Volume API

This API enables some endpoints to support catalog search in libraries.

Main code: https://github.com/hathitrust/catalog/blob/main/static/api/volumes.php
Public Documentation: https://www.hathitrust.org/member-libraries/resources-for-librarians/data-resources/bibliographic-api/

The rewrite rules in .htaccess are responsible for mapping api/volumes/... endpoints into static/api/volumes.php?... URLs

There are four variations on Bib API endpoints. The components will be abbreviated as follows:

b - brevity:, usually but not always enforced to be in {brief, full}
- The difference between a brief and full is that a complete MARC-XML is returned in a full response.
t - type: the output format is always json, no other output formats are implemented.
qf - query_field, fields defined on the Catalog Solr index to retrieve a record. The API allows Solr queries with the following fields
- recordid,
- sysid
- oclc
- htid
- issn
- isbn
- lccn
- umid. To see what each field means, access the public documentation.
qv - query value , such as mdp.39015048895836
Q, which is qf (query_field) combined with qv (query_value), e.g., htid:mdp.39015048895836
- Q may have multiple values for a field, e.g., htid:mdp.39015048895836|mdp.39015004074095 (treated as an OR and that allows for retrieving up to 20 records at a time)
- Q may have multiple fields or id types, e.g., htid:mdp.39015048895836;oclc:7107072 (treated as an AND, you will use different fields to find a record.)
- The exact semantics are not entirely clear from the documentation and are buried in the code

In order of appearance in .htaccess, they are:

brevity/type/Query
- e.g. /api/volumes/full/json/htid:mdp.39015048895836
- This form can be used to perform more complex queries with Q
- The public documentation calls this "The multi-id request format."
brevity/query_field/query_value.type
- e.g. /api/volumes/full/htid/mdp.39015048895836.json
- The public documentation calls this the "Simple, single-identifier API"
type/Query
- implies brevity brief
- e.g. https://catalog.hathitrust.org/api/volumes/htid/mdp.39015004074095.json
query_field/query_value.t
- implies brevity brief
- e.g. https://catalog.hathitrust.org/api/volumes/json/htid:mdp.39015004074095