How to wrap user mentions in a HTML link on PHP? - php

Question

Im working on a commenting web application and i want to parse user mentions (#user) as links. Here is what I have so far:
$text = "#user is not #user1 but #user3 is #user4";
$pattern = "/\#(\w+)/";
preg_match_all($pattern,$text,$matches);
if($matches){
$sql = "SELECT *
FROM users
WHERE username IN ('" .implode("','",$matches[1]). "')
ORDER BY LENGTH(username) DESC";
$users = $this->getQuery($sql);
foreach($users as $i=>$u){
$text = str_replace("#{$u['username']}",
"<a href='#' class='ct-userLink' rel='{$u['user_id']}'>#{$u['username']}</a> ", $text);
}
$echo $text;
}
The problem is that user links are being overlapped:
<a rel="11327" class="ct-userLink" href="#">
<a rel="21327" class="ct-userLink" href="#">#user</a>1
</a>
How can I avoid links overlapping?
Answer Update
Thanks to the answer picked, this is how my new foreach loop looks like:
foreach($users as $i=>$u){
$text = preg_replace("/#".$u['username']."\b/",
"<a href='#' title='{$u['user_id']}'>#{$u['username']}</a> ", $text);
}

Answer 1

Problem seems to be that some usernames can encompass other usernames. So you replace user1 properly with <a>user1</a>. Then, user matches and replaces with <a><a>user</a>1</a>. My suggestion is to change your string replace to a regex with a word boundary, \b, that is required after the username.

Answer 2

The Twitter widget has JavaScript code to do this. I ported it to PHP in my WordPress plugin. Here's the relevant part:
function format_tweet($tweet) {
// add #reply links
$tweet_text = preg_replace("/\B[#＠]([a-zA-Z0-9_]{1,20})/",
"#<a class='atreply' href='http://twitter.com/$1'>$1</a>",
$tweet);
// make other links clickable
$matches = array();
$link_info = preg_match_all("/\b(((https*\:\/\/)|www\.)[^\"\']+?)(([!?,.\)]+)?(\s|$))/",
$tweet_text, $matches, PREG_SET_ORDER);
if ($link_info) {
foreach ($matches as $match) {
$http = preg_match("/w/", $match[2]) ? 'http://' : '';
$tweet_text = str_replace($match[0],
"<a href='" . $http . $match[1] . "'>" . $match[1] . "</a>" . $match[4],
$tweet_text);
}
}
return $tweet_text;
}

Answer 3

instead of parsing for '#user' parse for '#user ' (with space in the end) or ' #user ' to even avoid wrong parsing of email addresses (eg: mailaddress#user.com) maybe ' #user: ' should also be allowed. this will only work, if usernames have no whitespaces...

Answer 4

You can go for a custom str replace function which stops at first replace.. Something like ...
function str_replace_once($needle , $replace , $haystack){
$pos = strpos($haystack, $needle);
if ($pos === false) {
// Nothing found
return $haystack;
}
return substr_replace($haystack, $replace, $pos, strlen($needle));
}
And use it like:
foreach($users as $i=>$u){
$text = str_replace_once("#{$u['username']}",
"<a href='#' class='ct-userLink' rel='{$u['user_id']}'>#{$u['username']}</a> ", $text);
}

Answer 5

You shouldn’t replace one certain user mention at a time but all at once. You could use preg_split to do that:
// split text at mention while retaining user name
$parts = preg_split("/#(\w+)/", $text, -1, PREG_SPLIT_DELIM_CAPTURE);
$n = count($parts);
// $n is always an odd number; 1 means no match found
if ($n > 1) {
// collect user names
$users = array();
for ($i=1; $i<$n; $i+=2) {
$users[$parts[$i]] = '';
}
// get corresponding user information
$sql = "SELECT *
FROM users
WHERE username IN ('" .implode("','", array_keys($users)). "')";
$users = array();
foreach ($this->getQuery($sql) as $user) {
$users[$user['username']] = $user;
}
// replace mentions
for ($i=1; $i<$n; $i+=2) {
$u = $users[$parts[$i]];
$parts[$i] = "<a href='#' class='ct-userLink' rel='{$u['user_id']}'>#{$u['username']}</a>";
}
// put everything back together
$text = implode('', $parts);
}

Answer 6

I like dnl solution of parsing ' #user', but maybe is not suitable for you.
Anyway, did you try to use strip_tags function to remove the anchor tags? That way you have the string without the links, and you can parse it building the links again.
strip_tags