Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / NetWebProxyFinder.cs / 1305376 / NetWebProxyFinder.cs
using System.IO;
using System.Collections;
using System.Collections.Specialized;
using System.Threading;
using System.Text;
using System.Net.Cache;
using System.Globalization;
using System.Net.Configuration;
using System.Security.Permissions;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using Microsoft.Win32;
using System.Diagnostics.CodeAnalysis;
namespace System.Net
{
// This WebProxyFinder implementation has the following purpose:
// - use WinHttp APIs to determine the location of the PAC file
// - use System.Net classes (WebRequest) to download the PAC file
// - use Microsoft.JScript to compile and execute the JavaScript in the PAC file.
internal sealed class NetWebProxyFinder : BaseWebProxyFinder
{
private static readonly char[] splitChars = new char[] { ';' };
private static TimerThread.Queue timerQueue;
private static readonly TimerThread.Callback timerCallback = new TimerThread.Callback(RequestTimeoutCallback);
private static readonly WaitCallback abortWrapper = new WaitCallback(AbortWrapper);
private RequestCache backupCache;
private AutoWebProxyScriptWrapper scriptInstance;
private Uri engineScriptLocation;
private Uri scriptLocation;
private bool scriptDetectionFailed;
private object lockObject;
// Keep the following fields volatile, since we're accessing them outside of lock blocks
private volatile WebRequest request;
private volatile bool aborted;
public NetWebProxyFinder(AutoWebProxyScriptEngine engine)
: base(engine)
{
backupCache = new SingleItemRequestCache(RequestCacheManager.IsCachingEnabled);
lockObject = new object();
}
public override bool GetProxies(Uri destination, out IList proxyList)
{
try
{
proxyList = null;
EnsureEngineAvailable();
// after EnsureEngineAvailable we expect State to be CompilationSuccess, otherwise return.
if (State != AutoWebProxyState.Completed)
{
// the script can't run, say we're not ready and bypass
return false;
}
bool result = false;
try
{
string proxyListString = scriptInstance.FindProxyForURL(destination.ToString(), destination.Host);
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::GetProxies() calling ExecuteFindProxyForURL() for destination:" + ValidationHelper.ToString(destination) + " returned scriptReturn:" + ValidationHelper.ToString(proxyList));
proxyList = ParseScriptResult(proxyListString);
result = true;
}
catch (Exception exception)
{
if (Logging.On) Logging.PrintWarning(Logging.Web, SR.GetString(SR.net_log_proxy_script_execution_error, exception));
}
return result;
}
finally
{
// Reset state of 'aborted', since next call to GetProxies() must not use previous aborted state.
aborted = false;
}
}
public override void Abort()
{
// All we abort is a running WebRequest. The following lock (and the one in DownloadAndCompile)
// is used to "atomically" access the two fields 'aborted' and 'request': If Abort() gets
// called before 'request' is set, the 'aborted' field will signal to DownloadAndCompile, that
// it should not bother creating a request and just throw. If 'request' was already created
// by DownloadAndCompile, the following code will make sure the request gets aborted.
lock (lockObject)
{
aborted = true;
if (request != null)
{
ThreadPool.UnsafeQueueUserWorkItem(abortWrapper, request);
}
}
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (scriptInstance != null)
{
scriptInstance.Close();
}
}
}
// Ensures that (if state is AutoWebProxyState.CompilationSuccess) there is an engine available to execute script.
// Figures out the script location (might discover if needed).
// Calls DownloadAndCompile().
private void EnsureEngineAvailable()
{
GlobalLog.Enter("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable");
if (State == AutoWebProxyState.Uninitialized || engineScriptLocation == null)
{
#if !FEATURE_PAL
if (Engine.AutomaticallyDetectSettings)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable() Attempting auto-detection.");
DetectScriptLocation();
if (scriptLocation != null)
{
//
// Successfully detected or user has flipped the automaticallyDetectSettings bit.
// Attempt a non conclusive DownloadAndCompile() so we can fallback
//
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable() discovered:" + ValidationHelper.ToString(scriptLocation) + " engineScriptLocation:" + ValidationHelper.ToString(engineScriptLocation));
if (scriptLocation.Equals(engineScriptLocation))
{
State = AutoWebProxyState.Completed;
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
return;
}
AutoWebProxyState newState = DownloadAndCompile(scriptLocation);
if (newState == AutoWebProxyState.Completed)
{
State = AutoWebProxyState.Completed;
engineScriptLocation = scriptLocation;
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
return;
}
}
}
#endif // !FEATURE_PAL
// Either Auto-Detect wasn't enabled or something failed with it. Try the manual script location.
