Annotation of libwww/Library/src/HTFilter.c, revision 2.25

2.1       frystyk     1: /*
                      2: **     BEFORE AND AFTER FILTERS
                      3: **
                      4: **     (c) COPYRIGHT MIT 1995.
                      5: **     Please first read the full copyright statement in the file COPYRIGH.
2.25    ! frystyk     6: **     @(#) $Id: HTFilter.c,v 2.24 1997/12/24 17:09:01 frystyk Exp $
2.1       frystyk     7: **
                      8: **     This module implrments a set of default filters that can be registerd
                      9: **     as BEFORE and AFTER filters to the Net manager
                     10: ** Authors
                     11: **     HFN     Henrik Frystyk, frystyk@w.org
                     12: ** History
                     13: **     Jul 4, 96       Written
                     14: */
                     15: 
                     16: /* Library include files */
                     17: #include "WWWLib.h"
                     18: #include "WWWCache.h"
                     19: #include "WWWHTTP.h"
                     20: #include "HTLog.h"
                     21: #include "HTAccess.h"
2.10      frystyk    22: #include "HTProxy.h"
                     23: #include "HTRules.h"
2.1       frystyk    24: #include "HTFilter.h"                                   /* Implemented here */
                     25: 
                     26: /* ------------------------------------------------------------------------- */
                     27: 
                     28: /*
                     29: **     Proxy and Gateway BEFORE filter
                     30: **     -------------------------------
                     31: **     Checks for registerd proxy servers or gateways and sees whether this
                     32: **     request should be redirected to a proxy or a gateway. Proxies have
                     33: **     higher priority than gateways so we look for them first!
                     34: **     For HTTP/1.0 and HTTP/1.1 we may only send a full URL (including the
                     35: **     host portion) to proxy servers. Therefore, we tell the Library whether
                     36: **     to use the full URL or the traditional HTTP one without the host part.
                     37: */
2.15      frystyk    38: PUBLIC int HTProxyFilter (HTRequest * request, void * param, int mode)
2.1       frystyk    39: {
                     40:     HTParentAnchor * anchor = HTRequest_anchor(request);
2.2       frystyk    41:     char * addr = HTAnchor_physical(anchor);
2.1       frystyk    42:     char * physical = NULL;
                     43:     if ((physical = HTProxy_find(addr))) {
2.6       frystyk    44:        HTRequest_setFullURI(request, YES);                       /* For now */
2.5       frystyk    45:        HTRequest_setProxy(request, physical);
2.8       frystyk    46:        HT_FREE(physical);
2.6       frystyk    47: #if 0
                     48:        /* Don't paste the URLs together anymore */
2.1       frystyk    49:        StrAllocCat(physical, addr);
2.5       frystyk    50:        HTAnchor_setPhysical(anchor, physical); 
2.6       frystyk    51: #endif
2.1       frystyk    52:     } else if ((physical = HTGateway_find(addr))) {
                     53:        /* 
                     54:        ** A gateway URL is crated by chopping off any leading "/" to make the
                     55:        ** host into part of path
                     56:        */
                     57:        char * path =
                     58:            HTParse(addr, "", PARSE_HOST + PARSE_PATH + PARSE_PUNCTUATION);
                     59:        char * gatewayed = HTParse(path+1, physical, PARSE_ALL);
                     60:        HTAnchor_setPhysical(anchor, gatewayed);
                     61:        HT_FREE(path);
                     62:        HT_FREE(gatewayed);
                     63:        HTRequest_setFullURI(request, NO);
2.6       frystyk    64:        HTRequest_deleteProxy(request);
2.1       frystyk    65:     } else {
2.6       frystyk    66:        HTRequest_setFullURI(request, NO);                        /* For now */
                     67:        HTRequest_deleteProxy(request);
2.1       frystyk    68:     }
                     69:     return HT_OK;
                     70: }
                     71: 
                     72: /*
                     73: **     Rule Translation BEFORE Filter
                     74: **     ------------------------------
                     75: **     If we have a set of rules loaded (see the Rule manager) then check
                     76: **     before each request whether how that should be translated. The trick
                     77: **     is that a parent anchor has a "address" which is the part from the URL
                     78: **     we used when we created the anchor. However, it also have a "physical
                     79: **     address" which is the place we are actually going to look for the
2.2       frystyk    80: **     resource. Hence this filter translates the physical address
                     81: **     (if any translations are found)
