@allmaps/id

Uses the SHA-1 algorithm to generate IDs from strings, random IDs from UUIDs and checksums from JSON objects.

Allmaps uses this module to create IDs from IIIF URIs. For example:

• Given the following manifest URL: https://digital.zlb.de/viewer/api/v1/records/34231682/manifest/,
• The output of the generateId function will be: 6f5a7b547c8f6fbe,
• We can use this ID to lookup the Georeference Annotation for the georeferenced maps in this manifest using Allmaps API: https://annotations.allmaps.org/manifests/6f5a7b547c8f6fbe.

To see @allmaps/id in action, view this Observable notebook.

Usage

This is an ESM-only module that works in browsers and Node.js.

Node.js:

The Node.js version of @allmaps/id usescrypto.createHash() and crypto.randomUUID() from the crypto module. First, run npm install @allmaps/id.

import { generateId } from '@allmaps/id'
const url = 'https://digital.zlb.de/viewer/api/v1/records/34231682/manifest/'
const id = await generateId(url)
// id = '6f5a7b547c8f6fbe'

Browser:

The browser version of @allmaps/id uses the SubtleCrypto.digest() and Crypto.randomUUID() Web APIs.

<script type="module">
  import { generateId } from 'https://esm.run/@allmaps/id'

  const url =
    'https://orka.bibliothek.uni-kassel.de/viewer/rest/iiif/manifests/1535113582549/manifest/'
  const id = await generateId(url)
  console.log(id)
</script>

CLI

Generating Allmaps IDs is also possible using the Allmaps CLI.

For example:

echo https://digital.zlb.de/viewer/api/v1/records/34231682/manifest/ | allmaps id

API

generateChecksum(obj, length)

Generates a checksum of a JSON object.

Parameters

• obj (unknown)
  • JSON object.
• length (number | undefined)
  • Length of returned hash. The maximum length of the hash is 40 characters.

Returns

First length characters of the SHA-1 hash of sorted and serialized version of obj (Promise<string>).

generateId(str, length)

Generates an ID from a string using the SHA-1 algorithm. Given the same input, the ID will always be the same.

Parameters

• str (string)
  • Input string
• length (number | undefined)
  • Length of returned hash. The maximum length of the hash is 40 characters. The default length is 16.

Returns

First length characters of the SHA-1 hash of str (Promise<string>).

generateRandomId(length)

Generates a random ID.

Parameters

• length (number | undefined)
  • Length of returned hash. The maximum length of the hash is 40 characters.

Returns

First length characters of the SHA-1 hash of a random UUID (Promise<string>).