How to load Image API info.json resources into vault?

[jbaiter]

I'm trying to load the full image service definition for a canvas' image into the vault, but so far was unsuccessful:

function loadFullService(imgService: ImageService): Promise<ImageService | undefined> {
  const serviceUrl = `${imgService.id ?? imgService['@id']}/info.json`;
  return vault.load<ImageService>(serviceUrl);
}

The outcome of this function differs between IIIF2 and IIIF3 services:

For IIIF2 services, I always get back undefined, even if the Image Service exists. Stepping through with the debugger, I can see that the info.json is fetched, but it then fails in actionListFromResource with ID is not defined in resource. This probably happens because the service has the identifier in @id, which is not checked in the test for this error condition. I tested it with https://api.digitale-sammlungen.de/iiif/image/v2/bsb10217074_00027/info.json.

For IIIF3 services, it crashes at this position:

file:///home/jojo/projects/pdiiif-ng/vault-playground/node_modules/.pnpm/@[email protected]/node_modules/@iiif/vault/dist/esm-node/index.node.mjs:98
  if (!resourceType || !state.iiif.entities[resourceType][request.resourceUri]) {
                                                         ^
TypeError: Cannot read properties of undefined (reading 'https://iiif.io/api/image/3.0/example/reference/918ecd18c2592080851777620de9bcb5-gottingen')

I tested it with https://iiif.io/api/image/3.0/example/reference/918ecd18c2592080851777620de9bcb5-gottingen/info.json.

[stephenwf]

Image API resources are not currently able to be loaded into Vault (although that could be something to explore).

There is another library here: https://github.com/atlas-viewer/iiif-image-api that I've been using to explore what might be possible, and what problems we could solve.

One of the main features is reducing info.json requests where possible in viewers. This avoid the need to load and store many hundreds of image descriptions.

import { ImageServiceLoader } from ['@atlas-viewer/iiif-image-api'](https://www.npmjs.com/package/@atlas-viewer/iiif-image-api);

const loader = new ImageServiceLoader();

loader.loadService({ id: '[...]/image-1/info.json '}); // Fetched remotely
loader.loadService({ id: '[...]/image-2/info.json '}); // Fetched remotely + predicts
loader.loadService({ id: '[...]/image-3/info.json '}); // Skips fetching
// ...
loader.loadService({ id: '[...]/image-n/info.json '}); // Skips fetching

And then trying to put together a set of utilities for feature-detection + safe construction of image requests.

import { supports } from '@atlas-viewer/iiif-image-api';

const [doesSupport, failedReason] = supports(myInfoJson, { extraQualities: ['default', 'grey'] })

(some more in: https://github.com/atlas-viewer/iiif-image-api/blob/main/__tests__/supports.test.ts)

finally some more server-y code ported from C# for parsing IIIF image URL requests: https://github.com/atlas-viewer/iiif-image-api/blob/main/__tests__/parameters.test.ts