2.1       frystyk    82: */
2.15      frystyk    83: PUBLIC int HTRuleFilter (HTRequest * request, void * param, int mode)
2.1       frystyk    84: {
                     85:     HTList * list = HTRule_global();
                     86:     HTParentAnchor * anchor = HTRequest_anchor(request);
2.2       frystyk    87:     char * addr = HTAnchor_physical(anchor);
2.1       frystyk    88:     char * physical = HTRule_translate(list, addr, NO);
                     89:     if (!physical) {
                     90:        HTRequest_addError(request, ERR_FATAL, NO, HTERR_FORBIDDEN,
                     91:                           NULL, 0, "HTRuleFilter");
                     92:        return HT_ERROR;
                     93:     }
                     94:     HTAnchor_setPhysical(anchor, physical);
                     95:     HT_FREE(physical);
                     96:     return HT_OK;
                     97: }
                     98: 
                     99: /*
                    100: **     Cache Validation BEFORE Filter
                    101: **     ------------------------------
                    102: **     Check the cache mode to see if we can use an already loaded version
                    103: **     of this document. If so and our copy is valid then we don't have
                    104: **     to go out and get it unless we are forced to
2.3       frystyk   105: **     We only check the cache in caseof a GET request. Otherwise, we go
                    106: **     directly to the source.
2.1       frystyk   107: */
2.15      frystyk   108: PUBLIC int HTCacheFilter (HTRequest * request, void * param, int mode)
2.1       frystyk   109: {
                    110:     HTParentAnchor * anchor = HTRequest_anchor(request);
2.12      frystyk   111:     HTCache * cache = NULL;
2.15      frystyk   112:     HTReload reload = HTRequest_reloadMode(request);
2.3       frystyk   113:     HTMethod method = HTRequest_method(request);
2.12      frystyk   114:     HTDisconnectedMode disconnect = HTCacheMode_disconnected();
                    115:     BOOL validate = NO;
2.3       frystyk   116: 
                    117:     /*
2.12      frystyk   118:     **  If the cache is disabled all together then it won't help looking, huh?
2.3       frystyk   119:     */
2.12      frystyk   120:     if (!HTCacheMode_enabled()) return HT_OK;
                    121:     if (CACHE_TRACE) HTTrace("Cachefilter. Checking persistent cache\n");
2.3       frystyk   122: 
2.1       frystyk   123:     /*
2.12      frystyk   124:     **  Now check the cache...
2.1       frystyk   125:     */
2.12      frystyk   126:     if (method != METHOD_GET) {
                    127:        if (CACHE_TRACE) HTTrace("Cachefilter. We only check GET methods\n");
2.15      frystyk   128:     } else if (reload == HT_CACHE_FLUSH) {
2.12      frystyk   129:        /*
                    130:        ** If the mode if "Force Reload" then don't even bother to check the
                    131:        ** cache - we flush everything we know abut this document anyway.
2.1       frystyk   132:        ** Add the appropriate request headers. We use both the "pragma"
                    133:        ** and the "cache-control" headers in order to be
2.12      frystyk   134:        ** backwards compatible with HTTP/1.0
2.1       frystyk   135:        */
2.12      frystyk   136:        validate = YES;
2.1       frystyk   137:        HTRequest_addGnHd(request, HT_G_PRAGMA_NO_CACHE);
2.11      frystyk   138:        HTRequest_addCacheControl(request, "no-cache", "");
2.1       frystyk   139: 
                    140:        /*
2.15      frystyk   141:        **  We also flush the information in the anchor as we don't want to
                    142:        **  inherit any "old" values
2.1       frystyk   143:        */
                    144:        HTAnchor_clearHeader(anchor);
                    145: 
2.12      frystyk   146:     } else {
                    147:        /*
                    148:        ** Check the persistent cache manager. If we have a cache hit then
                    149:        ** continue to see if the reload mode requires us to do a validation
                    150:        ** check. This filter assumes that we can get the cached version
                    151:        ** through one of our protocol modules (for example the file module)
                    152:        */
                    153:        cache = HTCache_find(anchor);
2.1       frystyk   154:        if (cache) {
2.20      frystyk   155:            HTReload cache_mode = HTCache_isFresh(cache, request);
                    156:            if (cache_mode == HT_CACHE_ERROR) cache = NULL;
                    157:            reload = HTMAX(reload, cache_mode);
2.15      frystyk   158:            HTRequest_setReloadMode(request, reload);
2.12      frystyk   159: 
                    160:            /*
                    161:            **  Now check the mode and add the right headers for the validation
                    162:            **  If we are to validate a cache entry then we get a lock
                    163:            **  on it so that not other requests can steal it.
