Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / Cache / _RequestCacheProtocol.cs / 1305376 / _RequestCacheProtocol.cs
/*++
Copyright (c) Microsoft Corporation
Module Name:
_RequestCacheProtocol.cs
Abstract:
The class is a cache protocol engine.
An application protocol such as HttpWebRequest or FtpWebRequest
gets all cache-related answers by talking to this class
Sometime in the future it will become public.
Author:
Alexei Vopilov 21-Dec-2002
Revision History:
Aug 25 2003 - moved into separate file and revised as per Whidbey-M3 spec.
--*/
namespace System.Net.Cache {
using System;
using System.Diagnostics;
using System.Text;
using System.IO;
using System.Collections.Specialized;
using System.Threading;
using System.Globalization;
//
//
//
internal class RequestCacheProtocol {
private CacheValidationStatus _ProtocolStatus;
private Exception _ProtocolException;
private Stream _ResponseStream;
private long _ResponseStreamLength;
private RequestCacheValidator _Validator;
private RequestCache _RequestCache;
private bool _IsCacheFresh;
private bool _CanTakeNewRequest;
// private string[] _ResponseMetadata;
// private string _CacheRetrieveKey;
// private string _CacheStoreKey;
//
// Public properties
//
internal CacheValidationStatus ProtocolStatus {get {return _ProtocolStatus;}}
internal Exception ProtocolException {get {return _ProtocolException;}}
internal Stream ResponseStream {get {return _ResponseStream;}}
internal long ResponseStreamLength {get {return _ResponseStreamLength;}}
internal RequestCacheValidator Validator {get {return _Validator;}}
internal bool IsCacheFresh {get {return _Validator != null && _Validator.CacheFreshnessStatus == CacheFreshnessStatus.Fresh;}}
// internal string[] ResponseMetadata {get {return _ResponseMetadata;}}
// internal string CacheRetrieveKey {get {return _CacheRetrieveKey;}}
// internal string CacheStoreKey {get {return _CacheStoreKey;}}
//
// Public methods
//
internal RequestCacheProtocol(RequestCache cache, RequestCacheValidator defaultValidator)
{
_RequestCache = cache;
_Validator = defaultValidator;
_CanTakeNewRequest = true;
}
//
internal CacheValidationStatus GetRetrieveStatus (Uri cacheUri, WebRequest request)
{
if (cacheUri == null)
throw new ArgumentNullException("cacheUri");
if (request == null)
throw new ArgumentNullException("request");
if (!_CanTakeNewRequest || _ProtocolStatus == CacheValidationStatus.RetryResponseFromServer)
return CacheValidationStatus.Continue;
_CanTakeNewRequest = false;
// Reset protocol state
_ResponseStream = null;
_ResponseStreamLength = 0L;
_ProtocolStatus = CacheValidationStatus.Continue;
_ProtocolException = null;
if(Logging.On) Logging.Enter(Logging.RequestCache, this, "GetRetrieveStatus", request);
try {
if (request.CachePolicy == null || request.CachePolicy.Level == RequestCacheLevel.BypassCache)
{
_ProtocolStatus = CacheValidationStatus.DoNotUseCache;
return _ProtocolStatus;
}
if (_RequestCache == null || _Validator == null)
{
_ProtocolStatus = CacheValidationStatus.DoNotUseCache;
return _ProtocolStatus;
}
_Validator.FetchRequest(cacheUri, request);
switch(_ProtocolStatus = ValidateRequest())
{
case CacheValidationStatus.Continue: // This is a green light for cache protocol
break;
case CacheValidationStatus.DoNotTakeFromCache: // no cache but response can be cached
case CacheValidationStatus.DoNotUseCache: // ignore cache entirely
break;
case CacheValidationStatus.Fail:
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "ValidateRequest"));
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "ValidateRequest", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "ValidateRequest()", _Validator.ValidationStatus.ToString()));
break;
}
if (_ProtocolStatus != CacheValidationStatus.Continue)
return _ProtocolStatus;
//
// Proceed with validation
//
CheckRetrieveBeforeSubmit();
}
catch (Exception e) {
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException)
throw;
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
if(Logging.On) Logging.Exit(Logging.RequestCache, this, "GetRetrieveStatus", "result = " + _ProtocolStatus.ToString());
}
return _ProtocolStatus;
}
//
// This optional method is only for protocols supporting a revalidation concept
// For a retried request this method must be called again.
//
internal CacheValidationStatus GetRevalidateStatus (WebResponse response, Stream responseStream)
{
if (response == null)
throw new ArgumentNullException("response");
if (_ProtocolStatus == CacheValidationStatus.DoNotUseCache)
return CacheValidationStatus.DoNotUseCache;
// If we returned cached response, switch the state to not call cache anymore.
