Tracking image views - PHP

I'd like for my app to be able to tell if an image hasn't been viewed in the last 30 days and remove it开发者_如何学Go (along with data in the DB associated with it). I know you can have PHP read and output the image dynamically but I've heard its quite taxing on the system. Is there a way to for me to track these hits even when the image is viewed directly? (would htaccess be able to do this?) Thanks in advance.

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For .htaccess something like this...

RewriteRule ^image/(.*)$ image.php?id=$1

And for PHP...

$id = $_GET["id"]; //don't forget to sanitize
mysql_query("UPDATE images SET views = views + 1 WHERE image = '$id'"); //update no of views
header("Content-Type: image/jpeg"); //send image header
readfile($id); //output file to browser

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You can parse out the HTTP logs and do this analysis post-factum.

That said, I'd still recommend going with a "dynamic PHP file outputting an image" approach - note that the PHP file can simply stream out a file. Yes, it'll be slower than not going through PHP at all, but it won't be a significant performance hit on your system.

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You can create a script that fetches images and pings your database to show that the image has been viewed. By setting the return type of your script to image/jpg you can just use this script instead of accessing images directly:

<?php
//simplified image display script

$imagepath="phpimages/$id.jpg";
$db->pingImage($id);
$image=imagecreatefromjpeg($imagepath);
header('Content-Type: image/jpeg');
imagejpeg($image);

?>

Then use:

<img src='fetchimage.php?id=478' alt='tracked image' />

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As far as I know, you'll need to have a database for this.

Sample schema:

Images
  id (int, PK)
  path (text)
  hits (int)

PHP:

// get_image.php
// note, this is just an example and I'm not considering security or hacking attempts
$sql = mysql_query('SELECT * FROM images WHERE id = '.$_GET['id']);
$img

if(mysql_num_rows($img) == 1)
  while($row = mysql_fetch_assoc($sql))
    $img = $row;
else
  // handle some error

mysql_query("UPDATE images SET hit = hits + 1 WHERE id = ".$_GET['id']);
$img = file_get_contents($img['path']);
header('image/jpg');
echo $img;

There could be errors here, I'm just giving you a general idea...