PHP caching include file

Question

I have the following test code in test.php:

<?php
$step = $_GET['step'];
switch($step) {
  case 1:
    include 'foo.php';   # line 5
    file_put_contents('foo.php', '<?php print "bar\\n"; ?>');
    header('Location: test.php?step=2');
  break;
  case 2:
    print "step 2:\n";
    include 'foo.php';
  break;
}
?>

foo.php initially has the following content:

<?php print "foo\n"; ?>

When I call test.php?step=1 in my browser I would expect the following output:

step 2:
bar

But I get this output:

step 2:
foo

When I comment out the include in line 5, I get the desired result. The conclusion is, that PHP caches the content of foo.php. When I reload the page with step=2 I also get the desired result.

Now... why is this and how to avoid this?

I'd guess that you never get redirected to ?step=2 since you are print'ing data before sending the Location header (which should cause an error). — cOle2
– cOle2, Commented Jan 5, 2015 at 19:58
It would not work with commented out line 5 if foo.php would not be overwritten. I also looked into foo.php... It is modified. — Peter
– Peter, Commented Jan 5, 2015 at 19:58
cOle2: It would not print "step 2:" if it would not get redirected! — Peter
– Peter, Commented Jan 5, 2015 at 19:59
If you still believe it is caching, you should check if OpCache is enabled. opcache.enable=0 in your php.ini. — britter
– britter, Commented Jan 5, 2015 at 20:03

Alessio Cantarella · Accepted Answer · 2017-04-26 10:26:31Z

9

Assuming you use OPcache, opcache.enable = 0 works.

A more efficient method is to use

opcache_invalidate ( string $script [, boolean $force = FALSE ] )

This will remove the cached version of the script from memory and force PHP to recompile.

edited Apr 26, 2017 at 10:26

Alessio Cantarella

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answered Oct 24, 2016 at 18:44

Philip Jones

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Comments

Moradnejad · Accepted Answer · 2018-12-22 07:49:00Z

5

Note that opcache_invalidate is not always available. So it is better to check if it exists. Also, you should check both of opcache_invalidate and apc_compile_file.

Following function will do everything:

    public static function clearCache($path){
        if (function_exists('opcache_invalidate') && strlen(ini_get("opcache.restrict_api")) < 1) {
            opcache_invalidate($path, true);
        } elseif (function_exists('apc_compile_file')) {
            apc_compile_file($path);
        }
    }

answered Dec 22, 2018 at 7:49

Moradnejad

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