PHP PREG_REPLACE REGEX Mention Username - php

Question

user_model.php
class User_model extends CI_Model{
function get_fullname_by_username($username){
$query=$this->db->select('user_first_name,user_last_name')->where('user_name',$username)->get('user');
if($query->num_rows()==0){
return FALSE;
} else {
return $query->row();
}
}
}
post_model.php
class Post_model extends CI_Model{
function input_post($content,$privacy==FALSE){
$this->load->library('privacy');
$this->load->helper('post');
$uid=uid();//user id based on sessions
if($privacy==FALSE){
$privacy=$this->privacy->post_privacy($uid);
} else {
$privacy=$privacy;
}
$content=mention($content);
$input=array('post_uid'=>$uid,'post_content'=>$content,'post_privacy'=>$privacy);
if($this->db->insert('posts',$input)){
return $this->fetch_single_post_data($this->db->insert_id());
} else {
return FALSE;
}
}
function fetch_single_post_data($post_id){
$query=$this->db->select('id,post_uid,post_content,post_privacy,post_created')->where('id',$post_id)->get('posts');
if($query->num_rows()==0){
return FALSE;
} else {
return $query->row();
}
}
}
post_helper.php
function get_mention_name($username){
$username=strtolower($username);
$CI=&get_instance();
$CI->load->model('user_model');
$name=$CI->user_model->get_fullname_by_username($username);
if($name==FALSE){
return "#".$username;
} else {
return "{$name->user_first_name} {$name->user_last_name}";
}
}
function mention($post_content){
return preg_replace_callback("REGEX","get_mention_name",$post_content);
}
First off all, English isn't my native language. So, please if my grammar is bad forgive me.
For my school final project i just want to create Facebook like website (social networking). My problem is, i want to create mention feature, based on username (user database). If at Facebook after I type the # symbol, Facebook system begin to query most possibly Friend/Page with cool ajax list display. But i don't want be like that, at my system there's no ajax list display.
If user post status update with string like #bias or #tegaralaga or #admin "#tegaralaga where are you?" for the example. My system check on database is there any user with username #tegaralaga, if yes based on user_model.php function get_fullname_by_username(); it will return user_first_name and user_last_name data. But if no it will give FALSE return. On my user table there's user with tegaralaga username, the user_first_name is Bias and user_last_name is Tegaralaga.
Move at post_helper.php, if $name==FALSE it will give current string, #tegaralaga. But if the username is exists, it will return "{$name->user_first_name} {$name->user_last_name}".
If exists, the string become
"Bias Tegaralaga where are you?"
If doesn't, the string still
"#tegaralaga where are you?"
So my question is :
1. Is it possible with my code above using preg_replace_callback? (take a look at post_helper.php)
2. If possible, what is the perfect REGEX if we can mention more than 1 username, and the exception for email address (because email address contains # symbol too)

Answer 1

This should work for you.. on your callback function you receive all the matches from the regexp.. you need to extract the part you need:
function get_mention_name($match){
$username=strtolower($match[1]);
$CI=&get_instance();
$CI->load->model('user_model');
$name=$CI->user_model->get_fullname_by_username($username);
if(empty($name)){
return "#".$username;
} else {
return "{$name->user_first_name} {$name->user_last_name}";
}
}
function mention($post_content){
return preg_replace_callback(
"#(?<!\w)#(\w+)#",
"get_mention_name",
$post_content);
}