[php] How do I count unique visitors to my site?

I am making a visitor counting system for user posts to show the most viewed posts on homepage. I have a visitor counting system now but all it registers a view at every page refresh. I cannot use Google Analytics.

What I need is a visitor counter which only counts the unique visitors. In my case, unique means one person can only view a post in a day? Even a week might work, I think. Can you write that php code in here? You can give me a link to some good tutorials too if you like too.

This is what the code needs to do (or equivalent):

1. Once the page loads, check if the visitor is new or old(I have no idea how to do it .. )
2. If he is old, ignore him
3. If he is new, in mysql, views = views + 1

I have edited the "Best answer" code, though I found a useful thing that was missing. This is will also track the ip of a user if they are using a Proxy or simply if the server has nginx installed as a proxy reverser.

I added this code to his script at the top of the function:

function getRealIpAddr()
{
    if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet
    {
      $ip=$_SERVER['HTTP_CLIENT_IP'];
    }
    elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))   //to check ip is pass from proxy
    {
      $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
    }
    else
    {
      $ip=$_SERVER['REMOTE_ADDR'];
    }
    return $ip;
}
$adresseip = getRealIpAddr();

Afther that I edited his code.

Find the line that says the following:

// get the user name if it is logged, or the visitors IP (and add the identifier)

    $uvon = isset($_SESSION['nume']) ? $_SESSION['nume'] : $_SERVER['SERVER_ADDR']. $vst_id;

and replace it with this:

$uvon = isset($_SESSION['nume']) ? $_SESSION['nume'] : $adresseip. $vst_id;

This will work.

Here is the full code if anything happens:

<?php

function getRealIpAddr()
{
    if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet
    {
      $ip=$_SERVER['HTTP_CLIENT_IP'];
    }
    elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))   //to check ip is pass from proxy
    {
      $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
    }
    else
    {
      $ip=$_SERVER['REMOTE_ADDR'];
    }
    return $ip;
}
$adresseip = getRealIpAddr();

// Script Online Users and Visitors - http://coursesweb.net/php-mysql/
if(!isset($_SESSION)) session_start();        // start Session, if not already started

$filetxt = 'userson.txt';  // the file in which the online users /visitors are stored
$timeon = 120;             // number of secconds to keep a user online
$sep = '^^';               // characters used to separate the user name and date-time
$vst_id = '-vst-';        // an identifier to know that it is a visitor, not logged user

/*
 If you have an user registration script,
 replace $_SESSION['nume'] with the variable in which the user name is stored.
 You can get a free registration script from:  http://coursesweb.net/php-mysql/register-login-script-users-online_s2
*/

// get the user name if it is logged, or the visitors IP (and add the identifier)

    $uvon = isset($_SESSION['nume']) ? $_SESSION['nume'] : $_SERVER['SERVER_ADDR']. $vst_id;

$rgxvst = '/^([0-9\.]*)'. $vst_id. '/i';         // regexp to recognize the line with visitors
$nrvst = 0;                                       // to store the number of visitors

// sets the row with the current user /visitor that must be added in $filetxt (and current timestamp)

    $addrow[] = $uvon. $sep. time();

// check if the file from $filetxt exists and is writable

    if(is_writable($filetxt)) {
      // get into an array the lines added in $filetxt
      $ar_rows = file($filetxt, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
      $nrrows = count($ar_rows);

            // number of rows

  // if there is at least one line, parse the $ar_rows array

      if($nrrows>0) {
        for($i=0; $i<$nrrows; $i++) {
          // get each line and separate the user /visitor and the timestamp
          $ar_line = explode($sep, $ar_rows[$i]);
      // add in $addrow array the records in last $timeon seconds
          if($ar_line[0]!=$uvon && (intval($ar_line[1])+$timeon)>=time()) {
            $addrow[] = $ar_rows[$i];
          }
        }
      }
    }

$nruvon = count($addrow);                   // total online
$usron = '';                                    // to store the name of logged users
// traverse $addrow to get the number of visitors and users
for($i=0; $i<$nruvon; $i++) {
 if(preg_match($rgxvst, $addrow[$i])) $nrvst++;       // increment the visitors
 else {
   // gets and stores the user's name
   $ar_usron = explode($sep, $addrow[$i]);
   $usron .= '<br/> - <i>'. $ar_usron[0]. '</i>';
 }
}
$nrusr = $nruvon - $nrvst;              // gets the users (total - visitors)

// the HTML code with data to be displayed
$reout = '<div id="uvon"><h4>Online: '. $nruvon. '</h4>Visitors: '. $nrvst. '<br/>Users: '. $nrusr. $usron. '</div>';

// write data in $filetxt
if(!file_put_contents($filetxt, implode("\n", $addrow))) $reout = 'Error: Recording file not exists, or is not writable';

// if access from <script>, with GET 'uvon=showon', adds the string to return into a JS statement
// in this way the script can also be included in .html files
if(isset($_GET['uvon']) && $_GET['uvon']=='showon') $reout = "document.write('$reout');";

echo $reout;             // output /display the result

Haven't tested this on the Sql script yet.

$user_ip=$_SERVER['REMOTE_ADDR'];

$check_ip = mysql_query("select userip from pageview where page='yourpage'  and userip='$user_ip'");
if(mysql_num_rows($check_ip)>=1)
{

}
else
{
  $insertview = mysql_query("insert into pageview values('','yourpage','$user_ip')");

  $updateview = mysql_query("update totalview set totalvisit = totalvisit+1 where page='yourpage' ");
}

code from talkerscode official tutorial if you have any problem http://talkerscode.com/webtricks/create-a-simple-pageviews-counter-using-php-and-mysql.php

Unique views is always a hard nut to crack. Checking the IP might work, but an IP can be shared by more than one user. A cookie could be a viable option, but a cookie can expire or be modified by the client.

In your case, it don't seem to be a big issue if the cookie is modified tho, so i would recommend using a cookie in a case like this. When the page is loaded, check if there is a cookie, if there is not, create one and add a +1 to views. If it is set, don't do the +1.

Set the cookies expiration date to whatever you want it to be, week or day if that's what you want, and it will expire after that time. After expiration, it will be a unique user again!

Edit:
Thought it might be a good idea to add this notice here...
Since around the end of 2016 a IP address (static or dynamic) is seen as personal data in the EU.
That means that you are only allowed to store a IP address with a good reason (and I'm not sure if tracking views is a good reason). So if you intend to store the IP address of visitors, I would recommend hashing or encrypting it with a algorithm which can not be reversed, to make sure that you are not breaching any law (especially after the GDPR laws have been implemented).

for finding out that user is new or old , Get user IP .

create a table for IPs and their visits timestamp .

check IF IP does not exists OR time()-saved_timestamp > 60*60*24 (for 1 day) ,edit the IP's timestamp to time() (means now) and increase your view one .

else , do nothing .

FYI : user IP is stored in $_SERVER['REMOTE_ADDR'] variable