Issue with PHP writing files to the server

[keystrike]

I am having a problem with PHP writing files. I have a set of PHP scripts that create files on the site, basically a

rudimentary content management system that automatically creates each week's edition onsite from the database.

 

However, there seems to be an issue with PHP writing files to the server - it works perfectly well the first time I try, but any subsequent attempts to write the same file fail unless I wait for 5 minutes or so. It is as if

the file, once written, if cached for a few minutes. If I wait a few minutes I am able to write to the file again fine, but then have to wait another few minutes in order to access the file.

 

Indecently, the same behavior is present on my Debian box at home with a default Apache / PHP setup, but not on any of my Windows boxes, so I guess this is a generic Linux / Debian issue.

 

I've attached an example of the code, but it affects quite a few scripts I have. I've tried it using the fopen(), fwrite(), fclose() combo, and also with the simpler file_put_contents() function, both with the same result.

 

In the attached script you can run it once, then change the contents of the $homepage variable (via changes to the SQL database it draws its data from) and then run the scrip again, but on the second run it wont update the target file unless I wait for a few minutes.

 

<?php

 

 

/* GET GLOBAL CONFIG FILE AND FUNCTIONS */

require_once '../storyAdmin/functions.php';

 

 

/* DATA PROCESSING SECTION */

 

// GET ISSUE ID

if (isset($_GET['issue']) && is_numeric($_GET['issue'])) {

 

$issueId = $_GET['issue'];

 

}

 

if (!isset($issueId)) {

if (DEBUG) echo "<br>edition.php :: data processing :: issueId not set ;; exiting silently <br>";

exit;

}

 

 

require '../storyAdmin/storyCreationFunctions.php';

 

 

// Homepage will be returned as a string, which is basically a full HTML file...

$homepage = makeHomepage($issueId);

 

 

if (file_exists('../index_temp.php')) unlink ('../index_temp.php');

if (!file_put_contents('../index_temp.php', $homepage)) {

 

echo "<h1>Couldn't write file</h1>";

 

}

 

$link = dirname($_SERVER['REQUEST_URI']).'/../index_temp.php';

 

//echo $_SERVER['REQUEST_URI']."<br />";

//echo $link;

 

header("Location: $link");

 

exit;

 

?>

 

Thanks!

[teamatomic]

I think you are creating what is called a race condition by unlinking and writing to the same file. Unlink is not finished and you try to start writing to the file that is being unlinked. Make sense?

 

The proper way to do this is to make a temp with the new index contents of 'file_tmp.txt'

copy file_tmp.txt to index_temp.php

unlink file_tmp.txt

[gevensen]

have you tried adding

ob_start(); at the very 1st line and ob_end_flush(); at the very last line?