1/* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17/* 18 * mod_expires.c 19 * version 0.0.11 20 * status beta 21 * 22 * Andrew Wilson <Andrew.Wilson@cm.cf.ac.uk> 26.Jan.96 23 * 24 * This module allows you to control the form of the Expires: header 25 * that Apache issues for each access. Directives can appear in 26 * configuration files or in .htaccess files so expiry semantics can 27 * be defined on a per-directory basis. 28 * 29 * DIRECTIVE SYNTAX 30 * 31 * Valid directives are: 32 * 33 * ExpiresActive on | off 34 * ExpiresDefault <code><seconds> 35 * ExpiresByType type/encoding <code><seconds> 36 * 37 * Valid values for <code> are: 38 * 39 * 'M' expires header shows file modification date + <seconds> 40 * 'A' expires header shows access time + <seconds> 41 * 42 * [I'm not sure which of these is best under different 43 * circumstances, I guess it's for other people to explore. 44 * The effects may be indistinguishable for a number of cases] 45 * 46 * <seconds> should be an integer value [acceptable to atoi()] 47 * 48 * There is NO space between the <code> and <seconds>. 49 * 50 * For example, a directory which contains information which changes 51 * frequently might contain: 52 * 53 * # reports generated by cron every hour. don't let caches 54 * # hold onto stale information 55 * ExpiresDefault M3600 56 * 57 * Another example, our html pages can change all the time, the gifs 58 * tend not to change often: 59 * 60 * # pages are hot (1 week), images are cold (1 month) 61 * ExpiresByType text/html A604800 62 * ExpiresByType image/gif A2592000 63 * 64 * Expires can be turned on for all URLs on the server by placing the 65 * following directive in a conf file: 66 * 67 * ExpiresActive on 68 * 69 * ExpiresActive can also appear in .htaccess files, enabling the 70 * behaviour to be turned on or off for each chosen directory. 71 * 72 * # turn off Expires behaviour in this directory 73 * # and subdirectories 74 * ExpiresActive off 75 * 76 * Directives defined for a directory are valid in subdirectories 77 * unless explicitly overridden by new directives in the subdirectory 78 * .htaccess files. 79 * 80 * ALTERNATIVE DIRECTIVE SYNTAX 81 * 82 * Directives can also be defined in a more readable syntax of the form: 83 * 84 * ExpiresDefault "<base> [plus] {<num> <type>}*" 85 * ExpiresByType type/encoding "<base> [plus] {<num> <type>}*" 86 * 87 * where <base> is one of: 88 * access 89 * now equivalent to 'access' 90 * modification 91 * 92 * where the 'plus' keyword is optional 93 * 94 * where <num> should be an integer value [acceptable to atoi()] 95 * 96 * where <type> is one of: 97 * years 98 * months 99 * weeks 100 * days 101 * hours 102 * minutes 103 * seconds 104 * 105 * For example, any of the following directives can be used to make 106 * documents expire 1 month after being accessed, by default: 107 * 108 * ExpiresDefault "access plus 1 month" 109 * ExpiresDefault "access plus 4 weeks" 110 * ExpiresDefault "access plus 30 days" 111 * 112 * The expiry time can be fine-tuned by adding several '<num> <type>' 113 * clauses: 114 * 115 * ExpiresByType text/html "access plus 1 month 15 days 2 hours" 116 * ExpiresByType image/gif "modification plus 5 hours 3 minutes" 117 * 118 * --- 119 * 120 * Change-log: 121 * 29.Jan.96 Hardened the add_* functions. Server will now bail out 122 * if bad directives are given in the conf files. 123 * 02.Feb.96 Returns DECLINED if not 'ExpiresActive on', giving other 124 * expires-aware modules a chance to play with the same 125 * directives. [Michael Rutman] 126 * 03.Feb.96 Call tzset() before localtime(). Trying to get the module 127 * to work properly in non GMT timezones. 128 * 12.Feb.96 Modified directive syntax to allow more readable commands: 129 * ExpiresDefault "now plus 10 days 20 seconds" 130 * ExpiresDefault "access plus 30 days" 131 * ExpiresDefault "modification plus 1 year 10 months 30 days" 132 * 13.Feb.96 Fix call to table_get() with NULL 2nd parameter [Rob Hartill] 133 * 19.Feb.96 Call gm_timestr_822() to get time formatted correctly, can't 134 * rely on presence of HTTP_TIME_FORMAT in Apache 1.1+. 