Annotation of libwww/Library/src/HTFilter.c, revision 2.37
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.
2.37 ! frystyk 6: ** @(#) $Id: HTFilter.c,v 2.36 1999/03/08 16:53:40 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);
2.26 frystyk 59: char * gatewayed = HTParse((*path=='/') ? path+1 : path, physical, PARSE_ALL);
2.1 frystyk 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: /*
2.16 frystyk 100: ** A small BEFORE filter that just finds a cache entry unconditionally
101: ** and loads the entry. All freshness and any other constraints are
102: ** ignored.
103: */
104: PUBLIC int HTCacheLoadFilter (HTRequest * request, void * param, int mode)
105: {
106: HTParentAnchor * anchor = HTRequest_anchor(request);
107: HTCache * cache = HTCache_find(anchor);
108: if (cache) {
109: char * name = HTCache_name(cache);
110: HTAnchor_setPhysical(anchor, name);
111: HTCache_addHit(cache);
112: HT_FREE(name);
113:
114: /*
115: ** Start request directly from the cache. As with the redirection
116: ** filter we reuse the same request object which means that we must
117: ** keep this around until the cache load request has terminated
118: */
119: {
120: HTLoad(request, NO);
121: return HT_ERROR;
122: }
123: }
124: return HT_OK;
125: }
126:
127: /*
2.15 frystyk 128: ** Check the Memory Cache (History list) BEFORE filter
129: ** ---------------------------------------------------
2.11 frystyk 130: ** Check if document is already loaded. The user can define whether
131: ** the history list should follow normal expiration or work as a
132: ** traditional history list where expired documents are not updated.
133: ** We don't check for anything but existence proof of a document
134: ** associated with the anchor as the definition is left to the application
135: */
2.15 frystyk 136: PUBLIC int HTMemoryCacheFilter (HTRequest * request, void * param, int mode)
2.11 frystyk 137: {
138: HTReload validation = HTRequest_reloadMode(request);
139: HTParentAnchor * anchor = HTRequest_anchor(request);
140: void * document = HTAnchor_document(anchor);
2.1 frystyk 141:
2.11 frystyk 142: /*
2.14 frystyk 143: ** We only check the memory cache if it's a GET method
144: */
145: if (HTRequest_method(request) != METHOD_GET) {
2.35 frystyk 146: HTTRACE(CACHE_TRACE, "Mem Cache... We only check GET methods\n");
2.14 frystyk 147: return HT_OK;
148: }
149:
150: /*
2.11 frystyk 151: ** If we are asked to flush the persistent cache then there is no reason
152: ** to do anything here - we're flushing it anyway. Also if no document
153: ** then just exit from this filter.
154: */
155: if (!document || validation > HT_CACHE_FLUSH_MEM) {
2.35 frystyk 156: HTTRACE(CACHE_TRACE, "Mem Cache... No fresh document...\n");
2.11 frystyk 157: return HT_OK;
158: }
2.1 frystyk 159:
2.11 frystyk 160: /*
161: ** If we have a document object associated with this anchor then we also
162: ** have the object in the history list. Depending on what the user asked,
163: ** we can add a cache validator
164: */
2.14 frystyk 165: if (document && validation != HT_CACHE_FLUSH_MEM) {
2.35 frystyk 166: HTTRACE(CACHE_TRACE, "Mem Cache... Document already in memory\n");
2.14 frystyk 167: return HT_LOADED;
2.15 frystyk 168: }
2.17 frystyk 169: return HT_OK;
2.15 frystyk 170: }
171:
172: /*
2.1 frystyk 173: ** Error and Information AFTER filter
174: ** ----------------------------------
175: ** It checks the status code from a request and generates an
176: ** error/information message if required.
