| /* Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "apr.h" |
| #include "apr_file_io.h" |
| #include "apr_strings.h" |
| #include "apr_lib.h" |
| |
| #define APR_WANT_STRFUNC |
| #include "apr_want.h" |
| |
| #include "httpd.h" |
| #include "http_core.h" |
| #include "http_config.h" |
| #include "http_request.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. |
| * |
| * Sep-1999 Hugo Haas <hugo@w3.org> |
| * o Added a CheckCaseOnly option to check only miscapitalized words. |
| * |
| * 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 AP_MODULE_DECLARE_DATA speling_module; |
| |
| typedef struct { |
| int enabled; |
| int check_case_only; |
| int check_basename_match; |
| } 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(apr_pool_t *p) |
| { |
| spconfig *cfg = apr_pcalloc(p, sizeof(spconfig)); |
| |
| cfg->enabled = 0; |
| cfg->check_case_only = 0; |
| cfg->check_basename_match = 0; |
| return cfg; |
| } |
| |
| /* |
| * Respond to a callback to create configuration record for a server or |
| * vhost environment. |
| */ |
| static void *create_mconfig_for_server(apr_pool_t *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(apr_pool_t *p, char *dir) |
| { |
| return mkconfig(p); |
| } |
| |
| /* |
| * Define the directives specific to this module. This structure is referenced |
| * later by the 'module' structure. |
| */ |
| static const command_rec speling_cmds[] = |
| { |
| AP_INIT_FLAG("CheckSpelling", ap_set_flag_slot, |
| (void*)APR_OFFSETOF(spconfig, enabled), OR_OPTIONS, |
| "whether or not to fix miscapitalized/misspelled requests"), |
| AP_INIT_FLAG("CheckCaseOnly", ap_set_flag_slot, |
| (void*)APR_OFFSETOF(spconfig, check_case_only), OR_OPTIONS, |
| "whether or not to fix only miscapitalized requests"), |
| AP_INIT_FLAG("CheckBasenameMatch", ap_set_flag_slot, |
| (void*)APR_OFFSETOF(spconfig, check_basename_match), OR_OPTIONS, |
| "whether or not to fix files with the same base name"), |
| { 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 (; apr_tolower(*s) == apr_tolower(*t); t++, s++) { |
| if (*t == '\0') { |
| return SP_MISCAPITALIZED; /* exact match (sans case) */ |
| } |
| } |
| if (*s) { |
| if (*t) { |
| if (s[1] && t[1] && apr_tolower(*s) == apr_tolower(t[1]) |
| && apr_tolower(*t) == apr_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; |
| apr_finfo_t dirent; |
| int filoc, dotloc, urlen, pglen; |
| apr_array_header_t *candidates = NULL; |
| apr_dir_t *dir; |
| |
| 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->finfo.filetype != APR_NOFILE) { |
| return DECLINED; |
| } |
| |
| /* Not a file request */ |
| if (r->proxyreq || !r->filename) { |
| 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 = apr_pstrndup(r->pool, r->filename, filoc); |
| /* bad = mispelling */ |
| bad = apr_pstrdup(r->pool, r->filename + filoc + 1); |
| /* postgood = mispelling/more */ |
| postgood = apr_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 = apr_pstrndup(r->pool, r->uri, (urlen - pglen)); |
| |
| /* Now open the directory and do ourselves a check... */ |
| if (apr_dir_open(&dir, good, r->pool) != APR_SUCCESS) { |
| /* Oops, not a directory... */ |
| return DECLINED; |
| } |
| |
| candidates = apr_array_make(r->pool, 2, sizeof(misspelled_file)); |
| |
| dotloc = ap_ind(bad, '.'); |
| if (dotloc == -1) { |
| dotloc = strlen(bad); |
| } |
| |
| while (apr_dir_read(&dirent, APR_FINFO_DIRENT, dir) == APR_SUCCESS) { |
| 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, dirent.name) == 0) { |
| apr_dir_close(dir); |
| return OK; |
| } |
| |
| /* |
| * miscapitalization errors are checked first (like, e.g., lower case |
| * file, upper case request) |
| */ |
| else if (strcasecmp(bad, dirent.name) == 0) { |
| misspelled_file *sp_new; |
| |
| sp_new = (misspelled_file *) apr_array_push(candidates); |
| sp_new->name = apr_pstrdup(r->pool, dirent.name); |
| sp_new->quality = SP_MISCAPITALIZED; |
| } |
| |
| /* |
| * simple typing errors are checked next (like, e.g., |
| * missing/extra/transposed char) |
| */ |
| else if ((cfg->check_case_only == 0) |
| && ((q = spdist(bad, dirent.name)) != SP_VERYDIFFERENT)) { |
| misspelled_file *sp_new; |
| |
| sp_new = (misspelled_file *) apr_array_push(candidates); |
| sp_new->name = apr_pstrdup(r->pool, dirent.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). |
| * |
| * If you're using MultiViews, and have a file named foobar.html, |
| * which you refer to as "foobar", and someone tried to access |
