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//---------------------------------------------------------------------
// <copyright file="BatchServiceHost.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <summary>
// Provides an internal implementation for IDataServiceHost to keep track of states
// for batch operations
// </summary>
//
// @owner Microsoft
//---------------------------------------------------------------------
namespace System.Data.Services
{
#region Namespaces.
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Diagnostics;
using System.IO;
using System.Web;
using System.Net;
#endregion Namespaces.
/// <summary>
/// Keeps track of the request and response headers for each
/// operation in the batch
/// </summary>
internal class BatchServiceHost : IDataServiceHost2
{
#region Private fields.
/// <summary>Response separator string.</summary>
private readonly string boundary;
/// <summary>Request Stream.</summary>
private readonly Stream requestStream;
/// <summary>Content Id for this operation.</summary>
private readonly string contentId;
/// <summary>Output writer.</summary>
private readonly StreamWriter writer;
/// <summary>Gets the absolute URI to the resource upon which to apply the request.</summary>
private readonly Uri absoluteRequestUri;
/// <summary>Gets the absolute URI to the service.</summary>
private readonly Uri absoluteServiceUri;
/// <summary>Request Http Method</summary>
private readonly string requestHttpMethod;
/// <summary>Collection of request headers for the current batch operation.</summary>
private readonly WebHeaderCollection requestHeaders;
/// <summary>Collection of response headers for the current batch operation.</summary>
private readonly WebHeaderCollection responseHeaders;
/// <summary>List of query parameters as specified in the request uri.</summary>
private NameValueCollection queryParameters;
/// <summary>Value of the response StatusCode header.</summary>
private int responseStatusCode;
#endregion Private fields.
#region Constructors.
/// <summary>
/// Initializes a new dummy host for the batch request.
/// This host represents a single operation in the batch.
/// </summary>
/// <param name="absoluteServiceUri">absolute Uri to the service</param>
/// <param name="batchStream">batch stream which contains the header information.</param>
/// <param name="contentId">content id for the given operation host.</param>
/// <param name='boundary'>Response separator string.</param>
/// <param name='writer'>Output writer.</param>
internal BatchServiceHost(Uri absoluteServiceUri, BatchStream batchStream, string contentId, string boundary, StreamWriter writer)
: this(boundary, writer)
{
Debug.Assert(absoluteServiceUri != null && absoluteServiceUri.IsAbsoluteUri, "absoluteServiceUri != null && absoluteServiceUri.IsAbsoluteUri");
Debug.Assert(batchStream != null, "batchStream != null");
this.absoluteServiceUri = absoluteServiceUri;
this.absoluteRequestUri = RequestUriProcessor.GetAbsoluteUriFromReference(batchStream.ContentUri, absoluteServiceUri);
this.requestHttpMethod = GetHttpMethodName(batchStream.State);
this.requestStream = batchStream.GetContentStream();
this.contentId = contentId;
foreach (KeyValuePair<string, string> header in batchStream.ContentHeaders)
{
this.requestHeaders.Add(header.Key, header.Value);
}
}
/// <summary>
/// Initializes a host for error scenarios - something to which we can write the response header values
/// and write them to the underlying stream.
/// </summary>
/// <param name='boundary'>Response separator string.</param>
/// <param name='writer'>Output writer.</param>
internal BatchServiceHost(string boundary, StreamWriter writer)
{
Debug.Assert(!string.IsNullOrEmpty(boundary), "!string.IsNullOrEmpty(boundary)");
Debug.Assert(writer != null, "writer != null");
this.boundary = boundary;
this.writer = writer;
this.requestHeaders = new WebHeaderCollection();
this.responseHeaders = new WebHeaderCollection();
}
#endregion Constructors.
#region Properties.
/// <summary>Gets the absolute URI to the resource upon which to apply the request.</summary>
Uri IDataServiceHost.AbsoluteRequestUri
{
[DebuggerStepThrough]
get { return this.absoluteRequestUri; }
}
/// <summary>Gets the absolute URI to the service.</summary>
Uri IDataServiceHost.AbsoluteServiceUri
{
[DebuggerStepThrough]
get { return this.absoluteServiceUri; }
}
/// <summary>
/// Gets the character set encoding that the client requested,
/// possibly null.
