@indexdata/oai-pmh

Copyright (C) 2022 Index Data Aps.

This software is distributed under the terms of the Apache License, Version 2.0. See the file "LICENSE" for more information.

Overview

This is a very simple OAI-PMH client library, written because all the various existing libraries known to Node are abandonware or undocumented.

It exists primarily for the use of ui-harvester-admin but should be of wider utility.

API

First, create an OAI-PMH client object associated with a specific service:

import OaiPmh from '@indexdata/oai-pmh';
const oaiPmh = new OaiPmh('https://ora.ox.ac.uk/oai2');

Now you can use it to ask the server to identify itself, supply a list of sets, etc:

const identity = await oaiPmh.identify();
const sets = await oaiPmh.listSets();
const formats = await oaiPmh.listMetadataFormats();

At present, only the Identify, ListSets and ListMetadataFormat verbs are supported: we will add others as we have a need for them. The optional parameters to the second and third of these are ignored.

All methods return a promise that resolves to a JavaScript object containing the data returned from the service. So for example:

formats.ListMetadataFormats[0].metadataFormat.map(x => {
  console.log(`prefix '${x.metadataPrefix} -> ${}`);
});

See the very simple example code.

Note on dependencies

The package file includes a dependencies on timers and stream even though we don't use those packages directly. This is because the xml2js library needs them but doesn't have dependencies, probably because it's relying on the behavior of Babel before v5.x which used to polyfill various node.js core modules.

Of CORS security is an issue

Understandably, when a browser loads the FOLIO SPA from one origin, it's unhappy about letting that SPA make OAI-PMH requests (or any HTTP requests) to other origins. We will need to figure out a way to address this in production, but for development it suffices to use the local-cors-anywhere web proxy. Install globally with yarn global add local-cors-anywhere and run as env PORT=8081 ~/.yarn/bin/local-cors-anywhere. Then prefix OAI-PMH service URLs with http://localhost:8081/, so that the SPA accesses services at URLs like http://localhost:8081/https://ora.ox.ac.uk/oai2