function _filter_url
7.x filter.module | _filter_url($text, |
6.x filter.module | _filter_url($text, $format) |
Implements callback_filter_process().
Converts text into hyperlinks automatically.
This filter identifies and makes clickable three types of "links".
- URLs like http://example.com.
- E-mail addresses like name@example.com.
- Web addresses without the "http://" protocol defined, like www.example.com.
Each type must be processed separately, as there is no one regular expression that could possibly match all of the cases in one pass.
Related topics
1 call to _filter_url()
- FilterUnitTestCase::testUrlFilterContent in drupal-7.x/
modules/ filter/ filter.test - Tests URL filter on longer content.
2 string references to '_filter_url'
- FilterUnitTestCase::testUrlFilter in drupal-7.x/
modules/ filter/ filter.test - Tests the URL filter.
- filter_filter_info in drupal-7.x/
modules/ filter/ filter.module - Implements hook_filter_info().
File
- drupal-7.x/
modules/ filter/ filter.module, line 1444 - Framework for handling the filtering of content.
Code
function _filter_url($text, $filter) {
// Tags to skip and not recurse into.
$ignore_tags = 'a|script|style|code|pre';
// Pass length to regexp callback.
_filter_url_trim(NULL, $filter->settings['filter_url_length']);
// Create an array which contains the regexps for each type of link.
// The key to the regexp is the name of a function that is used as
// callback function to process matches of the regexp. The callback function
// is to return the replacement for the match. The array is used and
// matching/replacement done below inside some loops.
$tasks = array();
// Prepare protocols pattern for absolute URLs.
// check_url() will replace any bad protocols with HTTP, so we need to support
// the identical list. While '//' is technically optional for MAILTO only,
// we cannot cleanly differ between protocols here without hard-coding MAILTO,
// so '//' is optional for all protocols.
// @see filter_xss_bad_protocol()
$protocols = variable_get('filter_allowed_protocols', array('ftp', 'http', 'https', 'irc', 'mailto', 'news', 'nntp', 'rtsp', 'sftp', 'ssh', 'tel', 'telnet', 'webcal'));
$protocols = implode(':(?://)?|', $protocols) . ':(?://)?';
// Prepare domain name pattern.
// The ICANN seems to be on track towards accepting more diverse top level
// domains, so this pattern has been "future-proofed" to allow for TLDs
// of length 2-64.
$domain = '(?:[A-Za-z0-9._+-]+\.)?[A-Za-z]{2,64}\b';
$ip = '(?:[0-9]{1,3}\.){3}[0-9]{1,3}';
$auth = '[a-zA-Z0-9:%_+*~#?&=.,/;-]+@';
$trail = '[a-zA-Z0-9:%_+*~#&\[\]=/;?!\.,-]*[a-zA-Z0-9:%_+*~#&\[\]=/;-]';
// Prepare pattern for optional trailing punctuation.
// Even these characters could have a valid meaning for the URL, such usage is
// rare compared to using a URL at the end of or within a sentence, so these
// trailing characters are optionally excluded.
$punctuation = '[\.,?!]*?';
// Match absolute URLs.
$url_pattern = "(?:$auth)?(?:$domain|$ip)/?(?:$trail)?";
$pattern = "`((?:$protocols)(?:$url_pattern))($punctuation)`";
$tasks['_filter_url_parse_full_links'] = $pattern;
// Match e-mail addresses.
$url_pattern = "[A-Za-z0-9._-]{1,254}@(?:$domain)";
$pattern = "`($url_pattern)`";
$tasks['_filter_url_parse_email_links'] = $pattern;
// Match www domains.
$url_pattern = "www\.(?:$domain)/?(?:$trail)?";
$pattern = "`($url_pattern)($punctuation)`";
$tasks['_filter_url_parse_partial_links'] = $pattern;
// Each type of URL needs to be processed separately. The text is joined and
// re-split after each task, since all injected HTML tags must be correctly
// protected before the next task.
foreach ($tasks as $task => $pattern) {
// HTML comments need to be handled separately, as they may contain HTML
// markup, especially a '>'. Therefore, remove all comment contents and add
// them back later.
_filter_url_escape_comments('', TRUE);
$text = preg_replace_callback('`<!--(.*?)-->`s', '_filter_url_escape_comments', $text);
// Split at all tags; ensures that no tags or attributes are processed.
$chunks = preg_split('/(<.+?>)/is', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
// PHP ensures that the array consists of alternating delimiters and
// literals, and begins and ends with a literal (inserting NULL as
// required). Therefore, the first chunk is always text:
$chunk_type = 'text';
// If a tag of $ignore_tags is found, it is stored in $open_tag and only
// removed when the closing tag is found. Until the closing tag is found,
// no replacements are made.
$open_tag = '';
for ($i = 0; $i < count($chunks); $i++) {
if ($chunk_type == 'text') {
// Only process this text if there are no unclosed $ignore_tags.
if ($open_tag == '') {
// If there is a match, inject a link into this chunk via the callback
// function contained in $task.
$chunks[$i] = preg_replace_callback($pattern, $task, $chunks[$i]);
}
// Text chunk is done, so next chunk must be a tag.
$chunk_type = 'tag';
}
else {
// Only process this tag if there are no unclosed $ignore_tags.
if ($open_tag == '') {
// Check whether this tag is contained in $ignore_tags.
if (preg_match("`<($ignore_tags)(?:\s|>)`i", $chunks[$i], $matches)) {
$open_tag = $matches[1];
}
}
// Otherwise, check whether this is the closing tag for $open_tag.
else {
if (preg_match("`<\/$open_tag>`i", $chunks[$i], $matches)) {
$open_tag = '';
}
}
// Tag chunk is done, so next chunk must be text.
$chunk_type = 'text';
}
}
$text = implode($chunks);
// Revert back to the original comment contents
_filter_url_escape_comments('', FALSE);
$text = preg_replace_callback('`<!--(.*?)-->`', '_filter_url_escape_comments', $text);
}
return $text;
}