135 * 21.Feb.96 This version (0.0.9) reverses assumptions made in 0.0.8 136 * about star/star handlers. Reverting to 0.0.7 behaviour. 137 * 08.Jun.96 allows ExpiresDefault to be used with responses that use 138 * the DefaultType by not DECLINING, but instead skipping 139 * the table_get check and then looking for an ExpiresDefault. 140 * [Rob Hartill] 141 * 04.Nov.96 'const' definitions added. 142 * 143 * TODO 144 * add support for Cache-Control: max-age=20 from the HTTP/1.1 145 * proposal (in this case, a ttl of 20 seconds) [ask roy] 146 * add per-file expiry and explicit expiry times - duplicates some 147 * of the mod_cern_meta.c functionality. eg: 148 * ExpiresExplicit index.html "modification plus 30 days" 149 * 150 * BUGS 151 * Hi, welcome to the internet. 152 */ 153 154#include "apr.h" 155#include "apr_strings.h" 156#include "apr_lib.h" 157 158#define APR_WANT_STRFUNC 159#include "apr_want.h" 160 161#include "ap_config.h" 162#include "httpd.h" 163#include "http_config.h" 164#include "http_log.h" 165#include "http_request.h" 166#include "http_protocol.h" 167 168typedef struct { 169 int active; 170 int wildcards; 171 char *expiresdefault; 172 apr_table_t *expiresbytype; 173} expires_dir_config; 174 175/* from mod_dir, why is this alias used? 176 */ 177#define DIR_CMD_PERMS OR_INDEXES 178 179#define ACTIVE_ON 1 180#define ACTIVE_OFF 0 181#define ACTIVE_DONTCARE 2 182 183module AP_MODULE_DECLARE_DATA expires_module; 184 185static void *create_dir_expires_config(apr_pool_t *p, char *dummy) 186{ 187 expires_dir_config *new = 188 (expires_dir_config *) apr_pcalloc(p, sizeof(expires_dir_config)); 189 new->active = ACTIVE_DONTCARE; 190 new->wildcards = 0; 191 new->expiresdefault = NULL; 192 new->expiresbytype = apr_table_make(p, 4); 193 return (void *) new; 194} 195 196static const char *set_expiresactive(cmd_parms *cmd, void *in_dir_config, int arg) 197{ 198 expires_dir_config *dir_config = in_dir_config; 199 200 /* if we're here at all it's because someone explicitly 201 * set the active flag 202 */ 203 dir_config->active = ACTIVE_ON; 204 if (arg == 0) { 205 dir_config->active = ACTIVE_OFF; 206 } 207 return NULL; 208} 209 210/* check_code() parse 'code' and return NULL or an error response 211 * string. If we return NULL then real_code contains code converted 212 * to the cnnnn format. 213 */ 214static char *check_code(apr_pool_t *p, const char *code, char **real_code) 215{ 216 char *word; 217 char base = 'X'; 218 int modifier = 0; 219 int num = 0; 220 int factor; 221 222 /* 0.0.4 compatibility? 223 */ 224 if ((code[0] == 'A') || (code[0] == 'M')) { 225 *real_code = (char *)code; 226 return NULL; 227 } 228 229 /* <base> [plus] {<num> <type>}* 230 */ 231 232 /* <base> 233 */ 234 word = ap_getword_conf(p, &code); 235 if (!strncasecmp(word, "now", 1) || 236 !strncasecmp(word, "access", 1)) { 237 base = 'A'; 238 } 239 else if (!strncasecmp(word, "modification", 1)) { 240 base = 'M'; 241 } 242 else { 243 return apr_pstrcat(p, "bad expires code, unrecognised <base> '", 244 word, "'", NULL); 245 } 246 247 /* [plus] 248 */ 249 word = ap_getword_conf(p, &code); 250 if (!strncasecmp(word, "plus", 1)) { 251 word = ap_getword_conf(p, &code); 252 } 253 254 /* {<num> <type>}* 255 */ 256 while (word[0]) { 257 /* <num> 258 */ 259 if (apr_isdigit(word[0])) { 260 num = atoi(word); 261 } 262 else { 263 return apr_pstrcat(p, "bad expires code, numeric value expected <num> '", 264 word, "'", NULL); 265 } 266 267 /* <type> 268 */ 269 word = ap_getword_conf(p, &code); 270 if (word[0] == '\0') { 271 return apr_pstrcat(p, "bad expires code, missing <type>", NULL); 272 } 273 274 if (!strncasecmp(word, "years", 1)) { 275 factor = 60 * 60 * 24 * 365; 276 } 277 else if (!strncasecmp(word, "months", 2)) { 278 factor = 60 * 60 * 24 * 30; 279 } 280 else if (!strncasecmp(word, "weeks", 1)) { 281 factor = 60 * 60 * 24 * 7; 282 } 283 else if (!strncasecmp(word, "days", 1)) { 284 factor = 60 * 60 * 24; 285 } 286 else if (!strncasecmp(word, "hours", 1)) { 