src/adaptation/icap/ModXact.h

   1
   2 /*
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  19  *  it under the terms of the GNU General Public License as published by
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  21  *  (at your option) any later version.
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  26  *  GNU General Public License for more details.
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  33
  34 #ifndef SQUID_ICAPMODXACT_H
  35 #define SQUID_ICAPMODXACT_H
  36
  37 #include "BodyPipe.h"
  38 #include "adaptation/icap/Xaction.h"
  39 #include "adaptation/icap/InOut.h"
  40 #include "adaptation/icap/Launcher.h"
  41
  42 /*
  43  * ICAPModXact implements ICAP REQMOD and RESPMOD transaction using
  44  * ICAPXaction as the base. The ICAPModXact receives a virgin HTTP message
  45  * from an ICAP vecoring point, (a.k.a., initiator), communicates with the
  46  * ICAP server, and sends the adapted HTTP message headers back.
  47  * Virgin/adapted HTTP message body is reveived/sent using BodyPipe
  48  * interface. The initiator (or its associate) is expected to send and/or
  49  * receive the HTTP body.
  50  */
  51
  52
  53 class ChunkedCodingParser;
  54
  55 namespace Adaptation
  56 {
  57 namespace Icap
  58 {
  59
  60 // estimated future presence and size of something (e.g., HTTP body)
  61
  62 class SizedEstimate
  63 {
  64
  65 public:
  66     SizedEstimate(); // not expected by default
  67     void expect(int64_t aSize); // expect with any, even unknown size
  68     bool expected() const;
  69
  70     /* other members can be accessed iff expected() */
  71
  72     bool knownSize() const;
  73     uint64_t size() const; // can be accessed iff knownSize()
  74
  75 private:
  76     enum { dtUnexpected = -2, dtUnknown = -1 };
  77     int64_t theData; // combines expectation and size info to save RAM
  78 };
  79
  80 // Virgin body may be used for two activities: (a) writing preview or prime
  81 // body to the ICAP server and (b) sending the body back in the echo mode.
  82 // Both activities use the same BodyPipe and may be active at the same time.
  83 // This class is used to maintain the state of body writing or sending
  84 // activity and to coordinate consumption of the shared virgin body buffer.
  85 class VirginBodyAct
  86 {
  87
  88 public:
  89     VirginBodyAct();
  90
  91     void plan(); // the activity may happen; do not consume at or above offset
  92     void disable(); // the activity wont continue; no consumption restrictions
  93
  94     bool active() const { return theState == stActive; }
  95     bool disabled() const { return theState == stDisabled; }
  96
  97     // methods below require active()
  98
  99     uint64_t offset() const; // the absolute beginning of not-yet-acted-on data
 100     void progress(size_t size); // note processed body bytes
 101
 102 private:
 103     int64_t theStart; // unprocessed virgin body data offset
 104
 105     typedef enum { stUndecided, stActive, stDisabled } State;
 106     State theState;
 107 };
 108
 109
 110 // maintains preview-related sizes
 111
 112 class Preview
 113 {
 114
 115 public:
 116     Preview();            // disabled
 117     void enable(size_t anAd); // enabled with advertised size
 118     bool enabled() const;
 119
 120     /* other members can be accessed iff enabled() */
 121
 122     size_t ad() const;      // advertised preview size
 123     size_t debt() const;    // remains to write
 124     bool done() const;      // wrote everything
 125     bool ieof() const;      // premature EOF
 126
 127     void wrote(size_t size, bool wroteEof);
 128
 129 private:
 130     size_t theWritten;
 131     size_t theAd;
 132     enum State { stDisabled, stWriting, stIeof, stDone } theState;
 133 };
 134
 135 class ModXact: public Xaction, public BodyProducer, public BodyConsumer
 136 {
 137
 138 public:
 139     ModXact(Adaptation::Initiator *anInitiator, HttpMsg *virginHeader, HttpRequest *virginCause, ServiceRep::Pointer &s);
 140
 141     // BodyProducer methods
 142     virtual void noteMoreBodySpaceAvailable(BodyPipe::Pointer);
 143     virtual void noteBodyConsumerAborted(BodyPipe::Pointer);
 144
 145     // BodyConsumer methods
 146     virtual void noteMoreBodyDataAvailable(BodyPipe::Pointer);
 147     virtual void noteBodyProductionEnded(BodyPipe::Pointer);
 148     virtual void noteBodyProducerAborted(BodyPipe::Pointer);
 149
 150     // comm handlers
 151     virtual void handleCommConnected();
 152     virtual void handleCommWrote(size_t size);
 153     virtual void handleCommRead(size_t size);
 154     void handleCommWroteHeaders();
 155     void handleCommWroteBody();
 156
 157     // service waiting
 158     void noteServiceReady();
 159
 160 public:
 161     InOut virgin;
 162     InOut adapted;
 163
 164 protected:
 165     // bypasses exceptions if needed and possible
 166     virtual void callException(const std::exception &e);
 167
 168 private:
 169     virtual void start();
 170
 171     /// locates the request, either as a cause or as a virgin message itself
 172     const HttpRequest &virginRequest() const; // Must always be available
 173
 174     void estimateVirginBody();
 175     void makeAdaptedBodyPipe(const char *what);
 176
 177     void waitForService();
 178
 179     // will not send anything [else] on the adapted pipe
 180     bool doneSending() const;
 181
 182     void startWriting();
 183     void writeMore();
 184     void writePreviewBody();
 185     void writePrimeBody();
 186     void writeSomeBody(const char *label, size_t size);
 187