if (_ProtocolStatus == CacheValidationStatus.ReturnCachedResponse)
{
_ProtocolStatus = CacheValidationStatus.DoNotUseCache;
return _ProtocolStatus;
}
try {
if(Logging.On) Logging.Enter(Logging.RequestCache, this, "GetRevalidateStatus", (_Validator == null? null: _Validator.Request));
_Validator.FetchResponse(response);
if (_ProtocolStatus != CacheValidationStatus.Continue && _ProtocolStatus != CacheValidationStatus.RetryResponseFromServer)
{
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_revalidation_not_needed, "GetRevalidateStatus()"));
return _ProtocolStatus;
}
CheckRetrieveOnResponse(responseStream);
}
finally {
if(Logging.On) Logging.Exit(Logging.RequestCache, this, "GetRevalidateStatus", "result = " + _ProtocolStatus.ToString());
}
return _ProtocolStatus;
}
//
// Returns UpdateResponseInformation if passed response stream has to be replaced (cache is updated in some way)
// Returns Fail if request is to fail
// Any other return value should be ignored
//
internal CacheValidationStatus GetUpdateStatus (WebResponse response, Stream responseStream)
{
if (response == null)
throw new ArgumentNullException("response");
if (_ProtocolStatus == CacheValidationStatus.DoNotUseCache)
return CacheValidationStatus.DoNotUseCache;
try {
if(Logging.On) Logging.Enter(Logging.RequestCache, this, "GetUpdateStatus", null);
if (_Validator.Response == null)
_Validator.FetchResponse(response);
if (_ProtocolStatus == CacheValidationStatus.RemoveFromCache)
{
EnsureCacheRemoval(_Validator.CacheKey);
return _ProtocolStatus;
}
if (_ProtocolStatus != CacheValidationStatus.DoNotTakeFromCache &&
_ProtocolStatus != CacheValidationStatus.ReturnCachedResponse &&
_ProtocolStatus != CacheValidationStatus.CombineCachedAndServerResponse)
{
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_not_updated_based_on_cache_protocol_status, "GetUpdateStatus()", _ProtocolStatus.ToString()));
return _ProtocolStatus;
}
CheckUpdateOnResponse(responseStream);
}
catch (Exception e) {
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
if(Logging.On)Logging.Exit(Logging.RequestCache, this, "GetUpdateStatus", "result = " + _ProtocolStatus.ToString());
}
return _ProtocolStatus;
}
//
// This must be the last call before starting a new request on this protocol instance
//
internal void Reset()
{
_CanTakeNewRequest = true;
}
//
internal void Abort()
{
// if _CanTakeNewRequest==true we should not be holding any cache stream
// Also we check on Abort() reentrancy this way.
if (_CanTakeNewRequest)
return;
// in case of abnormal termination this will release cache entry sooner than does it's finalizer
Stream stream = _ResponseStream;
if (stream != null)
{
try {
if(Logging.On) Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_closing_cache_stream, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), "Abort()", stream.GetType().FullName, _Validator.CacheKey));
ICloseEx closeEx = stream as ICloseEx;
if (closeEx != null)
closeEx.CloseEx(CloseExState.Abort | CloseExState.Silent);
else
stream.Close();
}
catch(Exception e) {
if (NclUtilities.IsFatal(e)) throw;
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_exception_ignored, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), "stream.Close()", e.ToString()));
}
}
Reset();
}
//
// Private methods
//
//
// This method may be invoked as part of the request submission but before issuing a live request
//
private void CheckRetrieveBeforeSubmit() {
GlobalLog.Assert(_ProtocolStatus == CacheValidationStatus.Continue, "CheckRetrieveBeforeSubmit()|Unexpected _ProtocolStatus = {0}", _ProtocolStatus);
try {
while (true)
{
RequestCacheEntry cacheEntry;
if (_Validator.CacheStream != null && _Validator.CacheStream != Stream.Null)
{
// Reset to Initial state
_Validator.CacheStream.Close();
_Validator.CacheStream = Stream.Null;
}
if (_Validator.StrictCacheErrors)
{
_Validator.CacheStream = _RequestCache.Retrieve(_Validator.CacheKey, out cacheEntry);
}
else
{
Stream stream;
_RequestCache.TryRetrieve(_Validator.CacheKey, out cacheEntry, out stream);
_Validator.CacheStream = stream;
}
if (cacheEntry == null)
{
cacheEntry = new RequestCacheEntry();
cacheEntry.IsPrivateEntry = _RequestCache.IsPrivateCache;
_Validator.FetchCacheEntry(cacheEntry);
}
if (_Validator.CacheStream == null)
{
// If entry does not have a stream an empty stream wrapper must be returned.
// A null or Stream.Null value stands for non existent cache entry.
_Validator.CacheStream = Stream.Null;
}
ValidateFreshness(cacheEntry);
_ProtocolStatus = ValidateCache();
// This will tell us what to do next
switch (_ProtocolStatus) {
case CacheValidationStatus.ReturnCachedResponse:
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null)
{
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_no_cache_entry, "ValidateCache()"));
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_no_stream, _Validator.CacheKey));
break;
}
// Final decision is made, check on a range response from cache
Stream stream = _Validator.CacheStream;
// The entry can now be replaced as we are not going for cache entry metadata-only update
_RequestCache.UnlockEntry(_Validator.CacheStream);
if (_Validator.CacheStreamOffset != 0L || _Validator.CacheStreamLength != _Validator.CacheEntry.StreamSize)
{
stream = new RangeStream(stream, _Validator.CacheStreamOffset, _Validator.CacheStreamLength);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_returned_range_cache, "ValidateCache()", _Validator.CacheStreamOffset, _Validator.CacheStreamLength));
}
_ResponseStream = stream;
_ResponseStreamLength = _Validator.CacheStreamLength;
break;
case CacheValidationStatus.Continue:
// copy a cache stream ref
_ResponseStream = _Validator.CacheStream;
break;
case CacheValidationStatus.RetryResponseFromCache:
// loop thought cache retrieve
continue;
case CacheValidationStatus.DoNotTakeFromCache:
case CacheValidationStatus.DoNotUseCache:
break;
case CacheValidationStatus.Fail:
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "ValidateCache"));
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "ValidateCache", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "ValidateCache()", _Validator.ValidationStatus.ToString()));
break;
}
break;
}
}
catch (Exception e) {
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = e;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
// This is to release cache entry on error
if (_ResponseStream == null && _Validator.CacheStream != null && _Validator.CacheStream != Stream.Null)
{
_Validator.CacheStream.Close();
_Validator.CacheStream = Stream.Null;
}
}
}
//
private void CheckRetrieveOnResponse(Stream responseStream) {
GlobalLog.Assert(_ProtocolStatus == CacheValidationStatus.Continue || _ProtocolStatus == CacheValidationStatus.RetryResponseFromServer, "CheckRetrieveOnResponse()|Unexpected _ProtocolStatus = ", _ProtocolStatus);
// if something goes wrong we release cache stream if any exists
bool closeCacheStream = true;
try {
// This will inspect the live response on the correctness matter
switch (_ProtocolStatus = ValidateResponse()) {
case CacheValidationStatus.Continue:
closeCacheStream = false;
// The response looks good
break;
case CacheValidationStatus.RetryResponseFromServer:
// The response is broken will need to retry or give up
closeCacheStream = false;
break;
case CacheValidationStatus.Fail:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "ValidateResponse"));
break;
case CacheValidationStatus.DoNotUseCache:
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "ValidateResponse", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "ValidateResponse()", _Validator.ValidationStatus.ToString()));
break;
}
}
catch (Exception e) {
closeCacheStream = true;
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
// This is to release cache entry in case we are not interested in it
if (closeCacheStream && _ResponseStream != null)
{
_ResponseStream.Close();
_ResponseStream = null;
_Validator.CacheStream = Stream.Null;
}
}
if (_ProtocolStatus != CacheValidationStatus.Continue) {
return;
}
//
// only CacheValidationStatus.Continue goes here with closeCacheStream == false
//
try {
// This will tell us what to do next
// Note this is a second time question to the caching protocol about a cached entry
// Except that we now have live response to consider
//
// The validator can at any time replace the cache stream and update cache Metadata (aka headers).