                    164:            */
2.15      frystyk   165:            if (reload == HT_CACHE_RANGE_VALIDATE) {
                    166:                /*
                    167:                **  If we were asked to range validate the cached object then
                    168:                **  use the etag or the last modified for cache validation
                    169:                */
                    170:                validate = YES;
                    171:                HTCache_getLock(cache, request);
                    172:                HTRequest_addRqHd(request, HT_C_IF_RANGE);
                    173:            } else if (reload == HT_CACHE_END_VALIDATE) {
2.12      frystyk   174:                /*
                    175:                **  If we were asked to end-to-end validate the cached object
                    176:                **  then use a max-age=0 cache control directive
                    177:                */
                    178:                validate = YES;
                    179:                HTCache_getLock(cache, request);
                    180:                HTRequest_addCacheControl(request, "max-age", "0");
2.15      frystyk   181:            } else if (reload == HT_CACHE_VALIDATE) {
2.11      frystyk   182:                /*
2.12      frystyk   183:                **  If we were asked to validate the cached object then
2.11      frystyk   184:                **  use the etag or the last modified for cache validation
2.15      frystyk   185:                **  We use both If-None-Match or If-Modified-Since.
2.11      frystyk   186:                */
2.12      frystyk   187:                validate = YES;
                    188:                HTCache_getLock(cache, request);
2.11      frystyk   189:                HTRequest_addRqHd(request, HT_C_IF_NONE_MATCH | HT_C_IMS);
2.20      frystyk   190:            } else if (cache) {
2.12      frystyk   191:                /*
                    192:                **  The entity does not require any validation at all. We
2.15      frystyk   193:                **  can just go ahead and get it from the cache. In case we
                    194:                **  have a fresh subpart of the entity, then we issue a 
                    195:                **  conditional GET request with the range set by the cache
                    196:                **  manager. Issuing the conditional range request is 
                    197:                **  equivalent to a validation as we have to go out on the
                    198:                **  net. This may have an effect if running in disconnected
                    199:                **  mode. We disable all BEFORE filters as they don't make
                    200:                **  sense while loading the cache entry.
2.12      frystyk   201:                */
2.15      frystyk   202:                {
                    203:                    char * name = HTCache_name(cache);
                    204:                    HTAnchor_setPhysical(anchor, name);
                    205:                    HTCache_addHit(cache);
                    206:                    HT_FREE(name);
                    207:                }
2.11      frystyk   208:            }
                    209:        }
2.12      frystyk   210:     }
                    211:     
                    212:     /*
                    213:     **  If we are in disconnected mode and we are to validate an entry
                    214:     **  then check whether what mode of disconnected mode we're in. If
                    215:     **  we are to use our own cache then return a "504 Gateway Timeout"
                    216:     */
                    217:     if ((!cache || validate) && disconnect != HT_DISCONNECT_NONE) {
                    218:        if (disconnect == HT_DISCONNECT_EXTERNAL)
                    219:            HTRequest_addCacheControl(request, "only-if-cached", "");
                    220:        else {
                    221:            HTRequest_addError(request, ERR_FATAL, NO,
                    222:                               HTERR_GATE_TIMEOUT, "Disconnected Cache Mode",
                    223:                               0, "HTCacheFilter");
                    224:            return HT_ERROR;
                    225:        }
2.11      frystyk   226:     }
                    227:     return HT_OK;
                    228: }
                    229: 
                    230: /*
2.16      frystyk   231: **     A small BEFORE filter that just finds a cache entry unconditionally
                    232: **     and loads the entry. All freshness and any other constraints are 
                    233: **     ignored.
