| #define WANT_BASENAME_MATCH |
| /* ==================================================================== |
| * Copyright (c) 1996-1999 The Apache Group. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. All advertising materials mentioning features or use of this |
| * software must display the following acknowledgment: |
| * "This product includes software developed by the Apache Group |
| * for use in the Apache HTTP server project (http://www.apache.org/)." |
| * |
| * 4. The names "Apache Server" and "Apache Group" must not be used to |
| * endorse or promote products derived from this software without |
| * prior written permission. For written permission, please contact |
| * apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache" |
| * nor may "Apache" appear in their names without prior written |
| * permission of the Apache Group. |
| * |
| * 6. Redistributions of any form whatsoever must retain the following |
| * acknowledgment: |
| * "This product includes software developed by the Apache Group |
| * for use in the Apache HTTP server project (http://www.apache.org/)." |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY |
| * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE APACHE GROUP OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Group and was originally based |
| * on public domain software written at the National Center for |
| * Supercomputing Applications, University of Illinois, Urbana-Champaign. |
| * For more information on the Apache Group and the Apache HTTP server |
| * project, please see <http://www.apache.org/>. |
| * |
| */ |
| |
| #include "httpd.h" |
| #include "http_core.h" |
| #include "http_config.h" |
| #include "http_log.h" |
| |
| /* mod_speling.c - by Alexei Kosut <akosut@organic.com> June, 1996 |
| * |
| * This module is transparent, and simple. It attempts to correct |
| * misspellings of URLs that users might have entered, namely by checking |
| * capitalizations. If it finds a match, it sends a redirect. |
| * |
| * 08-Aug-1997 <Martin.Kraemer@Mch.SNI.De> |
| * o Upgraded module interface to apache_1.3a2-dev API (more NULL's in |
| * speling_module). |
| * o Integrated tcsh's "spelling correction" routine which allows one |
| * misspelling (character insertion/omission/typo/transposition). |
| * Rewrote it to ignore case as well. This ought to catch the majority |
| * of misspelled requests. |
| * o Commented out the second pass where files' suffixes are stripped. |
| * Given the better hit rate of the first pass, this rather ugly |
| * (request index.html, receive index.db ?!?!) solution can be |
| * omitted. |
| * o wrote a "kind of" html page for mod_speling |
| * |
| * Activate it with "CheckSpelling On" |
| */ |
| |
| MODULE_VAR_EXPORT module speling_module; |
| |
| typedef struct { |
| int enabled; |
| } spconfig; |
| |
| /* |
| * Create a configuration specific to this module for a server or directory |
| * location, and fill it with the default settings. |
| * |
| * The API says that in the absence of a merge function, the record for the |
| * closest ancestor is used exclusively. That's what we want, so we don't |
| * bother to have such a function. |
| */ |
| |
| static void *mkconfig(pool *p) |
| { |
| spconfig *cfg = ap_pcalloc(p, sizeof(spconfig)); |
| |
| cfg->enabled = 0; |
| return cfg; |
| } |
| |
| /* |
| * Respond to a callback to create configuration record for a server or |
| * vhost environment. |
| */ |
