how to count repeated post in chat page using php or php session?

Question

I have some chat bot script and I need a way to stop spam of users who keep reposting same link in chat more than 2 times.

$a = file_get_contents($url);

$matches = explode('<tr id=', $a);  

for($i=2; $i<15; $i++) {

    $mess = $matches[$i];

    preg_match('%"(.*)">%U', $mess, $id);

    $id_user = $id[1];

    preg_match('%<b class="(.*)">(.*)</b>%U', $mess, $mem);

    $name = $mem[2];

    preg_match('%</b>:(.*)</td></tr>%U', $mess, $chat);

    $chat = $chat[1];

    $link = explode('<a href="', $chat);

    $link = explode('"', $link[1]);

    $link = $link[0];

Now what I need is for a function to count if the same link was posted 2 times by the same user $name and give a warning and if 3 times to call another function to ban which I do have.

Answer 1

Ok, one way to do this is to check the message before it's even been added to the chat file. A easy way to accomplish this with PHP is to use PHP Sessions that will store a counter for repeated values. Since I don't know the structure of your site, I'll give you basic instructions of how to do this:

1. Start the session for the "post to chat" function
PHP Sessions need to be started wherever you use them. This can be done with a simple.

session_start();

2. Create the two session variables if it doesn't exist

session_start();
if(!isset($_SESSION['latest_link'])){ //isset() checks whether or not the variable exists
   $_SESSION['latest_link'] = "";
}
if(!isset($_SESSION['duplicate_count'])){
   $_SESSION['duplicate_count'] = 0;
}

3. For new links check if it matches the last link

session_start();
if(!isset($_SESSION['latest_link'])){ //isset() checks whether or not the variable exists
   $_SESSION['latest_link'] = "";
}
if(!isset($_SESSION['duplicate_count'])){
   $_SESSION['duplicate_count'] = 0;
}
if($_SESSION['latest_link'] == trim(strtolower($link))){ //where $link is the new link being posted. trim() removes unneeded whitespace and strtolower() makes everything lowercase. This way, the poster can't fool the system through capitalization or extra spaces

}

5. If the link is a duplicate add one to the duplicate_count.

session_start();
if(!isset($_SESSION['latest_link'])){ //isset() checks whether or not the variable exists
   $_SESSION['latest_link'] = "";
}
if(!isset($_SESSION['duplicate_count'])){
   $_SESSION['duplicate_count'] = 0;
}
if($_SESSION['latest_link'] == trim(strtolower($link))){ //where $link is the new link being posted. trim() removes unneeded whitespace and strtolower() makes everything lowercase. This way, the poster can't fool the system through capitalization or extra spaces
   $_SESSION['duplicate_count']++; //add one to duplicate_count
}

6. Check if the duplicate_count is larger than 2

session_start();
if(!isset($_SESSION['latest_link'])){ //isset() checks whether or not the variable exists
   $_SESSION['latest_link'] = "";
}
if(!isset($_SESSION['duplicate_count'])){
   $_SESSION['duplicate_count'] = 0;
}
if($_SESSION['latest_link'] == trim(strtolower($link))){ //where $link is the new link being posted. trim() removes unneeded whitespace and strtolower() makes everything lowercase. This way, the poster can't fool the system through capitalization or extra spaces
   $_SESSION['duplicate_count']++; //add one to duplicate_count
}
if($_SESSION['duplicate_count'] > 2){
     //user has posted same link more than 2 times. Action should be taken.
}

7. Log the user's latest link if it is different, and reset the counter
Simply done with

session_start();
if(!isset($_SESSION['latest_link'])){ //isset() checks whether or not the variable exists
   $_SESSION['latest_link'] = "";
}
if(!isset($_SESSION['duplicate_count'])){
   $_SESSION['duplicate_count'] = 0;
}
if($_SESSION['latest_link'] == trim(strtolower($link))){ //where $link is the new link being posted. trim() removes unneeded whitespace and strtolower() makes everything lowercase. This way, the poster can't fool the system through capitalization or extra spaces
   $_SESSION['duplicate_count']++; //add one to duplicate_count
}else{
   $_SESSION['latest_link'] = trim(strtolower($link));
   $_SESSION['duplicate_count'] = 0;
}
if($_SESSION['duplicate_count'] > 2){
     //user has posted same link more than 2 times. Action should be taken.
}

Of course, you should also consider securing your sessions to prevent session hijacking, but that is another topic that you can find plenty of answers for on Stack Overflow. This post has some good pointers: PHP Session Security