Annotation of libwww/Library/src/HTFilter.c, revision 2.2
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.
2.2 ! frystyk 6: ** @(#) $Id: HTFilter.c,v 2.1 1996/07/08 19:10:42 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
97: */
98: PUBLIC int HTCacheFilter (HTRequest * request, void * param, int status)
99: {
100: HTParentAnchor * anchor = HTRequest_anchor(request);
101: HTReload mode = HTRequest_reloadMode(request);
102: /*
103: ** If the mode if "Force Reload" then don't even bother to check the
104: ** cache - we flush everything we know about this document
105: */
106: if (mode == HT_FORCE_RELOAD) {
107: /*
108: ** Add the appropriate request headers. We use both the "pragma"
109: ** and the "cache-control" headers in order to be
110: ** backwards compatible with HTP/1.0
111: */
112: HTRequest_addGnHd(request, HT_G_PRAGMA_NO_CACHE);
113:
114: /* @@@ CACHE CONTROL @@@ */
115:
116: /*
117: ** We also flush the information in the anchor
118: */
119: HTAnchor_clearHeader(anchor);
120: return HT_OK;
121: }
122:
123: /*
124: ** Check the application provided memory cache. This is equivalent to a
125: ** history list and does not follow the same cache mechanisms as the
126: ** persistent cache
127: */
128: if (HTMemoryCache_check(request) == HT_LOADED)
129: return HT_LOADED;
130:
131: /*
132: ** Check the persistent cache manager. If we have a cache hit then
133: ** continue to see if the reload mode requires us to do a validation check.
134: ** This filter assumes that we can get the cached version through one of
135: ** our protocol modules (for example the file module)
136: */
137: {
138: char * addr = HTAnchor_address((HTAnchor *) anchor);
139: char * cache = HTCache_getReference(addr);
140: if (cache) {
141: if (mode != HT_CACHE_REFRESH) {
142: HTAnchor_setPhysical(anchor, cache);
143: HTAnchor_setCacheHit(anchor, YES);
144: } else {
145:
146: /* @@@ Do cache validation @@@ */
147:
148: }
149: }
150: HT_FREE(addr);
151: }
152: return HT_OK;
153: }
154:
155: /*
156: ** Error and Information AFTER filter
157: ** ----------------------------------
158: ** It checks the status code from a request and generates an
159: ** error/information message if required.
160: */
161: PUBLIC int HTInfoFilter (HTRequest * request, void * param, int status)
162: {
163: HTParentAnchor * anchor = HTRequest_anchor(request);
164: char * uri = HTAnchor_address((HTAnchor*) anchor);
165: switch (status) {
166: case HT_RETRY:
167: if (PROT_TRACE)
168: HTTrace("Load End.... NOT AVAILABLE, RETRY AT %ld\n",
169: HTRequest_retryTime(request));
170: break;
171:
172: case HT_ERROR:
173: {
174: /*
175: ** See if we have a function registered for outputting errors.
176: ** If so then call it and present the message to the user
177: */
178: HTAlertCallback *cbf = HTAlert_find(HT_A_MESSAGE);
179: if (cbf) (*cbf)(request, HT_A_MESSAGE, HT_MSG_NULL, NULL,
180: HTRequest_error(request), NULL);
181: if (PROT_TRACE)
182: HTTrace("Load End.... ERROR: Can't access `%s\'\n",
183: uri ? uri : "<UNKNOWN>");
184: break;
185: }
186:
187: default:
188: if (PROT_TRACE)
189: HTTrace("Load End.... Request ended with code %d\n", status);
190: break;
191: }
192:
193: HT_FREE(uri);
194: return HT_OK;
195: }
196:
197: /*
198: ** Redirection AFTER filter
199: ** ------------------------
200: ** The redirection handler only handles redirections
201: ** on the GET or HEAD method (or any other safe method)
202: */
203: PUBLIC int HTRedirectFilter (HTRequest * request, void * param, int status)
204: {
205: HTMethod method = HTRequest_method(request);
206: HTAnchor * new_anchor = HTRequest_redirection(request);
207:
208: /*
209: ** Only do redirect on GET and HEAD
210: */
211: if (!HTMethod_isSafe(method) || !new_anchor) {
212: HTRequest_addError(request, ERR_FATAL, NO, HTERR_AUTO_REDIRECT,
213: NULL, 0, "RedirectionFilter");
214: return HT_ERROR;
215: }
216:
217: /*
218: ** Start new request with the redirect anchor found in the headers.