177: */
2.15 frystyk 178: PUBLIC int HTInfoFilter (HTRequest * request, HTResponse * response,
179: void * param, int status)
2.1 frystyk 180: {
181: HTParentAnchor * anchor = HTRequest_anchor(request);
182: char * uri = HTAnchor_address((HTAnchor*) anchor);
183: switch (status) {
2.28 frystyk 184: case HT_RETRY: {
185: HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
186: if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
187: HTRequest_error(request), NULL);
2.35 frystyk 188: HTTRACE(PROT_TRACE, "Load End.... NOT AVAILABLE, RETRY AT %ld\n" _
2.15 frystyk 189: HTResponse_retryTime(response));
2.28 frystyk 190: }
191: break;
2.1 frystyk 192:
2.7 frystyk 193: case HT_NO_DATA:
194: {
195: /*
196: ** The document was empty
197: */
198: HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
199: if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
200: HTRequest_error(request), NULL);
2.35 frystyk 201: HTTRACE(PROT_TRACE, "Load End.... EMPTY: No content `%s\'\n" _
2.7 frystyk 202: uri ? uri : "<UNKNOWN>");
203: break;
204: }
2.3 frystyk 205:
206: case HT_LOADED:
2.35 frystyk 207: HTTRACE(PROT_TRACE, "Load End.... OK: `%s\'\n" _ uri);
2.16 frystyk 208: break;
209:
210: default:
2.3 frystyk 211: {
212: /*
2.16 frystyk 213: ** See if we have a function registered for outputting errors.
214: ** If so then call it and present the message to the user
2.3 frystyk 215: */
216: HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
217: if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
218: HTRequest_error(request), NULL);
2.35 frystyk 219: HTTRACE(PROT_TRACE, "Load End.... Request ended with code %d\n" _ status);
2.1 frystyk 220: break;
221: }
2.16 frystyk 222: }
2.1 frystyk 223: HT_FREE(uri);
224: return HT_OK;
225: }
226:
227: /*
228: ** Redirection AFTER filter
229: ** ------------------------
230: ** The redirection handler only handles redirections
231: ** on the GET or HEAD method (or any other safe method)
232: */
2.15 frystyk 233: PUBLIC int HTRedirectFilter (HTRequest * request, HTResponse * response,
234: void * param, int status)
2.1 frystyk 235: {
236: HTMethod method = HTRequest_method(request);
2.15 frystyk 237: HTAnchor * new_anchor = HTResponse_redirection(response);
2.37 ! frystyk 238:
! 239: /* Check for destination */
2.7 frystyk 240: if (!new_anchor) {
2.35 frystyk 241: HTTRACE(PROT_TRACE, "Redirection. No destination\n");
2.7 frystyk 242: return HT_OK;
243: }
244:
2.1 frystyk 245: /*
2.21 frystyk 246: ** Only do automatic redirect on GET and HEAD. Ask for all
2.27 frystyk 247: ** other methods.
2.1 frystyk 248: */
2.21 frystyk 249: if (!HTMethod_isSafe(method)) {
250:
251: /*
252: ** If we got a 303 See Other then change the method to GET.
253: ** Otherwise ask the user whether we should continue.
254: */
255: if (status == HT_SEE_OTHER) {
2.35 frystyk 256: HTTRACE(PROT_TRACE, "Redirection. Changing method from %s to GET\n" _
2.21 frystyk 257: HTMethod_name(method));
258: HTRequest_setMethod(request, METHOD_GET);
259: } else {
260: HTAlertCallback * prompt = HTAlert_find(HT_A_CONFIRM);
261: if (prompt) {
262: if ((*prompt)(request, HT_A_CONFIRM, HT_MSG_REDIRECTION,
263: NULL, NULL, NULL) != YES)
2.27 frystyk 264: return HT_OK;
2.21 frystyk 265: }
2.4 frystyk 266: }
2.1 frystyk 267: }
2.36 frystyk 268:
269: /* Register the redirection as a link relationship */
270: {
271: HTLinkType ltype = status==HT_PERM_REDIRECT ? HT_LR_PERM_REDIRECT :
272: (status==HT_TEMP_REDIRECT || status==HT_FOUND) ? HT_LR_TEMP_REDIRECT :
273: status==HT_SEE_OTHER ? HT_LR_SEE_OTHER : NULL;
274: if (ltype) {
275: HTLink_add((HTAnchor *) HTRequest_anchor(request), new_anchor,
276: ltype, method);
277: }
278: }
279:
2.34 frystyk 280: /* Delete any auth credendials as they get regenerated */
281: HTRequest_deleteCredentialsAll(request);
282:
2.1 frystyk 283: /*
284: ** Start new request with the redirect anchor found in the headers.
