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Implement wildcard URI matching for http_server

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Ondřej Hruška 2018-10-17 22:57:37 +02:00 committed by Anurag Kar
parent 577f8d8527
commit 91d6b3b989
1 changed files with 70 additions and 4 deletions
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74
components/esp_http_server/src/httpd_uri.c
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@ -23,6 +23,73 @@
static const char *TAG = "httpd_uri";
/**
* @brief Test if a URI matches the given template.
*
* Template may end with "?" to make the previous character optional (typically a slash),
* "*" for a wildcard match, and "?*" to make the previous character optional, and if present,
* allow anything to follow.
*
* Example:
* - * matches everything
* - /foo/? matches /foo and /foo/
* - /foo/\* (sans the backslash) matches /foo/ and /foo/bar, but not /foo or /fo
* - /foo/?* or /foo/\*? (sans the backslash) matches /foo/, /foo/bar, and also /foo, but not /foox or /fo
*
* The special characters "?" and "*" anywhere else in the template will be taken literally.
*
* @param[in] template - URI template (pattern)
* @param[in] uri - tested URI
* @param[in] template - how many characters of the URI buffer to test
* (there may be trailing query string etc.)
*
* @return true if a match was found
*/
static bool uri_matches(const char *template, const char *uri, const unsigned int len)
{
const size_t tpl_len = strlen(template);
size_t exact_match_chars = tpl_len;
/* Check for trailing question mark and asterisk */
const char last = (const char) (tpl_len > 0 ? template[tpl_len - 1] : 0);
const char prevlast = (const char) (tpl_len > 1 ? template[tpl_len - 2] : 0);
const bool asterisk = last == '*' || (prevlast == '*' && last == '?');
const bool quest = last == '?' || (prevlast == '?' && last == '*');
/* abort in cases such as "?" with no preceding character (invalid template) */
if (exact_match_chars < asterisk + quest*2) return false;
/* account for special characters and the optional character if "?" is used */
exact_match_chars -= asterisk + quest*2;
if (len < exact_match_chars) return false;
if (!quest) {
if (!asterisk && len != exact_match_chars) {
/* no special characters and different length - strncmp would return false */
return false;
}
/* asterisk allows arbitrary trailing characters, we ignore these using
* exact_match_chars as the length limit */
return 0 == strncmp(template, uri, exact_match_chars);
} else {
/* question mark present */
if (len > exact_match_chars && template[exact_match_chars] != uri[exact_match_chars]) {
/* the optional character is present, but different */
return false;
}
if (0 != strncmp(template, uri, exact_match_chars)) {
/* the mandatory part differs */
return false;
}
/* Now we know the URI is longer than the required part of template,
* the mandatory part matches, and if the optional character is present, it is correct.
* Match is OK if we have asterisk, i.e. any trailing characters are OK, or if
* there are no characters beyond the optional character. */
return asterisk || len <= exact_match_chars + 1;
}
}
static int httpd_find_uri_handler(struct httpd_data *hd,
const char* uri,
httpd_method_t method)
@ -31,7 +98,7 @@ static int httpd_find_uri_handler(struct httpd_data *hd,
if (hd->hd_calls[i]) {
ESP_LOGD(TAG, LOG_FMT("[%d] = %s"), i, hd->hd_calls[i]->uri);
if ((hd->hd_calls[i]->method == method) && // First match methods
(strcmp(hd->hd_calls[i]->uri, uri) == 0)) { // Then match uri strings
uri_matches(hd->hd_calls[i]->uri, uri, strlen(uri))) { // Then match uri strings
return i;
}
}
@ -161,9 +228,8 @@ static httpd_uri_t* httpd_find_uri_handler2(httpd_err_resp_t *err,
for (int i = 0; i < hd->config.max_uri_handlers; i++) {
if (hd->hd_calls[i]) {
ESP_LOGD(TAG, LOG_FMT("[%d] = %s"), i, hd->hd_calls[i]->uri);
if ((strlen(hd->hd_calls[i]->uri) == uri_len) && // First match uri length
(strncmp(hd->hd_calls[i]->uri, uri, uri_len) == 0)) { // Then match uri strings
if (hd->hd_calls[i]->method == method) { // Finally match methods
if (uri_matches(hd->hd_calls[i]->uri, uri, uri_len)) {
if (hd->hd_calls[i]->method == method) { // Match methods
return hd->hd_calls[i];
}
/* URI found but method not allowed.