Check links in MARC records

Takes a public Koha report and checks each URL (856$u) to see if they resolve successfully. Logs output to console and a CSV file.

Environment Variables

The script uses the same .env file as the root project or it can take environment variables.

LINKCHECK_LIMIT number of links to check (leave undefined for all of them)
LINKCHECK_REPORT URL to a Koha report that returns item URLs (see report.sql). Report must be Public.
LINKCHECK_OPAC_URL catalog link for individual records, should include biblionumber={id} in it (id is interpolated)
LINKCHECK_LOGFILE path to logged CSV, defaults to the data dir named "YYYY-MM-DD-linkcheck.csv" with today's date

The app prints URLs with non-200 HTTP response statuses. It also catches HTTP exceptions within httpx, which can occur when a domain is unavailable.

Some websites have poor server hygiene and send successful HTTP responses with non-200 error codes. Not much we can do about that.