First, I am deeply appreciative of the ability to add and use z39.50 target directories for marc record harvesting.
I am now looking into adding open access resources to the catalog, and they do not operate z39.50 servers, but instead conform to the Open Archives Initiative Protocol for Metadata Harvesting standards (which would take as an input a provided base URL for OAI-PMH harvesting). A list of all the data and feeds provided by my current target (of all quality controlled and many peer reviewed monographs and chapters), is listed here: https://www.oapen.org/article/metadata. Note that this directory can also be accessed using a REST API (not listed on the page), see https://www.oapen.org/article/8185269-search-using-a-rest-api).
If possible, for implementation, I suspect you would need to add another subsection to the library general section for OAI-PMH harvesting servers, and another box, or drop down menu option to the "add resources" page to select for targeting a single specific OAI-PMH harvesting address. Likely you might need to allow the selection of a single OAI-PMH harvesting address at a time, for example, the target directory I am currently looking at, https://oapen.org/. This directory also offers a download of the full marc records for its collection, but that is over 30,000 records, from which I only want ~200 to add to the catalog (most easily by subject, but if I have to enter the book's URI, DOI or ISBN, that would also be acceptable. Adding the ability to build a query that would limit by year or date (for updates only!) would also be fantastic. (as would adding a library materials audit feature that checked for an returned broken links in item records).
This implementation would likely need to automatically build the query to the OAI-PMH harvesting address in order to return a MARC record based upon the search string entered.
see: http://www.openarchives.org/pmh/ for protocol specifications,
see: https://support.archive-it.org/hc/en-us/articles/210510506-Access-web-archives-with-the-OAI-PMH-metadata-feed for use implementation notes from a company providing open archive creation services.
A slightly dated but good overview of tools and implementation: https://www.journals.ala.org/index.php/lrts/article/view/5366/6577
Note: in the meantime I will be exploring the use of MarcEdit to extract the records I want an upload them in the standard way.
Thank you.