                    234: */
                    235: PUBLIC int HTCacheLoadFilter (HTRequest * request, void * param, int mode)
                    236: {
                    237:     HTParentAnchor * anchor = HTRequest_anchor(request);
                    238:     HTCache * cache = HTCache_find(anchor);
                    239:     if (cache) {
                    240:        char * name = HTCache_name(cache);
                    241:        HTAnchor_setPhysical(anchor, name);
                    242:        HTCache_addHit(cache);
                    243:        HT_FREE(name);
                    244: 
                    245:        /*
                    246:        **  Start request directly from the cache. As with the redirection
                    247:        **  filter we reuse the same request object which means that we must
                    248:        **  keep this around until the cache load request has terminated
                    249:        */
                    250:        {
                    251:            HTLoad(request, NO);
                    252:            return HT_ERROR;
                    253:        }
                    254:     }
                    255:     return HT_OK;
                    256: }
                    257: 
                    258: /*
2.15      frystyk   259: **     Check the Memory Cache (History list) BEFORE filter
                    260: **     ---------------------------------------------------
2.11      frystyk   261: **     Check if document is already loaded. The user can define whether
                    262: **     the history list should follow normal expiration or work as a
                    263: **     traditional history list where expired documents are not updated.
                    264: **     We don't check for anything but existence proof of a document
                    265: **     associated with the anchor as the definition is left to the application
                    266: */
2.15      frystyk   267: PUBLIC int HTMemoryCacheFilter (HTRequest * request, void * param, int mode)
2.11      frystyk   268: {
                    269:     HTReload validation = HTRequest_reloadMode(request);
                    270:     HTParentAnchor * anchor = HTRequest_anchor(request);
                    271:     void * document = HTAnchor_document(anchor);
2.1       frystyk   272: 
2.11      frystyk   273:     /*
2.14      frystyk   274:     **  We only check the memory cache if it's a GET method
                    275:     */
                    276:     if (HTRequest_method(request) != METHOD_GET) {
                    277:        if (CACHE_TRACE) HTTrace("Mem Cache... We only check GET methods\n");
                    278:        return HT_OK;
                    279:     }
                    280: 
                    281:     /*
2.11      frystyk   282:     **  If we are asked to flush the persistent cache then there is no reason
                    283:     **  to do anything here - we're flushing it anyway. Also if no document
                    284:     **  then just exit from this filter.
                    285:     */
                    286:     if (!document || validation > HT_CACHE_FLUSH_MEM) {
                    287:        if (CACHE_TRACE) HTTrace("Mem Cache... No fresh document...\n");
                    288:        return HT_OK;
                    289:     }
2.1       frystyk   290: 
2.11      frystyk   291:     /*
                    292:     **  If we have a document object associated with this anchor then we also
                    293:     **  have the object in the history list. Depending on what the user asked,
                    294:     **  we can add a cache validator
                    295:     */
2.14      frystyk   296:     if (document && validation != HT_CACHE_FLUSH_MEM) {
                    297:        if (CACHE_TRACE) HTTrace("Mem Cache... Document already in memory\n");
                    298:        return HT_LOADED;
2.1       frystyk   299:     }
                    300:     return HT_OK;
                    301: }
                    302: 
                    303: /*
2.15      frystyk   304: **     Cache Update AFTER filter
                    305: **     -------------------------
                    306: **     On our way out we catch the metainformation and stores it in
                    307: **     our persistent store. If we have a cache validation (a 304
                    308: **     response then we use the new metainformation and merges it with
                    309: **     the existing information already captured in the cache.
