Sending a 404 error in PHP

Question

if (strstr($_SERVER['REQUEST_URI'],'index.php')){
header('HTTP/1.0 404 Not Found');
}

Why wont this work? I get a blank page.

Answer 1

That is correct behaviour, its up to you to create the contents for the 404 page.
The 404 header is used by spiders and download-managers to determine if the file exists. The page won't be indexed by google or other search-engines.

Normal users however don't look at http-headers and use the page as a normal page.

Answer 2

if (strstr($_SERVER['REQUEST_URI'],'index.php')){
    header('HTTP/1.0 404 Not Found');
}
echo "<h1>404 Not Found</h1>";
echo "The page that you have requested could not be found."
exit();

If you look at the last two echo lines, that's where you'll see the content. You can customize it however you want.

Answer 3

If you want the server’s default error page to be displayed, you have to handle this in the server.

Answer 4

Your code is technically correct. If you looked at the headers of that blank page, you'd see a 404 header, and other computers/programs would be able to correctly identify the response as file not found.

Of course, your users are still SOL. Normally, 404s are handled by the web server.

• User: Hey, do you have anything for me at this URI webserver?
• Webserver: No, I don't, 404! Here's a page to display for 404s.

The problem is, once the web server starts processing the PHP page, it's already passed the point where it would handle a 404

• User: Hey, do you have anything for me at this URI webserver?
• Webserver: Yes, I do, it's a PHP page. It'll tell you what the response code is
• PHP: Hey, OMG 404!!!!!!!
• Webserver: Well crap, the 404 page people have already gone home, so I'll just send along whatever PHP gave me

In addition to providing a 404 header, PHP is now responsible for outputting the actual 404 page.

Answer 5

A little bit shorter version. Suppress odd echo.

if (strstr($_SERVER['REQUEST_URI'],'index.php')){
  header('HTTP/1.0 404 Not Found');
  exit("<h1>404 Not Found</h1>\nThe page that you have requested could not be found.");
}