CODEWITHSUNDEEP
phpformsfile-upload
Bruce Button
Bruce Button

Reputation: 55

How do I get the value of $_FILES['uploadtFile']['error'] on a PHP form?

I have an html form, including an input file element. The form is processed by a php script. Most of the time, everything works fine — I can access the form data through $_POST and $_FILES, I can check the data submitted and I can manipulate the file. The action on the form is set to return to the same page as that on which the form appears.

However, I am unable to process anything when the user tries to upload a file which is too large. This is what happens:

  1. Nothing gets uploaded and the page reloads.
  2. $_FILES['uploadFile']['error'] is null, so I can't catch the error.
  3. isset($_POST['submit']) is false, so I can't process the input.
  4. There is no error message.

My form looks like this:

<form action="hwsa.html?form[id_assignment]=<?php echo($id_assignment); ?>" method="post" enctype="multipart/form-data" class="assignment-submission">

    <p>Select file to upload. N.B. Only pdf files allowed; maximum size 5 MB.</p>
        <input type="hidden" name="MAX_FILE_SIZE" value="5120000" />
        <input type="file" name="uploadFile" id="assignment-file">
    </p>
    <p>
        <input type="submit" name="submit" value="Submit" class="btn-reverse">
        <input type="submit" name="submit" value="Cancel" class="btn-reverse">
    </p>
</form>

I can process other errors, like using the wrong file type, in a block like this:

If (isset($_POST['submit']))
{
    If ($_POST['submit']=='Cancel')
    {
        //Process cancel
    }
    If ($_POST['submit']=='Submit')
    {
        $size=$_FILES['uploadFile']['size'];
        $sizeWarning = ($_FILES['uploadFile']['size'] > 5120000);

        $fileType = strtolower(pathinfo($_FILES['uploadFile']['name'], PATHINFO_EXTENSION));
        $typeWarning = ($fileType != 'pdf');

        $emptyWarning = ($_FILES['upLoadFile']['size'] == 0);
        // Process errors or process successful upload.
    }
}

Any help would be greatly appreciated!

Thank you in advance.

Upvotes: 0

Views: 122

Answers (1)

&#193;lvaro Gonz&#225;lez
&#193;lvaro Gonz&#225;lez

Reputation: 146390

When a file upload is so large that it gets discarded you get an empty post request but original request headers are kept so you can do the following checks:

  • Determine if it's a post request and skip checks if isn't:

    $is_post = strtolower(filter_input(INPUT_SERVER, 'REQUEST_METHOD')) === 'post';

  • Determine if user agent (browser or script) sent a Content-Length header, maybe with a fallback check when $post_size is null (which will throw false positives if all form fields are optional):

    $post_size = $_SERVER['CONTENT_LENGTH'] ?? null;
if (($post_size === null || $post_size > 0) && !$_POST && !$_FILES) {
    // Error: post body was too large
}

You can test this code by setting an arbitrarily small size limit, e.g.:

post_max_size = 1K

Try thoroughly (I've used these ideas but I haven't tested this exact code).

Upvotes: 0

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