/// </summary>
string IDataServiceHost.RequestAccept
{
get { return this.requestHeaders[HttpRequestHeader.Accept]; }
}
/// <summary>
/// Gets the character set encoding that the client requested,
/// possibly null.
/// </summary>
string IDataServiceHost.RequestAcceptCharSet
{
get { return this.requestHeaders[HttpRequestHeader.AcceptCharset]; }
}
/// <summary>Gets the HTTP MIME type of the input stream.</summary>
string IDataServiceHost.RequestContentType
{
get { return this.requestHeaders[HttpRequestHeader.ContentType]; }
}
/// <summary>
/// Gets the HTTP data transfer method (such as GET, POST, or HEAD) used by the client.
/// </summary>
string IDataServiceHost.RequestHttpMethod
{
[DebuggerStepThrough]
get { return this.requestHttpMethod; }
}
/// <summary>Gets the value of the If-Match header from the request made</summary>
string IDataServiceHost.RequestIfMatch
{
get { return this.requestHeaders[HttpRequestHeader.IfMatch]; }
}
/// <summary>Gets the value of the If-None-Match header from the request made</summary>
string IDataServiceHost.RequestIfNoneMatch
{
get { return this.requestHeaders[HttpRequestHeader.IfNoneMatch]; }
}
/// <summary>Gets the value for the MaxDataServiceVersion request header.</summary>
string IDataServiceHost.RequestMaxVersion
{
get { return this.requestHeaders[XmlConstants.HttpMaxDataServiceVersion]; }
}
/// <summary>Gets the value for the DataServiceVersion request header.</summary>
string IDataServiceHost.RequestVersion
{
get { return this.requestHeaders[XmlConstants.HttpDataServiceVersion]; }
}
/// <summary>Gets or sets the Cache-Control header on the response.</summary>
string IDataServiceHost.ResponseCacheControl
{
get { return this.responseHeaders[HttpResponseHeader.CacheControl]; }
set { this.responseHeaders[HttpResponseHeader.CacheControl] = value; }
}
/// <summary>Gets or sets the HTTP MIME type of the output stream.</summary>
string IDataServiceHost.ResponseContentType
{
get { return this.responseHeaders[HttpResponseHeader.ContentType]; }
set { this.responseHeaders[HttpResponseHeader.ContentType] = value; }
}
/// <summary>Gets/Sets the value of the ETag header on the outgoing response</summary>
string IDataServiceHost.ResponseETag
{
get { return this.responseHeaders[HttpResponseHeader.ETag]; }
set { this.responseHeaders[HttpResponseHeader.ETag] = value; }
}
/// <summary>Gets or sets the Location header on the response.</summary>
string IDataServiceHost.ResponseLocation
{
get { return this.responseHeaders[HttpResponseHeader.Location]; }
set { this.responseHeaders[HttpResponseHeader.Location] = value; }
}
/// <summary>
/// Gets/Sets the status code for the request made.
/// </summary>
int IDataServiceHost.ResponseStatusCode
{
get { return this.responseStatusCode; }
set { this.responseStatusCode = value; }
}
/// <summary>
/// Gets the <see cref="Stream"/> to be written to send a response
/// to the client.
/// </summary>
Stream IDataServiceHost.ResponseStream
{
get
{
// There is a batch stream for writing requests for batch operations.
// Hence this method should never be called.
throw Error.NotSupported();
}
}
/// <summary>Gets or sets the value for the DataServiceVersion response header.</summary>
string IDataServiceHost.ResponseVersion
{
get { return this.responseHeaders[XmlConstants.HttpDataServiceVersion]; }
set { this.responseHeaders[XmlConstants.HttpDataServiceVersion] = value; }
}
/// <summary>
/// Gets the <see cref="Stream"/> from which the request data can be read from
/// to the client.