if ((Engine.AutomaticConfigurationScript != null) && !aborted)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable() using automaticConfigurationScript:" + ValidationHelper.ToString(Engine.AutomaticConfigurationScript) + " engineScriptLocation:" + ValidationHelper.ToString(engineScriptLocation));
if (Engine.AutomaticConfigurationScript.Equals(engineScriptLocation))
{
State = AutoWebProxyState.Completed;
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
return;
}
State = DownloadAndCompile(Engine.AutomaticConfigurationScript);
if (State == AutoWebProxyState.Completed)
{
engineScriptLocation = Engine.AutomaticConfigurationScript;
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
return;
}
}
}
else
{
// We always want to call DownloadAndCompile to check the expiration.
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable() State:" + State + " engineScriptLocation:" + ValidationHelper.ToString(engineScriptLocation));
State = DownloadAndCompile(engineScriptLocation);
if (State == AutoWebProxyState.Completed)
{
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
return;
}
// There's still an opportunity to fail over to the automaticConfigurationScript.
if (!engineScriptLocation.Equals(Engine.AutomaticConfigurationScript) && !aborted)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable() Update failed. Falling back to automaticConfigurationScript:" + ValidationHelper.ToString(Engine.AutomaticConfigurationScript));
State = DownloadAndCompile(Engine.AutomaticConfigurationScript);
if (State == AutoWebProxyState.Completed)
{
engineScriptLocation = Engine.AutomaticConfigurationScript;
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
return;
}
}
}
// Everything failed. Set this instance to mostly-dead. It will wake up again if there's a reg/connectoid change.
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable() All failed.");
State = AutoWebProxyState.DiscoveryFailure;
if (scriptInstance != null)
{
scriptInstance.Close();
scriptInstance = null;
}
engineScriptLocation = null;
GlobalLog.Leave("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::EnsureEngineAvailable", ValidationHelper.ToString(State));
}
// Downloads and compiles the script from a given Uri.
// This code can be called by config for a downloaded control, we need to assert.
// This code is called holding the lock.
private AutoWebProxyState DownloadAndCompile(Uri location)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() location:" + ValidationHelper.ToString(location));
AutoWebProxyState newState = AutoWebProxyState.DownloadFailure;
WebResponse response = null;
TimerThread.Timer timer = null;
AutoWebProxyScriptWrapper newScriptInstance = null;
// Can't assert this in declarative form (DCR?). This Assert() is needed to be able to create the request to download the proxy script.
ExceptionHelper.WebPermissionUnrestricted.Assert();
try
{
lock (lockObject)
{
if (aborted)
{
throw new WebException(NetRes.GetWebStatusString("net_requestaborted",
WebExceptionStatus.RequestCanceled), WebExceptionStatus.RequestCanceled);
}
request = WebRequest.Create(location);
}
request.Timeout = Timeout.Infinite;
request.CachePolicy = new RequestCachePolicy(RequestCacheLevel.Default);
request.ConnectionGroupName = "__WebProxyScript";
// We have an opportunity here, if caching is disabled AppDomain-wide, to override it with a
// custom, trivial cache-provider to get a similar semantic.
//
// We also want to have a backup caching key in the case when IE has locked an expired script response
//
if (request.CacheProtocol != null)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() Using backup caching.");
request.CacheProtocol = new RequestCacheProtocol(backupCache, request.CacheProtocol.Validator);
}
HttpWebRequest httpWebRequest = request as HttpWebRequest;
if (httpWebRequest != null)
{
httpWebRequest.Accept = "*/*";
httpWebRequest.UserAgent = this.GetType().FullName + "/" + Environment.Version;
httpWebRequest.KeepAlive = false;
httpWebRequest.Pipelined = false;
httpWebRequest.InternalConnectionGroup = true;
}
else
{
FtpWebRequest ftpWebRequest = request as FtpWebRequest;
if (ftpWebRequest != null)
{
ftpWebRequest.KeepAlive = false;
}
}
// Use no proxy, default cache - initiate the download.
request.Proxy = null;
request.Credentials = Engine.Credentials;
// Use our own timeout timer so that it can encompass the whole request, not just the headers.
if (timerQueue == null)
{
timerQueue = TimerThread.GetOrCreateQueue(SettingsSectionInternal.Section.DownloadTimeout);
}
timer = timerQueue.CreateTimer(timerCallback, request);
response = request.GetResponse();
// Check Last Modified.
