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 = 0; 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]) { 271 /* do nothing */ 272 } 273 else { 274 return apr_pstrcat(p, "bad expires code, missing <type>", NULL); 275 } 276 277 factor = 0; 278 if (!strncasecmp(word, "years", 1)) { 279 factor = 60 * 60 * 24 * 365; 280 } 281 else if (!strncasecmp(word, "months", 2)) { 282 factor = 60 * 60 * 24 * 30; 283 } 284 else if (!strncasecmp(word, "weeks", 1)) { 285 factor = 60 * 60 * 24 * 7; 286 } 287 else if (!strncasecmp(word, "days", 1)) { 288 factor = 60 * 60 * 24; 289 } 290 else if (!strncasecmp(word, "hours", 1)) { 291 factor = 60 * 60; 292 } 293 else if (!strncasecmp(word, "minutes", 2)) { 294 factor = 60; 295 } 296 else if (!strncasecmp(word, "seconds", 1)) { 297 factor = 1; 298 } 299 else { 300 return apr_pstrcat(p, "bad expires code, unrecognised <type>", 301 "'", word, "'", NULL); 302 } 303 304 modifier = modifier + factor * num; 305 306 /* next <num> 307 */ 308 word = ap_getword_conf(p, &code); 309 } 310 311 *real_code = apr_psprintf(p, "%c%d", base, modifier); 312 313 return NULL; 314} 315 316static const char *set_expiresbytype(cmd_parms *cmd, void *in_dir_config, 317 const char *mime, const char *code) 318{ 319 expires_dir_config *dir_config = in_dir_config; 320 char *response, *real_code; 321 const char *check; 322 323 check = ap_strrchr_c(mime, '/'); 324 if (check == NULL) { 325 return "Invalid mimetype: should contain a slash"; 326 } 327 if ((strlen(++check) == 1) && (*check == '*')) { 328 dir_config->wildcards = 1; 329 } 330 331 if ((response = check_code(cmd->pool, code, &real_code)) == NULL) { 332 apr_table_setn(dir_config->expiresbytype, mime, real_code); 333 return NULL; 334 } 335 return apr_pstrcat(cmd->pool, 336 "'ExpiresByType ", mime, " ", code, "': ", response, NULL); 337} 338 339static const char *set_expiresdefault(cmd_parms *cmd, void *in_dir_config, 340 const char *code) 341{ 342 expires_dir_config * dir_config = in_dir_config; 343 char *response, *real_code; 344 345 if ((response = check_code(cmd->pool, code, &real_code)) == NULL) { 346 dir_config->expiresdefault = real_code; 347 return NULL; 348 } 349 return apr_pstrcat(cmd->pool, 350 "'ExpiresDefault ", code, "': ", response, NULL); 351} 352 353static const command_rec expires_cmds[] = 354{ 355 AP_INIT_FLAG("ExpiresActive", set_expiresactive, NULL, DIR_CMD_PERMS, 356 "Limited to 'on' or 'off'"), 357 AP_INIT_TAKE2("ExpiresByType", set_expiresbytype, NULL, DIR_CMD_PERMS, 358 "a MIME type followed by an expiry date code"), 359 AP_INIT_TAKE1("ExpiresDefault", set_expiresdefault, NULL, DIR_CMD_PERMS, 360 "an expiry date code"), 361 {NULL} 362}; 363 364static void *merge_expires_dir_configs(apr_pool_t *p, void *basev, void *addv) 365{ 366 expires_dir_config *new = (expires_dir_config *) apr_pcalloc(p, sizeof(expires_dir_config)); 367 expires_dir_config *base = (expires_dir_config *) basev; 368 expires_dir_config *add = (expires_dir_config *) addv; 369 370 if (add->active == ACTIVE_DONTCARE) { 371 new->active = base->active; 372 } 373 else { 374 new->active = add->active; 375 } 376 377 if (add->expiresdefault != NULL) { 378 new->expiresdefault = add->expiresdefault; 379 } 380 else { 381 new->expiresdefault = base->expiresdefault; 382 } 383 new->wildcards = add->wildcards; 384 new->expiresbytype = apr_table_overlay(p, add->expiresbytype, 385 base->expiresbytype); 386 return new; 387} 388 389/* 390 * Handle the setting of the expiration response header fields according 391 * to our criteria. 392 */ 393 394static int set_expiration_fields(request_rec *r, const char *code, 395 apr_table_t *t) 396{ 397 apr_time_t base; 398 apr_time_t additional; 399 apr_time_t expires; 400 int additional_sec; 401 char *timestr; 402 403 switch (code[0]) { 404 case 'M': 405 if (r->finfo.filetype == 0) { 406 /* file doesn't exist on disk, so we can't do anything based on 407 * modification time. Note that this does _not_ log an error. 