| * "Foobar", without CheckBasenameMatch, mod_speling won't find it, |
| * because it won't find anything matching that spelling. |
| * With the extension-munging, it would locate "foobar.html". |
| */ |
| else if (cfg->check_basename_match == 1) { |
| /* |
| * 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(dirent.name, '.'); |
| if (entloc == -1) { |
| entloc = strlen(dirent.name); |
| } |
| |
| if ((dotloc == entloc) |
| && !strncasecmp(bad, dirent.name, dotloc)) { |
| misspelled_file *sp_new; |
| |
| sp_new = (misspelled_file *) apr_array_push(candidates); |
| sp_new->name = apr_pstrdup(r->pool, dirent.name); |
| sp_new->quality = SP_VERYDIFFERENT; |
| } |
| } |
| } |
| apr_dir_close(dir); |
| |
| 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 = apr_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_escape_uri(r->pool, apr_pstrcat(r->pool, url, |
| variant[0].name, |
| r->path_info, NULL)); |
| if (r->parsed_uri.query) |
| nuri = apr_pstrcat(r->pool, nuri, "?", r->parsed_uri.query, NULL); |
| |
| apr_table_setn(r->headers_out, "Location", |
| ap_construct_url(r->pool, nuri, r)); |
| |
| ap_log_rerror(APLOG_MARK, APLOG_INFO, APR_SUCCESS, |
| r, |
| ref ? APLOGNO(03224) "Fixed spelling: %s to %s from %s" |
| : APLOGNO(03225) "Fixed spelling: %s to %s%s", |
| r->uri, nuri, |
| (ref ? ref : "")); |
| |
| return HTTP_MOVED_PERMANENTLY; |
| } |
| /* |
| * Otherwise, a "[300] Multiple Choices" list with the variants is |
| * returned. |
| */ |
| else { |
| apr_pool_t *p; |
| apr_table_t *notes; |
| apr_pool_t *sub_pool; |
| apr_array_header_t *t; |
| apr_array_header_t *v; |
| |
| |
| if (r->main == NULL) { |
| p = r->pool; |
| notes = r->notes; |
| } |
| else { |
| p = r->main->pool; |
| notes = r->main->notes; |
| } |
| |
| if (apr_pool_create(&sub_pool, p) != APR_SUCCESS) |
| return DECLINED; |
| |
| t = apr_array_make(sub_pool, candidates->nelts * 8 + 8, |
| sizeof(char *)); |
| v = apr_array_make(sub_pool, candidates->nelts * 5, |
| sizeof(char *)); |
| |
| /* Generate the response text. */ |
| |
| *(const char **)apr_array_push(t) = |
| "The document name you requested (<code>"; |
| *(const char **)apr_array_push(t) = ap_escape_html(sub_pool, r->uri); |
| *(const char **)apr_array_push(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 = apr_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 **)apr_array_push(v) = "\""; |
| *(const char **)apr_array_push(v) = ap_escape_uri(sub_pool, vuri); |
| *(const char **)apr_array_push(v) = "\";\""; |
| *(const char **)apr_array_push(v) = reason; |
| *(const char **)apr_array_push(v) = "\""; |
| |
| *(const char **)apr_array_push(t) = "<li><a href=\""; |
| *(const char **)apr_array_push(t) = ap_escape_uri(sub_pool, vuri); |
| *(const char **)apr_array_push(t) = "\">"; |
| *(const char **)apr_array_push(t) = ap_escape_html(sub_pool, vuri); |
| *(const char **)apr_array_push(t) = "</a> ("; |
| *(const char **)apr_array_push(t) = reason; |
| *(const char **)apr_array_push(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 **)apr_array_push(t) = |
| "</ul>\nFurthermore, the following related " |
| "documents were found:\n<ul>\n"; |
| } |
| } |
| *(const char **)apr_array_push(t) = "</ul>\n"; |
| |
| /* If we know there was a referring page, add a note: */ |
| if (ref != NULL) { |
| *(const char **)apr_array_push(t) = |
| "Please consider informing the owner of the " |
| "<a href=\""; |
| *(const char **)apr_array_push(t) = ap_escape_uri(sub_pool, ref); |
| *(const char **)apr_array_push(t) = "\">referring page</a> " |
| "about the broken link.\n"; |
| } |
| |
| |
| /* Pass our apr_table_t to http_protocol.c (see mod_negotiation): */ |
| apr_table_setn(notes, "variant-list", apr_array_pstrcat(p, t, 0)); |
| |
| apr_table_mergen(r->subprocess_env, "VARIANTS", |
| apr_array_pstrcat(p, v, ',')); |
| |
| apr_pool_destroy(sub_pool); |
| |
| ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, |
| ref ? APLOGNO(03226) "Spelling fix: %s: %d candidates from %s" |
| : APLOGNO(03227) "Spelling fix: %s: %d candidates%s", |
| r->uri, candidates->nelts, |
| (ref ? ref : "")); |
| |
| return HTTP_MULTIPLE_CHOICES; |
| } |
| } |
| |
| return OK; |
| } |
| |
| static void register_hooks(apr_pool_t *p) |
| { |
| ap_hook_fixups(check_speling,NULL,NULL,APR_HOOK_LAST); |
| } |
| |
| AP_DECLARE_MODULE(speling) = |
| { |
| STANDARD20_MODULE_STUFF, |
| 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 apr_table_t */ |
| register_hooks /* register hooks */ |
| }; |