//
switch (_ProtocolStatus = RevalidateCache()) {
case CacheValidationStatus.DoNotUseCache:
case CacheValidationStatus.RemoveFromCache:
case CacheValidationStatus.DoNotTakeFromCache:
closeCacheStream = true;
break;
case CacheValidationStatus.ReturnCachedResponse:
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null)
{
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_no_stream, _Validator.CacheKey));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_null_cached_stream, "RevalidateCache()"));
break;
}
Stream stream = _Validator.CacheStream;
if (_Validator.CacheStreamOffset != 0L || _Validator.CacheStreamLength != _Validator.CacheEntry.StreamSize)
{
stream = new RangeStream(stream, _Validator.CacheStreamOffset, _Validator.CacheStreamLength);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_returned_range_cache, "RevalidateCache()", _Validator.CacheStreamOffset, _Validator.CacheStreamLength));
}
_ResponseStream = stream;
_ResponseStreamLength = _Validator.CacheStreamLength;
break;
case CacheValidationStatus.CombineCachedAndServerResponse:
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null)
{
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_no_stream, _Validator.CacheKey));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_requested_combined_but_null_cached_stream, "RevalidateCache()"));
break;
}
//
// FTP cannot give the tail of the combined stream at that point
// Consider: Revisit the design of the CacheProtocol class
if (responseStream != null)
{
stream = new CombinedReadStream(_Validator.CacheStream, responseStream);
}
else
{
// So Abort can close the cache stream
stream = _Validator.CacheStream;
}
_ResponseStream = stream;
_ResponseStreamLength = _Validator.CacheStreamLength;
break;
case CacheValidationStatus.Fail:
closeCacheStream = true;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "RevalidateCache"));
break;
default:
closeCacheStream = true;
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "RevalidateCache", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "RevalidateCache()", _Validator.ValidationStatus.ToString()));
break;
}
}
catch (Exception e) {
closeCacheStream = true;
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
// This is to release cache entry in case we are not interested in it
if (closeCacheStream && _ResponseStream != null)
{
_ResponseStream.Close();
_ResponseStream = null;
_Validator.CacheStream = Stream.Null;
}
}
}
//
// This will decide on cache update and construct the effective response stream
//
private void CheckUpdateOnResponse(Stream responseStream)
{
if (_Validator.CacheEntry == null)
{
// There was no chance to create an empty entry yet
RequestCacheEntry cacheEntry = new RequestCacheEntry();
cacheEntry.IsPrivateEntry = _RequestCache.IsPrivateCache;
_Validator.FetchCacheEntry(cacheEntry);
}
// With NoCache we may end up storing whole response as a new entry in Cache.
// Otherwise we may end up updating Context+Metadata or just Context
//
// In any case we may end up doing nothing.
//
string retrieveKey = _Validator.CacheKey;
bool unlockEntry = true;
try {
switch (_ProtocolStatus=UpdateCache()) {
case CacheValidationStatus.RemoveFromCache:
EnsureCacheRemoval(retrieveKey);
unlockEntry = false;
break;
case CacheValidationStatus.UpdateResponseInformation:
// NB: Just invoked validator must have updated CacheEntry and transferred
// ONLY allowed headers from the response to the Context.xxxMetadata member
_ResponseStream = new MetadataUpdateStream(
responseStream,
_RequestCache,
_Validator.CacheKey,
_Validator.CacheEntry.ExpiresUtc,
_Validator.CacheEntry.LastModifiedUtc,
_Validator.CacheEntry.LastSynchronizedUtc,
_Validator.CacheEntry.MaxStale,
_Validator.CacheEntry.EntryMetadata,
_Validator.CacheEntry.SystemMetadata,
_Validator.StrictCacheErrors);
//
// This can be looked as a design hole since we have to keep the entry
// locked for the case when we want to update that previously retrieved entry.
// I think RequestCache contract should allow to detect that a new physical cache entry
// does not match to the "entry being updated" and so to should ignore updates on replaced entries.