| static void *create_mconfig_for_server(pool *p, server_rec *s) |
| { |
| return mkconfig(p); |
| } |
| |
| /* |
| * Respond to a callback to create a config record for a specific directory. |
| */ |
| static void *create_mconfig_for_directory(pool *p, char *dir) |
| { |
| return mkconfig(p); |
| } |
| |
| /* |
| * Handler for the CheckSpelling directive, which is FLAG. |
| */ |
| static const char *set_speling(cmd_parms *cmd, void *mconfig, int arg) |
| { |
| spconfig *cfg = (spconfig *) mconfig; |
| |
| cfg->enabled = arg; |
| return NULL; |
| } |
| |
| /* |
| * Define the directives specific to this module. This structure is referenced |
| * later by the 'module' structure. |
| */ |
| static const command_rec speling_cmds[] = |
| { |
| { "CheckSpelling", set_speling, NULL, OR_OPTIONS, FLAG, |
| "whether or not to fix miscapitalized/misspelled requests" }, |
| { NULL } |
| }; |
| |
| typedef enum { |
| SP_IDENTICAL = 0, |
| SP_MISCAPITALIZED = 1, |
| SP_TRANSPOSITION = 2, |
| SP_MISSINGCHAR = 3, |
| SP_EXTRACHAR = 4, |
| SP_SIMPLETYPO = 5, |
| SP_VERYDIFFERENT = 6 |
| } sp_reason; |
| |
| static const char *sp_reason_str[] = |
| { |
| "identical", |
| "miscapitalized", |
| "transposed characters", |
| "character missing", |
| "extra character", |
| "mistyped character", |
| "common basename", |
| }; |
| |
| typedef struct { |
| const char *name; |
| sp_reason quality; |
| } misspelled_file; |
| |
| /* |
| * spdist() is taken from Kernighan & Pike, |
| * _The_UNIX_Programming_Environment_ |
| * and adapted somewhat to correspond better to psychological reality. |
| * (Note the changes to the return values) |
| * |
| * According to Pollock and Zamora, CACM April 1984 (V. 27, No. 4), |
| * page 363, the correct order for this is: |
| * OMISSION = TRANSPOSITION > INSERTION > SUBSTITUTION |
| * thus, it was exactly backwards in the old version. -- PWP |
| * |
| * This routine was taken out of tcsh's spelling correction code |
| * (tcsh-6.07.04) and re-converted to apache data types ("char" type |
| * instead of tcsh's NLS'ed "Char"). Plus it now ignores the case |
| * during comparisons, so is a "approximate strcasecmp()". |
| * NOTE that is still allows only _one_ real "typo", |
| * it does NOT try to correct multiple errors. |
| */ |
| |
| static sp_reason spdist(const char *s, const char *t) |
| { |
| for (; ap_tolower(*s) == ap_tolower(*t); t++, s++) { |
| if (*t == '\0') { |
| return SP_MISCAPITALIZED; /* exact match (sans case) */ |
| } |
| } |
| if (*s) { |
| if (*t) { |
| if (s[1] && t[1] && ap_tolower(*s) == ap_tolower(t[1]) |
| && ap_tolower(*t) == ap_tolower(s[1]) |
| && strcasecmp(s + 2, t + 2) == 0) { |
| return SP_TRANSPOSITION; /* transposition */ |
| } |
| if (strcasecmp(s + 1, t + 1) == 0) { |
| return SP_SIMPLETYPO; /* 1 char mismatch */ |
| } |
| } |
| if (strcasecmp(s + 1, t) == 0) { |
| return SP_EXTRACHAR; /* extra character */ |
| } |
| } |
| if (*t && strcasecmp(s, t + 1) == 0) { |
| return SP_MISSINGCHAR; /* missing character */ |
| } |
| return SP_VERYDIFFERENT; /* distance too large to fix. */ |
| } |
| |
| static int sort_by_quality(const void *left, const void *rite) |
| { |
| return (int) (((misspelled_file *) left)->quality) |
| - (int) (((misspelled_file *) rite)->quality); |
| } |
| |
| static int check_speling(request_rec *r) |
| { |
| spconfig *cfg; |
| char *good, *bad, *postgood, *url; |
| int filoc, dotloc, urlen, pglen; |
| DIR *dirp; |
| struct DIR_TYPE *dir_entry; |
