Annotation of libwww/Library/src/HTFilter.c, revision 2.3
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.
2.3 ! frystyk 6: ** @(#) $Id: HTFilter.c,v 2.2 1996/07/16 02:26:51 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 "WWWRules.h"
20: #include "WWWHTTP.h"
21: #include "HTLog.h"
22: #include "HTAccess.h"
23: #include "HTFilter.h" /* Implemented here */
24:
25: /* ------------------------------------------------------------------------- */
26:
27: /*
28: ** Proxy and Gateway BEFORE filter
29: ** -------------------------------
30: ** Checks for registerd proxy servers or gateways and sees whether this
31: ** request should be redirected to a proxy or a gateway. Proxies have
32: ** higher priority than gateways so we look for them first!
33: ** For HTTP/1.0 and HTTP/1.1 we may only send a full URL (including the
34: ** host portion) to proxy servers. Therefore, we tell the Library whether
35: ** to use the full URL or the traditional HTTP one without the host part.
36: */
37: PUBLIC int HTProxyFilter (HTRequest * request, void * param, int status)
38: {
39: HTParentAnchor * anchor = HTRequest_anchor(request);
2.2 frystyk 40: char * addr = HTAnchor_physical(anchor);
2.1 frystyk 41: char * physical = NULL;
42: if ((physical = HTProxy_find(addr))) {
43: StrAllocCat(physical, addr);
44: HTAnchor_setPhysical(anchor, physical);
45: HTRequest_setFullURI(request, YES);
46: } else if ((physical = HTGateway_find(addr))) {
47: /*
48: ** A gateway URL is crated by chopping off any leading "/" to make the
49: ** host into part of path
50: */
51: char * path =
52: HTParse(addr, "", PARSE_HOST + PARSE_PATH + PARSE_PUNCTUATION);
53: char * gatewayed = HTParse(path+1, physical, PARSE_ALL);
54: HTAnchor_setPhysical(anchor, gatewayed);
55: HT_FREE(path);
56: HT_FREE(gatewayed);
57: HTRequest_setFullURI(request, NO);
58: } else {
59: HTRequest_setFullURI(request, NO);
60: }
61: return HT_OK;
62: }
63:
64: /*
65: ** Rule Translation BEFORE Filter
66: ** ------------------------------
67: ** If we have a set of rules loaded (see the Rule manager) then check
68: ** before each request whether how that should be translated. The trick
69: ** is that a parent anchor has a "address" which is the part from the URL
70: ** we used when we created the anchor. However, it also have a "physical
71: ** address" which is the place we are actually going to look for the
2.2 frystyk 72: ** resource. Hence this filter translates the physical address
73: ** (if any translations are found)
2.1 frystyk 74: */
75: PUBLIC int HTRuleFilter (HTRequest * request, void * param, int status)
76: {
77: HTList * list = HTRule_global();
78: HTParentAnchor * anchor = HTRequest_anchor(request);
2.2 frystyk 79: char * addr = HTAnchor_physical(anchor);
2.1 frystyk 80: char * physical = HTRule_translate(list, addr, NO);
81: if (!physical) {
82: HTRequest_addError(request, ERR_FATAL, NO, HTERR_FORBIDDEN,
83: NULL, 0, "HTRuleFilter");
84: return HT_ERROR;
85: }
86: HTAnchor_setPhysical(anchor, physical);
87: HT_FREE(physical);
88: return HT_OK;
89: }
90:
91: /*
92: ** Cache Validation BEFORE Filter
93: ** ------------------------------
94: ** Check the cache mode to see if we can use an already loaded version
95: ** of this document. If so and our copy is valid then we don't have
96: ** to go out and get it unless we are forced to
2.3 ! frystyk 97: ** We only check the cache in caseof a GET request. Otherwise, we go
! 98: ** directly to the source.
