Broken Link Checker for WordPress
Sometimes, links get broken. A page is deleted, a subdirectory forgotten, a site moved to a different domain. Most likely many of your blog posts contain links. It is almost inevitable that over time some of them will lead to a “404 Not Found” error page. Obviously you don’t want your readers to be annoyed by clicking a link that leads nowhere. You can check the links yourself but that might be quite a task if you have a lot of posts. You could use your webserver’s stats but that only works for local links.
So I’ve made a plugin for WordPress that will check your posts (and pages), looking for broken links, and let you know if any are found.
Download it now! (40 KB)
Note : This page, and the feature list below are slightly out of date as a major update has been released recently (see details). I’ll get around to updating this page eventually.
Features
- Checks your posts (and pages) in the background (whenever the WP admin panel is open ).
- Detects links that don’t work and missing images. Checks both internal and outbound links.
- Notifies you on the Dashboard if any problems are found.
- Link checking intervals can be configured.
- New/modified posts are checked ASAP.
The broken links show up in the Manage -> Broken Links tab. If any invalid URLs are found a notification will also show up in the sidebar on the Dashboard.
The Broken Links tab displays a list of invalid URLs found along with the relevant posts and the anchor text of the links. “View” and “Edit Post” do exactly what they say and “Discard” will remove the message about a broken link, but not the link itself (so it will show up again later unless you fix it; this plugin doesn’t modify your links).
By default all old posts/links are re-checked every 72 hours, or you can set a different time period.
Notes (Semi-Technical)
I realize there’s a lot of features that could be added to improve this plugin considerably. However, this release is intended to “test the waters” and see if there’s demand for a plugin like this, so I only implemented the most basic functions. The plugin has been upgraded to be slightly beyond “basic” 
I thought about using WP’s pseudo-cron to run the link checker by schedule and decided against it. AFAIK the cronjobs execute when a page is requested; since this plugin does some lengthy processing it may increase page load times unacceptably when used in this manner. That’s why I set it to run the checks asynchronously (AJAX) and invisibly in the admin panel.
Installation
Just like any other WordPress plugin -
- Download (see below).
- Unzip.
- Upload the broken-link-checker folder to you wp-content/plugins directory.
- Activate the plugin in the Plugins tab.
Upgrading
- Deactivate the plugin (important!).
- Do steps 1.-3. from “Installation”.
- Upload the broken-link-checker folder to you wp-content/plugins directory.
- Re-activate the plugin in the Plugins tab.
Download
Version 0.5.3 : broken-link-checker.zip (40 Kb)
Requirements
- WordPress 2.7 or later
- MySQL 4.1 or later
Starting with version 0.5 this plugin is only compatible with WordPress 2.7 and up. Older versions (e.g. ver. 0.4.14) should work with WP 2.1 – 2.6.x.
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Thank you for update.
> using “isset($wpdb)” instead of “class_exists(’wpdb’)” will be a better choice
I guess you’re right, actually, it works fine.
‘wp-db.php’ is not one of the “Popular Libraries” like PclZip, but a part of
WordPress system.
The article is may not suitable for this situation.
Anyway, the problem has gone.
I won’t have to edit when this plugin updated.
If you need, I’ll try to find out which plugin cause the conflict I wrote.
@Dai – Nah, it’s fine, though feel free to investigate if that helps your peace of mind.
This is a great plugin – found loads of dead links on one of my blogs. But on another, I can’t get it to run.
Both blogs are 2.6.1, and both are hosted on the same server, so I think there must be some interference with another plugin, one that I’m not using with the first, successful installation. Specifically, what happens is that it doesn’t run automatically, and when I click ‘re-check all pages’ in an attempt to trigger it, I get my ‘no results of a search’ page, suggesting other links, up for a few seconds. Then the default Broken Link Checker start page comes up again. Very odd!
I’ve tried deactivating all the obvious plugins – do you have any suggestions?
@Lucy – Hmm, here are some ideas :
* When you click the “re-check all” button note the URL of the “search page” (before it redirects). That might give some clues.
* Check your .htaccess. Maybe there are some security-related rules that are blocking parts of the plugin.