| array_header *candidates = NULL; |
| |
| cfg = ap_get_module_config(r->per_dir_config, &speling_module); |
| if (!cfg->enabled) { |
| return DECLINED; |
| } |
| |
| /* We only want to worry about GETs */ |
| if (r->method_number != M_GET) { |
| return DECLINED; |
| } |
| |
| /* We've already got a file of some kind or another */ |
| if (r->proxyreq || (r->finfo.st_mode != 0)) { |
| return DECLINED; |
| } |
| |
| /* This is a sub request - don't mess with it */ |
| if (r->main) { |
| return DECLINED; |
| } |
| |
| /* |
| * The request should end up looking like this: |
| * r->uri: /correct-url/mispelling/more |
| * r->filename: /correct-file/mispelling r->path_info: /more |
| * |
| * So we do this in steps. First break r->filename into two pieces |
| */ |
| |
| filoc = ap_rind(r->filename, '/'); |
| /* |
| * Don't do anything if the request doesn't contain a slash, or |
| * requests "/" |
| */ |
| if (filoc == -1 || strcmp(r->uri, "/") == 0) { |
| return DECLINED; |
| } |
| |
| /* good = /correct-file */ |
| good = ap_pstrndup(r->pool, r->filename, filoc); |
| /* bad = mispelling */ |
| bad = ap_pstrdup(r->pool, r->filename + filoc + 1); |
| /* postgood = mispelling/more */ |
| postgood = ap_pstrcat(r->pool, bad, r->path_info, NULL); |
| |
| urlen = strlen(r->uri); |
| pglen = strlen(postgood); |
| |
| /* Check to see if the URL pieces add up */ |
| if (strcmp(postgood, r->uri + (urlen - pglen))) { |
| return DECLINED; |
| } |
| |
| /* url = /correct-url */ |
| url = ap_pstrndup(r->pool, r->uri, (urlen - pglen)); |
| |
| /* Now open the directory and do ourselves a check... */ |
| dirp = ap_popendir(r->pool, good); |
| if (dirp == NULL) { /* Oops, not a directory... */ |
| return DECLINED; |
| } |
| |
| candidates = ap_make_array(r->pool, 2, sizeof(misspelled_file)); |
| |
| dotloc = ap_ind(bad, '.'); |
| if (dotloc == -1) { |
| dotloc = strlen(bad); |
| } |
| |
| while ((dir_entry = readdir(dirp)) != NULL) { |
| sp_reason q; |
| |
| /* |
| * If we end up with a "fixed" URL which is identical to the |
| * requested one, we must have found a broken symlink or some such. |
| * Do _not_ try to redirect this, it causes a loop! |
| */ |
| if (strcmp(bad, dir_entry->d_name) == 0) { |
| ap_pclosedir(r->pool, dirp); |
| return OK; |
| } |
| /* |
| * miscapitalization errors are checked first (like, e.g., lower case |
| * file, upper case request) |
| */ |
| else if (strcasecmp(bad, dir_entry->d_name) == 0) { |
| misspelled_file *sp_new; |
| |
| sp_new = (misspelled_file *) ap_push_array(candidates); |
| sp_new->name = ap_pstrdup(r->pool, dir_entry->d_name); |
| sp_new->quality = SP_MISCAPITALIZED; |
| } |
| /* |
| * simple typing errors are checked next (like, e.g., |
| * missing/extra/transposed char) |
| */ |
| else if ((q = spdist(bad, dir_entry->d_name)) != SP_VERYDIFFERENT) { |
| misspelled_file *sp_new; |
| |
| sp_new = (misspelled_file *) ap_push_array(candidates); |
| sp_new->name = ap_pstrdup(r->pool, dir_entry->d_name); |
| sp_new->quality = q; |
| } |
| /* |
| * The spdist() should have found the majority of the misspelled |
| * requests. It is of questionable use to continue looking for |
| * files with the same base name, but potentially of totally wrong |
| * type (index.html <-> index.db). |
| * I would propose to not set the WANT_BASENAME_MATCH define. |
| * 08-Aug-1997 <Martin.Kraemer@Mch.SNI.De> |
| * |
| * However, Alexei replied giving some reasons to add it anyway: |
| * > Oh, by the way, I remembered why having the |