287 factor = 60 * 60; 288 } 289 else if (!strncasecmp(word, "minutes", 2)) { 290 factor = 60; 291 } 292 else if (!strncasecmp(word, "seconds", 1)) { 293 factor = 1; 294 } 295 else { 296 return apr_pstrcat(p, "bad expires code, unrecognised <type>", 297 "'", word, "'", NULL); 298 } 299 300 modifier = modifier + factor * num; 301 302 /* next <num> 303 */ 304 word = ap_getword_conf(p, &code); 305 } 306 307 *real_code = apr_psprintf(p, "%c%d", base, modifier); 308 309 return NULL; 310} 311 312static const char *set_expiresbytype(cmd_parms *cmd, void *in_dir_config, 313 const char *mime, const char *code) 314{ 315 expires_dir_config *dir_config = in_dir_config; 316 char *response, *real_code; 317 const char *check; 318 319 check = ap_strrchr_c(mime, '/'); 320 if (check == NULL) { 321 return "Invalid mimetype: should contain a slash"; 322 } 323 if ((strlen(++check) == 1) && (*check == '*')) { 324 dir_config->wildcards = 1; 325 } 326 327 if ((response = check_code(cmd->pool, code, &real_code)) == NULL) { 328 apr_table_setn(dir_config->expiresbytype, mime, real_code); 329 return NULL; 330 } 331 return apr_pstrcat(cmd->pool, 332 "'ExpiresByType ", mime, " ", code, "': ", response, NULL); 333} 334 335static const char *set_expiresdefault(cmd_parms *cmd, void *in_dir_config, 336 const char *code) 337{ 338 expires_dir_config * dir_config = in_dir_config; 339 char *response, *real_code; 340 341 if ((response = check_code(cmd->pool, code, &real_code)) == NULL) { 342 dir_config->expiresdefault = real_code; 343 return NULL; 344 } 345 return apr_pstrcat(cmd->pool, 346 "'ExpiresDefault ", code, "': ", response, NULL); 347} 348 349static const command_rec expires_cmds[] = 350{ 351 AP_INIT_FLAG("ExpiresActive", set_expiresactive, NULL, DIR_CMD_PERMS, 352 "Limited to 'on' or 'off'"), 353 AP_INIT_TAKE2("ExpiresByType", set_expiresbytype, NULL, DIR_CMD_PERMS, 354 "a MIME type followed by an expiry date code"), 355 AP_INIT_TAKE1("ExpiresDefault", set_expiresdefault, NULL, DIR_CMD_PERMS, 356 "an expiry date code"), 357 {NULL} 358}; 359 360static void *merge_expires_dir_configs(apr_pool_t *p, void *basev, void *addv) 361{ 362 expires_dir_config *new = (expires_dir_config *) apr_pcalloc(p, sizeof(expires_dir_config)); 363 expires_dir_config *base = (expires_dir_config *) basev; 364 expires_dir_config *add = (expires_dir_config *) addv; 365 366 if (add->active == ACTIVE_DONTCARE) { 367 new->active = base->active; 368 } 369 else { 370 new->active = add->active; 371 } 372 373 if (add->expiresdefault != NULL) { 374 new->expiresdefault = add->expiresdefault; 375 } 376 else { 377 new->expiresdefault = base->expiresdefault; 378 } 379 new->wildcards = add->wildcards; 380 new->expiresbytype = apr_table_overlay(p, add->expiresbytype, 381 base->expiresbytype); 382 return new; 383} 384 385/* 386 * Handle the setting of the expiration response header fields according 387 * to our criteria. 388 */ 389 390static int set_expiration_fields(request_rec *r, const char *code, 391 apr_table_t *t) 392{ 393 apr_time_t base; 394 apr_time_t additional; 395 apr_time_t expires; 396 int additional_sec; 397 char *timestr; 398 399 switch (code[0]) { 400 case 'M': 401 if (r->finfo.filetype == APR_NOFILE) { 402 /* file doesn't exist on disk, so we can't do anything based on 403 * modification time. Note that this does _not_ log an error. 404 */ 405 return DECLINED; 406 } 407 base = r->finfo.mtime; 408 additional_sec = atoi(&code[1]); 409 additional = apr_time_from_sec(additional_sec); 410 break; 411 case 'A': 412 /* there's been some discussion and it's possible that 413 * 'access time' will be stored in request structure 414 */ 415 base = r->request_time; 416 additional_sec = atoi(&code[1]); 417 additional = apr_time_from_sec(additional_sec); 418 break; 419 default: 420 /* expecting the add_* routines to be case-hardened this 421 * is just a reminder that module is beta 422 */ 423 ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01500) 424 "internal error: bad expires code: %s", r->filename); 425 return HTTP_INTERNAL_SERVER_ERROR; 