/*++ Copyright (c) Microsoft Corporation Module Name: HttpRequestCacheValidator.cs Abstract: The class implements HTTP Caching validators as per RFC2616 Author: Alexei Vopilov 21-Dec-2002 Revision History: Jan 25 2004 - Changed the visibility of the class from public to internal. --*/ namespace System.Net.Cache { using System; using System.Net; using System.IO; using System.Collections; using System.Text; using System.Collections.Specialized; using System.Globalization; using System.Threading; ///

The class represents an adavanced way for an application to control caching protocol

internal class HttpRequestCacheValidator: RequestCacheValidator { internal const string Warning_110 = "110 Response is stale"; internal const string Warning_111 = "111 Revalidation failed"; internal const string Warning_112 = "112 Disconnected operation"; internal const string Warning_113 = "113 Heuristic expiration"; private struct RequestVars { internal HttpMethod Method; internal bool IsCacheRange; internal bool IsUserRange; internal string IfHeader1; internal string Validator1; internal string IfHeader2; internal string Validator2; } private HttpRequestCachePolicy m_HttpPolicy; private HttpStatusCode m_StatusCode; private string m_StatusDescription; private Version m_HttpVersion; private WebHeaderCollection m_Headers; private NameValueCollection m_SystemMeta; private bool m_DontUpdateHeaders; private bool m_HeuristicExpiration; private Vars m_CacheVars; private Vars m_ResponseVars; private RequestVars m_RequestVars; private struct Vars { internal DateTime Date; internal DateTime Expires; internal DateTime LastModified; internal long EntityLength; internal TimeSpan Age; internal TimeSpan MaxAge; internal ResponseCacheControl CacheControl; internal long RangeStart; internal long RangeEnd; internal void Initialize() { EntityLength = RangeStart = RangeEnd = -1; Date = DateTime.MinValue; Expires = DateTime.MinValue; LastModified = DateTime.MinValue; Age = TimeSpan.MinValue; MaxAge = TimeSpan.MinValue; } } //public internal HttpStatusCode CacheStatusCode {get{return m_StatusCode;} set{m_StatusCode = value;}} //public internal string CacheStatusDescription {get{return m_StatusDescription;} set{m_StatusDescription = value;}} //public internal Version CacheHttpVersion {get{return m_HttpVersion;} set{m_HttpVersion = value;}} //public internal WebHeaderCollection CacheHeaders {get{return m_Headers;} set{m_Headers = value;}} //public internal new HttpRequestCachePolicy Policy { get { if(m_HttpPolicy != null) return m_HttpPolicy; m_HttpPolicy = base.Policy as HttpRequestCachePolicy; if(m_HttpPolicy != null) return m_HttpPolicy; // promote base policy to Http one m_HttpPolicy = new HttpRequestCachePolicy((HttpRequestCacheLevel)base.Policy.Level); return m_HttpPolicy; } } internal NameValueCollection SystemMeta {get{return m_SystemMeta;} set{m_SystemMeta = value;}} internal HttpMethod RequestMethod {get{return m_RequestVars.Method;} set{m_RequestVars.Method = value;}} internal bool RequestRangeCache {get{return m_RequestVars.IsCacheRange;} set{m_RequestVars.IsCacheRange = value;}} internal bool RequestRangeUser {get{return m_RequestVars.IsUserRange;} set{m_RequestVars.IsUserRange = value;}} internal string RequestIfHeader1 {get{return m_RequestVars.IfHeader1;} set{m_RequestVars.IfHeader1 = value;}} internal string RequestValidator1 {get{return m_RequestVars.Validator1;} set{m_RequestVars.Validator1 = value;}} internal string RequestIfHeader2 {get{return m_RequestVars.IfHeader2;} set{m_RequestVars.IfHeader2 = value;}} internal string RequestValidator2 {get{return m_RequestVars.Validator2;} set{m_RequestVars.Validator2 = value;}} internal bool CacheDontUpdateHeaders {get{return m_DontUpdateHeaders;} set{m_DontUpdateHeaders = value;}} internal DateTime CacheDate {get{return m_CacheVars.Date;} set{m_CacheVars.Date = value;}} internal DateTime CacheExpires {get{return m_CacheVars.Expires;} set{m_CacheVars.Expires = value;}} internal DateTime CacheLastModified {get{return m_CacheVars.LastModified;} set{m_CacheVars.LastModified = value;}} internal long CacheEntityLength {get{return m_CacheVars.EntityLength ;} set{m_CacheVars.EntityLength = value;}} internal TimeSpan CacheAge {get{return m_CacheVars.Age;} set{m_CacheVars.Age = value;}} internal TimeSpan CacheMaxAge {get{return m_CacheVars.MaxAge;} set{m_CacheVars.MaxAge = value;}} internal bool HeuristicExpiration {get{return m_HeuristicExpiration;} set{m_HeuristicExpiration = value;}} internal ResponseCacheControl CacheCacheControl {get{return m_CacheVars.CacheControl;} set{m_CacheVars.CacheControl = value;}} internal DateTime ResponseDate {get{return m_ResponseVars.Date;} set{m_ResponseVars.Date = value;}} internal DateTime ResponseExpires {get{return