* Try disabling/enabling any cache-related plugins. My intuition tells me those could have something to do with it (somehow).
* Check file permissions/file owner of broken-link-checker.php and wsblc_ajax.php (especially the second one). The “right” permissions depend on your server configuration, but in general these files should both have the same permissions as the .php files of other, working WP plugins on your server.
Hi man.
I just tested a hack:
http://wordpress.org/support/topic/190128?replies=4#post-840910
And I have this problems, can you kindly search the wp-config file in a relative way?:
Warning: require_once(../../../wp-config.php) [function.require-once]: failed to open stream: No such file or directory in /home/wordpress/plugins/broken-link-checker/wsblc_ajax.php on line 5
Fatal error: require_once() [function.require]: Failed opening required ‘../../../wp-config.php’ (include_path=’.:/usr/share/pear:/usr/share/php’) in /home/wordpress/plugins/broken-link-checker/wsblc_ajax.php on line 5
@Nokao – I see why the plugin wouldn’t work in that configuration, but I’m not quite sure what you mean by “in a relative way”. It’s already using a relative path to include wp-config.php, do you mean I should use an absolute path, or what?
Hi White Shadow (and compliments for your storms pictures, we have the same photographic taste for natural strength).
I said “relative” because someway, your plugin recognizes that he is in a “symbolic link jailed folder”.
The point is that it’s the only plugin that it’s not working and I think that it’s not the only that uses the wp-config someway.
I’m not a WordPress hacker, so maybe you can look how do plugins like nextgen gallery look into the wp-config file…
I also have another question I posted months ago:
to remove the check of links that have different protocols from http, like for example skype://
Your plugin hates my msn and skype “addme” buttons
Thanks again for your work!
@Nokao – It doesn’t “recognize” it, it just tries to include the file as if the plugin was in the usual location, and, obviously, fails. I don’t think there’s anything I can do to the plugin to fix this except overhauling the entire AJAX part of it and getting rid of wsblc_ajax.php altogether. That would take a lot of time & work, so it probably won’t happen in the foreseeable future.
For the time being, you should just edit the plugin and replace “../../../wp-config.php” with a full path to the wp-config.php file. Hopefully I’ll be able to remove this need for hacks in the next version – but, as I said, it probably won’t be soon.
Ah, and thanks for the compliments
@White Shadow –
Ok… I’ll surrender to the fact that I can’t use your plugin in that server
(i’ll continue to use that for my personal blog)
Infact, I can’t change the ../../../ folder with something, because, you know, I did that “hack” to have the SAME plugins folder with more than 25 wordpress websites.
So I can’t know wich website is calling the function, and I can’t address a wp-config.php in an absolute way.
I really hope that your plugin is the only that have that problem… I’m curious about that.
Actually, all seems to be working fine.
@Nokao – Oops, I forgot about that. You’re right, my suggestion wouldn’t work.
Other plugins work because either they don’t use AJAX at all or use it in a different way (possible, but as I mentioned it would take a while to convert this plugin to use the other method).
@White Shadow –
Uh
Even nextgen-gallery have SOME problems, in the admin menu’, the link is wrong and it’s a mix of server path and symlink.
I don’t understand honestly why this is happening… and why you need to look for wp-config.php
@Nokao – Do you really want to know all the details?…
Okay, for my plugin it’s like that : the link checks run in the background using AJAX in the admin menu. This is necessary because I can’t expect every user to set up a cronjob for the broken link script.
In WordPress plugins an AJAX-y component can be built in several ways. This plugin uses a different PHP file for the AJAX tasks. The file, wsblc_ajax.php, needs to be able to access the WordPress database to be able to read posts and check links in them, etc. That’s why it needs to load the WP core engine and blog configuration. This is done by including wp-config.php. Also, the plugin needs to load the database layer, so it includes wpdb.php.
That’s it
That seems to happen on CGI and FastCGI installations of PHP, which is the vast majority. Apparently the symlink is getting dereferenced when the file is loaded. So the script has no idea where it was called from, but instead sees where it actually is on the filesystem. Therefore it can’t figure out where anything else is because it isn’t in the directory tree you expected. My test Apache/mod_php install doesn’t seem to have this problem, though my FastCGI install does. As far as I know there’s no good way to “fix” this.