//
unlockEntry = false;
_ProtocolStatus = CacheValidationStatus.UpdateResponseInformation;
break;
case CacheValidationStatus.CacheResponse:
// NB: Just invoked validator must have updated CacheEntry and transferred
// ONLY allowed headers from the response to the Context.xxxMetadata member
Stream stream;
if (_Validator.StrictCacheErrors)
{stream = _RequestCache.Store(_Validator.CacheKey, _Validator.CacheEntry.StreamSize, _Validator.CacheEntry.ExpiresUtc, _Validator.CacheEntry.LastModifiedUtc, _Validator.CacheEntry.MaxStale, _Validator.CacheEntry.EntryMetadata, _Validator.CacheEntry.SystemMetadata);}
else
{_RequestCache.TryStore(_Validator.CacheKey, _Validator.CacheEntry.StreamSize, _Validator.CacheEntry.ExpiresUtc, _Validator.CacheEntry.LastModifiedUtc, _Validator.CacheEntry.MaxStale, _Validator.CacheEntry.EntryMetadata, _Validator.CacheEntry.SystemMetadata, out stream);}
// Wrap the response stream into forwarding one
if (stream == null) {
_ProtocolStatus = CacheValidationStatus.DoNotUpdateCache;
}
else {
_ResponseStream = new ForwardingReadStream(responseStream, stream, _Validator.CacheStreamOffset, _Validator.StrictCacheErrors);
_ProtocolStatus = CacheValidationStatus.UpdateResponseInformation;
}
break;
case CacheValidationStatus.DoNotUseCache:
case CacheValidationStatus.DoNotUpdateCache:
break;
case CacheValidationStatus.Fail:
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "UpdateCache"));
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "UpdateCache", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "UpdateCache()", _Validator.ValidationStatus.ToString()));
break;
}
}
finally {
if (unlockEntry)
{
// The entry can now be replaced as we are not going for cache entry metadata-only update
_RequestCache.UnlockEntry(_Validator.CacheStream);
}
}
}
//
private CacheValidationStatus ValidateRequest() {
if(Logging.On) Logging.PrintInfo(Logging.RequestCache,
"Request#" + _Validator.Request.GetHashCode().ToString(NumberFormatInfo.InvariantInfo) +
", Policy = " + _Validator.Request.CachePolicy.ToString() +
", Cache Uri = " + _Validator.Uri);
CacheValidationStatus result = _Validator.ValidateRequest();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, "Selected cache Key = " + _Validator.CacheKey);
return result;
}
//
//
//
private void ValidateFreshness(RequestCacheEntry fetchEntry) {
_Validator.FetchCacheEntry(fetchEntry);
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null) {
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_entry_not_found_freshness_undefined, "ValidateFreshness()"));
_Validator.SetFreshnessStatus(CacheFreshnessStatus.Undefined);
return;
}
if(Logging.On) {
if (Logging.IsVerbose(Logging.RequestCache)) {
Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_dumping_cache_context));
if (fetchEntry == null) {
Logging.PrintInfo(Logging.RequestCache, "");
}
else {
string[] context = fetchEntry.ToString(Logging.IsVerbose(Logging.RequestCache)).Split(RequestCache.LineSplits);
for (int i = 0; i< context.Length; ++i) {
if (context[i].Length != 0) {
Logging.PrintInfo(Logging.RequestCache, context[i]);
}
}
}
}
}
CacheFreshnessStatus result = _Validator.ValidateFreshness();
_Validator.SetFreshnessStatus(result);
_IsCacheFresh = result == CacheFreshnessStatus.Fresh;
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "ValidateFreshness()", result.ToString()));
}
//
//
//
private CacheValidationStatus ValidateCache() {
CacheValidationStatus result = _Validator.ValidateCache();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "ValidateCache()", result.ToString()));
return result;
}
//
private CacheValidationStatus RevalidateCache() {
CacheValidationStatus result = _Validator.RevalidateCache();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "RevalidateCache()", result.ToString()));
return result;
}
//
private CacheValidationStatus ValidateResponse()
{
CacheValidationStatus result = _Validator.ValidateResponse();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "ValidateResponse()", result.ToString()));
return result;
}
//
private CacheValidationStatus UpdateCache()
{
CacheValidationStatus result = _Validator.UpdateCache();
_Validator.SetValidationStatus(result);
return result;
}
//
private void EnsureCacheRemoval(string retrieveKey)
{
// The entry can now be replaced as we are not going for cache entry metadata-only update
_RequestCache.UnlockEntry(_Validator.CacheStream);
if (_Validator.StrictCacheErrors)
{_RequestCache.Remove(retrieveKey);}
else
{_RequestCache.TryRemove(retrieveKey);}
// We may need to remove yet another reference from the cache
if (retrieveKey != _Validator.CacheKey)
{
if (_Validator.StrictCacheErrors)
{_RequestCache.Remove(_Validator.CacheKey);}
else
{_RequestCache.TryRemove(_Validator.CacheKey);}
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
/*++
Copyright (c) Microsoft Corporation
Module Name:
_RequestCacheProtocol.cs
Abstract:
The class is a cache protocol engine.
An application protocol such as HttpWebRequest or FtpWebRequest
gets all cache-related answers by talking to this class
Sometime in the future it will become public.
Author:
Alexei Vopilov 21-Dec-2002
Revision History:
Aug 25 2003 - moved into separate file and revised as per Whidbey-M3 spec.
