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//-----------------------------------------------------------------------
// <copyright file="CachedDirectWebResponse.cs" company="Outercurve Foundation">
// Copyright (c) Outercurve Foundation. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------
namespace DotNetOpenAuth.Messaging {
using System;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Diagnostics.Contracts;
using System.IO;
using System.Net;
using System.Text;
/// <summary>
/// Cached details on the response from a direct web request to a remote party.
/// </summary>
[ContractVerification(true)]
[DebuggerDisplay("{Status} {ContentType.MediaType}, length: {ResponseStream.Length}")]
internal class CachedDirectWebResponse : IncomingWebResponse {
/// <summary>
/// A seekable, repeatable response stream.
/// </summary>
private MemoryStream responseStream;
/// <summary>
/// Initializes a new instance of the <see cref="CachedDirectWebResponse"/> class.
/// </summary>
internal CachedDirectWebResponse() {
}
/// <summary>
/// Initializes a new instance of the <see cref="CachedDirectWebResponse"/> class.
/// </summary>
/// <param name="requestUri">The request URI.</param>
/// <param name="response">The response.</param>
/// <param name="maximumBytesToRead">The maximum bytes to read.</param>
internal CachedDirectWebResponse(Uri requestUri, HttpWebResponse response, int maximumBytesToRead)
: base(requestUri, response) {
Requires.NotNull(requestUri, "requestUri");
Requires.NotNull(response, "response");
this.responseStream = CacheNetworkStreamAndClose(response, maximumBytesToRead);
// BUGBUG: if the response was exactly maximumBytesToRead, we'll incorrectly believe it was truncated.
this.ResponseTruncated = this.responseStream.Length == maximumBytesToRead;
}
/// <summary>
/// Initializes a new instance of the <see cref="CachedDirectWebResponse"/> class.
/// </summary>
/// <param name="requestUri">The request URI.</param>
/// <param name="responseUri">The final URI to respond to the request.</param>
/// <param name="headers">The headers.</param>
/// <param name="statusCode">The status code.</param>
/// <param name="contentType">Type of the content.</param>
/// <param name="contentEncoding">The content encoding.</param>
/// <param name="responseStream">The response stream.</param>
internal CachedDirectWebResponse(Uri requestUri, Uri responseUri, WebHeaderCollection headers, HttpStatusCode statusCode, string contentType, string contentEncoding, MemoryStream responseStream)
: base(requestUri, responseUri, headers, statusCode, contentType, contentEncoding) {
Requires.NotNull(requestUri, "requestUri");
Requires.NotNull(responseStream, "responseStream");
this.responseStream = responseStream;
}
/// <summary>
/// Gets a value indicating whether the cached response stream was
/// truncated to a maximum allowable length.
/// </summary>
public bool ResponseTruncated { get; private set; }
/// <summary>
/// Gets the body of the HTTP response.
/// </summary>
public override Stream ResponseStream {
get { return this.responseStream; }
}
/// <summary>
/// Gets or sets the cached response stream.
/// </summary>
internal MemoryStream CachedResponseStream {
get { return this.responseStream; }
set { this.responseStream = value; }
}
/// <summary>
/// Creates a text reader for the response stream.
/// </summary>
/// <returns>The text reader, initialized for the proper encoding.</returns>
public override StreamReader GetResponseReader() {
this.ResponseStream.Seek(0, SeekOrigin.Begin);
string contentEncoding = this.Headers[HttpResponseHeader.ContentEncoding];
Encoding encoding = null;
if (!string.IsNullOrEmpty(contentEncoding)) {
try {
encoding = Encoding.GetEncoding(contentEncoding);
} catch (ArgumentException ex) {
Logger.Messaging.ErrorFormat("Encoding.GetEncoding(\"{0}\") threw ArgumentException: {1}", contentEncoding, ex);
}
}
return encoding != null ? new StreamReader(this.ResponseStream, encoding) : new StreamReader(this.ResponseStream);
}
/// <summary>
/// Gets the body of the response as a string.
/// </summary>
/// <returns>The entire body of the response.</returns>
internal string GetResponseString() {
if (this.ResponseStream != null) {
string value = this.GetResponseReader().ReadToEnd();
this.ResponseStream.Seek(0, SeekOrigin.Begin);
return value;
} else {
return null;
}
}
/// <summary>
/// Gets an offline snapshot version of this instance.
/// </summary>
/// <param name="maximumBytesToCache">The maximum bytes from the response stream to cache.</param>
/// <returns>A snapshot version of this instance.</returns>
/// <remarks>
/// If this instance is a <see cref="NetworkDirectWebResponse"/> creating a snapshot
/// will automatically close and dispose of the underlying response stream.
/// If this instance is a <see cref="CachedDirectWebResponse"/>, the result will
/// be the self same instance.
/// </remarks>
internal override CachedDirectWebResponse GetSnapshot(int maximumBytesToCache) {
return this;
}
/// <summary>
/// Sets the response to some string, encoded as UTF-8.
/// </summary>
/// <param name="body">The string to set the response to.</param>
internal void SetResponse(string body) {
if (body == null) {
this.responseStream = null;
return;
}
Encoding encoding = Encoding.UTF8;
this.Headers[HttpResponseHeader.ContentEncoding] = encoding.HeaderName;
this.responseStream = new MemoryStream();
StreamWriter writer = new StreamWriter(this.ResponseStream, encoding);
writer.Write(body);
writer.Flush();
this.ResponseStream.Seek(0, SeekOrigin.Begin);
}
/// <summary>
/// Caches the network stream and closes it if it is open.
/// </summary>
/// <param name="response">The response whose stream is to be cloned.</param>
/// <param name="maximumBytesToRead">The maximum bytes to cache.</param>
/// <returns>The seekable Stream instance that contains a copy of what was returned in the HTTP response.</returns>
[SuppressMessage("Microsoft.Globalization", "CA1303:Do not pass literals as localized parameters", MessageId = "System.Diagnostics.Contracts.__ContractsRuntime.Assume(System.Boolean,System.String,System.String)", Justification = "No localization required.")]
private static MemoryStream CacheNetworkStreamAndClose(HttpWebResponse response, int maximumBytesToRead) {
Requires.NotNull(response, "response");
Contract.Ensures(Contract.Result<MemoryStream>() != null);
// Now read and cache the network stream
Stream networkStream = response.GetResponseStream();
MemoryStream cachedStream = new MemoryStream(response.ContentLength < 0 ? 4 * 1024 : Math.Min((int)response.ContentLength, maximumBytesToRead));
try {
Contract.Assume(networkStream.CanRead, "HttpWebResponse.GetResponseStream() always returns a readable stream."); // CC missing
Contract.Assume(cachedStream.CanWrite, "This is a MemoryStream -- it's always writable."); // CC missing
networkStream.CopyTo(cachedStream);
cachedStream.Seek(0, SeekOrigin.Begin);
networkStream.Dispose();
response.Close();
return cachedStream;
} catch {
cachedStream.Dispose();
throw;
}
}
}
}
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