                    310: */
                    311: PUBLIC int HTCacheUpdateFilter (HTRequest * request, HTResponse * response,
                    312:                                void * param, int status)
                    313: {
                    314:     HTParentAnchor * anchor = HTRequest_anchor(request);
                    315:     HTCache * cache = HTCache_find(anchor);
2.17      frystyk   316:     if (cache) {
2.15      frystyk   317: 
2.17      frystyk   318:        /*
                    319:        **  It may in fact be that the information in the 304 response
                    320:        **  told us that we can't cache the entity anymore. If this is the
                    321:        **  case then flush it now. Otherwise prepare for a cache read
                    322:        */
                    323:        if (CACHE_TRACE) HTTrace("Cache....... Merging metainformation\n");
                    324:        if (HTResponse_isCachable(response) == NO) {
                    325:            HTCache_remove(cache);
                    326:        } else {
                    327:            char * name = HTCache_name(cache);
                    328:            HTAnchor_setPhysical(anchor, name);
                    329:            HTCache_addHit(cache);
                    330:            HT_FREE(name);
                    331:            HTCache_updateMeta(cache, request, response);
                    332:        }
2.15      frystyk   333: 
2.17      frystyk   334:        /*
                    335:        **  Start request directly from the cache. As with the redirection filter
                    336:        **  we reuse the same request object which means that we must
                    337:        **  keep this around until the cache load request has terminated
                    338:        **  In the case of a 
                    339:        */
2.19      frystyk   340: #define SINGLE_CACHE_LOAD
                    341: #ifdef SINGLE_CACHE_LOAD
2.17      frystyk   342:        {
                    343:            static BOOL done = NO;
                    344:            if (!done) {        
                    345:                HTLoad(request, YES);
                    346:                done = YES;
                    347:                return HT_ERROR;
                    348:            }
                    349:        }
                    350: #else
                    351:        HTLoad(request, YES);
2.15      frystyk   352:        return HT_ERROR;
2.19      frystyk   353: #endif /* SINGLE_CACHE_LOAD */
2.15      frystyk   354:     }
2.17      frystyk   355:     return HT_OK;
2.15      frystyk   356: }
                    357: 
                    358: /*
2.1       frystyk   359: **     Error and Information AFTER filter
                    360: **     ----------------------------------
                    361: **     It checks the status code from a request and generates an 
                    362: **     error/information message if required.
                    363: */
2.15      frystyk   364: PUBLIC int HTInfoFilter (HTRequest * request, HTResponse * response,
                    365:                         void * param, int status)
2.1       frystyk   366: {
                    367:     HTParentAnchor * anchor = HTRequest_anchor(request);
                    368:     char * uri = HTAnchor_address((HTAnchor*) anchor);
                    369:     switch (status) {
                    370:     case HT_RETRY:
                    371:        if (PROT_TRACE)
                    372:            HTTrace("Load End.... NOT AVAILABLE, RETRY AT %ld\n",
2.15      frystyk   373:                    HTResponse_retryTime(response));
2.1       frystyk   374:        break;
                    375: 
2.7       frystyk   376:     case HT_NO_DATA:
                    377:     {
                    378:        /*
                    379:        ** The document was empty
                    380:        */
                    381:        HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
                    382:        if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
                    383:                        HTRequest_error(request), NULL);
                    384:        if (PROT_TRACE)
                    385:            HTTrace("Load End.... EMPTY: No content `%s\'\n",
                    386:                    uri ? uri : "<UNKNOWN>");
                    387:        break;
                    388:     }    
2.3       frystyk   389: 
                    390:     case HT_LOADED:
2.16      frystyk   391:        if (PROT_TRACE) HTTrace("Load End.... OK: `%s\'\n", uri);
                    392:        break;
                    393: 
                    394:     default:
2.3       frystyk   395:     {
                    396:        /*
2.16      frystyk   397:        ** See if we have a function registered for outputting errors.
                    398:        ** If so then call it and present the message to the user
2.3       frystyk   399:        */
                    400:        HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
                    401:        if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
                    402:                        HTRequest_error(request), NULL);
2.1       frystyk   403:        if (PROT_TRACE)
                    404:            HTTrace("Load End.... Request ended with code %d\n", status);
                    405:        break;
                    406:     }
2.16      frystyk   407:     }
2.1       frystyk   408:     HT_FREE(uri);
                    409:     return HT_OK;
                    410: }
                    411: 
                    412: /*
                    413: **     Redirection AFTER filter
                    414: **     ------------------------
                    415: **     The redirection handler only handles redirections
                    416: **     on the GET or HEAD method (or any other safe method)
                    417: */
2.15      frystyk   418: PUBLIC int HTRedirectFilter (HTRequest * request, HTResponse * response,
                    419:                             void * param, int status)
2.1       frystyk   420: {
                    421:     HTMethod method = HTRequest_method(request); 
2.15      frystyk   422:     HTAnchor * new_anchor = HTResponse_redirection(response); 
2.7       frystyk   423:     if (!new_anchor) {
                    424:        if (PROT_TRACE) HTTrace("Redirection. No destination\n");
                    425:        return HT_OK;
                    426:     }
                    427: 
2.1       frystyk   428:     /*
2.21      frystyk   429:     ** Only do automatic redirect on GET and HEAD. Ask for all
                    430:     ** other methods
2.1       frystyk   431:     */
2.21      frystyk   432:     if (!HTMethod_isSafe(method)) {
                    433: 
                    434:        /*
                    435:        ** If we got a 303 See Other then change the method to GET.
