asked on

How to make a button to start a configured file download in PHP?

Hi Experts!

I'm facing difficulties to make a form with a button to fire a download.
This form must send a parametrized name of a file to be downloaded.

            ....
               <tr>
                    <td class="tg-yw4l">
                    <!-- The point where I intend to fire the download  -->
                   <form action="download_pdf_publicacoes.php" method="post">

                  // This is the file to be downloaded:
                  <?php "base_url("."cesanshome/carregando_arquivo/".$idpublicacoes.")" ?>

                    // Here:  How to configure it to send to the other page?

                    <input type="submit" name="download_pdf" value="PDF"/>
 

                   </form>
                    </td>
              </tr>

...

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The download_pdf_publicacoes.php

 <?php

                // How the $filename name must be received here?

	$post = filter_input(INPUT_POST,"download_pdf");
 

    if ($post)
	{
		$filename = ???;
		header("Content-Type: application/octet-stream");
		header("Content-Length: " . filesize($filename));
		header("Content-Disposition: attachment; filename=" . basename($filename));
		readfile($filename);
	}
?>

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Thanks in advance!

Ray Paseur

I can show you how to force a file download. This seems to work correctly in every browser. Perhaps you can change the "link" to a "button" and get what you need.

<?php // demo/force_download.php

/**
 * Show how to force a file download
 *
 * Choose a file to download, either via a hard-coded file path
 * or via a URL parameter like this
 *
 * path/to/demo/force_download.php?url=path/to/file.txt
 *
 * If you wanted to use the URL parameter, you might want to
 * (1) Secure the script with password protection
 * (2) replace the $url variable with something like this:
 * $url = $_GET['url'];
 *
 * If you use the URL parameter, be careful that the script
 * does not expose sensitive data on your server!
 */
error_reporting(E_ALL);


// WHAT FILE DO WE WANT TO DOWNLOAD?
$url = "http://www.IcoNoun.com/demo/short_text_file.txt";


// USE CASE
force_download($url);


// FUNCTION TO FORCE A DOWNLOAD FROM A FILE
function force_download($url, $filename=NULL)
{
    // GET THE DOWNLOAD FILE NAME
    if (empty($filename)) $filename = basename($url);

    // GET LENGTH AND FILE RESOURCE POINTER
    $hdr = get_headers($url, TRUE);
    $len = trim($hdr['Content-Length']);
    $fpr = fopen($url,'rb');

    // ON SUCCESS
    if ($fpr)
    {
        // THESE HEADERS ARE USED ON ALL BROWSERS
        header("Content-Type: application-x/force-download");
        header("Content-Disposition: attachment; filename=$filename");
        header("Content-length: $len");
        header("Expires: ".gmdate("D, d M Y H:i:s", mktime(date("H")+2, date("i"), date("s"), date("m"), date("d"), date("Y")))." GMT");
        header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");

        // THIS HEADER MUST BE OMITTED FOR IE 6+
        if (FALSE === strpos($_SERVER["HTTP_USER_AGENT"], 'MSIE '))
        {
            header("Cache-Control: no-cache, must-revalidate");
        }

        // THIS IS THE LAST HEADER
        header("Pragma: no-cache");

        // FLUSH THE HEADERS TO THE BROWSER
        flush();

        // WRITE THE FILE
        fpassthru($fpr);
    }

    // ERROR
    else
    {
        trigger_error("Unable to open $url", E_USER_ERROR);
    }
}

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Eduardo Fuerte

ASKER

Hello

Could you give me just one more help?

Using your function in a button.
This piece of code doesn't work out, what's wrong and what coudl be done to fix it?

   <form action="force_download(<?php echo base_url("cesanshome/carregando_arquivo/$idpublicacoes)"); ?>" method="post">
                        <input type="submit" value="PDF"/>
                    </form>

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To make it more difficult this Project uses CodeIgniter... so the localization is much more complex.

ASKER CERTIFIED SOLUTION

Ray Paseur

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Eduardo Fuerte

ASKER

Thank you very much for the assistance, Ray!

Ray Paseur

Glad to help! Best of luck with the project, ~Ray