2.1 frystyk 99: */
100: PUBLIC int HTCacheFilter (HTRequest * request, void * param, int status)
101: {
102: HTParentAnchor * anchor = HTRequest_anchor(request);
103: HTReload mode = HTRequest_reloadMode(request);
2.3 ! frystyk 104: HTMethod method = HTRequest_method(request);
! 105:
! 106: /*
! 107: ** Check the method of the request
! 108: */
! 109: if (method != METHOD_GET) {
! 110: if (CACHE_TRACE) HTTrace("Cachefilter. We only check GET methods\n");
! 111: return HT_OK;
! 112: }
! 113:
2.1 frystyk 114: /*
115: ** If the mode if "Force Reload" then don't even bother to check the
116: ** cache - we flush everything we know about this document
117: */
118: if (mode == HT_FORCE_RELOAD) {
119: /*
120: ** Add the appropriate request headers. We use both the "pragma"
121: ** and the "cache-control" headers in order to be
122: ** backwards compatible with HTP/1.0
123: */
124: HTRequest_addGnHd(request, HT_G_PRAGMA_NO_CACHE);
125:
126: /* @@@ CACHE CONTROL @@@ */
127:
128: /*
129: ** We also flush the information in the anchor
130: */
131: HTAnchor_clearHeader(anchor);
132: return HT_OK;
133: }
134:
135: /*
136: ** Check the application provided memory cache. This is equivalent to a
137: ** history list and does not follow the same cache mechanisms as the
138: ** persistent cache
139: */
140: if (HTMemoryCache_check(request) == HT_LOADED)
141: return HT_LOADED;
142:
143: /*
144: ** Check the persistent cache manager. If we have a cache hit then
145: ** continue to see if the reload mode requires us to do a validation check.
146: ** This filter assumes that we can get the cached version through one of
147: ** our protocol modules (for example the file module)
148: */
149: {
150: char * addr = HTAnchor_address((HTAnchor *) anchor);
151: char * cache = HTCache_getReference(addr);
152: if (cache) {
153: if (mode != HT_CACHE_REFRESH) {
154: HTAnchor_setPhysical(anchor, cache);
155: HTAnchor_setCacheHit(anchor, YES);
156: } else {
157:
158: /* @@@ Do cache validation @@@ */
159:
160: }
161: }
162: HT_FREE(addr);
163: }
164: return HT_OK;
165: }
166:
167: /*
168: ** Error and Information AFTER filter
169: ** ----------------------------------
170: ** It checks the status code from a request and generates an
171: ** error/information message if required.
172: */
173: PUBLIC int HTInfoFilter (HTRequest * request, void * param, int status)
174: {
175: HTParentAnchor * anchor = HTRequest_anchor(request);
176: char * uri = HTAnchor_address((HTAnchor*) anchor);
177: switch (status) {
178: case HT_RETRY:
179: if (PROT_TRACE)
180: HTTrace("Load End.... NOT AVAILABLE, RETRY AT %ld\n",
181: HTRequest_retryTime(request));
182: break;
183:
184: case HT_ERROR:
185: {
186: /*
187: ** See if we have a function registered for outputting errors.
188: ** If so then call it and present the message to the user
189: */
190: HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
191: if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
192: HTRequest_error(request), NULL);
193: if (PROT_TRACE)
194: HTTrace("Load End.... ERROR: Can't access `%s\'\n",
195: uri ? uri : "<UNKNOWN>");
2.3 ! frystyk 196: break;
! 197: }
! 198:
! 199: case HT_LOADED:
! 200: {
! 201: /*
! 202: ** Even though we have received a loaded status the thing we have
! 203: ** loaded successfully may in fact be an error message. We therefore
! 204: ** look at the error stack to see what to do.