m_ResponseVars.Expires;} set{m_ResponseVars.Expires = value;}} internal DateTime ResponseLastModified {get{return m_ResponseVars.LastModified;} set{m_ResponseVars.LastModified = value;}} internal long ResponseEntityLength {get{return m_ResponseVars.EntityLength ;}set{m_ResponseVars.EntityLength = value;}} internal long ResponseRangeStart {get{return m_ResponseVars.RangeStart;} set{m_ResponseVars.RangeStart = value;}} internal long ResponseRangeEnd {get{return m_ResponseVars.RangeEnd;} set{m_ResponseVars.RangeEnd = value;}} internal TimeSpan ResponseAge {get{return m_ResponseVars.Age;} set{m_ResponseVars.Age = value;}} internal ResponseCacheControl ResponseCacheControl {get{return m_ResponseVars.CacheControl;} set{m_ResponseVars.CacheControl = value;}} // private void ZeroPrivateVars() { // Set default values for private members here m_RequestVars = new RequestVars(); m_HttpPolicy = null; m_StatusCode = (HttpStatusCode)0; m_StatusDescription = null; m_HttpVersion = null; m_Headers = null; m_SystemMeta = null; m_DontUpdateHeaders = false; m_HeuristicExpiration = false; m_CacheVars = new Vars(); m_CacheVars.Initialize(); m_ResponseVars= new Vars(); m_ResponseVars.Initialize(); } //public internal override RequestCacheValidator CreateValidator() { return new HttpRequestCacheValidator(StrictCacheErrors, UnspecifiedMaxAge); } /* //public // Consider removing. internal HttpRequestCacheValidator(): base() { } */ //public internal HttpRequestCacheValidator(bool strictCacheErrors, TimeSpan unspecifiedMaxAge): base(strictCacheErrors, unspecifiedMaxAge) { } // // This validation method is called first and before any Cache access is done. // Given the request instance the code has to decide whether the request is ever suitable for caching. // // Returns: // Continue = Proceed to the next protocol stage. // DoNotTakeFromCache = Don't used caches value for this request // DoNotUseCache = Cache is not used for this request and response is not cached. protected internal override CacheValidationStatus ValidateRequest() { // cleanup context after previous request ZeroPrivateVars(); string method = Request.Method.ToUpper(CultureInfo.InvariantCulture); if(Logging.On)Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_request_method, method)); switch (method) { case "GET" : RequestMethod = HttpMethod.Get; break; case "POST": RequestMethod = HttpMethod.Post; break; case "HEAD": RequestMethod = HttpMethod.Head; break; case "PUT" : RequestMethod = HttpMethod.Put; break; case "DELETE": RequestMethod = HttpMethod.Delete; break; case "OPTIONS": RequestMethod = HttpMethod.Options; break; case "TRACE": RequestMethod = HttpMethod.Trace; break; case "CONNECT": RequestMethod = HttpMethod.Connect; break; default: RequestMethod = HttpMethod.Other; break; } // Apply our best knowledge of HTTP caching and return the result // that can be hooked up and revised by the upper level return Rfc2616.OnValidateRequest(this); } // // This validation method is called after caching protocol has retrieved the metadata of a cached entry. // Given the cached entry context, the request instance and the effective caching policy, // the handler has to decide whether a cached item can be considered as fresh. protected internal override CacheFreshnessStatus ValidateFreshness() { // Transfer cache entry metadata into status line and headers. string s = ParseStatusLine(); if(Logging.On) { if ((int) CacheStatusCode == 0) { Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_http_status_parse_failure, (s == null ? "null" : s))); } else { Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_http_status_line, (CacheHttpVersion != null ? CacheHttpVersion.ToString() : "null"), (int)CacheStatusCode, CacheStatusDescription)); } } CreateCacheHeaders((int)CacheStatusCode != 0); CreateSystemMeta(); // We will need quick access to cache-control and other headers coming with the cached item FetchHeaderValues(true); if(Logging.On) Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_cache_control, CacheCacheControl.ToString())); // Now we try to apply our best knowledge of HTTP caching and return the result // that can be hooked up and revised on the upper level return Rfc2616.OnValidateFreshness(this); } /// This method may add headers under the "Warning" header name protected internal override CacheValidationStatus ValidateCache() { if (this.Policy.Level != HttpRequestCacheLevel.Revalidate && base.Policy.Level >= RequestCacheLevel.Reload) { // For those policies cache is never returned GlobalLog.Assert("OnValidateCache()", "This validator should not be called for policy = " + Policy.ToString()); if(Logging.On)Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_validator_invalid_for_policy, Policy.ToString())); return CacheValidationStatus.DoNotTakeFromCache; } // First