Why PHP continue to output to CSV file after fclose()? - php

Question

On a web page, I am writing some data into a CSV file using the below code and finally closing with fclose();
header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename='.$filename);
$out = fopen('php://output', 'w');
fputcsv($out, $cvs_cols);
fclose($out);
echo "HELLO WORLD"; // sneaks into CSV!?
Why is it that "HELLO WORLD" gets into the CSV download file when it has already fclose()? I want to output the rest of the HTML for the page to be displayed in the browser. How can I do that?

Answer 1

After 1 HTTP request follows 1 response. You cannot send content type text/csv and content type text/html at the same time (maybe yes with SPDY, but not with pure HTTP).
fclose closes your file descriptor but not the output to the browser.
You should also set a Content-Length header and put in the filesize.
Mark Baker already gave the most important point in the comments:
echo and writing to php://output puts content into the same stream: STDOUT. Other options would be to write the CSV to memory (but its senseless if you don't use it) or to a file. Read more about the those streams: http://www.php.net/manual/en/features.commandline.io-streams.php
Possible solution:
You need 2 HTTP requests. 1 For the download, the other for your HTML. Most popular way is it to first use the HTML response and put something in like
<meta http-equiv="refresh"
content="3; URL=http://yourserver.com/download.php?id=pdf&id=123" />
This starts the download after 3 seconds.

Answer 2

There is no 'CSV File' (yet).
What you are doing is sending a data stream to the client, and telling the client that this stream has a Content-Type of text/csv and a filename of $filename. The client can then chose to save this as a CSV file or just display it in the browser.
This code:
$out = fopen('php://output', 'w');
fputcsv($out, $cvs_cols);
fclose($out);
Is effectively doing the same thing that echo $cvs_cols would do (with a little extra stuff to format a csv output).
So when there is a call to echo "HELLO WORLD"; it gets sent in the same data steam as the contents of the $cvs_cols variable.
When you call fopen('php://output', 'w') you are creating a second file handle to php://output as one is created by default to output from calls to echo etc. So when you are calling fclose($out) you're only closing the second file handle.

Answer 3

A very old thread here but to fix this I just added a simple exit(); command. So a button calls the same page with a query string of 'action=export_csv' then that action is run with the exit(); on the last line, hope that helps out.
Export CSV
Then the 'action' on the page is:
if(isset($_GET['action']) && $_GET['action']=='export_csv'){
// output headers so that the file is downloaded rather than displayed
header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename=email-responses.csv');
// create a file pointer connected to the output stream
$output = fopen('php://output', 'w');
// output the column headings
fputcsv($output, array('Email address'));
$db = new PDO('mysql:host=hostname_mysql;dbname=database_mysql;charset=UTF8', username_mysql, password_mysql);
$query = "SELECT XXX FROM XXXX";
$result = $db->query($query);
$data = $result->fetchAll(PDO::FETCH_ASSOC);
// loop over the rows, outputting them
foreach($data as $row){
fputcsv($output, $row);
}
fclose($output);
exit();
}

Answer 4

use
ob_clean() : ob_clean — Clean (erase) the output buffer
flush() : flush — Flush the output buffer(flush)
ob_start();
header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename='.$filename);
$out = fopen('php://output', 'w');
fputcsv($out, $cvs_cols);
fclose($out);
ob_end_clean(); // the buffer and never prints or returns anything.
echo "HELLO WORLD"; // sneaks into CSV!?