DateTime lastModified = DateTime.MinValue;
HttpWebResponse httpResponse = response as HttpWebResponse;
if (httpResponse != null)
{
lastModified = httpResponse.LastModified;
}
else
{
FtpWebResponse ftpResponse = response as FtpWebResponse;
if (ftpResponse != null)
{
lastModified = ftpResponse.LastModified;
}
}
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() lastModified:" + lastModified.ToString() + " (script):" + (scriptInstance == null ? "(null)" : scriptInstance.LastModified.ToString()));
if (scriptInstance != null && lastModified != DateTime.MinValue && scriptInstance.LastModified == lastModified)
{
newScriptInstance = scriptInstance;
newState = AutoWebProxyState.Completed;
}
else
{
string scriptBody = null;
byte[] scriptBuffer = null;
using (Stream responseStream = response.GetResponseStream())
{
SingleItemRequestCache.ReadOnlyStream ros = responseStream as SingleItemRequestCache.ReadOnlyStream;
if (ros != null)
{
scriptBuffer = ros.Buffer;
}
if (scriptInstance != null && scriptBuffer != null && scriptBuffer == scriptInstance.Buffer)
{
scriptInstance.LastModified = lastModified;
newScriptInstance = scriptInstance;
newState = AutoWebProxyState.Completed;
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() Buffer matched - reusing Engine.");
}
else
{
using (StreamReader streamReader = new StreamReader(responseStream))
{
scriptBody = streamReader.ReadToEnd();
}
}
}
WebResponse tempResponse = response;
response = null;
tempResponse.Close();
timer.Cancel();
timer = null;
if (newState != AutoWebProxyState.Completed)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() IsFromCache:" + tempResponse.IsFromCache.ToString() + " scriptInstance:" + ValidationHelper.HashString(scriptInstance));
if (scriptInstance != null && scriptBody == scriptInstance.ScriptBody)
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() Script matched - using existing Engine.");
scriptInstance.LastModified = lastModified;
if (scriptBuffer != null)
{
scriptInstance.Buffer = scriptBuffer;
}
newScriptInstance = scriptInstance;
newState = AutoWebProxyState.Completed;
}
else
{
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() Creating AutoWebProxyScriptWrapper.");
newScriptInstance = new AutoWebProxyScriptWrapper();
newScriptInstance.LastModified = lastModified;
if (newScriptInstance.Compile(location, scriptBody, scriptBuffer))
{
newState = AutoWebProxyState.Completed;
}
else
{
newState = AutoWebProxyState.CompilationFailure;
}
}
}
}
}
catch (Exception exception)
{
if (Logging.On) Logging.PrintWarning(Logging.Web, SR.GetString(SR.net_log_proxy_script_download_compile_error, exception));
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() Download() threw:" + ValidationHelper.ToString(exception));
}
finally
{
if (timer != null)
{
timer.Cancel();
}
//
try
{
if (response != null)
{
response.Close();
}
}
finally
{
WebPermission.RevertAssert();
// The request is not needed anymore. Set it to null, so if Abort() gets called,
// after this point, it will result in a no-op.
request = null;
}
}
if ((newState == AutoWebProxyState.Completed) && (scriptInstance != newScriptInstance))
{
if (scriptInstance != null)
{
scriptInstance.Close();
}
scriptInstance = newScriptInstance;
}
GlobalLog.Print("NetWebProxyFinder#" + ValidationHelper.HashString(this) + "::DownloadAndCompile() retuning newState:" + ValidationHelper.ToString(newState));
return newState;
}
private static IList ParseScriptResult(string scriptReturn)
{
IList result = new List();
if (scriptReturn == null)
{
return result;
}
string[] proxyListStrings = scriptReturn.Split(splitChars);
string proxyAuthority;
foreach (string s in proxyListStrings)
{
string proxyString = s.Trim(' ');
if (!proxyString.StartsWith("PROXY ", StringComparison.OrdinalIgnoreCase))
{
if (string.Compare("DIRECT", proxyString, StringComparison.OrdinalIgnoreCase) == 0)
{
proxyAuthority = null;
}
else
{
continue;
}
}
else
{
// remove prefix "PROXY " (6 chars) from the string and trim additional leading spaces.
proxyAuthority = proxyString.Substring(6).TrimStart(' ');
Uri uri = null;
bool tryParse = Uri.TryCreate("http://" + proxyAuthority, UriKind.Absolute, out uri);
if (!tryParse || uri.UserInfo.Length > 0 || uri.HostNameType == UriHostNameType.Basic || uri.AbsolutePath.Length != 1 || proxyAuthority[proxyAuthority.Length - 1] == '/' || proxyAuthority[proxyAuthority.Length - 1] == '#' || proxyAuthority[proxyAuthority.Length - 1] == '?')
