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Note : This page, and the feature list below are slightly out of date as a major update has been released recently (see details).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)
Compatibility : 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.
@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 [...]
Hi there,
I thought I’d give BLC a try in WP 2.6(.1). No (PHP/WP) errors but it marks perfectly fine links as ‘broken’ while they’re obviously not! At first I thought it only did that with ’shorthand’ links like domain dot com instead of www dot domain dot com but it has now also marked other ‘good’ links as ‘broken’…
This somewhat negates the use of BLC…
However: Great plugin and I’m looking forward to seeing any issues resolved or more documentation on ‘why BLC marks those links as broken’ becomes available.
Thanx!!!
@CID – If you have the latest version (0.4.8) you should be able to get some clues as to why those links were marked as broken by clicking the new “Details” button(s) in Manage -> Broken Links. However, meaningful info will only be available about “broken” links that were checked with this newer version.
Hey WhiteShadow,
Thanks for your quick response!
Yes, I do have version 0.4.8 and it lists ‘details’. However, every link detail (except the URL’s and time ofcourse) reads:
——————————————————————————
Last checked : 2008-09-09 12:06:09
Final URL : http://www.cid-iv.com
HTTP code : 0
Log :
=== First try : No response. ===
Trying a second time with different settings…
=== Second try : No response. ===
Link is broken.
——————————————————————————
The sites load fine but BLC keeps getting ‘no response’…
@CID – It’s probably timing out. The timeout is hardcoded to be about 30 seconds (when using CURL). Maybe I should add an option to configure it…
Yes, well, that would, in any case, be a welcome addition. Always nice to be able to set the threshold for this kind of functionality. But I don’t think that that’s the case here because the site (mentioned in the example) loads in under 2 seconds… (Checked with Fasterfox.)
@CID – Maybe the site has some kind of security software in place to prevent suspicious bots from accessing it. Wouldn’t be the first time.
Ok, yes, that would cause such behaviour, I will check!
But how about the internal links it marks as ‘broken’?
And to me it seams that it has problems handling shorthand URL’s. Or can’t that be the case?
@CID – “shorthand” URLs shouldn’t be a problem if the URL is otherwise valid and working. In particular, external links should always include the protocol part (usually http://).
Are the local links using relative URLs? The plugin should handle it, but the algorithm is not perfect.
~ bug ~
When I activate the plug-in my website bleeds through the admin. So I can actually see my website below with some themes the admin, and integrated with the admin in other themes.
~ end bug ~
has this been fixed yet?
When I search for “broken link checker” in the wordpress plugins search I do not see your plugin any more. What happened?
http://wordpress.org/extend/plugins/search.php?q=broken+link+checker
@Bart Gibby – The WordPress.org plugin search is notoriously bad. The plugin page is still up.
As for the “bug”, check that wsblc_ajax.php is present in the plugin’s folder (i.e. in wp-content/plugins/broken-link-checker/) and that it doesn’t have any weird permissions set. Actually, just see if you can access yourblog.com/wp-content/plugins/broken-link-checker/wsblc_ajax.php. You might have a .htaccess rule or some security module blocking it. Or possibly your “wp-content” folder isn’t where the plugin expects it to be.
Broken Link Checker is not compatible with Ozh Better Feed