Custom 404 page - PHP

问题:

I have a custom 404 page which works fine except for the message I want to display on this page.

I would like it to say the url of the page which can't be found but instead it displays the url of the 404 page.

Here's what I have...

You were looking for <?php echo $_SERVER['REQUEST_URI'] ?>.

The htaccess file contains the line: ErrorDocument 404 /404/

回答1:

You need to use $_SERVER['HTTP_REFERER'] instead - that will be the address they requested first.

This only works in the exact case described in the question - where the browser has actually been redirected to the 404 page. In that situation, $_SERVER['REQUEST_URI'] contains the URI of the 404 page rather than the originally requested page as described.

Using Apache's ErrorDocument 404 /handle404.php in the site config or .htaccess would mean that $_SERVER['REQUEST_URI'] would actually work, but a more robust solution is the option in the update below.

Update:

Apparently $_SERVER['REDIRECT_URL'] might be a better bet however, having searched around a bit.

For both cases, as mentioned by the commenters below, bear in mind that any headers are just as prone to malicious content as $_POST, $_GET and others, so process them before outputting anything.

Update 2:

Didn't see the post from @Janoz below - he correctly mentions REDIRECT_URL.

回答2:

From the perspective of the php page, that really is the request uri. Showing the error page is done by the webserver. Apache for example will add some extra server variables. REDIRECT_URL is probably the one you are looking for.

回答3:

I did not write this function but it is what I use to do the same thing:

    function selfURL() {
    $s = empty($_SERVER["HTTPS"]) ? ''
        : ($_SERVER["HTTPS"] == "on") ? "s"
        : "";
    $protocol = strleft(strtolower($_SERVER["SERVER_PROTOCOL"]), "/").$s;
    $port = ($_SERVER["SERVER_PORT"] == "80") ? ""
        : (":".$_SERVER["SERVER_PORT"]);
    return $protocol."://".$_SERVER['SERVER_NAME'].$port.$_SERVER['REQUEST_URI'];
}
function strleft($s1, $s2) {
    return substr($s1, 0, strpos($s1, $s2));
}

then to print it:

<?php print(selfURL()); ?>

回答4:

If a page doesn't exist you redirect him to the 404 page? Idealy, I would display the 404 directly on the page which wasn't found. This way, you don't have to redirect, and you can correctly use REQUEST_URI. And the code for your 404 can still be centralized!

回答5:

use file_exists to check whether the file your user is looking for exists or not. if it doesn't the redirect them to a custom made error page.