 188     void startReading();
 189     void readMore();
 190     virtual bool doneReading() const { return commEof || state.doneParsing(); }
 191     virtual bool doneWriting() const { return state.doneWriting(); }
 192
 193     size_t virginContentSize(const VirginBodyAct &act) const;
 194     const char *virginContentData(const VirginBodyAct &act) const;
 195     bool virginBodyEndReached(const VirginBodyAct &act) const;
 196
 197     void makeRequestHeaders(MemBuf &buf);
 198     void makeUsernameHeader(const HttpRequest *request, MemBuf &buf);
 199     void addLastRequestChunk(MemBuf &buf);
 200     void openChunk(MemBuf &buf, size_t chunkSize, bool ieof);
 201     void closeChunk(MemBuf &buf);
 202     void virginConsume();
 203     void finishNullOrEmptyBodyPreview(MemBuf &buf);
 204
 205     void decideOnPreview();
 206     void decideOnRetries();
 207     bool shouldAllow204();
 208     bool canBackupEverything() const;
 209
 210     void prepBackup(size_t expectedSize);
 211     void backup(const MemBuf &buf);
 212
 213     void parseMore();
 214
 215     void parseHeaders();
 216     void parseIcapHead();
 217     void parseHttpHead();
 218     bool parseHead(HttpMsg *head);
 219
 220     void decideOnParsingBody();
 221     void parseBody();
 222     void maybeAllocateHttpMsg();
 223
 224     void handle100Continue();
 225     bool validate200Ok();
 226     void handle200Ok();
 227     void handle204NoContent();
 228     void handleUnknownScode();
 229
 230     void bypassFailure();
 231
 232     void startSending();
 233     void disableBypass(const char *reason, bool includeGroupBypass);
 234
 235     void prepEchoing();
 236     void echoMore();
 237
 238     virtual bool doneAll() const;
 239     virtual void swanSong();
 240
 241     void stopReceiving();
 242     void stopSending(bool nicely);
 243     void stopWriting(bool nicely);
 244     void stopParsing();
 245     void stopBackup();
 246
 247     virtual void fillPendingStatus(MemBuf &buf) const;
 248     virtual void fillDoneStatus(MemBuf &buf) const;
 249     virtual bool fillVirginHttpHeader(MemBuf&) const;
 250
 251 private:
 252     void packHead(MemBuf &httpBuf, const HttpMsg *head);
 253     void encapsulateHead(MemBuf &icapBuf, const char *section, MemBuf &httpBuf, const HttpMsg *head);
 254     bool gotEncapsulated(const char *section) const;
 255     void checkConsuming();
 256
 257     virtual void finalizeLogInfo();
 258
 259     SizedEstimate virginBody;
 260     VirginBodyAct virginBodyWriting; // virgin body writing state
 261     VirginBodyAct virginBodySending;  // virgin body sending state
 262     uint64_t virginConsumed;        // virgin data consumed so far
 263     Preview preview; // use for creating (writing) the preview
 264
 265     ChunkedCodingParser *bodyParser; // ICAP response body parser
 266
 267     bool canStartBypass; // enables bypass of transaction failures
 268     bool protectGroupBypass; // protects ServiceGroup-wide bypass of failures
 269
 270     uint64_t replyBodySize; ///< dechunked ICAP reply body size
 271
 272     int adaptHistoryId; ///< adaptation history slot reservation
 273
 274     class State
 275     {
 276
 277     public:
 278         State();
 279
 280     public:
 281
 282         bool serviceWaiting; // waiting for ICAP service options
 283         bool allowedPostview204; // mmust handle 204 No Content outside preview
 284
 285         // will not write anything [else] to the ICAP server connection
 286         bool doneWriting() const { return writing == writingReallyDone; }
 287
 288         // will not use virgin.body_pipe
 289         bool doneConsumingVirgin() const {
 290             return writing >= writingAlmostDone
 291                    && (sending == sendingAdapted || sending == sendingDone);
 292         }
 293
 294         // parsed entire ICAP response from the ICAP server
 295         bool doneParsing() const { return parsing == psDone; }
 296
 297         // is parsing ICAP or HTTP headers read from the ICAP server
 298         bool parsingHeaders() const {
 299             return parsing == psIcapHeader ||
 300                    parsing == psHttpHeader;
 301         }
 302
 303         enum Parsing { psIcapHeader, psHttpHeader, psBody, psDone } parsing;
 304
 305         // measures ICAP request writing progress
 306         enum Writing { writingInit, writingConnect, writingHeaders,
 307                        writingPreview, writingPaused, writingPrime,
 308                        writingAlmostDone, // waiting for the last write() call to finish
 309                        writingReallyDone
 310                      } writing;
 311
 312         enum Sending { sendingUndecided, sendingVirgin, sendingAdapted,
 313                        sendingDone
 314                      } sending;
 315     } state;
 316
 317     CBDATA_CLASS2(ModXact);
 318 };
 319
 320 // An Launcher that stores ModXact construction info and
 321 // creates ModXact when needed
 322 class ModXactLauncher: public Launcher
 323 {
 324 public:
 325     ModXactLauncher(Adaptation::Initiator *anInitiator, HttpMsg *virginHeader, HttpRequest *virginCause, Adaptation::ServicePointer s);
 326
 327 protected:
 328     virtual Xaction *createXaction();
 329
 330     virtual void swanSong();
 331
 332     /// starts or stops transaction accounting in ICAP history
 333     void updateHistory(bool start);
 334
 335     InOut virgin;
 336
 337 private:
 338     CBDATA_CLASS2(ModXactLauncher);
 339 };
 340
 341
 342 } // namespace Icap
 343 } // namespace Adaptation
 344
 345 #endif /* SQUID_ICAPMOD_XACT_H */