285: ** Note that we reuse the same request object which means that we must
286: ** keep this around until the redirected request has terminated. It also
287: ** allows us in an easy way to keep track of the number of redirections
288: ** so that we can detect endless loops.
289: */
2.4 frystyk 290: if (HTRequest_doRetry(request)) {
2.1 frystyk 291: HTLoadAnchor(new_anchor, request);
2.9 frystyk 292: } else {
293: HTRequest_addError(request, ERR_FATAL, NO, HTERR_MAX_REDIRECT,
294: NULL, 0, "HTRedirectFilter");
2.37 ! frystyk 295: return HT_OK; /* Wanna fall through */
2.9 frystyk 296: }
297:
298: /*
299: ** By returning HT_ERROR we make sure that this is the last handler to be
300: ** called. We do this as we don't want any other filter to delete the
301: ** request object now when we have just started a new one ourselves
302: */
303: return HT_ERROR;
304: }
305:
306: /*
2.15 frystyk 307: ** Retry through Proxy AFTER Filter
308: ** --------------------------------
2.9 frystyk 309: ** This filter handles a 305 Use Proxy response and retries the request
310: ** through the proxy
311: */
2.15 frystyk 312: PUBLIC int HTUseProxyFilter (HTRequest * request, HTResponse * response,
313: void * param, int status)
2.9 frystyk 314: {
2.20 frystyk 315: HTAlertCallback * cbf = HTAlert_find(HT_A_CONFIRM);
2.15 frystyk 316: HTAnchor * proxy_anchor = HTResponse_redirection(response);
2.9 frystyk 317: if (!proxy_anchor) {
2.35 frystyk 318: HTTRACE(PROT_TRACE, "Use Proxy... No proxy location\n");
2.9 frystyk 319: return HT_OK;
320: }
321:
322: /*
323: ** Add the proxy to the list. Assume HTTP access method only!
2.20 frystyk 324: ** Because evil servers may rediret the client to an untrusted
325: ** proxy, we can only accept redirects for this particular
326: ** server. Also, we do not know whether this is for HTTP or all
327: ** other requests as well
2.9 frystyk 328: */
2.20 frystyk 329: if ((cbf && (*cbf)(request, HT_A_CONFIRM, HT_MSG_PROXY, NULL,NULL,NULL))) {
2.9 frystyk 330: char * addr = HTAnchor_address(proxy_anchor);
331: HTProxy_add("http", addr);
332: HT_FREE(addr);
333:
2.20 frystyk 334: /*
335: ** Start new request through the proxy if we haven't reached the max
336: ** number of redirections for this request
337: */
338: if (HTRequest_doRetry(request)) {
339: HTLoadAnchor(proxy_anchor, request);
340: } else {
341: HTRequest_addError(request, ERR_FATAL, NO, HTERR_MAX_REDIRECT,
342: NULL, 0, "HTRedirectFilter");
343: }
344:
345: /*
346: ** By returning HT_ERROR we make sure that this is the last handler to be
347: ** called. We do this as we don't want any other filter to delete the
348: ** request object now when we have just started a new one ourselves
349: */
350: return HT_ERROR;
351:
2.1 frystyk 352: } else {
2.20 frystyk 353: HTRequest_addError(request, ERR_FATAL, NO, HTERR_NO_AUTO_PROXY,
354: NULL, 0, "HTUseProxyFilter");
355: return HT_OK;
2.1 frystyk 356: }
357: }
358:
359: /*
360: ** Client side authentication BEFORE filter
361: ** ----------------------------------------
362: ** The filter generates the credentials required to access a document
363: ** Getting the credentials may involve asking the user
364: */
2.15 frystyk 365: PUBLIC int HTCredentialsFilter (HTRequest * request, void * param, int mode)
2.1 frystyk 366: {
367: /*
