PHP fopen contains unwanted content - php

Question

Of course after hours of pondering this problem, the first comment on my question lead me to solve it immediately.
The problem was that, although I was including this code within its own function at the top of the page, I was calling it only if a certain flag was set in the $_POST array. I wasn't checking for the flag until the end of the PHP file. I moved that check before the function, and it worked.
The original question is below:
I'm trying to use the fopen() function in PHP to output a CSV file, and although it contains the data I want, it also contains the entire HTML structure of the page, as well as inline stylesheets, before the content that I actually want to output.
I'm using this code (from here) pretty much unchanged. I'm very unfamiliar with PHP streaming and output, so I started from what I hope was a firm foundation:
$fileName = 'somefile.csv';
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header('Content-Description: File Transfer');
header("Content-type: text/csv");
header("Content-Disposition: attachment; filename={$fileName}");
header("Expires: 0");
header("Pragma: public");
$fh = #fopen( 'php://output', 'w' );
global $wpdb;
$query = "SELECT * FROM `{$wpdb->prefix}my_table`";
$results = $wpdb->get_results( $query, ARRAY_A );
$headerDisplayed = false;
foreach ( $results as $data ) {
// Add a header row if it hasn't been added yet
if ( !$headerDisplayed ) {
// Use the keys from $data as the titles
fputcsv($fh, array_keys($data));
$headerDisplayed = true;
}
// Put the data into the stream
fputcsv($fh, $data);
}
// Close the file
fclose($fh);
// Make sure nothing else is sent, our file is done
exit;
My assumption is that this example was intended to be included in its own external PHP file, but due to the constraints I'm dealing with, I'm trying to include it inline instead. I've mucked about with output buffering a bit with no positive results, but the PHP documentation on these is quite sparse, so there's probably something I'm missing.

Answer 1

Problem seems to be that, at the same time you try to output from the same PHP file, the CSV file AND some html content. You've got to separate them, to have 2 different URLs.
I guess your PHP code is surrounded by the html code (and css inline) you're talking about.
What you've got to do is:
have a PHP script that only outputs the CSV content (which only contains the code you showed us, with the opening php tag of course)
have another PHP script which produces html code, and provides a link to the previous script (for example).

Answer 2

You are on the right track with the 'include it inline' reason to why you're getting everything else before the data.
This script will need to be it's own separate file called directly, instead of including it inline in another script. I understand you have other database connections and such that have to be set up first. You'll have to extract those out of your standard pages and include those on this page.

Answer 3

Of course after hours of pondering this problem, the first comment on my question lead me to solve it immediately.
The problem was that, although I was including this code within its own function at the top of the page, I was calling it only if a certain flag was set in the $_POST array. I wasn't checking for the flag until the end of the PHP file. I moved that check before the function, and it worked.