The Link checker module extracts links from your content when saved and periodically tries to detect broken hypertext links by checking the remote sites and evaluating the HTTP response codes. It shows all broken links in the reports/logs section and on the content edit page, if a link check has been failed. An author specific broken links report is also available in "My Account".
Features:
Scan configurable fields on each entity incl. node, comment, block etc.
Checks internal and by default external links
JSON:API support [from 2.1.0-alpha1]
Parallel link checking with optional HTTPRL module
Configurable link check intervals
Can update permanently moved (301) links after specified link check fail count
Can unpublish nodes after specified file not found (404) fail count
Output created by input filters is supported
Supported HTML elements: a, area, audio, embed, iframe, img, object, param, source, video
Watcher offers your site's users, registered and anonymous visitors, a way to easily watch nodes for changes and new comments without having to post themselves.
Search Files allows searching for files in node attachments and in arbitrary directories. Text is extracted by externally provided helper applications.
Helper Applications
In order to extract text, this module calls 'helper apps' such as cat and pdftotext. Drupal administrators can configure any helpers they like. Helper apps need to be installed on the server and need to be setup to print to stdout.