PHP：从服务器下载文件

Question

I have tried all sorts of codes I've found but nothing has worked for me...

When I use readfile() or fopen() or something like this:

function makeDownload($file, $dir, $type) {

header("Content-Type: $type");

header("Content-Disposition: attachment; filename=\"$file\"");

readfile($dir.$file);

}

... A download is started but the file is always empty...

here's the last code I've tried:

$filename = "gandalf.jpg";
// define error message
$err = '<p style="color:#990000">Sorry, the file you are requesting is unavailable.</p>';
if (!$filename) {
// if variable $filename is NULL or false display the message
echo " filename NULL";
echo $err;

} else {
// define the path to your download folder plus assign the file name
$path = 'upload/'.$filename;

// check that file exists and is readable
if (file_exists($path) && is_readable($path)) {
    echo "file exists";
    // get the file size and send the http headers
    $size = filesize($path);
    header('Content-Type: image/png');
    header('Content-Length: '.$size);
    header('Content-Disposition: attachment; filename='.$filename);
    header('Content-Transfer-Encoding: binary');
    // open the file in binary read-only mode
    // display the error message if file can't be opened

    //readfile($path.$filename);
    $file = @ fopen($path, 'rb');
    if ($file) {
        // stream the file and exit the script when complete
        fpassthru($file);
        exit;
    } else {
        echo $err;
    }
} else {
    echo $err;
}
}

This is the source of my code: Source code

I hope you can help me :)

I use google chrome I need your help for this little project: Link to Project

When you click on a file in the drop down appears "herunterladen" (download in german) here is where I want to start the php download code

I just need the most basic download function for PHP... why is there an upload example on w3schools but NOT a download example? oO

Answer 1

$fileSource= $_GET['fileSource'];     //If you are passing the filename as a URL parameter
$fileSource= "sample.pdf"     //If the filename is fixed in the current folder
if($fileSource) {
     $filesize = filesize($fileSource);
     $path_parts = pathinfo($fileSource);
     $ext = strtolower($path_parts["extension"]);
     switch ($ext) {
     case "pdf":
         header("Content-Disposition: attachment; 
         filename=\"".$path_parts["basename"]."\""); // use 'attachment' to 
         force a download
         header("Content-type: application/pdf"); // add here more headers 
         for diff. extensions
         break;
    default:
    header("Content-type: application/octet-stream");
    header("Content-Disposition: filename=\"".$path_parts["basename"]."\"");
    }
    if($filesize) {
         header("Content-length: $filesize");
    }
    readfile($fileSource);
    exit;

}