426 } 427 428 expires = base + additional; 429 if (expires < r->request_time) { 430 expires = r->request_time; 431 } 432 apr_table_mergen(t, "Cache-Control", 433 apr_psprintf(r->pool, "max-age=%" APR_TIME_T_FMT, 434 apr_time_sec(expires - r->request_time))); 435 timestr = apr_palloc(r->pool, APR_RFC822_DATE_LEN); 436 apr_rfc822_date(timestr, expires); 437 apr_table_setn(t, "Expires", timestr); 438 return OK; 439} 440 441/* 442 * Output filter to set the Expires response header field 443 * according to the content-type of the response -- if it hasn't 444 * already been set. 445 */ 446static apr_status_t expires_filter(ap_filter_t *f, 447 apr_bucket_brigade *b) 448{ 449 request_rec *r; 450 expires_dir_config *conf; 451 const char *expiry; 452 apr_table_t *t; 453 454 r = f->r; 455 conf = (expires_dir_config *) ap_get_module_config(r->per_dir_config, 456 &expires_module); 457 458 /* 459 * Check to see which output header table we should use; 460 * mod_cgi loads script fields into r->err_headers_out, 461 * for instance. 462 */ 463 expiry = apr_table_get(r->err_headers_out, "Expires"); 464 if (expiry != NULL) { 465 t = r->err_headers_out; 466 } 467 else { 468 expiry = apr_table_get(r->headers_out, "Expires"); 469 t = r->headers_out; 470 } 471 if (expiry == NULL) { 472 /* 473 * No expiration has been set, so we can apply any managed by 474 * this module. First, check to see if there is an applicable 475 * ExpiresByType directive. 476 */ 477 expiry = apr_table_get(conf->expiresbytype, 478 ap_field_noparam(r->pool, r->content_type)); 479 if (expiry == NULL) { 480 int usedefault = 1; 481 /* 482 * See if we have a wildcard entry for the major type. 483 */ 484 if (conf->wildcards) { 485 char *checkmime; 486 char *spos; 487 checkmime = apr_pstrdup(r->pool, r->content_type); 488 spos = checkmime ? ap_strchr(checkmime, '/') : NULL; 489 if (spos != NULL) { 490 /* 491 * Without a '/' character, nothing we have will match. 492 * However, we have one. 493 */ 494 if (strlen(++spos) > 0) { 495 *spos++ = '*'; 496 *spos = '\0'; 497 } 498 else { 499 checkmime = apr_pstrcat(r->pool, checkmime, "*", NULL); 500 } 501 expiry = apr_table_get(conf->expiresbytype, checkmime); 502 usedefault = (expiry == NULL); 503 } 504 } 505 if (usedefault) { 506 /* 507 * Use the ExpiresDefault directive 508 */ 509 expiry = conf->expiresdefault; 510 } 511 } 512 if (expiry != NULL) { 513 set_expiration_fields(r, expiry, t); 514 } 515 } 516 ap_remove_output_filter(f); 517 return ap_pass_brigade(f->next, b); 518} 519 520static void expires_insert_filter(request_rec *r) 521{ 522 expires_dir_config *conf; 523 524 /* Don't add Expires headers to errors */ 525 if (ap_is_HTTP_ERROR(r->status)) { 526 return; 527 } 528 /* Say no to subrequests */ 529 if (r->main != NULL) { 530 return; 531 } 532 conf = (expires_dir_config *) ap_get_module_config(r->per_dir_config, 533 &expires_module); 534 535 /* Check to see if the filter is enabled and if there are any applicable 536 * config directives for this directory scope 537 */ 538 if (conf->active != ACTIVE_ON || 539 (apr_is_empty_table(conf->expiresbytype) && !conf->expiresdefault)) { 540 return; 541 } 542 ap_add_output_filter("MOD_EXPIRES", NULL, r, r->connection); 543 return; 544} 545static void register_hooks(apr_pool_t *p) 546{ 547 /* mod_expires needs to run *before* the cache save filter which is 548 * AP_FTYPE_CONTENT_SET-1. Otherwise, our expires won't be honored. 549 */ 550 ap_register_output_filter("MOD_EXPIRES", expires_filter, NULL, 551 AP_FTYPE_CONTENT_SET-2); 552 ap_hook_insert_error_filter(expires_insert_filter, NULL, NULL, APR_HOOK_MIDDLE); 553 ap_hook_insert_filter(expires_insert_filter, NULL, NULL, APR_HOOK_MIDDLE); 554} 555 556AP_DECLARE_MODULE(expires) = 557{ 558 STANDARD20_MODULE_STUFF, 559 create_dir_expires_config, /* dir config creater */ 560 merge_expires_dir_configs, /* dir merger --- default is to override */ 561 NULL, /* server config */ 562 NULL, /* merge server configs */ 563 expires_cmds, /* command apr_table_t */ 564 register_hooks /* register hooks */ 565}; 566