| * > extension-stripping-and-matching stuff is a good idea: |
| * > |
| * > If you're using MultiViews, and have a file named foobar.html, |
| * > which you refer to as "foobar", and someone tried to access |
| * > "Foobar", mod_speling won't find it, because it won't find |
| * > anything matching that spelling. With the extension-munging, |
| * > it would locate "foobar.html". Not perfect, but I ran into |
| * > that problem when I first wrote the module. |
| */ |
| else { |
| #ifdef WANT_BASENAME_MATCH |
| /* |
| * Okay... we didn't find anything. Now we take out the hard-core |
| * power tools. There are several cases here. Someone might have |
| * entered a wrong extension (.htm instead of .html or vice |
| * versa) or the document could be negotiated. At any rate, now |
| * we just compare stuff before the first dot. If it matches, we |
| * figure we got us a match. This can result in wrong things if |
| * there are files of different content types but the same prefix |
| * (e.g. foo.gif and foo.html) This code will pick the first one |
| * it finds. Better than a Not Found, though. |
| */ |
| int entloc = ap_ind(dir_entry->d_name, '.'); |
| if (entloc == -1) { |
| entloc = strlen(dir_entry->d_name); |
| } |
| |
| if ((dotloc == entloc) |
| && !strncasecmp(bad, dir_entry->d_name, dotloc)) { |
| misspelled_file *sp_new; |
| |
| sp_new = (misspelled_file *) ap_push_array(candidates); |
| sp_new->name = ap_pstrdup(r->pool, dir_entry->d_name); |
| sp_new->quality = SP_VERYDIFFERENT; |
| } |
| #endif |
| } |
| } |
| ap_pclosedir(r->pool, dirp); |
| |
| if (candidates->nelts != 0) { |
| /* Wow... we found us a mispelling. Construct a fixed url */ |
| char *nuri; |
| const char *ref; |
| misspelled_file *variant = (misspelled_file *) candidates->elts; |
| int i; |
| |
| ref = ap_table_get(r->headers_in, "Referer"); |
| |
| qsort((void *) candidates->elts, candidates->nelts, |
| sizeof(misspelled_file), sort_by_quality); |
| |
| /* |
| * Conditions for immediate redirection: |
| * a) the first candidate was not found by stripping the suffix |
| * AND b) there exists only one candidate OR the best match is not |
| * ambiguous |
| * then return a redirection right away. |
| */ |
| if (variant[0].quality != SP_VERYDIFFERENT |
| && (candidates->nelts == 1 |
| || variant[0].quality != variant[1].quality)) { |
| |
| nuri = ap_pstrcat(r->pool, url, variant[0].name, r->path_info, |
| r->parsed_uri.query ? "?" : "", |
| r->parsed_uri.query ? r->parsed_uri.query : "", |
| NULL); |
| |
| ap_table_setn(r->headers_out, "Location", |
| ap_construct_url(r->pool, nuri, r)); |
| |
| ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_INFO, r, |
| ref ? "Fixed spelling: %s to %s from %s" |
| : "Fixed spelling: %s to %s", |
| r->uri, nuri, ref); |
| |
| return HTTP_MOVED_PERMANENTLY; |
| } |
| /* |
| * Otherwise, a "[300] Multiple Choices" list with the variants is |
| * returned. |
| */ |
| else { |
| pool *p; |
| table *notes; |
| pool *sub_pool; |
| array_header *t; |
| array_header *v; |
| |
| |
| if (r->main == NULL) { |
| p = r->pool; |
| notes = r->notes; |
| } |
| else { |
| p = r->main->pool; |
| notes = r->main->notes; |
| } |
| |
| sub_pool = ap_make_sub_pool(p); |
| t = ap_make_array(sub_pool, candidates->nelts * 8 + 8, |
| sizeof(char *)); |
| v = ap_make_array(sub_pool, candidates->nelts * 5, |
| sizeof(char *)); |
| |
| /* Generate the response text. */ |
| |
| *(const char **)ap_push_array(t) = |