                    436:        ** Otherwise ask the user whether we should continue.
                    437:        */
                    438:        if (status == HT_SEE_OTHER) {
                    439:            if (PROT_TRACE)
                    440:                HTTrace("Redirection. Changing method from %s to GET\n",
                    441:                        HTMethod_name(method));
                    442:            HTRequest_setMethod(request, METHOD_GET);
                    443:        } else {
                    444:            HTAlertCallback * prompt = HTAlert_find(HT_A_CONFIRM);
                    445:            if (prompt) {
                    446:                if ((*prompt)(request, HT_A_CONFIRM, HT_MSG_REDIRECTION,
                    447:                              NULL, NULL, NULL) != YES)
                    448:                    return HT_ERROR;
                    449:            }
2.4       frystyk   450:        }
2.1       frystyk   451:     } 
                    452:  
                    453:     /*
                    454:     **  Start new request with the redirect anchor found in the headers.
                    455:     ** Note that we reuse the same request object which means that we must
                    456:     **  keep this around until the redirected request has terminated. It also
                    457:     **  allows us in an easy way to keep track of the number of redirections
                    458:     ** so that we can detect endless loops.
                    459:     */ 
2.4       frystyk   460:     if (HTRequest_doRetry(request)) { 
2.1       frystyk   461:        HTLoadAnchor(new_anchor, request);
2.9       frystyk   462:     } else {
                    463:        HTRequest_addError(request, ERR_FATAL, NO, HTERR_MAX_REDIRECT,
                    464:                           NULL, 0, "HTRedirectFilter");
                    465:     }
                    466: 
                    467:     /*
                    468:     **  By returning HT_ERROR we make sure that this is the last handler to be
                    469:     **  called. We do this as we don't want any other filter to delete the 
                    470:     **  request object now when we have just started a new one ourselves
                    471:     */
                    472:     return HT_ERROR;
                    473: } 
                    474: 
                    475: /*
2.15      frystyk   476: **     Retry through Proxy AFTER Filter
                    477: **     --------------------------------
2.9       frystyk   478: **     This filter handles a 305 Use Proxy response and retries the request
                    479: **     through the proxy
                    480: */
2.15      frystyk   481: PUBLIC int HTUseProxyFilter (HTRequest * request, HTResponse * response,
                    482:                             void * param, int status)
2.9       frystyk   483: {
2.20      frystyk   484:     HTAlertCallback * cbf = HTAlert_find(HT_A_CONFIRM);
2.15      frystyk   485:     HTAnchor * proxy_anchor = HTResponse_redirection(response); 
2.9       frystyk   486:     if (!proxy_anchor) {
                    487:        if (PROT_TRACE) HTTrace("Use Proxy... No proxy location\n");
                    488:        return HT_OK;
                    489:     }
                    490: 
                    491:     /*
                    492:     **  Add the proxy to the list. Assume HTTP access method only!
