IsaacVarner Link Scanner

Broken links cost you readers and search rankings. This plugin finds them, and it is built so that looking for them never costs you anything while you are not looking.

It does nothing at all until you open it and press Start.

The scan runs from the Tools screen, one small batch at a time, and stops the moment you close the tab. There is no scheduled task and no background worker. When the scan finishes, the plugin returns to using no resources.

How it works

• No background cron. The plugin registers no scheduled events of any kind.
• Each unique link is checked once, however many posts it appears in. A link in your footer that appears on five hundred pages is one request, not five hundred.
• HEAD requests first, falling back to a full request only when a server needs one, so remote sites are asked for as little as possible.
• Nothing runs on the front end. No code executes for your visitors. When idle, the plugin holds two small database tables and does nothing else.

Four results, not one

Not every link that fails an automated check is actually broken. Results are separated so you can tell the difference:

• Broken — the link is genuinely gone. 404, DNS failure, connection refused.
• Blocked — the server answered but refused an automated request (401, 403, 429). These normally work fine in a browser, so they are listed apart from real failures.
• Redirect — the link resolves, but somewhere else now. The destination is shown. If that destination is itself dead, the link is reported as broken instead.
• Working — verified reachable.

Any link you do not care about can be ignored, and it stays ignored.

Polite to the sites it checks

Checking a link means making a request to somebody else’s server. This plugin waits at least a second between requests to the same host, sets a short timeout, and identifies itself with a user agent containing your site address. These are not configurable.

Honest about incomplete scans

If a scan is stopped or interrupted, the plugin says so and tells you how many links were never checked, so a short list of broken links is never mistaken for a clean site.

1. Install through Plugins → Add New, or upload the folder to /wp-content/plugins/.
2. Activate the plugin.
3. Go to Tools → IsaacVarner Link Scanner and press Start scan.

That is the whole setup. There is nothing to configure.

1. 

   Broken links, grouped by URL and showing which post each one appears in.

2. 

   A link that answered but refused an automated request is listed under Blocked rather than Broken, so a link that works for your readers is never reported as dead.

3. 

   Before a scan. The plugin has registered nothing and is doing nothing.

4. 

   A scan in progress. It runs only while this page is open and stops when you leave.

1.0.1

• Fixed: the results from a previous scan stayed on screen while a new scan was running, even though starting a scan clears them. The list is now replaced for the duration of the scan.
• Fixed: stopping a scan now refreshes the page, so the partial results and the unchecked count are accurate immediately.
• Fixed: status messages no longer break words in the middle when they wrap. The status column is also wider, so most messages now fit on one or two lines.

1.0.0

• First release.