check is do we have a cached entry at all? // Also we include some very special case where cache got a 304 (NotModified) response somehow if (CacheStream == Stream.Null || (int)CacheStatusCode == 0 || CacheStatusCode == HttpStatusCode.NotModified) { if (this.Policy.Level == HttpRequestCacheLevel.CacheOnly) { // Throw because entry was not found and it's cache-only policy FailRequest(WebExceptionStatus.CacheEntryNotFound); } return CacheValidationStatus.DoNotTakeFromCache; } if (RequestMethod == HttpMethod.Head) { // For a HEAD request we release the cache entry stream asap since we will have to suppress it anyway CacheStream.Close(); CacheStream = new SyncMemoryStream(new byte[] {}); } // Apply our best knowledge of HTTP caching and return the result // that can be hooked up and revised by the upper level CacheValidationStatus result = CacheValidationStatus.DoNotTakeFromCache; // // Before request submission validation // // If we return from cache we should remove existing 1xx warnings RemoveWarnings_1xx(); // default values for a response from cache. CacheStreamOffset = 0; CacheStreamLength = CacheEntry.StreamSize; result = Rfc2616.OnValidateCache(this); if (result != CacheValidationStatus.ReturnCachedResponse && this.Policy.Level == HttpRequestCacheLevel.CacheOnly) { // Throw because entry was not found and it's cache-only policy FailRequest(WebExceptionStatus.CacheEntryNotFound); } if (result == CacheValidationStatus.ReturnCachedResponse) { if (CacheFreshnessStatus == CacheFreshnessStatus.Stale) { CacheHeaders.Add(HttpKnownHeaderNames.Warning, HttpRequestCacheValidator.Warning_110); } if (base.Policy.Level == RequestCacheLevel.CacheOnly) { CacheHeaders.Add(HttpKnownHeaderNames.Warning, HttpRequestCacheValidator.Warning_112); } if (HeuristicExpiration && (int)CacheAge.TotalSeconds >= 24*3600) { CacheHeaders.Add(HttpKnownHeaderNames.Warning, HttpRequestCacheValidator.Warning_113); } } if (result == CacheValidationStatus.DoNotTakeFromCache) { // We signal that current cache entry can be only replaced and not updated CacheStatusCode = (HttpStatusCode) 0; } else if (result == CacheValidationStatus.ReturnCachedResponse) { CacheHeaders[HttpKnownHeaderNames.Age] = ((int)(CacheAge.TotalSeconds)).ToString(NumberFormatInfo.InvariantInfo); } return result; } // // This is (optionally) called after receiveing a live response // protected internal override CacheValidationStatus RevalidateCache() { if (this.Policy.Level != HttpRequestCacheLevel.Revalidate && base.Policy.Level >= RequestCacheLevel.Reload) { // For those policies cache is never returned GlobalLog.Assert("RevalidateCache()", "This validator should not be called for policy = " + Policy.ToString()); if(Logging.On)Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_validator_invalid_for_policy, Policy.ToString())); return CacheValidationStatus.DoNotTakeFromCache; } // First check is do we have a cached entry at all? // Also we include some very special case where cache got a 304 (NotModified) response somehow if (CacheStream == Stream.Null || (int)CacheStatusCode == 0 || CacheStatusCode == HttpStatusCode.NotModified) { return CacheValidationStatus.DoNotTakeFromCache; } // // This is a second+ time validation after receiving at least one response // // Apply our best knowledge of HTTP caching and return the result // that can be hooked up and revised by the upper level CacheValidationStatus result = CacheValidationStatus.DoNotTakeFromCache; HttpWebResponse resp = Response as HttpWebResponse; if (resp == null) { // This will result to an application error return CacheValidationStatus.DoNotTakeFromCache; } if (resp.StatusCode >= HttpStatusCode.InternalServerError) { // If server returned a 5XX server error if (Rfc2616.Common.ValidateCacheOn5XXResponse(this) == CacheValidationStatus.ReturnCachedResponse) { // We can substitute the response from cache if (CacheFreshnessStatus == CacheFreshnessStatus.Stale) { CacheHeaders.Add(HttpKnownHeaderNames.Warning, HttpRequestCacheValidator.Warning_110); } if (HeuristicExpiration && (int)CacheAge.TotalSeconds >= 24*3600) { CacheHeaders.Add(HttpKnownHeaderNames.Warning, HttpRequestCacheValidator.Warning_113); } // We actually failed to reach the origin server hence we don't reset the current Cache Age } } else { // if there was already one retry, then cache should not be taken into account if (ResponseCount > 1) { result = CacheValidationStatus.DoNotTakeFromCache; } else { /* Section 13.2.3: HTTP/1.1 uses the Age response-header to convey the estimated age of the response message when obtained from a cache. The Age field value is the cache's estimate of the amount of time since the response was generated or >>revalidated<< by the origin server. */ // Reset Cache Age to be 0 seconds CacheAge = TimeSpan.Zero; result = Rfc2616.Common.ValidateCacheAfterResponse(this, resp); } } if (result == CacheValidationStatus.ReturnCachedResponse) { CacheHeaders[HttpKnownHeaderNames.Age] = ((int)(CacheAge.TotalSeconds)).ToString(NumberFormatInfo.InvariantInfo); } return result; } ///