/// </summary>
Stream IDataServiceHost.RequestStream
{
[DebuggerStepThrough]
get { return this.requestStream; }
}
#region IDataServiceHost2 Properties
/// <summary>Dictionary of all request headers.</summary>
WebHeaderCollection IDataServiceHost2.RequestHeaders
{
get { return this.requestHeaders; }
}
/// <summary>Enumerates all response headers that has been set.</summary>
WebHeaderCollection IDataServiceHost2.ResponseHeaders
{
get { return this.responseHeaders; }
}
#endregion IDataServiceHost2 Properties
/// <summary>Response separator string.</summary>
internal string BoundaryString
{
get { return this.boundary; }
}
/// <summary>
/// Gets/Sets the content id as specified in the batch request.
/// This same value is written out in the response headers also to allow mapping requests on the client.
/// </summary>
internal string ContentId
{
get { return this.contentId; }
}
/// <summary>Output writer.</summary>
internal StreamWriter Writer
{
get { return this.writer; }
}
#endregion Properties.
#region Methods.
/// <summary>Gets the value for the specified item in the request query string.</summary>
/// <param name="item">Item to return.</param>
/// <returns>
/// The value for the specified item in the request query string;
/// null if <paramref name="item"/> is not found.
/// </returns>
string IDataServiceHost.GetQueryStringItem(string item)
{
this.GetUriAndQueryParameters();
string[] result = this.queryParameters.GetValues(item);
if (result == null || result.Length == 0)
{
return null;
}
else if (result.Length == 1)
{
return result[0];
}
else
{
throw DataServiceException.CreateBadRequestError(
Strings.DataServiceHost_MoreThanOneQueryParameterSpecifiedWithTheGivenName(item, this.absoluteRequestUri));
}
}
/// <summary>Method to handle a data service exception during processing.</summary>
/// <param name="args">Exception handling description.</param>
void IDataServiceHost.ProcessException(HandleExceptionArgs args)
{
// This would typically set headers on the host.
WebUtil.CheckArgumentNull(args, "args");
Debug.Assert(WebUtil.IsCatchableExceptionType(args.Exception), "WebUtil.IsCatchableExceptionType(args.Exception)");
this.responseStatusCode = args.ResponseStatusCode;
this.responseHeaders[HttpResponseHeader.ContentType] = args.ResponseContentType;
this.responseHeaders[HttpResponseHeader.Allow] = args.ResponseAllowHeader;
// Only write the headers if the response is not written
if (!args.ResponseWritten)
{
System.Data.Services.Serializers.BatchWriter.WriteBoundaryAndHeaders(this.writer, this, this.contentId, this.boundary);
}
}
/// <summary>
/// Returns the http method name given the batch stream state
/// </summary>
/// <param name="state">state of the batch stream.</param>
/// <returns>returns the http method name</returns>
private static string GetHttpMethodName(BatchStreamState state)
{
Debug.Assert(
state == BatchStreamState.Get ||
state == BatchStreamState.Post ||
state == BatchStreamState.Put ||
state == BatchStreamState.Delete ||
state == BatchStreamState.Merge,
"Expecting BatchStreamState (" + state + ") to be Delete, Get, Post or Put");
switch (state)
{
case BatchStreamState.Delete:
return XmlConstants.HttpMethodDelete;
case BatchStreamState.Get:
return XmlConstants.HttpMethodGet;
case BatchStreamState.Post:
return XmlConstants.HttpMethodPost;
case BatchStreamState.Merge:
return XmlConstants.HttpMethodMerge;
default:
Debug.Assert(BatchStreamState.Put == state, "BatchStreamState.Put == state");
return XmlConstants.HttpMethodPut;
}
}
/// <summary>
/// Given the request uri, parse the uri and query parameters and cache them
/// </summary>
private void GetUriAndQueryParameters()
{
if (this.queryParameters == null)
{
this.queryParameters = HttpUtility.ParseQueryString(this.absoluteRequestUri.Query);
}
}
#endregion Methods.
}
}
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