Delete files with AJAX/PHP

Question

The problem

---

I want to delete a file with AJAX/PHP.

But the php says that the file name what I send with AJAX is not a file, but when I go directly to the link I can delete the files. Check out my current PHP, I've put in the IF/ELSE statement to check if the string is a file with: is_file, the result is false.

Without is_file says this:

Warning: unlink("image.jpg") [function.unlink]: Invalid argument in C:\wamp\www\images\users\delete.php on line 8

The file what calls the ajax is inside the folder where are the files too what I want to delete.

The PHP

---

<?php
    // I save the file sources from the URL what was sent by AJAX to these variables.
    $photo_id = $_GET['photo_id'];
    $thumbnail_id = $_GET['thumbnail_id'];

    function deletePhotos($id){
        // If is a file then delete the file.
        if(is_file($id)){
            return unlink($id);
        // Else show error.
        } else {
            echo $id . " is not a file, or there is a problem with it.<br />" ; 
        }
    }

    if(isset($photo_id)){
        deletePhotos($photo_id);
    }
    if(isset($thumbnail_id)){
        deletePhotos($thumbnail_id);
    }

 ?>

The AJAX

---

function deletePhoto(photo, thumbnail){

        var photos = encodeURIComponent(photo);
        var thumbnails = encodeURIComponent(thumbnail);

        if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
          xmlhttp=new XMLHttpRequest();
        } else {// code for IE6, IE5
          xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
        }

        xmlhttp.onreadystatechange=function() {
            if (xmlhttp.readyState==4 && xmlhttp.status==200) {
                document.getElementById("media").innerHTML=xmlhttp.responseText;
            }
        }
        xmlhttp.open("GET", "http://192.168.2.104/images/users/delete.php?photo_id=\""+photos+"\"&thumbnail_id=\""+thumbnails+"\"", true);
        xmlhttp.send();
    }

Answer 1

Your ajax request has the data in quotes.

//Bad
delete.php?photo_id="1234"

//Good
delete.php?photo_id=1234

//So use this:
xmlhttp.open("GET", "http://192.168.2.104/images/users/delete.php?photo_id="+photos+"&thumbnail_id="+thumbnails, true);

Answer 2

• You need to give a full path to is_file. A partial path like image.jpg doesn't tell it where that file is located. If it's supposed to be relative to the document root, you'll need to prepend that.

• This is one of the most dangerous scripts I've ever seen. You could pass any file into photo_id, and as long as the web server has the right permissions, it would delete it. You should at least make sure you're restricting it to only delete files within a certain directory.

Answer 3

you might need to specify the path for example

file_exists( realpath('.') . '/' . $id );

(assuming your files are in the same folder as your script) ditto what others have said, this is a dangerous script unless there is other security in place!

Answer 4

try to use trim in your post or get variable, ex:

$photo_id=trim($_GET['blah..blah']);

in my case the problem is $photo_id returns no file name - its returns something like this '\nfilename', when it should be 'filename' so I added trim and its worked for me now.