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Creating an Error 404 Page

While you work hard to make sure that every link actually goes to a specific web page on your site, there is always a chance that a link clicked will slam dunk and become a famous 404 ERROR PAGE NOT FOUND.

All is not lost. If your visitors encounter an error, why not be a helpful WordPress site administrator and present them with a message more useful than "NOT FOUND".

This lesson will teach you how to edit your "error" and "page not found" messages so they are more helpful to your visitors. We'll also show how to ensure your web server displays your helpful custom messages. Finally, we'll go over how to create a custom error page consistent with your Theme's style.

An Ounce of Prevention

Some errors are avoidable, you should regularly check and double check all your links. Also, if you are deleting a popular but out-of-date post, consider deleting the body of the post, and replacing it with a link referring visitors to the new page.

Understanding Web Error Handling

Visitors encounter errors at even the best websites. As site administrator, you may delete out-of-date posts, but another website may have a link to your inside page for that post.

When a user clicks on a link to a missing page, the web server will send the user an error message such as 404 Not Found. Unless your webmaster has already written custom error messages, the standard message will be in plain text and that leaves the users feeling a bit lost.

Most users are quite capable of hitting the back key, but then you've lost a visitor who may not care to waste their time hunting for the information. So as not to lose that visitor, at the very least, you'll want your custom message to provide a link to your home page.

The friendly way to handle errors is to acknowledge the error and help them find their way. This involves creating a custom Error Page or editing the one that came with your WordPress Theme.

Editing an Error 404 Page

Every theme that is shipped with WordPress has a 404.php file, but not all Themes have their own custom 404 error template file. If they do, it will be named 404.php. WordPress will automatically use that page if a Page Not Found error occurs.

The normal 404.php page shipped with your Theme will work, but does it say what you want it to say, and does it offer the kind of help you want it to offer? If the answer is no, you will want to customize the message in the template file.

To edit your Theme's 404 error template file, open it in your favorite text editor and edit the message text to say what you want it to say. Then save your changes and upload it to the theme directory of your WordPress install.

While you are examining and editing your 404 template file, take a look at the simple structure of the 404.php file that is shipped with Twenty Thirteen. It basically features tags that display the header, sidebar, and footer, and also an area for your message:

<?php
/**
 * The template for displaying 404 pages (Not Found)
 *
 * @package WordPress
 * @subpackage Twenty_Thirteen
 * @since Twenty Thirteen 1.0
 */

get_header(); ?>

	<div id="primary" class="content-area">
		<div id="content" class="site-content" role="main">

			<header class="page-header">
				<h1 class="page-title"><?php _e( 'Not Found', 'twentythirteen' ); ?></h1>
			</header>

			<div class="page-wrapper">
				<div class="page-content">
					<h2><?php _e( 'This is somewhat embarrassing, isn’t it?', 'twentythirteen' ); ?></h2>
					<p><?php _e( 'It looks like nothing was found at this location. Maybe try a search?', 'twentythirteen' ); ?></p>

					<?php get_search_form(); ?>
				</div><!-- .page-content -->
			</div><!-- .page-wrapper -->

		</div><!-- #content -->
	</div><!-- #primary -->

<?php get_footer(); ?>

So, to change the error message your visitor sees, revise the text within the h1 heading and within the page-content class; if necessary, add more paragraphs below that.

Creating an Error 404 Page

If your WordPress Theme does not include a template file named 404.php, you can create your own.

Because every theme is different, there is no guarantee that copying over the 404.php template file found in the Twenty Thirteen Theme will work, but it's a good place to start. The error page you copy from the Twenty Thirteen Theme will adopt the style of the current theme because it actually calls the header and footer of the current theme. That's less work for you, and you may only have to edit the message to suit your particular needs.

To use the 404.php template file from the WordPress Twenty Thirteen Theme:

  1. Copy the file /wp-content/themes/twentythirteen/404.php into the directory of your current theme.
  2. Then, as described in the previous section, edit the error message to present your desired error message.

If copying the default 404.php into your theme directory does not work well with your theme, you can also:

  • Change the Default Theme's 404.php template file's header, sidebar, footer, and other codes to match the rest of the Theme's layout.

Or

  • Copy the index.php file of your current theme to a file called 404.php.
  • Open that file and delete all sections dealing with posts or comments, see The Loop.
  • Then, edit your 404 error message.

Tips for Error Pages

There are various improvements you can make to your 404 Error web pages so let's look at some of your options.

Writing Friendly Messages

When an error message is displayed, you can say many things to help a visitor feel reassured they've only encountered a minor glitch, and you're doing the best you can to help them find the information they want. You can say something clever like:

"Oops, I screwed up and you discovered my fatal flaw. 
Well, we're not all perfect, but we try.  Can you try this
again or maybe visit our <a 
title="Our Site" href="http://example.com/index.php">Home 
Page</a> to start fresh.  We'll do better next time."

