Using input[type="file"] to prompt the user to save the file

Question

I am trying to achieve two actions from an input file tag. I have the following input:

<input id='file-input' name='attach' type='file' style='margin-left:15px;'/> 

This is found in messages.php. What I am trying to achieve are two things:

1. If the file uploaded is over 1mb in size (or is a file which is not an image), then produce a button which on click opens the save as menu, from where a user can select where they wish to download the data.
2. And secondly, as mentioned, if the file size is lower than 1mb, then simply display the data on the page (only works for image files).

I have other pages where I have used input type="file" to upload profile images, and have just displayed the image on the page. But I am unsure on how I can execute (1) - how I can open a menu from where the user can save the data?

Answer 1

Just serve the file with a Content-Disposition: attachment header, see PHP Outputting File Attachments with Headers

Answer 2

You won't need to fake a click or something. You probably need something like this.

1. User selects file and clicks the "Upload file" button.
2. File gets uploaded using e.g. PHP.
3. PHP displays the contents of the file, using the correct headers.
4. PHP determines if the file is smaller or larger than 1MB.
   41. If the file is larger, set a header that forces the user to download the file (causing a select location popup).
   42. If the file is smaller, do not set the header, causing the file to display in the browser.

Where Italic is a user action and Bold is a server action.

Answer 3

Among other nice answers I will do it this way.

I have made it possible by clicking on your suggested Download button, if file is greater than 1Mb you will get download pop up like this

Otherwise if file less than 1Mb it will just show it on browser will look like this:

Btw, the code is self explaining.

PHP part called index.php

<?php
$filename = "test3.jpg";
$maxSize = 1000000; // 1Mb

if (isset($_POST['save']))
    fileHandler($filename, $maxSize);

function fileHandler($filename, $maxSize)
{
    $fileinfo = getimagesize($filename);
    $filesize = filesize($filename);
    $fp = fopen($filename, "rb");
    if ($fileinfo && $fp)
    {
        header("Content-Type: {$fileinfo['mime']}");
        if ($filesize > $maxSize)
        {
            header('Content-Disposition: attachment; filename="NewName.jpg"');
        }
        fpassthru($fp);
        exit;
    } else
    {
        echo "Error! please contact administrator";
    }
}

?>

HTML part inside index.php but it is important this code should comes after php tags and not before.

<form action="index.php" method="post">
    <button type="submit" style="border: 0; background: transparent" name="save">
        <img src="download.jpg" alt="submit" />
    </button>
</form>

Note: it is important your php document start directly with <?php ..., please read

Answer 4

You can do this by getting the image mime type and setting the content disposition and content type headers:

$file = 'path/to/file';

    if (file_exists($file)) {

            $contents = file_get_contents($file);
            $fileSize = filesize($file);
            $image_info = getImageSize($file);
            $mimeType = $image_info['mime'];
            header("content-disposition: attachment; filename=" . basename($file));
            header("content-type:$mimeType");
            header("Content-length: $fileSize");
            echo $contents;
            exit;
    }