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I have a problem with understanding mod_rewrite behavior. I'll illustrate this with an example. I have 3 files in my root directory: .htaccess, index.php and test.php. The content of files:

.htaccess

RewriteEngine On
RewriteBase /

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule (.+) ?link=$1 [L]

index.php

<?php
$db = mysqli_connect('localhost', 'root', '', 'mydb'); 
$db->real_query ("INSERT INTO `test` (`str`) VALUES ('test_string')");
print_r($_GET);
?>

test.php

<?php
$db = mysqli_connect('localhost', 'root', '', 'mydb'); 
$db->real_query ("INSERT INTO `test` (`str`) VALUES ('another_test_string')");
print_r($_GET);
?>

So when I go to my site's root folder with the browser, two strings are inserted in database - 'test_string' and 'test_string'. If I go to /test.php, also two strings will be inserted - one from index.php script - 'test_string' and one from test.php string - 'another_test_string'. If I remove rewrite rules from .htacess, only one string will be inserted for both pages. I cannot understand such behavior - why all scripts are executed twice? And especially I don't understand why this happens with test.php since I wrote RewriteCond %{REQUEST_FILENAME} !-f, so no rewrites should be done.
Thank you in advance.

undone
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Kirill Smirnov
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    You're almost certainly going to be getting a request from the browser for favicon.ico - check your access logs or put the current url (`$_SERVER['REQUEST_URI']`) into the string you store to determine which request is responsible. – AD7six Aug 15 '12 at 11:14
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    If you are that sure that it will only be done once per request, it would only be logical that whenever you do one request, another one is done, too. So why do you think the rewrite rules are the culprit? – hakre Aug 15 '12 at 11:14

1 Answers1

2

The php code you have will insert into the database once that fragment of code is processed.

If you execute it more than once, you will see more inserts in the database.

However rewrite rules are executed once only, too.

So what you experience is likely totally unrelated with your rewrite rules. If you do not trust me, enable logging for the rewrites (see apace docs) and follow the trail.

You probably have sit too long in front of the computer, so just get a cup of tea, relax and find that bug.

hakre
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  • Of course I undertstand that code will make only one insert. And I specially add **test.php** page to demonstrate my question. If I go to this page **once**, one string will be inserted from this script and one from **index.php**! How does this happen? I don't launch **index.php**, there are no includes, redirects or other things. All code is written in question. – Kirill Smirnov Aug 15 '12 at 11:05
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    Only you will able to tell us in the end, why this does happen. This needs you to actually make use of all the logging and tracing mechanisms, the softwares in your stack do provide. Including - but not limited to - even an network sniffer that tells you the exact number of requests that happen in fact - not by guess. I did not say that debugging is easy (indeed it's much more hard than you might think), but rule number one is: Stop Guessing! Now search for the logs you have available: http://httpd.apache.org/docs/current/logs.html – hakre Aug 15 '12 at 11:09
  • @DaveRandom: Oh, please do not ruin the lesson :) – hakre Aug 15 '12 at 11:10
  • DaveRandom, you were rigth, the problem was with requests to icon, which was missing. Who would have thought. Thanks a lot! – Kirill Smirnov Aug 15 '12 at 11:14
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    Yes, that will help you to even solve much more complicated problems. Also you might want to use a commandline HTTP request tool like `curl` to debug things because you can better view what happens. Or install firebug with your browser and see the request send etc. pp. The network sniffer is also a good tool. – hakre Aug 15 '12 at 11:17