| "The document name you requested (<code>"; |
| *(const char **)ap_push_array(t) = r->uri; |
| *(const char **)ap_push_array(t) = |
| "</code>) could not be found on this server.\n" |
| "However, we found documents with names similar " |
| "to the one you requested.<p>" |
| "Available documents:\n<ul>\n"; |
| |
| for (i = 0; i < candidates->nelts; ++i) { |
| char *vuri; |
| const char *reason; |
| |
| reason = sp_reason_str[(int) (variant[i].quality)]; |
| /* The format isn't very neat... */ |
| vuri = ap_pstrcat(sub_pool, url, variant[i].name, r->path_info, |
| (r->parsed_uri.query != NULL) ? "?" : "", |
| (r->parsed_uri.query != NULL) |
| ? r->parsed_uri.query : "", |
| NULL); |
| *(const char **)ap_push_array(v) = "\""; |
| *(const char **)ap_push_array(v) = vuri; |
| *(const char **)ap_push_array(v) = "\";\""; |
| *(const char **)ap_push_array(v) = reason; |
| *(const char **)ap_push_array(v) = "\""; |
| |
| *(const char **)ap_push_array(t) = "<li><a href=\""; |
| *(const char **)ap_push_array(t) = vuri; |
| *(const char **)ap_push_array(t) = "\">"; |
| *(const char **)ap_push_array(t) = vuri; |
| *(const char **)ap_push_array(t) = "</a> ("; |
| *(const char **)ap_push_array(t) = reason; |
| *(const char **)ap_push_array(t) = ")\n"; |
| |
| /* |
| * when we have printed the "close matches" and there are |
| * more "distant matches" (matched by stripping the suffix), |
| * then we insert an additional separator text to suggest |
| * that the user LOOK CLOSELY whether these are really the |
| * files she wanted. |
| */ |
| if (i > 0 && i < candidates->nelts - 1 |
| && variant[i].quality != SP_VERYDIFFERENT |
| && variant[i + 1].quality == SP_VERYDIFFERENT) { |
| *(const char **)ap_push_array(t) = |
| "</ul>\nFurthermore, the following related " |
| "documents were found:\n<ul>\n"; |
| } |
| } |
| *(const char **)ap_push_array(t) = "</ul>\n"; |
| |
| /* If we know there was a referring page, add a note: */ |
| if (ref != NULL) { |
| *(const char **)ap_push_array(t) = |
| "Please consider informing the owner of the " |
| "<a href=\""; |
| *(const char **)ap_push_array(t) = ref; |
| *(const char **)ap_push_array(t) = "\">referring page</a> " |
| "about the broken link.\n"; |
| } |
| |
| |
| /* Pass our table to http_protocol.c (see mod_negotiation): */ |
| ap_table_setn(notes, "variant-list", ap_array_pstrcat(p, t, 0)); |
| |
| ap_table_mergen(r->subprocess_env, "VARIANTS", |
| ap_array_pstrcat(p, v, ',')); |
| |
| ap_destroy_pool(sub_pool); |
| |
| ap_log_rerror(APLOG_MARK, APLOG_NOERRNO | APLOG_INFO, r, |
| ref ? "Spelling fix: %s: %d candidates from %s" |
| : "Spelling fix: %s: %d candidates", |
| r->uri, candidates->nelts, ref); |
| |
| return HTTP_MULTIPLE_CHOICES; |
| } |
| } |
| |
| return OK; |
| } |
| |
| module MODULE_VAR_EXPORT speling_module = |
| { |
| STANDARD_MODULE_STUFF, |
| NULL, /* initializer */ |
| create_mconfig_for_directory, /* create per-dir config */ |
| NULL, /* merge per-dir config */ |
| create_mconfig_for_server, /* server config */ |
| NULL, /* merge server config */ |
| speling_cmds, /* command table */ |
| NULL, /* handlers */ |
| NULL, /* filename translation */ |
| NULL, /* check_user_id */ |
| NULL, /* check auth */ |
| NULL, /* check access */ |
| NULL, /* type_checker */ |
| check_speling, /* fixups */ |
| NULL, /* logger */ |
| NULL, /* header parser */ |
| NULL, /* child_init */ |
| NULL, /* child_exit */ |
| NULL /* post read-request */ |
| }; |