! 205: */
! 206: HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
! 207: if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
! 208: HTRequest_error(request), NULL);
! 209: if (PROT_TRACE) HTTrace("Load End.... OK: `%s\'\n", uri);
2.1 frystyk 210: break;
211: }
212:
213: default:
214: if (PROT_TRACE)
215: HTTrace("Load End.... Request ended with code %d\n", status);
216: break;
217: }
218:
219: HT_FREE(uri);
220: return HT_OK;
221: }
222:
223: /*
224: ** Redirection AFTER filter
225: ** ------------------------
226: ** The redirection handler only handles redirections
227: ** on the GET or HEAD method (or any other safe method)
228: */
229: PUBLIC int HTRedirectFilter (HTRequest * request, void * param, int status)
230: {
231: HTMethod method = HTRequest_method(request);
232: HTAnchor * new_anchor = HTRequest_redirection(request);
233:
234: /*
235: ** Only do redirect on GET and HEAD
236: */
237: if (!HTMethod_isSafe(method) || !new_anchor) {
238: HTRequest_addError(request, ERR_FATAL, NO, HTERR_AUTO_REDIRECT,
239: NULL, 0, "RedirectionFilter");
240: return HT_ERROR;
241: }
242:
243: /*
244: ** Start new request with the redirect anchor found in the headers.
245: ** Note that we reuse the same request object which means that we must
246: ** keep this around until the redirected request has terminated. It also
247: ** allows us in an easy way to keep track of the number of redirections
248: ** so that we can detect endless loops.
249: */
250: if (HTRequest_retry(request)) {
251: HTLoadAnchor(new_anchor, request);
252: } else {
253: HTRequest_addError(request, ERR_FATAL, NO, HTERR_MAX_REDIRECT,
254: NULL, 0, "HTRedirectFilter");
255: }
256:
257: /*
258: ** By returning HT_ERROR we make sure that this is the last handler to be
259: ** called. We do this as we don't want any other filter to delete the
260: ** request object now when we have just started a new one ourselves
261: */
262: return HT_ERROR;
263: }
264:
265: /*
266: ** Client side authentication BEFORE filter
267: ** ----------------------------------------
268: ** The filter generates the credentials required to access a document
269: ** Getting the credentials may involve asking the user
270: */
271: PUBLIC int HTCredentialsFilter (HTRequest * request, void * param, int status)
272: {
273: /*
274: ** Ask the authentication module to call the right credentials generator
275: ** that understands this scheme
276: */
277: if (HTAA_beforeFilter(request, param, status) == HT_OK) {
278: if (PROT_TRACE) HTTrace("Credentials. verified\n");
279: return HT_OK;
280: } else {
281: HTRequest_addError(request, ERR_FATAL, NO, HTERR_UNAUTHORIZED,
282: NULL, 0, "HTCredentialsFilter");
283: return HT_ERROR;
284: }
285: }
286:
287: /*
288: ** Client side authentication AFTER filter
289: ** ---------------------------------------
290: ** The client side authentication filter uses the
291: ** user dialog messages registered in the HTAlert module.
292: ** By default these are the ones used by the line mode browser but you can
293: ** just register something else.
294: */
295: PUBLIC int HTAuthFilter (HTRequest * request, void * param, int status)
296: {
297: /*
298: ** Ask the authentication module to call the right challenge parser
299: ** that understands this scheme
300: */
301: if (HTAA_afterFilter(request, param, status) == HT_OK) {
302: HTMethod method = HTRequest_method(request);
303:
304: if (HTMethod_hasEntity(method)) {
305: if (APP_TRACE)
306: HTTrace("Auth filter. Can't authenticate PUT or POST\n");
307: return HT_ERROR;
308: }
309:
310: /*
311: ** Start request with new credentials. As with the redirection filter
312: ** we reuse the same request object which means that we must
313: ** keep this around until the redirected request has terminated
314: */
315: HTLoad(request, NO);
316:
317: /*
318: ** We return HT_ERROR to make sure that this is the last handler to be
319: ** called. We do this as we don't want any other filter to delete the
320: ** request object now when we have just started a new one ourselves
321: */
322: return HT_ERROR;
323: }
324: return HT_OK;
325: }
326:
327: /*
328: ** Request Loggin AFTER filter
329: ** ---------------------------
330: ** Default Logging filter using the log manager provided by HTLog.c
331: */
332: PUBLIC int HTLogFilter (HTRequest * request, void * param, int status)
333: {
334: if (request) {
335: if (HTLog_isOpen()) HTLog_add(request, status);
336: return HT_OK;
337: }
338: return HT_ERROR;
339: }
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