/// /// This validation method is responsible to answer whether the live response is sufficient to make /// the final decision for caching protocol. /// This is useful in case of possible failure or inconsistent results received from /// the remote cache. /// ///

/// Invalid response from this method means the request was internally modified and should be retried protected internal override CacheValidationStatus ValidateResponse() { if (this.Policy.Level != HttpRequestCacheLevel.CacheOrNextCacheOnly && this.Policy.Level != HttpRequestCacheLevel.Default && this.Policy.Level != HttpRequestCacheLevel.Revalidate) { // Those policy levels do not modify requests if(Logging.On)Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_response_valid_based_on_policy, Policy.ToString())); return CacheValidationStatus.Continue; } // We will need quick access to cache controls coming with the live response HttpWebResponse resp = Response as HttpWebResponse; if (resp == null) { if(Logging.On)Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_null_response_failure)); return CacheValidationStatus.Continue; } FetchHeaderValues(false); if(Logging.On) Logging.PrintInfo(Logging.RequestCache, "StatusCode=" + ((int)resp.StatusCode).ToString(CultureInfo.InvariantCulture) + ' ' +resp.StatusCode.ToString() + (resp.StatusCode == HttpStatusCode.PartialContent ?", Content-Range: " + resp.Headers[HttpKnownHeaderNames.ContentRange] :string.Empty) ); // Apply our best knowledge of HTTP caching and return the result // that can be hooked up and revised by the upper level return Rfc2616.OnValidateResponse(this); } ///

/// /// This action handler is responsible for making final decision on whether /// a received response can be cached. /// ///

/// Invalid result from this method means the response must not be cached protected internal override CacheValidationStatus UpdateCache() { if (this.Policy.Level == HttpRequestCacheLevel.NoCacheNoStore) { if(Logging.On)Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_removed_existing_based_on_policy, Policy.ToString())); return CacheValidationStatus.RemoveFromCache; } if (this.Policy.Level == HttpRequestCacheLevel.CacheOnly) { if(Logging.On)Logging.PrintInfo(Logging.RequestCache, SR.GetString(SR.net_log_cache_not_updated_based_on_policy, Policy.ToString())); return CacheValidationStatus.DoNotUpdateCache; } if (CacheHeaders == null) CacheHeaders = new WebHeaderCollection(); if (SystemMeta == null) SystemMeta = new NameValueCollection(1, CaseInsensitiveAscii.StaticInstance); if (ResponseCacheControl == null) { //ValidateResponse was not invoked FetchHeaderValues(false); } // Apply our best knowledge of HTTP caching and return the result // that can be hooked up and revised by the upper level CacheValidationStatus result = Rfc2616.OnUpdateCache(this); if (result == CacheValidationStatus.UpdateResponseInformation || result == CacheValidationStatus.CacheResponse) { FinallyUpdateCacheEntry(); } return result; } // // // private void FinallyUpdateCacheEntry() { // Transfer the context status line back to the metadata CacheEntry.EntryMetadata = null; CacheEntry.SystemMetadata = null; if (CacheHeaders == null) { //must be an entry update without updating the headers return; } CacheEntry.EntryMetadata = new StringCollection(); CacheEntry.SystemMetadata = new StringCollection(); if (CacheHttpVersion == null) { if(Logging.On)Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_invalid_http_version)); CacheHttpVersion = new Version(1, 0); } // HTTP/1.1 200 OK System.Text.StringBuilder sb = new System.Text.StringBuilder(CacheStatusDescription.Length + 20); sb.Append("HTTP/"); sb.Append(CacheHttpVersion.ToString(2)); sb.Append(' '); sb.Append(((int)CacheStatusCode).ToString(NumberFormatInfo.InvariantInfo)); sb.Append(' '); sb.Append(CacheStatusDescription); // Fetch the status line into cache metadata CacheEntry.EntryMetadata.Add(sb.ToString()); UpdateStringCollection(CacheEntry.EntryMetadata, CacheHeaders, false); if (SystemMeta != null) { UpdateStringCollection(CacheEntry.SystemMetadata, SystemMeta, true); } // Update other entry values if (ResponseExpires != DateTime.MinValue) { CacheEntry.ExpiresUtc = ResponseExpires; } if (ResponseLastModified != DateTime.MinValue) { CacheEntry.LastModifiedUtc = ResponseLastModified; } if (this.Policy.Level == HttpRequestCacheLevel.Default) { CacheEntry.MaxStale = this.Policy.MaxStale; } CacheEntry.LastSynchronizedUtc = DateTime.UtcNow; } // // // private