408 */ 409 return DECLINED; 410 } 411 base = r->finfo.mtime; 412 additional_sec = atoi(&code[1]); 413 additional = apr_time_from_sec(additional_sec); 414 break; 415 case 'A': 416 /* there's been some discussion and it's possible that 417 * 'access time' will be stored in request structure 418 */ 419 base = r->request_time; 420 additional_sec = atoi(&code[1]); 421 additional = apr_time_from_sec(additional_sec); 422 break; 423 default: 424 /* expecting the add_* routines to be case-hardened this 425 * is just a reminder that module is beta 426 */ 427 ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, 428 "internal error: bad expires code: %s", r->filename); 429 return HTTP_INTERNAL_SERVER_ERROR; 430 } 431 432 expires = base + additional; 433 if (expires < r->request_time) { 434 expires = r->request_time; 435 } 436 apr_table_mergen(t, "Cache-Control", 437 apr_psprintf(r->pool, "max-age=%" APR_TIME_T_FMT, 438 apr_time_sec(expires - r->request_time))); 439 timestr = apr_palloc(r->pool, APR_RFC822_DATE_LEN); 440 apr_rfc822_date(timestr, expires); 441 apr_table_setn(t, "Expires", timestr); 442 return OK; 443} 444 445/* 446 * Output filter to set the Expires response header field 447 * according to the content-type of the response -- if it hasn't 448 * already been set. 449 */ 450static apr_status_t expires_filter(ap_filter_t *f, 451 apr_bucket_brigade *b) 452{ 453 request_rec *r; 454 expires_dir_config *conf; 455 const char *expiry; 456 apr_table_t *t; 457 458 r = f->r; 459 conf = (expires_dir_config *) ap_get_module_config(r->per_dir_config, 460 &expires_module); 461 462 /* 463 * Check to see which output header table we should use; 464 * mod_cgi loads script fields into r->err_headers_out, 465 * for instance. 466 */ 467 expiry = apr_table_get(r->err_headers_out, "Expires"); 468 if (expiry != NULL) { 469 t = r->err_headers_out; 470 } 471 else { 472 expiry = apr_table_get(r->headers_out, "Expires"); 473 t = r->headers_out; 474 } 475 if (expiry == NULL) { 476 /* 477 * No expiration has been set, so we can apply any managed by 478 * this module. First, check to see if there is an applicable 479 * ExpiresByType directive. 480 */ 481 expiry = apr_table_get(conf->expiresbytype, 482 ap_field_noparam(r->pool, r->content_type)); 483 if (expiry == NULL) { 484 int usedefault = 1; 485 /* 486 * See if we have a wildcard entry for the major type. 487 */ 488 if (conf->wildcards) { 489 char *checkmime; 490 char *spos; 491 checkmime = apr_pstrdup(r->pool, r->content_type); 492 spos = checkmime ? ap_strchr(checkmime, '/') : NULL; 493 if (spos != NULL) { 494 /* 495 * Without a '/' character, nothing we have will match. 496 * However, we have one. 497 */ 498 if (strlen(++spos) > 0) { 499 *spos++ = '*'; 500 *spos = '\0'; 501 } 502 else { 503 checkmime = apr_pstrcat(r->pool, checkmime, "*", NULL); 504 } 505 expiry = apr_table_get(conf->expiresbytype, checkmime); 506 usedefault = (expiry == NULL); 507 } 508 } 509 if (usedefault) { 510 /* 511 * Use the ExpiresDefault directive 512 */ 513 expiry = conf->expiresdefault; 514 } 515 } 516 if (expiry != NULL) { 517 set_expiration_fields(r, expiry, t); 518 } 519 } 520 ap_remove_output_filter(f); 521 return ap_pass_brigade(f->next, b); 522} 523 524static void expires_insert_filter(request_rec *r) 525{ 526 expires_dir_config *conf; 527 528 /* Don't add Expires headers to errors */ 529 if (ap_is_HTTP_ERROR(r->status)) { 530 return; 531 } 532 /* Say no to subrequests */ 533 if (r->main != NULL) { 534 return; 535 } 536 conf = (expires_dir_config *) ap_get_module_config(r->per_dir_config, 537 &expires_module); 538 539 /* Check to see if the filter is enabled and if there are any applicable 540 * config directives for this directory scope 541 */ 542 if (conf->active != ACTIVE_ON || 543 (apr_is_empty_table(conf->expiresbytype) && !conf->expiresdefault)) { 544 return; 545 } 546 ap_add_output_filter("MOD_EXPIRES", NULL, r, r->connection); 547 return; 548} 549static void register_hooks(apr_pool_t *p) 550{ 551 /* mod_expires needs to run *before* the cache save filter which is 552 * AP_FTYPE_CONTENT_SET-1. Otherwise, our expires won't be honored. 553 */ 554 ap_register_output_filter("MOD_EXPIRES", expires_filter, NULL, 555 AP_FTYPE_CONTENT_SET-2); 556 ap_hook_insert_error_filter(expires_insert_filter, NULL, NULL, APR_HOOK_MIDDLE); 557 ap_hook_insert_filter(expires_insert_filter, NULL, NULL, APR_HOOK_MIDDLE); 558} 559 560module AP_MODULE_DECLARE_DATA expires_module = 561{ 562 STANDARD20_MODULE_STUFF, 563 create_dir_expires_config, /* dir config creater */ 564 merge_expires_dir_configs, /* dir merger --- default is to override */ 565 NULL, /* server config */ 566 NULL, /* merge server configs */ 567 expires_cmds, /* command apr_table_t */ 568 register_hooks /* register hooks */ 569}; 570