--*/
namespace System.Net.Cache {
using System;
using System.Diagnostics;
using System.Text;
using System.IO;
using System.Collections.Specialized;
using System.Threading;
using System.Globalization;
//
//
//
internal class RequestCacheProtocol {
private CacheValidationStatus _ProtocolStatus;
private Exception _ProtocolException;
private Stream _ResponseStream;
private long _ResponseStreamLength;
private RequestCacheValidator _Validator;
private RequestCache _RequestCache;
private bool _IsCacheFresh;
private bool _CanTakeNewRequest;
// private string[] _ResponseMetadata;
// private string _CacheRetrieveKey;
// private string _CacheStoreKey;
//
// Public properties
//
internal CacheValidationStatus ProtocolStatus {get {return _ProtocolStatus;}}
internal Exception ProtocolException {get {return _ProtocolException;}}
internal Stream ResponseStream {get {return _ResponseStream;}}
internal long ResponseStreamLength {get {return _ResponseStreamLength;}}
internal RequestCacheValidator Validator {get {return _Validator;}}
internal bool IsCacheFresh {get {return _Validator != null && _Validator.CacheFreshnessStatus == CacheFreshnessStatus.Fresh;}}
// internal string[] ResponseMetadata {get {return _ResponseMetadata;}}
// internal string CacheRetrieveKey {get {return _CacheRetrieveKey;}}
// internal string CacheStoreKey {get {return _CacheStoreKey;}}
//
// Public methods
//
internal RequestCacheProtocol(RequestCache cache, RequestCacheValidator defaultValidator)
{
_RequestCache = cache;
_Validator = defaultValidator;
_CanTakeNewRequest = true;
}
//
internal CacheValidationStatus GetRetrieveStatus (Uri cacheUri, WebRequest request)
{
if (cacheUri == null)
throw new ArgumentNullException("cacheUri");
if (request == null)
throw new ArgumentNullException("request");
if (!_CanTakeNewRequest || _ProtocolStatus == CacheValidationStatus.RetryResponseFromServer)
return CacheValidationStatus.Continue;
_CanTakeNewRequest = false;
// Reset protocol state
_ResponseStream = null;
_ResponseStreamLength = 0L;
_ProtocolStatus = CacheValidationStatus.Continue;
_ProtocolException = null;
if(Logging.On) Logging.Enter(Logging.RequestCache, this, "GetRetrieveStatus", request);
try {
if (request.CachePolicy == null || request.CachePolicy.Level == RequestCacheLevel.BypassCache)
{
_ProtocolStatus = CacheValidationStatus.DoNotUseCache;
return _ProtocolStatus;
}
if (_RequestCache == null || _Validator == null)
{
_ProtocolStatus = CacheValidationStatus.DoNotUseCache;
return _ProtocolStatus;
}
_Validator.FetchRequest(cacheUri, request);
switch(_ProtocolStatus = ValidateRequest())
{
case CacheValidationStatus.Continue: // This is a green light for cache protocol
break;
case CacheValidationStatus.DoNotTakeFromCache: // no cache but response can be cached
case CacheValidationStatus.DoNotUseCache: // ignore cache entirely
break;
case CacheValidationStatus.Fail:
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "ValidateRequest"));
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "ValidateRequest", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "ValidateRequest()", _Validator.ValidationStatus.ToString()));
break;
}
if (_ProtocolStatus != CacheValidationStatus.Continue)
return _ProtocolStatus;
//
// Proceed with validation
//
CheckRetrieveBeforeSubmit();
}
catch (Exception e) {
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException)
throw;
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
if(Logging.On) Logging.Exit(Logging.RequestCache, this, "GetRetrieveStatus", "result = " + _ProtocolStatus.ToString());
}
return _ProtocolStatus;
}
//
// This optional method is only for protocols supporting a revalidation concept
// For a retried request this method must be called again.
//
internal CacheValidationStatus GetRevalidateStatus (WebResponse response, Stream responseStream)
{
if (response == null)
throw new ArgumentNullException("response");
if (_ProtocolStatus == CacheValidationStatus.DoNotUseCache)
return CacheValidationStatus.DoNotUseCache;
// If we returned cached response, switch the state to not call cache anymore.
if (_ProtocolStatus == CacheValidationStatus.ReturnCachedResponse)
{
_ProtocolStatus = CacheValidationStatus.DoNotUseCache;
return _ProtocolStatus;
}
try {
if(Logging.On) Logging.Enter(Logging.RequestCache, this, "GetRevalidateStatus", (_Validator == null? null: _Validator.Request));
_Validator.FetchResponse(response);
if (_ProtocolStatus != CacheValidationStatus.Continue && _ProtocolStatus != CacheValidationStatus.RetryResponseFromServer)
{
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_revalidation_not_needed, "GetRevalidateStatus()"));
return _ProtocolStatus;
}
CheckRetrieveOnResponse(responseStream);
}
finally {
if(Logging.On) Logging.Exit(Logging.RequestCache, this, "GetRevalidateStatus", "result = " + _ProtocolStatus.ToString());
}
return _ProtocolStatus;
}
//
// Returns UpdateResponseInformation if passed response stream has to be replaced (cache is updated in some way)
// Returns Fail if request is to fail
// Any other return value should be ignored
//
internal CacheValidationStatus GetUpdateStatus (WebResponse response, Stream responseStream)
{
if (response == null)
throw new ArgumentNullException("response");
if (_ProtocolStatus == CacheValidationStatus.DoNotUseCache)
return CacheValidationStatus.DoNotUseCache;
try {
if(Logging.On) Logging.Enter(Logging.RequestCache, this, "GetUpdateStatus", null);
if (_Validator.Response == null)
_Validator.FetchResponse(response);
if (_ProtocolStatus == CacheValidationStatus.RemoveFromCache)
{
EnsureCacheRemoval(_Validator.CacheKey);
return _ProtocolStatus;
}
if (_ProtocolStatus != CacheValidationStatus.DoNotTakeFromCache &&
_ProtocolStatus != CacheValidationStatus.ReturnCachedResponse &&
_ProtocolStatus != CacheValidationStatus.CombineCachedAndServerResponse)
{
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_not_updated_based_on_cache_protocol_status, "GetUpdateStatus()", _ProtocolStatus.ToString()));
return _ProtocolStatus;
}
CheckUpdateOnResponse(responseStream);
}
catch (Exception e) {
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
if(Logging.On)Logging.Exit(Logging.RequestCache, this, "GetUpdateStatus", "result = " + _ProtocolStatus.ToString());
}
return _ProtocolStatus;
}
//
// This must be the last call before starting a new request on this protocol instance
//
internal void Reset()
{
_CanTakeNewRequest = true;
}
//
internal void Abort()
{
// if _CanTakeNewRequest==true we should not be holding any cache stream
// Also we check on Abort() reentrancy this way.