static void UpdateStringCollection(StringCollection result, NameValueCollection cc, bool winInetCompat) { StringBuilder sb; // Transfer headers for (int i=0; i < cc.Count; ++i) { sb = new StringBuilder(40); string key = cc.GetKey(i) as string; sb.Append(key).Append(':'); string[] val = cc.GetValues(i); if (val.Length != 0) { if (winInetCompat) {sb.Append(val[0]);} else {sb.Append(' ').Append(val[0]);} } for (int j = 1; j < val.Length; ++j) { sb.Append(key).Append(", ").Append(val[j]); } result.Add(sb.ToString()); } // Transfer last \r\n result.Add(string.Empty); } // The format is // HTTP/X.Y SP NUMBER SP STRING // HTTP/1.1 200 OK // private string ParseStatusLine() { // This will indicate an invalid result CacheStatusCode = (HttpStatusCode)0; if (CacheEntry.EntryMetadata == null || CacheEntry.EntryMetadata.Count == 0) { return null; } string s = CacheEntry.EntryMetadata[0]; if (s == null) { return null; } int idx = 0; char ch = (char)0; while (++idx < s.Length && (ch=s[idx]) != '/') { ; } if (idx == s.Length) {return s;} int major = -1; int minor = -1; int status= -1; while (++idx < s.Length && (ch=s[idx]) >= '0' && ch <= '9') { major = (major<0? 0: major*10) +(ch - '0'); } if (major < 0 || ch != '.') {return s;} while (++idx < s.Length && (ch=s[idx]) >= '0' && ch <= '9') { minor = (minor<0? 0: minor*10) + (ch - '0'); } if (minor < 0 || (ch != ' ' && ch != '\t')) {return s;} while (++idx < s.Length && ((ch=s[idx]) == ' ' || ch == '\t')) ; if (idx >= s.Length) {return s;} while (ch >= '0' && ch <= '9') { status = (status<0? 0: status*10) +(ch - '0'); if (++idx == s.Length) break; ch=s[idx]; } if (status < 0 || (idx <= s.Length && (ch != ' ' && ch != '\t'))) {return s;} while (idx < s.Length && (s[idx] == ' ' || s[idx] == '\t')) ++idx; CacheStatusDescription = s.Substring(idx); CacheHttpVersion = new Version(major, minor); CacheStatusCode = (HttpStatusCode)status; return s; } // private void CreateCacheHeaders(bool ignoreFirstString) { if (CacheHeaders == null) CacheHeaders = new WebHeaderCollection(); if (CacheEntry.EntryMetadata == null || CacheEntry.EntryMetadata.Count == 0) { if(Logging.On)Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_no_http_response_header)); return; } string s = ParseNameValues(CacheHeaders, CacheEntry.EntryMetadata, ignoreFirstString?1:0); if (s != null) { if(Logging.On)Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_http_header_parse_error, s)); CacheHeaders.Clear(); } } // private void CreateSystemMeta() { if (SystemMeta == null) { SystemMeta = new NameValueCollection((CacheEntry.EntryMetadata == null || CacheEntry.EntryMetadata.Count == 0? 2: CacheEntry.EntryMetadata.Count), CaseInsensitiveAscii.StaticInstance); } if (CacheEntry.EntryMetadata == null || CacheEntry.EntryMetadata.Count == 0) {return;} string s = ParseNameValues(SystemMeta, CacheEntry.SystemMetadata, 0); if (s != null) { if(Logging.On)Logging.PrintWarning(Logging.RequestCache, SR.GetString(SR.net_log_cache_metadata_name_value_parse_error, s)); } } // // Returns null on success, otherwise the offending string. // private string ParseNameValues(NameValueCollection cc, StringCollection sc, int start) { WebHeaderCollection wc = cc as WebHeaderCollection; string lastHeaderName = null; if (sc != null) { for (int i = start; i < sc.Count; ++i) { string s = sc[i]; if (s == null || s.Length == 0) { //An empty string stands for \r\n //Treat that as the end of headers and ignore the rest return null; } if (s[0] == ' ' || s[0] == '\t') { if (lastHeaderName == null) {return s;} if (wc != null) wc.AddInternal(lastHeaderName, s); else cc.Add(lastHeaderName, s); } int colpos = s.IndexOf(':'); if (colpos < 0) {return s;} lastHeaderName = s.Substring(0, colpos); while (++colpos < s.Length && (s[colpos] == ' ' || s[colpos] == '\t')) {;} try { if (wc != null) wc.AddInternal(lastHeaderName, s.Substring(colpos)); else cc.Add(lastHeaderName, s.Substring(colpos)); } catch(Exception e) { if (e is ThreadAbortException || e is StackOverflowException || e is OutOfMemoryException) throw; // Otherwise the value of 's' will be used to log an error. // The fact that we cannot parse headers may stand for corrupted metadata that we try to ignore return s; } } } return null; } // // // private void FetchHeaderValues(bool forCache) { WebHeaderCollection cc = forCache? CacheHeaders: Response.Headers; FetchCacheControl(cc.CacheControl, forCache); // Parse Date Header string s = cc.Date; DateTime date = DateTime.MinValue; if (s != null && HttpDateParse.ParseHttpDate(s, out date)) { date = date.ToUniversalTime(); } if (forCache) { CacheDate = date; } else { ResponseDate = date; } // Parse Expires Header s = cc.Expires; date = DateTime.MinValue; if (s != null && HttpDateParse.ParseHttpDate(s, out date)) { date = date.ToUniversalTime(); } if (forCache) { CacheExpires = date; } else { ResponseExpires = date; } // Parse LastModified Header s = cc.LastModified; date = DateTime.MinValue; if (s != null && HttpDateParse.ParseHttpDate(s, out date)) { date = date.ToUniversalTime(); } if (forCache) { CacheLastModified = date; } else { ResponseLastModified = date; } long totalLength = -1; long startRange = -1; long end = -1; HttpWebResponse resp = Response as HttpWebResponse; if ((forCache? CacheStatusCode: resp.StatusCode) != HttpStatusCode.PartialContent) { // Parse Content-Length Header s = cc.ContentLength; if (s != null && s.Length != 0) { int i = 0; char ch = s[0]; while (i < s.Length && ch == ' ') { ch = s[++i]; } if (i != s.Length && ch >= '0' && ch <= '9') { totalLength = ch-'0'; while(++i < s.Length && (ch = s[i]) >= '0' && ch <= '9') { totalLength = totalLength*10+(ch-'0'); } } } } else { //Parse Content-Range s = cc[HttpKnownHeaderNames.ContentRange]; if(s == null || !Rfc2616.Common.GetBytesRange(s, ref startRange, ref end, ref totalLength, false)) { if(Logging.On)Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_content_range_error, (s==null ? "" : s))); startRange=end=totalLength = -1; } else if (forCache && totalLength == CacheEntry.StreamSize) { // This is a whole response, step back to 200 startRange = -1; end = -1; CacheStatusCode = HttpStatusCode.OK; CacheStatusDescription = Rfc2616.Common.OkDescription; } } if (forCache) { CacheEntityLength = totalLength; ResponseRangeStart = startRange; ResponseRangeEnd = end; } else { ResponseEntityLength = totalLength; ResponseRangeStart = startRange; ResponseRangeEnd = end; } //Parse Age Header TimeSpan span = TimeSpan.MinValue; s = cc[HttpKnownHeaderNames.Age]; if (s != null) { int i = 0; int sec = 0; while(i < s.Length && s[i++] == ' ') { ; } while(i < s.Length && s[i] >= '0' && s[i] <= '9') { sec = sec*10 + (s[i++] - '0'); } span = TimeSpan.FromSeconds(sec); } if (forCache) { CacheAge = span; } else { ResponseAge = span; } } const long LO = 0x0020002000200020L; const int LOI = 0x00200020; const long _prox = 'p'|('r'<<16)|((long)'o'<<32)|((long)'x'<<48); const long _y_re = 'y'|('-'<<16)|((long)'r'<<32)|((long)'e'<<48); const long _vali = 'v'|('a'<<16)|((long)'l'<<32)|((long)'i'<<48); const long _date = 'd'|('a'<<16)|((long)'t'<<32)|((long)'e'<<48); const long _publ = 'p'|('u'<<16)|((long)'b'<<32)|((long)'l'<<48); const int _ic = 'i'|('c'<<16); const long _priv = 'p'|('r'<<16)|((long)'i'<<32)|((long)'v'<<48); const int _at = 'a'|('t'<<16); const long _no_c = 'n'|('o'<<16)|((long)'-'<<32)|((long)'c'<<48); const long _ache = 'a'|('c'<<16)|((long)'h'<<32)|((long)'e'<<48); const long _no_s = 'n'|('o'<<16)|((long)'-'<<32)|((long)'s'<<48); const long _tore = 't'|('o'<<16)|((long)'r'<<32)|((long)'e'<<48); const long _must = 'm'|('u'<<16)|((long)'s'<<32)|((long)'t'<<48); const long __rev = '-'|('r'<<16)|((long)'e'<<32)|((long)'v'<<48); const long _alid = 'a'|('l'<<16)|((long)'i'<<32)|((long)'d'<<48); const long _max_ = 'm'|('a'<<16)|((long)'x'<<32)|((long)'-'<<48); const int _ag = 'a'|('g'<<16); const long _s_ma = 's'|('-'<<16)|((long)'m'<<32)|((long)'a'<<48); const long _xage = 'x'|('a'<<16)|((long)'g'<<32)|((long)'e'<<48); // // // private unsafe void FetchCacheControl(string s, bool forCache) { //Initialize it ResponseCacheControl control = new ResponseCacheControl(); if (forCache) { CacheCacheControl = control; } else { ResponseCacheControl = control; } if (s != null && s.Length != 0) { fixed (char *sp = s) { int len = s.Length; for (int i = 0; i < len-4; ++i) { if (sp[i] < ' ' || sp[i] >= 0x7F) { if(Logging.On)Logging.PrintError(Logging.RequestCache, SR.GetString(SR.net_log_cache_cache_control_error, s)); //invalid format return; } if (sp[i] == ' ' || sp[i] == ',') { continue; } // These if-else are two logically identical blocks that differ only in the way of how text search is done. // The text search is done differently for 32 and X-bits platforms. // ATTN: You are responsible for keeping the rest of the logic in sync. if (IntPtr.Size == 4) { // We are on 32-bits platform long *mask = (long*)&(sp[i]); //making interested chars lowercase, others are ignored anyway switch(*mask|LO) { case _prox: if (i+16 > len) continue; if ((*(mask+1)|LO) != _y_re || (*(mask+2)|LO) != _vali || (*(mask+3)|LO) != _date) continue; control.ProxyRevalidate = true; i+=15; break; case _publ: if (i+6 > len) return; if ((*((int*)(mask+1))|LOI) != _ic) continue; control.Public = true; i+=5; break; case _priv: if (i+7 > len) return; if ((*((int*)(mask+1))|LOI) != _at || (sp[i+6]|0x20) != 'e') continue; control.Private = true; i+=6; // Check for a case: private = "name1,name2" while (i < len && sp[i] == ' ') {++i;} if (i >= len || sp[i] != '=') {--i;break;} while (i < len && sp[++i] == ' ') {;} if (i >= len || sp[i] != '\"') {--i;break;} System.Collections.ArrayList privateList = new System.Collections.ArrayList(); ++i; while(i < len && sp[i] != '\"') { while (i < len && sp[i] == ' ') {++i;} int start = i; while (i < len && sp[i] != ' ' && sp[i] != ',' && sp[i] != '\"') {++i;} if (start != i) { privateList.Add(s.Substring(start, i-start)); } while (i < len && sp[i] != ',' && sp[i] != '\"') {++i;} } if (privateList.Count != 0) { control.PrivateHeaders = (string[])privateList.ToArray(typeof(string)); } break; case _no_c: if (i+8 > len) return; if ((*(mask+1)|LOI) != _ache) continue; control.NoCache = true; i+=7; // Check for a case: no-cache = "name1,name2" while (i < len && sp[i] == ' ') {++i;} if (i >= len || sp[i] != '=') {--i;break;} while (i < len && sp[++i] == ' ') {;} if (i >= len || sp[i] != '\"') {--i;break;} System.Collections.ArrayList nocacheList = new System.Collections.ArrayList(); ++i; while(i < len && sp[i] != '\"') { while (i < len && sp[i] == ' ') {++i;} int start = i; while (i < len && sp[i] != ' ' && sp[i] != ',' && sp[i] != '\"') {++i;} if (start != i) { nocacheList.Add(s.Substring(start, i-start)); } while (i < len && sp[i] != ',' && sp[i] != '\"') {++i;} } if (nocacheList.Count != 0) { control.NoCacheHeaders = (string[])nocacheList.ToArray(typeof(string)); } break; case _no_s: if (i+8 > len) return; if ((*(mask+1)|LOI) != _tore) continue; control.NoStore = true; i+=7; break; case _must: if (i+15 > len) continue; if ((*(mask+1)|LO) != __rev || (*(mask+2)|LO) != _alid || (*(int*)(mask+3)|LOI) != _at || (sp[i+14]|0x20) != 'e') continue; control.MustRevalidate = true; i+=14; break; case _max_: if (i+7 > len) return; if ((*((int*)(mask+1))|LOI) != _ag || (sp[i+6]|0x20) != 'e') continue; i+=7; while (i < len && sp[i] == ' ') { ++i; } if (i == len || sp[i++] != '=') return; while (i < len && sp[i] == ' ') { ++i; } if (i == len) return; control.MaxAge = 0; while (i < len && sp[i] >= '0' && sp[i] <= '9') { control.MaxAge =control.MaxAge*10 + (sp[i++]-'0'); } --i; break; case _s_ma: if (i+8 > len) return; if ((*(mask+1)|LOI) != _xage) continue; i+=8; while (i < len && sp[i] == ' ') { ++i; } if (i == len || sp[i++] != '=') return; while (i < len && sp[i] == ' ') { ++i; } if (i == len) return; control.SMaxAge = 0; while (i < len && sp[i] >= '0' && sp[i] <= '9') { control.SMaxAge = control.SMaxAge*10 + (sp[i++]-'0'); } --i; break; } } else { // We cannot use optimized code path due to IA-64 memory alligment problems see VSWhidbey 118967 if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "proxy-revalidate")) { control.ProxyRevalidate = true; i+=15; } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "public")) { control.Public = true; i+=5; } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "private")) { control.Private = true; i+=6; // Check for a case: private = "name1,name2" while (i < len && sp[i] == ' ') {++i;} if (i >= len || sp[i] != '=') {--i;break;} while (i < len && sp[++i] == ' ') {;} if (i >= len || sp[i] != '\"') {--i;break;} System.Collections.ArrayList privateList = new System.Collections.ArrayList(); ++i; while(i < len && sp[i] != '\"') { while (i < len && sp[i] == ' ') {++i;} int start = i; while (i < len && sp[i] != ' ' && sp[i] != ',' && sp[i] != '\"') {++i;} if (start != i) { privateList.Add(s.Substring(start, i-start)); } while (i < len && sp[i] != ',' && sp[i] != '\"') {++i;} } if (privateList.Count != 0) { control.PrivateHeaders = (string[])privateList.ToArray(typeof(string)); } } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "no-cache")) { control.NoCache = true; i+=7; // Check for a case: no-cache = "name1,name2" while (i < len && sp[i] == ' ') {++i;} if (i >= len || sp[i] != '=') {--i;break;} while (i < len && sp[++i] == ' ') {;} if (i >= len || sp[i] != '\"') {--i;break;} System.Collections.ArrayList nocacheList = new System.Collections.ArrayList(); ++i; while(i < len && sp[i] != '\"') { while (i < len && sp[i] == ' ') {++i;} int start = i; while (i < len && sp[i] != ' ' && sp[i] != ',' && sp[i] != '\"') {++i;} if (start != i) { nocacheList.Add(s.Substring(start, i-start)); } while (i < len && sp[i] != ',' && sp[i] != '\"') {++i;} } if (nocacheList.Count != 0) { control.NoCacheHeaders = (string[])nocacheList.ToArray(typeof(string)); } } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "no-store")) { control.NoStore = true; i+=7; } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "must-revalidate")) { control.MustRevalidate = true; i+=14; } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "max-age")) { i+=7; while (i < len && sp[i] == ' ') { ++i; } if (i == len || sp[i++] != '=') return; while (i < len && sp[i] == ' ') { ++i; } if (i == len) return; control.MaxAge = 0; while (i < len && sp[i] >= '0' && sp[i] <= '9') { control.MaxAge =control.MaxAge*10 + (sp[i++]-'0'); } --i; } else if (Rfc2616.Common.UnsafeAsciiLettersNoCaseEqual(sp, i, len, "smax-age")) { i+=8; while (i < len && sp[i] == ' ') { ++i; } if (i == len || sp[i++] != '=') return; while (i < len && sp[i] == ' ') { ++i; } if (i == len) return; control.SMaxAge = 0; while (i < len && sp[i] >= '0' && sp[i] <= '9') { control.SMaxAge = control.SMaxAge*10 + (sp[i++]-'0'); } --i; } } } } } } /* - any stored Warning headers with warn-code 1xx (see section 14.46) MUST be deleted from the cache entry and the forwarded response. - any stored Warning headers with warn-code 2xx MUST be retained in the cache entry and the forwarded response. */ private void RemoveWarnings_1xx() { string[] warnings = CacheHeaders.GetValues(HttpKnownHeaderNames.Warning); if (warnings == null) { return; } ArrayList remainingWarnings = new ArrayList(); ParseHeaderValues(warnings, ParseWarningsCallback, remainingWarnings); CacheHeaders.Remove(HttpKnownHeaderNames.Warning); for (int i=0; i < remainingWarnings.Count; ++i) { CacheHeaders.Add(HttpKnownHeaderNames.Warning, (string)remainingWarnings[i]); } } private static readonly ParseCallback ParseWarningsCallback = new ParseCallback(ParseWarningsCallbackMethod); private static void ParseWarningsCallbackMethod(string s, int start, int end, IList list) { if (end >= start && s[start] != '1') { ParseValuesCallbackMethod(s, start, end, list); } } // // This is used by other classes to get the list if values from a header string // internal delegate void ParseCallback(string s, int start, int end, IList list); internal static readonly ParseCallback ParseValuesCallback = new ParseCallback(ParseValuesCallbackMethod); private static void ParseValuesCallbackMethod(string s, int start, int end, IList list) { // Deal with the cases: '' ' ' 'value' 'value ' while (end >= start && s[end] == ' ') { --end; } if (end >= start) { list.Add(s.Substring(start, end-start+1)); } } // // Parses header values calls a callback one value after other. // Note a single string can contain multiple values and any value may have a quoted string in. // The parser will not cut trailing spaces when invoking a callback // internal static void ParseHeaderValues(string[] values, ParseCallback calback, IList list) { if (values == null) { return; } for (int i = 0; i < values.Length; ++i) { string val = values[i]; int end = 0; int start = 0; while (end < val.Length) { //skip spaces while (start < val.Length && val[start] == ' ') { ++start; } if (start == val.Length ) { //empty header value break; } // find comma or quote end = start; find_comma: while (end < val.Length && val[end] != ',' && val[end] != '\"') { ++end; } if (end == val.Length ) { calback(val, start, end-1, list); break; } if (val[end] == '\"') { while (++end < val.Length && val[end] != '"') { ; } if (end == val.Length ) { //warning: no closing quote, accepting calback(val, start, end-1, list); break; } goto find_comma; } else { //Comma calback(val, start, end-1, list); // skip leading spaces while (++end < val.Length && val[end] == ' ') { ; } if (end >= val.Length) { break; } start = end; } } } } } // // // //ATTN: The values order is importent internal enum HttpMethod { Other = -1, Head = 0, Get, Post, Put, Delete, Options, Trace, Connect } // // // internal class ResponseCacheControl { internal bool Public; internal bool Private; internal string[] PrivateHeaders; internal bool NoCache; internal string[] NoCacheHeaders; internal bool NoStore; internal bool MustRevalidate; internal bool ProxyRevalidate; internal int MaxAge; internal int SMaxAge; internal ResponseCacheControl() { MaxAge = SMaxAge = -1; } internal bool IsNotEmpty { get { return (Public || Private || NoCache || NoStore || MustRevalidate || ProxyRevalidate || MaxAge != -1 || SMaxAge != -1); } } public override string ToString() { System.Text.StringBuilder sb = new System.Text.StringBuilder(); if (Public) { sb.Append(" public"); } if (Private) { sb.Append(" private"); if (PrivateHeaders != null) { sb.Append('='); for (int i = 0; i < PrivateHeaders.Length-1; ++i) { sb.Append(PrivateHeaders[i]).Append(','); } sb.Append(PrivateHeaders[PrivateHeaders.Length-1]); } } if (NoCache) { sb.Append(" no-cache"); if (NoCacheHeaders != null) { sb.Append('='); for (int i = 0; i < NoCacheHeaders.Length-1; ++i) { sb.Append(NoCacheHeaders[i]).Append(','); } sb.Append(NoCacheHeaders[NoCacheHeaders.Length-1]); } } if (NoStore) { sb.Append(" no-store"); } if (MustRevalidate) { sb.Append(" must-revalidate"); } if (ProxyRevalidate) { sb.Append(" proxy-revalidate"); } if (MaxAge != -1) { sb.Append(" max-age=").Append(MaxAge); } if (SMaxAge != -1) { sb.Append(" s-maxage=").Append(SMaxAge); } return sb.ToString(); } } }