This Check finds broken or invalid dependencies. These might be:
- Links to files which no longer exist (404 / 410 errors)
- Other HTTP error codes
- Malformed URLs
- Non-contactable servers (timeouts etc.)
- Links with too many chained redirections
Types of dependencies checked include:
- Css files
- Font files in css3
- Meta refresh instructions in the document <head>
DeepTrawl can check hyperlinks too. See Check Hyperlinks.
Most of the time a 404 error is caused because the owner of the destination website has removed or moved the target page. Either remove the link from or point it to an alternative page.
Malformed URL errors
Most of the time, malformed URL errors are caused by a typo in your HTML. Try reviewing the link URL to make sure it is valid.
Non-contactable server errors
A server may only be temporarily non-contactable. If you are worried the server is unavailable too often, it is recommended you remove this link from your site.
Configuring this check
Select the Settings link next to the check in the Checks tab or select: Settings > Check settings > Check Dependencies from the menus.
- Css; Checks css imports both in html and css files
- iFrames; checks iframes in html files
- Fonts: checks font imports in css3
- Meta refresh. Checks refresh targets in code like this: <meta http-equiv="refresh" content="5; url=http://example.com/">
Note: De-selecting any of the following may hide other errors.
Find malformed URLs
Check for badly structured URLs (for example full URLs which have a protocol which is not widely recognized)
Find errors contacting remote servers
Stop DeepTrawl from showing a problem when a server cannot be reached over the Internet. This should usually be left on.
An error will be shown if the link times out (the timeout setting is in advanced settings, connection tab).
Follow HTTP redirections and report any errors which occur with any of the redirections or the resource found at the end of the redirection(s).
All redirections are errors
Ignore any HTTP redirections when downloading links. An error will be shown for any redirection when downloading a link.
Error if too many redirections
Switch this off to suppress errors where DeepTrawl could not reach a linked resource because too many redirections were used. For changing the maximum number of redirections, see advanced settings, connection tab.
Error HTTP codes
Switch on or off to search for specific HTTP error codes. For instance you may wish to never see errors caused by 401 (unauthorized) HTTP codes.