoft.", StringComparison.OrdinalIgnoreCase))
{
try
{
assembly = Assembly.Load(assemblyName);
}
catch (ArgumentException ex)
{
this.Logger.Error(ex);
}
catch (BadImageFormatException ex)
{
this.Logger.Error(ex);
}
catch (IOException ex)
{
this.Logger.Error(ex);
}
catch (ReflectionTypeLoadException ex)
{
this.Logger.Error(ex);
}
catch (SecurityException ex)
{
this.Logger.Error(ex);
}
}
try
{
if (assembly != null && assembly.GetTypes().Any(t => HttpApplicationProbe.IsHttpApplication(t)))
{
result.Add(assembly);
}
}
catch (ReflectionTypeLoadException ex)
{
try
{
this.Logger.Error(ex);
}
catch
{
// This can fail for various reasons...
}
}
}
}
return(result);
}