You should also attempt to show the user what they want. Check out the AskApache Google 404 Plugin to add google search results to your 404.php

Or, say something shorter and sweeter. Almost anything you say is better than 404 Error Page Not Found. You can find more information about writing 404 Error pages on the Internet, like List Apart's Perfect 404.

As an implementation of the Perfect 404 page, this solution will tell the user it's not their fault and email the site admin. Helpful 404 page

When a visitor gets a 404 error page, it can be intimidating, and unhelpful. Using WordPress, you can take the edge off a 404 and make it helpful to users, and yourself, too, by emailing whenever the user clicks a link to a non-existent page.

<p>You 
<?php
#some variables for the script to use
#if you have some reason to change these, do.  but wordpress can handle it
$adminemail = get_option('admin_email'); #the administrator email address, according to wordpress
$website = get_bloginfo('url'); #gets your blog's url from wordpress
$websitename = get_bloginfo('name'); #sets the blog's name, according to wordpress

  if (!isset($_SERVER['HTTP_REFERER'])) {
    #politely blames the user for all the problems they caused
        echo "tried going to "; #starts assembling an output paragraph
	$casemessage = "All is not lost!";
  } elseif (isset($_SERVER['HTTP_REFERER'])) {
    #this will help the user find what they want, and email me of a bad link
	echo "clicked a link to"; #now the message says You clicked a link to...
        #setup a message to be sent to me
	$failuremess = "A user tried to go to $website"
        .$_SERVER['REQUEST_URI']." and received a 404 (page not found) error. ";
	$failuremess .= "It wasn't their fault, so try fixing it.  
        They came from ".$_SERVER['HTTP_REFERER'];
	mail($adminemail, "Bad Link To ".$_SERVER['REQUEST_URI'],
        $failuremess, "From: $websitename <noreply@$website>"); #email you about problem
	$casemessage = "An administrator has been emailed 
        about this problem, too.";#set a friendly message
  }
  echo " ".$website.$_SERVER['REQUEST_URI']; ?> 
and it doesn't exist. <?php echo $casemessage; ?>  You can click back 
and try again or search for what you're looking for:
  <?php include(TEMPLATEPATH . "/searchform.php"); ?>
</p>

Add Useful Links

If you encounter a "page not found" situation on the WordPress site, it is filled with helpful links to direct you to the various categories and areas of information within the WordPress site. Check it out at http://wordpress.org/brokenlink.php.

To add similar useful links to your 404 page, create a list, or a paragraph, so the visitor can easily determine which section might be useful to visit. Information of that nature is much better than having the user just reach a dead-end. To help you understand how to link to documents within your site, especially to Pages and Categories, see Linking_Posts_Pages_and_Categories.

Testing 404 Error Messages

To test your custom 404 page and message, just type a URL address into your browser for your website that doesn't exist. Make one up or use something like:

http://example.com/fred.php

This is sure to result in an error unless you actually have a php file called fred. If your error page doesn't look "right", you can go back and edit it so it works correctly and matches your Theme's look and feel.

Help Your Server Find the 404 Page

WARNING: If you are using custom permalink, the trick below does not work, see this: http://core.trac.wordpress.org/ticket/7592.

By default, if WordPress cannot find a particular page it will look for the 404.php web page. However, there may be cases where the web server encounters a problem before WordPress is aware of it. In that case, you can still guarantee that your web server sends the visitor to your 404.php template file by configuring your web server for custom 404 error handling.

To tell your web server to use your custom error files, you'll need to edit the .htaccess file in the main directory (where main index.php file resides) of your WordPress installation. If you don't have an .htaccess file, see Editing Rewrite Rules (.htaccess) on how to create an .htaccess file.

To ensure the server finds your 404 page, add the following line to your .htaccess file:

ErrorDocument 404 /index.php?error=404

The url /index.php is root-relative, which means that the forward slash begins with the root folder of your site. If WordPress is in a subfolder or subdirectory of your site's root folder named 'wordpress', the line you add to your .htaccess file might be:

ErrorDocument 404 /wordpress/index.php?error=404

Questions About Error Files

Why not just hard code the path all the way to the 404.php file?
By allowing index.php to call the error file, you ensure that the 404.php file used will change automatically as you change your theme.
What happens if I switch to a theme that does not have a 404.php file?
Visitors clicking on a broken link will just see a copy of the home page of your WordPress site (index.php), but the URL they see will be the URL of the broken link. That can confuse them, especially since there is no acknowledgement of the error. But this is still better than a getting a "NOT FOUND" message without any links or information that could help them find what they seek.