{
continue;
}
}
result.Add(proxyAuthority);
}
return result;
}
private void DetectScriptLocation()
{
if (scriptDetectionFailed || scriptLocation != null)
{
return;
}
GlobalLog.Print("NetWebProxyFinder::DetectScriptLocation() Attempting discovery PROXY_AUTO_DETECT_TYPE_DHCP.");
scriptLocation = SafeDetectAutoProxyUrl(UnsafeNclNativeMethods.WinHttp.AutoDetectType.Dhcp);
if (scriptLocation == null)
{
GlobalLog.Print("NetWebProxyFinder::DetectScriptLocation() Attempting discovery AUTO_DETECT_TYPE_DNS_A.");
scriptLocation = SafeDetectAutoProxyUrl(UnsafeNclNativeMethods.WinHttp.AutoDetectType.DnsA);
}
if (scriptLocation == null)
{
GlobalLog.Print("NetWebProxyFinder::DetectScriptLocation() Discovery failed.");
scriptDetectionFailed = true;
}
}
// from wininet.h
//
// #define INTERNET_MAX_PATH_LENGTH 2048
// #define INTERNET_MAX_PROTOCOL_NAME "gopher" // longest protocol name
// #define INTERNET_MAX_URL_LENGTH ((sizeof(INTERNET_MAX_PROTOCOL_NAME) - 1) \
// + sizeof("://") \
// + INTERNET_MAX_PATH_LENGTH)
//
private const int MaximumProxyStringLength = 2058;
///
///
/// Called to discover script location. This performs
/// autodetection using the method specified in the detectFlags.
///
///
[SuppressMessage("Microsoft.Reliability","CA2001:AvoidCallingProblematicMethods", MessageId="System.Runtime.InteropServices.SafeHandle.DangerousGetHandle", Justification="Implementation requires DangerousGetHandle")]
private static unsafe Uri SafeDetectAutoProxyUrl(
UnsafeNclNativeMethods.WinHttp.AutoDetectType discoveryMethod)
{
Uri autoProxy = null;
#if !FEATURE_PAL
string url = null;
if (ComNetOS.IsWinHttp51)
{
GlobalLog.Print("NetWebProxyFinder::SafeDetectAutoProxyUrl() Using WinHttp.");
SafeGlobalFree autoProxyUrl;
bool success = UnsafeNclNativeMethods.WinHttp.WinHttpDetectAutoProxyConfigUrl(discoveryMethod, out autoProxyUrl);
if (!success)
{
if (autoProxyUrl != null)
{
autoProxyUrl.SetHandleAsInvalid();
}
}
else
{
url = new string((char*)autoProxyUrl.DangerousGetHandle());
autoProxyUrl.Close();
}
}
else
{
GlobalLog.Print("NetWebProxyFinder::SafeDetectAutoProxyUrl() Using WinInet.");
StringBuilder autoProxyUrl = new StringBuilder(MaximumProxyStringLength);
bool success = UnsafeNclNativeMethods.WinInet.DetectAutoProxyUrl(
autoProxyUrl,
MaximumProxyStringLength,
(int)discoveryMethod);
if (success)
{
url = autoProxyUrl.ToString();
}
}
if (url != null)
{
bool parsed = Uri.TryCreate(url, UriKind.Absolute, out autoProxy);
if (!parsed)
{
if (Logging.On) Logging.PrintWarning(Logging.Web, SR.GetString(SR.net_log_proxy_autodetect_script_location_parse_error, ValidationHelper.ToString(url)));
GlobalLog.Print("NetWebProxyFinder::SafeDetectAutoProxyUrl() Uri.TryParse() failed url:" + ValidationHelper.ToString(url));
}
}
else
{
if (Logging.On) Logging.PrintWarning(Logging.Web, SR.GetString(SR.net_log_proxy_autodetect_failed));
GlobalLog.Print("NetWebProxyFinder::SafeDetectAutoProxyUrl() DetectAutoProxyUrl() returned false");
}
#endif // !FEATURE_PAL
return autoProxy;
}
// RequestTimeoutCallback - Called by the TimerThread to abort a request. This just posts ThreadPool work item - Abort() does too
// much to be done on the timer thread (timer thread should never block or call user code).
private static void RequestTimeoutCallback(TimerThread.Timer timer, int timeNoticed, object context)
{
ThreadPool.UnsafeQueueUserWorkItem(abortWrapper, context);
}
private static void AbortWrapper(object context)
{
#if DEBUG
GlobalLog.SetThreadSource(ThreadKinds.Worker);
using (GlobalLog.SetThreadKind(ThreadKinds.System))
{
#endif
if (context != null)
{
((WebRequest)context).Abort();
}
#if DEBUG
}
#endif
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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