if (_CanTakeNewRequest)
return;
// in case of abnormal termination this will release cache entry sooner than does it's finalizer
Stream stream = _ResponseStream;
if (stream != null)
{
try {
if(Logging.On) Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_closing_cache_stream, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), "Abort()", stream.GetType().FullName, _Validator.CacheKey));
ICloseEx closeEx = stream as ICloseEx;
if (closeEx != null)
closeEx.CloseEx(CloseExState.Abort | CloseExState.Silent);
else
stream.Close();
}
catch(Exception e) {
if (NclUtilities.IsFatal(e)) throw;
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_exception_ignored, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), "stream.Close()", e.ToString()));
}
}
Reset();
}
//
// Private methods
//
//
// This method may be invoked as part of the request submission but before issuing a live request
//
private void CheckRetrieveBeforeSubmit() {
GlobalLog.Assert(_ProtocolStatus == CacheValidationStatus.Continue, "CheckRetrieveBeforeSubmit()|Unexpected _ProtocolStatus = {0}", _ProtocolStatus);
try {
while (true)
{
RequestCacheEntry cacheEntry;
if (_Validator.CacheStream != null && _Validator.CacheStream != Stream.Null)
{
// Reset to Initial state
_Validator.CacheStream.Close();
_Validator.CacheStream = Stream.Null;
}
if (_Validator.StrictCacheErrors)
{
_Validator.CacheStream = _RequestCache.Retrieve(_Validator.CacheKey, out cacheEntry);
}
else
{
Stream stream;
_RequestCache.TryRetrieve(_Validator.CacheKey, out cacheEntry, out stream);
_Validator.CacheStream = stream;
}
if (cacheEntry == null)
{
cacheEntry = new RequestCacheEntry();
cacheEntry.IsPrivateEntry = _RequestCache.IsPrivateCache;
_Validator.FetchCacheEntry(cacheEntry);
}
if (_Validator.CacheStream == null)
{
// If entry does not have a stream an empty stream wrapper must be returned.
// A null or Stream.Null value stands for non existent cache entry.
_Validator.CacheStream = Stream.Null;
}
ValidateFreshness(cacheEntry);
_ProtocolStatus = ValidateCache();
// This will tell us what to do next
switch (_ProtocolStatus) {
case CacheValidationStatus.ReturnCachedResponse:
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null)
{
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_no_cache_entry, "ValidateCache()"));
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_no_stream, _Validator.CacheKey));
break;
}
// Final decision is made, check on a range response from cache
Stream stream = _Validator.CacheStream;
// The entry can now be replaced as we are not going for cache entry metadata-only update
_RequestCache.UnlockEntry(_Validator.CacheStream);
if (_Validator.CacheStreamOffset != 0L || _Validator.CacheStreamLength != _Validator.CacheEntry.StreamSize)
{
stream = new RangeStream(stream, _Validator.CacheStreamOffset, _Validator.CacheStreamLength);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_returned_range_cache, "ValidateCache()", _Validator.CacheStreamOffset, _Validator.CacheStreamLength));
}
_ResponseStream = stream;
_ResponseStreamLength = _Validator.CacheStreamLength;
break;
case CacheValidationStatus.Continue:
// copy a cache stream ref
_ResponseStream = _Validator.CacheStream;
break;
case CacheValidationStatus.RetryResponseFromCache:
// loop thought cache retrieve
continue;
case CacheValidationStatus.DoNotTakeFromCache:
case CacheValidationStatus.DoNotUseCache:
break;
case CacheValidationStatus.Fail:
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "ValidateCache"));
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "ValidateCache", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "ValidateCache()", _Validator.ValidationStatus.ToString()));
break;
}
break;
}
}
catch (Exception e) {
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = e;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
// This is to release cache entry on error
if (_ResponseStream == null && _Validator.CacheStream != null && _Validator.CacheStream != Stream.Null)
{
_Validator.CacheStream.Close();
_Validator.CacheStream = Stream.Null;
}
}
}
//
private void CheckRetrieveOnResponse(Stream responseStream) {
GlobalLog.Assert(_ProtocolStatus == CacheValidationStatus.Continue || _ProtocolStatus == CacheValidationStatus.RetryResponseFromServer, "CheckRetrieveOnResponse()|Unexpected _ProtocolStatus = ", _ProtocolStatus);
// if something goes wrong we release cache stream if any exists
bool closeCacheStream = true;
try {
// This will inspect the live response on the correctness matter
switch (_ProtocolStatus = ValidateResponse()) {
case CacheValidationStatus.Continue:
closeCacheStream = false;
// The response looks good
break;
case CacheValidationStatus.RetryResponseFromServer:
// The response is broken will need to retry or give up
closeCacheStream = false;
break;
case CacheValidationStatus.Fail:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "ValidateResponse"));
break;
case CacheValidationStatus.DoNotUseCache:
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "ValidateResponse", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "ValidateResponse()", _Validator.ValidationStatus.ToString()));
break;
}
}
catch (Exception e) {
closeCacheStream = true;
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
// This is to release cache entry in case we are not interested in it
if (closeCacheStream && _ResponseStream != null)
{
_ResponseStream.Close();
_ResponseStream = null;
_Validator.CacheStream = Stream.Null;
}
}
if (_ProtocolStatus != CacheValidationStatus.Continue) {
return;
}
//
// only CacheValidationStatus.Continue goes here with closeCacheStream == false
//
try {
// This will tell us what to do next
// Note this is a second time question to the caching protocol about a cached entry
// Except that we now have live response to consider
//
// The validator can at any time replace the cache stream and update cache Metadata (aka headers).