@Michael Hampton –
Maybe we can try with an hard-link ?
Can you contact me in private so we don’t go off-topic here on White Shadow’s website?
info at
nokao dot
com
If someone reads my previous questions about having a multi-blog engine installed to have only one WP and of course only one plugins/themes folder… and wants to know if there is a solution…
Yes, there is, and it’s called:
http://striderweb.com/nerdaphernalia/features/virtual-multiblog/
I’m astonished… now I have more than 20 WP websites with a single WP installation, no more multi-update-caring and balls-breaking.
Bye
Thanks a lot for the great add-on, should save me having to use a manual solution.
I just installed the plug in and works really great but since then the wp admin becomes really slow, do you know or anybody knows or have the same issue?
thx!
@Dan – Some users have had similar issues, but the only thing I can suggest is trying a different browser. I think the problem is site/browser specific.
I think the broken link checker hmight have a problem with del.icio.us (wonder if their nofollow is part of it?) BLC is showing false positives for just about ALL my del.icio.us tag links. For about a month earlier this year I was doing a LOT of bookmarking on delicious and was having del.icio.us do a daily post to my blog since the bookmarks were of mostly useful, relevant content – in a nutshell, I have LOT of del.icio.us bookmark links on my site and BLC is showing 3000+ bad links I have nary the time to go thru by hand so I ‘d be tickled pink if there arose a automagical remedy to this problem. – thx
@R. Richard Hobbs – Del.icio.us links seem to work fine on my test blog, so I’m guessing the problem is site-specific. I can only suggest you add del.icio.us and delicious.com to the exclusion list in Settings -> Link Checker.
>>> I can only suggest you add del.icio.us and delicious.com to the exclusion list in Settings -> Link Checker.
<<< thanks for that – I really only turned BLC back on yesterday after I had deactivated a while back. I have been keeping it updated but I hadnt really noticed that feature – thx again
Feature request: make links to check open in new tab or window
Feature request: make your comment form remember me
thx
@R. Richard Hobbs – Could you clarify what you mean by “links to check”?
As for the comment form, I’m aware of the problem – it’s caused by the same plugin that handles comment paging. I’ve let the author know about this bug, but it’s not fixed yet. And I think disabling the plugin would be a bad idea – for example, this page would take forever to load with >250 comments on one page.
>>> Could you clarify what you mean by “links to check”?
<<< after the BLC has done its work you are presented with a list of bad links it has found (it’s”edit” link is next to each of these) I’ll call this the “work page”… Normally I will confirm for myself they are bad if just click on each link you are moved off the work page and have to go back after following the link unless it is opened in a new tab or window. Its a relatively small chore but little things matter if there are a lot of links to check. Automatically opening the link in a new tab (or giving users the option on the config page would please me immensely.
Another suggestion might be to be able to select all the text automatically (like the “embed” box on Youtube) in the edit form window. There appear to be lots of free javascripts that do this. Admittedly I havent gotten in there and tried it so I cant say exactly how easy or hard it might be to implement this, but for me it would be a helpful feature.
Thanks again for your hard work and kind ear.
@R. Richard Hobbs – Ah, I usually just middle-click those links which opens the link in a background tab in Opera. Anyway, I’ll make them open in a new window by default (the window/tab distinction is browser-specific, can’t control it from JS AFAIK).
I’ll see what I can do about auto-selecting the text.
We’ve been able to fix many bad links in the resources lists on our site. But there are four links that it keeps marking as bad links that are really good links. Why are these URLs being marked as bad? (I tried putting them in normally but your comment form thinks it is spam so I’ll try the following to see if that gets accepted.)
www dot accessible dot ie
www dot accessible dot ie/?p=50
www dot natural-access dot com
www dot eschoolnews dot com
Thanks.
@SleeplessinDC – Those links work fine in my tests. Anyway, the next version of the plugin will have more detailed reporting which should help you figure out why the links get marked as broken.
[...] of link checkers on the internet, but for all you WordPress-ers, there’s an easier way – the broken link checker plugin. I recently installed and ran it on one of the sites I look after, and it came up with a list of [...]