368: ** Ask the authentication module to call the right credentials generator
369: ** that understands this scheme
370: */
2.15 frystyk 371: if (HTAA_beforeFilter(request, param, mode) == HT_OK) {
2.35 frystyk 372: HTTRACE(PROT_TRACE, "Credentials. verified\n");
2.1 frystyk 373: return HT_OK;
374: } else {
375: HTRequest_addError(request, ERR_FATAL, NO, HTERR_UNAUTHORIZED,
376: NULL, 0, "HTCredentialsFilter");
377: return HT_ERROR;
378: }
379: }
380:
381: /*
382: ** Client side authentication AFTER filter
383: ** ---------------------------------------
384: ** The client side authentication filter uses the
385: ** user dialog messages registered in the HTAlert module.
386: ** By default these are the ones used by the line mode browser but you can
387: ** just register something else.
388: */
2.15 frystyk 389: PUBLIC int HTAuthFilter (HTRequest * request, HTResponse * response,
390: void * param, int status)
2.1 frystyk 391: {
392: /*
393: ** Ask the authentication module to call the right challenge parser
394: ** that understands this scheme
395: */
2.15 frystyk 396: if (HTAA_afterFilter(request, response, param, status) == HT_OK) {
2.1 frystyk 397:
398: /*
399: ** Start request with new credentials. As with the redirection filter
400: ** we reuse the same request object which means that we must
401: ** keep this around until the redirected request has terminated
402: */
403: HTLoad(request, NO);
404:
405: /*
406: ** We return HT_ERROR to make sure that this is the last handler to be
407: ** called. We do this as we don't want any other filter to delete the
408: ** request object now when we have just started a new one ourselves
409: */
410: return HT_ERROR;
411: }
412: return HT_OK;
2.32 kahan 413: }
414:
415: /*
416: ** Client side authentication info AFTER filter
417: ** ---------------------------------------
418: */
419: PUBLIC int HTAuthInfoFilter (HTRequest * request, HTResponse * response,
420: void * param, int status)
421: {
422: /*
423: ** Ask the authentication module to call the right authentication info
424: ** parser
425: */
426: if (! HTResponse_challenge (response))
427: return HT_OK;
428: else if (HTAA_updateFilter(request, response, param, status) == HT_OK)
429: return HT_OK;
430: else
431: return HT_ERROR;
2.1 frystyk 432: }
433:
434: /*
2.24 frystyk 435: ** Request Logging AFTER filter
436: ** ----------------------------
2.1 frystyk 437: ** Default Logging filter using the log manager provided by HTLog.c
438: */
2.15 frystyk 439: PUBLIC int HTLogFilter (HTRequest * request, HTResponse * response,
440: void * param, int status)
2.1 frystyk 441: {
442: if (request) {
2.23 frystyk 443: HTLog * log = (HTLog *) param;
444: if (log) HTLog_addCLF(log, request, status);
2.24 frystyk 445: return HT_OK;
446: }
447: return HT_ERROR;
448: }
449:
450: /*
451: ** Request Referer AFTER filter
452: ** ----------------------------
453: ** Default Referer Log filter using the log manager provided by HTLog.c
454: */
455: PUBLIC int HTRefererFilter (HTRequest * request, HTResponse * response,
456: void * param, int status)
457: {
458: if (request) {
459: HTLog * log = (HTLog *) param;
460: if (log) HTLog_addReferer(log, request, status);
2.1 frystyk 461: return HT_OK;
462: }
463: return HT_ERROR;
464: }
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