RestHandler.cs :  » 2.6.4-mono-.net-core » System.Web » System » Web » Script » Services » C# / CSharp Open Source

//
// RestHandler.cs
//
// Author:
//   Konstantin Triger <kostat@mainsoft.com>
//
// (C) 2007 Mainsoft, Inc.  http://www.mainsoft.com
//
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;
using System.Collections.Generic;
using System.Text;
using System.Web.Script.Serialization;
using System.Collections.Specialized;
using System.IO;
using System.Web.SessionState;
using System.Reflection;

namespace System.Web.Script.Services{
  sealed class RestHandler : IHttpHandler
  {
    #region SessionWrappers

    class SessionWrapperHandler : IHttpHandler, IRequiresSessionState
    {
      readonly IHttpHandler _handler;

      public SessionWrapperHandler (IHttpHandler handler) {
        _handler = handler;
      }

      public bool IsReusable {
        get { return _handler.IsReusable; }
      }

      public void ProcessRequest (HttpContext context) {
        _handler.ProcessRequest (context);
      }
    }

    sealed class ReadOnlySessionWrapperHandler : SessionWrapperHandler, IReadOnlySessionState
    {
      public ReadOnlySessionWrapperHandler (IHttpHandler handler) : base (handler) { }
    }

    #endregion

    #region ExceptionSerializer

    sealed class ExceptionSerializer
    {
      readonly Exception _e;
      public ExceptionSerializer (Exception e) {
        _e = e;
      }

      public string Message {
        get { return _e.Message; }
      }

      public string StackTrace {
        get { return _e.StackTrace; }
      }

      public string ExceptionType {
        get { return _e.GetType ().FullName; }
      }      
    }

    #endregion

    readonly LogicalTypeInfo.LogicalMethodInfo _logicalMethodInfo;

    private RestHandler (HttpContext context, Type type, string filePath) {
      LogicalTypeInfo logicalTypeInfo = LogicalTypeInfo.GetLogicalTypeInfo (type, filePath);
      HttpRequest request = context.Request;
      string methodName = request.PathInfo.Substring (1);
      if (logicalTypeInfo == null || String.IsNullOrEmpty(methodName))
        ThrowInvalidOperationException (methodName);

      _logicalMethodInfo = logicalTypeInfo [methodName];
      if (_logicalMethodInfo == null)
        ThrowInvalidOperationException (methodName);
    }

    static void ThrowInvalidOperationException (string pathInfo) {
      throw new InvalidOperationException (
          string.Format ("Request format is unrecognized unexpectedly ending in '{0}'.", pathInfo));
    }

    static readonly Type IRequiresSessionStateType = typeof (IRequiresSessionState);
    static readonly Type IReadOnlySessionStateType = typeof (IReadOnlySessionState);
    public static IHttpHandler GetHandler (HttpContext context, Type type, string filePath) {
      RestHandler handler = new RestHandler (context, type, filePath);
      LogicalTypeInfo.LogicalMethodInfo mi = handler._logicalMethodInfo;
      if (mi.MethodInfo.IsStatic) {
        if (IRequiresSessionStateType.IsAssignableFrom (type))
          return IReadOnlySessionStateType.IsAssignableFrom (type) ?
            new ReadOnlySessionWrapperHandler (handler) : new SessionWrapperHandler (handler);
      }
      else
        if (mi.EnableSession)
          return new SessionWrapperHandler (handler);

      return handler;

    }
    #region IHttpHandler Members

    public bool IsReusable {
      get { return false; }
    }
    
    public void ProcessRequest (HttpContext context) {
      HttpRequest request = context.Request;
      HttpResponse response = context.Response;
      response.ContentType =
        _logicalMethodInfo.ResponseFormat == ResponseFormat.Json ?
        "application/json" : "text/xml";
      response.Cache.SetCacheability (HttpCacheability.Private);
      response.Cache.SetMaxAge (TimeSpan.Zero);

      try {
        _logicalMethodInfo.Invoke (request, response);
      }
      catch (TargetInvocationException e) {
        response.AddHeader ("jsonerror", "true");
        response.ContentType = "application/json";
        response.StatusCode = 500;
        JavaScriptSerializer.DefaultSerializer.Serialize (new ExceptionSerializer (e.GetBaseException ()), response.Output);
        response.End ();
      }
    }
    
    #endregion
  }
}