//
switch (_ProtocolStatus = RevalidateCache()) {
case CacheValidationStatus.DoNotUseCache:
case CacheValidationStatus.RemoveFromCache:
case CacheValidationStatus.DoNotTakeFromCache:
closeCacheStream = true;
break;
case CacheValidationStatus.ReturnCachedResponse:
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null)
{
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_no_stream, _Validator.CacheKey));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_null_cached_stream, "RevalidateCache()"));
break;
}
Stream stream = _Validator.CacheStream;
if (_Validator.CacheStreamOffset != 0L || _Validator.CacheStreamLength != _Validator.CacheEntry.StreamSize)
{
stream = new RangeStream(stream, _Validator.CacheStreamOffset, _Validator.CacheStreamLength);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_returned_range_cache, "RevalidateCache()", _Validator.CacheStreamOffset, _Validator.CacheStreamLength));
}
_ResponseStream = stream;
_ResponseStreamLength = _Validator.CacheStreamLength;
break;
case CacheValidationStatus.CombineCachedAndServerResponse:
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null)
{
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_no_stream, _Validator.CacheKey));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_requested_combined_but_null_cached_stream, "RevalidateCache()"));
break;
}
//
// FTP cannot give the tail of the combined stream at that point
// Consider: Revisit the design of the CacheProtocol class
if (responseStream != null)
{
stream = new CombinedReadStream(_Validator.CacheStream, responseStream);
}
else
{
// So Abort can close the cache stream
stream = _Validator.CacheStream;
}
_ResponseStream = stream;
_ResponseStreamLength = _Validator.CacheStreamLength;
break;
case CacheValidationStatus.Fail:
closeCacheStream = true;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "RevalidateCache"));
break;
default:
closeCacheStream = true;
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "RevalidateCache", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "RevalidateCache()", _Validator.ValidationStatus.ToString()));
break;
}
}
catch (Exception e) {
closeCacheStream = true;
_ProtocolException = e;
_ProtocolStatus = CacheValidationStatus.Fail;
if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) {
throw;
}
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_object_and_exception, "CacheProtocol#" + this.GetHashCode().ToString(NumberFormatInfo.InvariantInfo), (e is WebException? e.Message: e.ToString())));
}
finally {
// This is to release cache entry in case we are not interested in it
if (closeCacheStream && _ResponseStream != null)
{
_ResponseStream.Close();
_ResponseStream = null;
_Validator.CacheStream = Stream.Null;
}
}
}
//
// This will decide on cache update and construct the effective response stream
//
private void CheckUpdateOnResponse(Stream responseStream)
{
if (_Validator.CacheEntry == null)
{
// There was no chance to create an empty entry yet
RequestCacheEntry cacheEntry = new RequestCacheEntry();
cacheEntry.IsPrivateEntry = _RequestCache.IsPrivateCache;
_Validator.FetchCacheEntry(cacheEntry);
}
// With NoCache we may end up storing whole response as a new entry in Cache.
// Otherwise we may end up updating Context+Metadata or just Context
//
// In any case we may end up doing nothing.
//
string retrieveKey = _Validator.CacheKey;
bool unlockEntry = true;
try {
switch (_ProtocolStatus=UpdateCache()) {
case CacheValidationStatus.RemoveFromCache:
EnsureCacheRemoval(retrieveKey);
unlockEntry = false;
break;
case CacheValidationStatus.UpdateResponseInformation:
// NB: Just invoked validator must have updated CacheEntry and transferred
// ONLY allowed headers from the response to the Context.xxxMetadata member
_ResponseStream = new MetadataUpdateStream(
responseStream,
_RequestCache,
_Validator.CacheKey,
_Validator.CacheEntry.ExpiresUtc,
_Validator.CacheEntry.LastModifiedUtc,
_Validator.CacheEntry.LastSynchronizedUtc,
_Validator.CacheEntry.MaxStale,
_Validator.CacheEntry.EntryMetadata,
_Validator.CacheEntry.SystemMetadata,
_Validator.StrictCacheErrors);
//
// This can be looked as a design hole since we have to keep the entry
// locked for the case when we want to update that previously retrieved entry.
// I think RequestCache contract should allow to detect that a new physical cache entry
// does not match to the "entry being updated" and so to should ignore updates on replaced entries.
//
unlockEntry = false;
_ProtocolStatus = CacheValidationStatus.UpdateResponseInformation;
break;
case CacheValidationStatus.CacheResponse:
// NB: Just invoked validator must have updated CacheEntry and transferred
// ONLY allowed headers from the response to the Context.xxxMetadata member
Stream stream;
if (_Validator.StrictCacheErrors)
{stream = _RequestCache.Store(_Validator.CacheKey, _Validator.CacheEntry.StreamSize, _Validator.CacheEntry.ExpiresUtc, _Validator.CacheEntry.LastModifiedUtc, _Validator.CacheEntry.MaxStale, _Validator.CacheEntry.EntryMetadata, _Validator.CacheEntry.SystemMetadata);}
else
{_RequestCache.TryStore(_Validator.CacheKey, _Validator.CacheEntry.StreamSize, _Validator.CacheEntry.ExpiresUtc, _Validator.CacheEntry.LastModifiedUtc, _Validator.CacheEntry.MaxStale, _Validator.CacheEntry.EntryMetadata, _Validator.CacheEntry.SystemMetadata, out stream);}
// Wrap the response stream into forwarding one
if (stream == null) {
_ProtocolStatus = CacheValidationStatus.DoNotUpdateCache;
}
else {
_ResponseStream = new ForwardingReadStream(responseStream, stream, _Validator.CacheStreamOffset, _Validator.StrictCacheErrors);
_ProtocolStatus = CacheValidationStatus.UpdateResponseInformation;
}
break;
case CacheValidationStatus.DoNotUseCache:
case CacheValidationStatus.DoNotUpdateCache:
break;
case CacheValidationStatus.Fail:
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_fail, "UpdateCache"));
break;
default:
_ProtocolStatus = CacheValidationStatus.Fail;
