Have file data (garbage code) - need to download actual file - php

Question

We are receiving file data from a third party API call that returns the content type in one variable and the file contents in another. The file contents are "garbage code." For example:
$doc->fileContents = "A�[�j쎪A����Kb����m��= ....";
$doc->fileType = "application/msword";
I need to be able to provide my users a clickable method for downloading the file, but simply writing the contents to a file and forcing a download with that content type simply opens a file containing all that garbage... not the real file contents.
EDIT: Per Patrick Q's request, I did it the standard fwrite way:
$fp = fopen($filename, 'w'); // filename is generated elsewhere
fwrite($fp, $doc->fileContents);
fclose($fp);
So the question is, how do I create a real, usable file out of this garbage?

Answer 1

The data looks like binary file data. There's no need to write it to a file first, just make sure you set the Content-Transfer-Encoding header to binary when you send it to the browser for downloading.
I'm assuming you already have a way of mapping $doc->fileType to a filename with the proper extension, I'll just hardwire .doc here since your example is an application/msword document.
// your logic here to determine the filename sent to the browser
$filename = "file.doc";
// set the minimum appropriate HTTP headers
header('Content-Type: ' . $doc->fileType);
header('Content-Length: ' . strlen($doc->fileContents));
header('Content-Disposition: attachment; filename="' . $filename . '"');
header('Content-Transfer-Encoding: binary'); // this is an important one
// send the file and stop
echo $doc->fileContents;
exit;
If you are writing it to file first, make sure you open it in binary mode:
$fp = fopen($filename, 'wb');
fwrite($fp, $doc->fileContents);
fclose($fp);