2.20      frystyk   493:     **  Because evil servers may rediret the client to an untrusted
                    494:     **  proxy, we can only accept redirects for this particular
                    495:     **  server. Also, we do not know whether this is for HTTP or all
                    496:     **  other requests as well
2.9       frystyk   497:     */
2.20      frystyk   498:     if ((cbf && (*cbf)(request, HT_A_CONFIRM, HT_MSG_PROXY, NULL,NULL,NULL))) {
2.9       frystyk   499:        char * addr = HTAnchor_address(proxy_anchor);
                    500:        HTProxy_add("http", addr);
                    501:        HT_FREE(addr);
                    502:  
2.20      frystyk   503:        /*
                    504:        **  Start new request through the proxy if we haven't reached the max
                    505:        **  number of redirections for this request
                    506:        */ 
                    507:        if (HTRequest_doRetry(request)) { 
                    508:            HTLoadAnchor(proxy_anchor, request);
                    509:        } else {
                    510:            HTRequest_addError(request, ERR_FATAL, NO, HTERR_MAX_REDIRECT,
                    511:                               NULL, 0, "HTRedirectFilter");
                    512:        }
                    513: 
                    514:        /*
                    515:        **  By returning HT_ERROR we make sure that this is the last handler to be
                    516:        **  called. We do this as we don't want any other filter to delete the 
                    517:        **  request object now when we have just started a new one ourselves
                    518:        */
                    519:        return HT_ERROR;
                    520: 
2.1       frystyk   521:     } else {
2.20      frystyk   522:        HTRequest_addError(request, ERR_FATAL, NO, HTERR_NO_AUTO_PROXY,
                    523:                           NULL, 0, "HTUseProxyFilter");
                    524:        return HT_OK;
2.1       frystyk   525:     }
                    526: } 
                    527: 
                    528: /*
                    529: **     Client side authentication BEFORE filter
                    530: **     ----------------------------------------
                    531: **     The filter generates the credentials required to access a document
                    532: **     Getting the credentials may involve asking the user
                    533: */
2.15      frystyk   534: PUBLIC int HTCredentialsFilter (HTRequest * request, void * param, int mode)
2.1       frystyk   535: {
                    536:     /*
                    537:     ** Ask the authentication module to call the right credentials generator
                    538:     ** that understands this scheme
                    539:     */
2.15      frystyk   540:     if (HTAA_beforeFilter(request, param, mode) == HT_OK) {
2.1       frystyk   541:        if (PROT_TRACE) HTTrace("Credentials. verified\n");
                    542:        return HT_OK;
                    543:     } else {
                    544:        HTRequest_addError(request, ERR_FATAL, NO, HTERR_UNAUTHORIZED,
                    545:                           NULL, 0, "HTCredentialsFilter");
                    546:        return HT_ERROR;
                    547:     }
                    548: }
                    549: 
                    550: /*
                    551: **     Client side authentication AFTER filter
                    552: **     ---------------------------------------
                    553: **     The client side authentication filter uses the 
                    554: **     user dialog messages registered in the HTAlert module.
                    555: **     By default these are the ones used by the line mode browser but you can
                    556: **     just register something else.
                    557: */
2.15      frystyk   558: PUBLIC int HTAuthFilter (HTRequest * request, HTResponse * response,
                    559:                         void * param, int status)
2.1       frystyk   560: {
                    561:     /*
                    562:     ** Ask the authentication module to call the right challenge parser
                    563:     ** that understands this scheme
                    564:     */
2.15      frystyk   565:     if (HTAA_afterFilter(request, response, param, status) == HT_OK) {
2.1       frystyk   566: 
                    567:        /*
                    568:        ** Start request with new credentials. As with the redirection filter
                    569:        ** we reuse the same request object which means that we must
                    570:        ** keep this around until the redirected request has terminated
                    571:        */
                    572:        HTLoad(request, NO);
                    573: 
                    574:        /*
                    575:        **  We return HT_ERROR to make sure that this is the last handler to be
                    576:        **  called. We do this as we don't want any other filter to delete the 
                    577:        **  request object now when we have just started a new one ourselves
                    578:        */
                    579:        return HT_ERROR;
                    580:     }
                    581:     return HT_OK;
                    582: }
                    583: 
                    584: /*
2.24      frystyk   585: **     Request Logging AFTER filter
                    586: **     ----------------------------
2.1       frystyk   587: **     Default Logging filter using the log manager provided by HTLog.c
                    588: */
2.15      frystyk   589: PUBLIC int HTLogFilter (HTRequest * request, HTResponse * response,
                    590:                        void * param, int status)
2.1       frystyk   591: {
                    592:     if (request) {
2.23      frystyk   593:        HTLog * log = (HTLog *) param;
                    594:        if (log) HTLog_addCLF(log, request, status);
2.24      frystyk   595:        return HT_OK;
                    596:     }
                    597:     return HT_ERROR;
                    598: }
                    599: 
                    600: /*
                    601: **     Request Referer AFTER filter
                    602: **     ----------------------------
                    603: **     Default Referer Log filter using the log manager provided by HTLog.c
                    604: */
                    605: PUBLIC int HTRefererFilter (HTRequest * request, HTResponse * response,
                    606:                            void * param, int status)
                    607: {
                    608:     if (request) {
                    609:        HTLog * log = (HTLog *) param;
                    610:        if (log) HTLog_addReferer(log, request, status);
2.1       frystyk   611:        return HT_OK;
                    612:     }
                    613:     return HT_ERROR;
                    614: }

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