_ProtocolException = new InvalidOperationException(SR.GetString(SR.net_cache_validator_result, "UpdateCache", _Validator.ValidationStatus.ToString()));
if(Logging.On) Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_unexpected_status, "UpdateCache()", _Validator.ValidationStatus.ToString()));
break;
}
}
finally {
if (unlockEntry)
{
// The entry can now be replaced as we are not going for cache entry metadata-only update
_RequestCache.UnlockEntry(_Validator.CacheStream);
}
}
}
//
private CacheValidationStatus ValidateRequest() {
if(Logging.On) Logging.PrintInfo(Logging.RequestCache,
"Request#" + _Validator.Request.GetHashCode().ToString(NumberFormatInfo.InvariantInfo) +
", Policy = " + _Validator.Request.CachePolicy.ToString() +
", Cache Uri = " + _Validator.Uri);
CacheValidationStatus result = _Validator.ValidateRequest();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, "Selected cache Key = " + _Validator.CacheKey);
return result;
}
//
//
//
private void ValidateFreshness(RequestCacheEntry fetchEntry) {
_Validator.FetchCacheEntry(fetchEntry);
if (_Validator.CacheStream == null || _Validator.CacheStream == Stream.Null) {
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_entry_not_found_freshness_undefined, "ValidateFreshness()"));
_Validator.SetFreshnessStatus(CacheFreshnessStatus.Undefined);
return;
}
if(Logging.On) {
if (Logging.IsVerbose(Logging.RequestCache)) {
Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_dumping_cache_context));
if (fetchEntry == null) {
Logging.PrintInfo(Logging.RequestCache, "");
}
else {
string[] context = fetchEntry.ToString(Logging.IsVerbose(Logging.RequestCache)).Split(RequestCache.LineSplits);
for (int i = 0; i< context.Length; ++i) {
if (context[i].Length != 0) {
Logging.PrintInfo(Logging.RequestCache, context[i]);
}
}
}
}
}
CacheFreshnessStatus result = _Validator.ValidateFreshness();
_Validator.SetFreshnessStatus(result);
_IsCacheFresh = result == CacheFreshnessStatus.Fresh;
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "ValidateFreshness()", result.ToString()));
}
//
//
//
private CacheValidationStatus ValidateCache() {
CacheValidationStatus result = _Validator.ValidateCache();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "ValidateCache()", result.ToString()));
return result;
}
//
private CacheValidationStatus RevalidateCache() {
CacheValidationStatus result = _Validator.RevalidateCache();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "RevalidateCache()", result.ToString()));
return result;
}
//
private CacheValidationStatus ValidateResponse()
{
CacheValidationStatus result = _Validator.ValidateResponse();
_Validator.SetValidationStatus(result);
if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_result, "ValidateResponse()", result.ToString()));
return result;
}
//
private CacheValidationStatus UpdateCache()
{
CacheValidationStatus result = _Validator.UpdateCache();
_Validator.SetValidationStatus(result);
return result;
}
//
private void EnsureCacheRemoval(string retrieveKey)
{
// The entry can now be replaced as we are not going for cache entry metadata-only update
_RequestCache.UnlockEntry(_Validator.CacheStream);
if (_Validator.StrictCacheErrors)
{_RequestCache.Remove(retrieveKey);}
else
{_RequestCache.TryRemove(retrieveKey);}
// We may need to remove yet another reference from the cache
if (retrieveKey != _Validator.CacheKey)
{
if (_Validator.StrictCacheErrors)
{_RequestCache.Remove(_Validator.CacheKey);}
else
{_RequestCache.TryRemove(_Validator.CacheKey);}
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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- WebColorConverter.cs
- XmlQueryType.cs
- UrlPath.cs
- AttachedPropertyBrowsableAttribute.cs
- ValueConversionAttribute.cs
- DrawToolTipEventArgs.cs
- DataStreams.cs
- ResXResourceSet.cs
- ImportCatalogPart.cs
- InvalidDataContractException.cs
- RSAOAEPKeyExchangeFormatter.cs
- KeysConverter.cs
- SQLMoneyStorage.cs
- OleDbConnectionFactory.cs
- WebPartTransformerAttribute.cs
- XmlParserContext.cs
- IteratorFilter.cs
- datacache.cs
- InfoCard.cs
- SoapServerProtocol.cs
- ZipFileInfo.cs
- DbMetaDataFactory.cs
- EntityCommandDefinition.cs
- LogWriteRestartAreaAsyncResult.cs
- BitmapCacheBrush.cs
- BitVector32.cs
- DatatypeImplementation.cs
- SafeWaitHandle.cs
- InstanceKeyCollisionException.cs
- ObservableCollectionDefaultValueFactory.cs
- Control.cs
- RangeBase.cs
- StateDesigner.LayoutSelectionGlyph.cs
- EUCJPEncoding.cs
- WrappingXamlSchemaContext.cs
- PopupRootAutomationPeer.cs
- Column.cs
- StringUtil.cs
- _NestedMultipleAsyncResult.cs
- DataRelation.cs
- DbConnectionClosed.cs
- AccessText.cs
- DataGridHelper.cs
- ExpressionEditorAttribute.cs
- TrustManager.cs
- SessionStateSection.cs
- HtmlElementCollection.cs
- PageStatePersister.cs
- NamedObject.cs
- XmlCDATASection.cs
- LocationFactory.cs
- DataGridViewHeaderCell.cs
- FileChangesMonitor.cs
- DataControlLinkButton.cs
- GeometryValueSerializer.cs
- safesecurityhelperavalon.cs
- Accessors.cs
- DataBoundControlDesigner.cs
- MouseButtonEventArgs.cs
- HtmlAnchor.cs
- SHA384Managed.cs
- ListBox.cs
- ConstructorBuilder.cs
- InputScopeConverter.cs
- ExeContext.cs
- X509ClientCertificateAuthenticationElement.cs
- PrintPageEvent.cs
- CollectionExtensions.cs
- DocumentViewer.cs
- EventLogInformation.cs
- ConfigurationManagerInternalFactory.cs
- PointCollectionValueSerializer.cs
- InputMethodStateTypeInfo.cs
- TagMapCollection.cs
- CompressStream.cs
- TreeView.cs
- OdbcConnectionHandle.cs
- RC2.cs
- XmlSerializer.cs
- CultureInfo.cs
- CodeExpressionRuleDeclaration.cs
- StorageModelBuildProvider.cs
- ImageListUtils.cs
- DictionaryMarkupSerializer.cs
- XPathException.cs
- WebPartMinimizeVerb.cs
- DateTime.cs
- RootBrowserWindow.cs
- XhtmlTextWriter.cs
- SplineKeyFrames.cs
- FilterQuery.cs
- TextSegment.cs
- WebPartActionVerb.cs
- CellPartitioner.cs
- TreeNodeBinding.cs
- ConstrainedDataObject.cs
- SecUtil.cs
- WebPartPersonalization.cs
- NonBatchDirectoryCompiler.cs
- bidPrivateBase.cs