Mysql Blob to xls using php without making a file on server? - php

Question

I'm trying to extract a BLOB from mysql and send it to the requester without saving it on the server. I've gotten it to work with PDF files, but some of our clients want xls files. When getting the xls file, the downloaded file is garbage. In HxD it looks like it is putting an extra 11 bytes on the front of the file.
Here is my code, both working and not working:
function blob_download_xls() {
$mysqli = openMySQLconnetion();
$sql = "SELECT * FROM Uploads;";
$results = $mysqli->query($sql);
$row = $results->fetch_assoc();
$bytes = $row['filedata'];
header('Content-type: application/vnd.ms-excel');
header('Content-Disposition: attachment; filename="report.xls"');
print $bytes;
}
function blob_download_pdf() {
$mysqli = openMySQLconnetion();
$sql = "SELECT * FROM Uploads;";
$results = $mysqli->query($sql);
$row = $results->fetch_assoc();
$bytes = $row['filedata'];
header("Content-type: application/pdf");
header('Content-Disposition: inline; filename="report.pdf"');
print $bytes;
}
Any idea what I'm doing wrong?

Answer 1

I asked this question with a new account without realizing that I already had an account here. I've solved the problem and it was stupid.
When writing my function.php, I put a closing tag '?>' on the end of the file. After this tag was a 0d0a for a line feed return and then 9 20's for 9 spaces. I removed the closing tag and now it works perfectly.

Answer 2

The correct way to deal with this is to die() immediately after printing the bytes, before the server has a chance to output any HTML that may succeed the PHP code.
function blob_download_xls() {
$mysqli = openMySQLconnetion();
$sql = "SELECT * FROM Uploads;";
$results = $mysqli->query($sql);
$row = $results->fetch_assoc();
$bytes = $row['filedata'];
header('Content-type: application/vnd.ms-excel');
header('Content-Disposition: attachment; filename="report.xls"');
print $bytes;
die();
}