Why does this .htaccess not work? - .htaccess

Question

I have a url like this:
http://domain.com/index.php?id=223
And this .htaccess code:
RewriteEngine On
RewriteRule ^([^/]*)\.html$ /index.php?id=$1 [L]
From what I understand this should output:
http://domain.com/223.html
But its not doing anything, can someone please explain how this works and what I'm doing wrong?

Answer 1

Your original rule takes any file that does not include a slash and ends with ".html" at the root level (including a file called ".html") and redirects the request to a file called index.php and it takes the first part of the filename from the request (before the dot) and passes it as a query called "id."
RewriteRule ^([^/]*)\.html$ /index.php?id=$1 [L]
Since this is .htaccess you should take the slash off
You should do this:
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]+)\.html$ /index.php?id=$1 [L]
In your html itself in the links, you'll need to call filename.html.
<a href='/223.html'>Some page with an id of 223</a>
For SEO you can take the start match off
RewriteRule ([^/]+)\.html$ /index.php?id=$1 [L]
This would make it so you could reference a file like:
/somedirectory/someseotitle/223.html
Additionally you should then create 301 redirects from all of the id=$id links and make them go to their intended targets with the full URL. The code below would go into the index.php file at the top before any cookies are set or sessions started. As an example of what you could do... I'm only guessing about table structure:
<?php
if ($_SERVER['REQUEST_URI']=='/index.php' && !empty($_GET['id']){
if (is_numeric($_GET['id'])){
$id = $_GET['id'];
$cquery = "select count(*) from table where id = $id";
$count = mysqli_result(mysqli_query($cquery),0);
if($count == 1){
$tquery = "select title from table where id = $id";
$result = mysqli_query($tquery);
while ($row=mysqli_fetch_array($result)){
$title = urlencode($row['title']);
$headerString = "Location: /$title/$id.html";
header( "HTTP/1.1 301 Moved Permanently" );
header($headerString);
}
}
}
}
?>

Answer 2

In addition to what you already have in .htaccess you will need a rule for external redirection of /index.php?id=223 to /223.html. This should be your complete .htaccess:
Options +FollowSymLinks -MultiViews
# Turn mod_rewrite on
RewriteEngine On
RewriteBase /
RewriteCond %{THE_REQUEST} ^[A-Z]{3,}\s/+(?:index\.php|)\?id=([^&\s]+) [NC]
RewriteRule ^ /%1.html? [R=302,L]
RewriteRule ^([^.]+)\.html$ /index.php?id=$1 [L,QSA,NC]
Once you verify it is working fine, replace R=302 to R=301. Avoid using R=301 (Permanent Redirect) while testing your mod_rewrite rules.