219: ** Note that we reuse the same request object which means that we must
220: ** keep this around until the redirected request has terminated. It also
221: ** allows us in an easy way to keep track of the number of redirections
222: ** so that we can detect endless loops.
223: */
224: if (HTRequest_retry(request)) {
225: HTLoadAnchor(new_anchor, request);
226: } else {
227: HTRequest_addError(request, ERR_FATAL, NO, HTERR_MAX_REDIRECT,
228: NULL, 0, "HTRedirectFilter");
229: }
230:
231: /*
232: ** By returning HT_ERROR we make sure that this is the last handler to be
233: ** called. We do this as we don't want any other filter to delete the
234: ** request object now when we have just started a new one ourselves
235: */
236: return HT_ERROR;
237: }
238:
239: /*
240: ** Client side authentication BEFORE filter
241: ** ----------------------------------------
242: ** The filter generates the credentials required to access a document
243: ** Getting the credentials may involve asking the user
244: */
245: PUBLIC int HTCredentialsFilter (HTRequest * request, void * param, int status)
246: {
247: /*
248: ** Ask the authentication module to call the right credentials generator
249: ** that understands this scheme
250: */
251: if (HTAA_beforeFilter(request, param, status) == HT_OK) {
252: if (PROT_TRACE) HTTrace("Credentials. verified\n");
253: return HT_OK;
254: } else {
255: HTRequest_addError(request, ERR_FATAL, NO, HTERR_UNAUTHORIZED,
256: NULL, 0, "HTCredentialsFilter");
257: return HT_ERROR;
258: }
259: }
260:
261: /*
262: ** Client side authentication AFTER filter
263: ** ---------------------------------------
264: ** The client side authentication filter uses the
265: ** user dialog messages registered in the HTAlert module.
266: ** By default these are the ones used by the line mode browser but you can
267: ** just register something else.
268: */
269: PUBLIC int HTAuthFilter (HTRequest * request, void * param, int status)
270: {
271: /*
272: ** Ask the authentication module to call the right challenge parser
273: ** that understands this scheme
274: */
275: if (HTAA_afterFilter(request, param, status) == HT_OK) {
276: HTMethod method = HTRequest_method(request);
277:
278: if (HTMethod_hasEntity(method)) {
279: if (APP_TRACE)
280: HTTrace("Auth filter. Can't authenticate PUT or POST\n");
281: return HT_ERROR;
282: }
283:
284: /*
285: ** Start request with new credentials. As with the redirection filter
286: ** we reuse the same request object which means that we must
287: ** keep this around until the redirected request has terminated
288: */
289: HTLoad(request, NO);
290:
291: /*
292: ** We return HT_ERROR to make sure that this is the last handler to be
293: ** called. We do this as we don't want any other filter to delete the
294: ** request object now when we have just started a new one ourselves
295: */
296: return HT_ERROR;
297: }
298: return HT_OK;
299: }
300:
301: /*
302: ** Request Loggin AFTER filter
303: ** ---------------------------
304: ** Default Logging filter using the log manager provided by HTLog.c
305: */
306: PUBLIC int HTLogFilter (HTRequest * request, void * param, int status)
307: {
308: if (request) {
309: if (HTLog_isOpen()) HTLog_add(request, status);
310: return HT_OK;
311: }
312: return HT_ERROR;
313: }
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