Displays buttons to open SLV digitised maps in AllMaps for viewing and/or georeferencing

link-slv-allmaps.user.js

// ==UserScript==
// @name        Link SLV maps to AllMaps for georeferencing
// @namespace   wraggelabs.com/link-slv-allmaps
// @match       *://viewer.slv.vic.gov.au/?entity=IE*
// @grant       GM.xmlHttpRequest
// @connect     viewerapi.slv.vic.gov.au
// @connect     annotations.allmaps.org
// @version     1.0
// @author      Tim Sherratt (tim@timsherratt.au)
// @description Displays buttons to open SLV digitised maps in AllMaps for viewing and/or georeferencing.
// @require https://cdn.jsdelivr.net/gh/CoeJoder/waitForKeyElements.js@v1.3/waitForKeyElements.js
// ==/UserScript==

const DEFAULT_LENGTH = 16;

// These two functions are from the AllMaps id module.
// https://github.com/allmaps/allmaps/tree/main/packages/id
/**
 * Computes SHA-1 hash of input string.
 *
 * @param Input string.
 * @returns SHA-1 hash of `str`.
 */
async function generateHash(str) {
    const hashBuffer = await crypto.subtle.digest('SHA-1', new TextEncoder().encode(str));
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    const hashHex = hashArray
        .map((byte) => byte.toString(16).padStart(2, '0'))
        .join('');
    return hashHex;
}
/**
 * Generates an ID from a string using the SHA-1 algorithm. Given the same input, the ID will always be the same.
 *
 * @param str - Input string
 * @param length - 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`.
 */
async function generateId(str, length = DEFAULT_LENGTH) {
    const hash = await generateHash(String(str));
    return hash.slice(0, length);
}

// Adds links to Allmaps in the summary information section
function addButtons(ieID, hashId, status) {
  let summary = document.querySelector("div.cell.summaryCell.small-12.medium-8");
  let geoHeader = document.createElement("h3");
  geoHeader.innerText = "Georeferencing";
  geoHeader.style.marginTop = "2rem";
  summary.appendChild(geoHeader);
  let geoMessage = document.createElement("p");
  // Create button to georeference in AllMaps editor
  // Text of button will change depending on whether item is already georeferenced.
  let editButton = document.createElement("a");
  editButton.className = "button viewCatalogueEntry";
  editButton.href = "https://editor.allmaps.org/images?url=" + encodeURIComponent("https://wraggelabs.com/slv_iiif/" + ieID);
  if (status == 200) {
    // Item has been georeferenced
    geoMessage.innerHTML = "This item has been georeferenced using <a href='https://allmaps.org'>AllMaps</a>."
    summary.appendChild(geoMessage);
    editButton.textContent = "Edit georeferencing using AllMaps";
    summary.appendChild(editButton);
    // Add button to open in AllMaps viewer
    let viewButton = document.createElement("a");
    viewButton.className = "button viewCatalogueEntry";
    viewButton.href = "https://viewer.allmaps.org?url=" + encodeURIComponent("https://annotations.allmaps.org/manifests/" + hashId);
    viewButton.textContent = "View georeferenced item using AllMaps";
    viewButton.style.marginLeft = "2rem";
    summary.appendChild(viewButton);
    // Add iframe showing Allmaps viewer
    let embed = document.createElement("iframe");
    embed.src = "https://viewer.allmaps.org?url=" + encodeURIComponent("https://annotations.allmaps.org/manifests/" + hashId);
    embed.width = "100%";
    embed.height = "500px";
    embed.style.marginTop = "1rem";
    embed.style.border = "0";
    summary.appendChild(embed);
  } else {
    // Item has not been georeferenced
    geoMessage.innerHTML = "This item can be georeferenced using <a href='https://allmaps.org'>AllMaps</a>."
    summary.appendChild(geoMessage);
    editButton.textContent = "Georeference using AllMaps";
    summary.appendChild(editButton);
  }
}

// Checks to see if a manifest has already been georeferenced using Allmaps
async function checkAllmaps(ieID) {
  // Create a SLV manifest url
  let manifestUrl = "https://rosetta.slv.vic.gov.au/delivery/iiif/presentation/2.1/" + ieID + "/manifest";
  // Generate an AllMaps id from the manifest url
  let hashId = await generateId(manifestUrl);
  console.log(hashId);
  // Fire off a HEAD request to see if the id exists on AllMaps
  GM.xmlHttpRequest({
    method: 'HEAD',
    url: "https://annotations.allmaps.org/manifests/" + hashId,
    onload: function(response) {
      addButtons(ieID, hashId, response.status);
    }
  });
}

// Look at the item metadata to see if it is a map (or contains maps)
function getMetadata(ieID) {
  // Get item metadata from the JSON API
  GM.xmlHttpRequest({
    method: 'GET',
    url: "https://viewerapi.slv.vic.gov.au/?entity=" + ieID + "&dc_arrays=1",
    onload: function(response) {
      const data = JSON.parse(response.responseText);
      const md = data["viewer_md"];
      // Look for the word map or maps
      let regexp = /\b(?:map|maps)\b/i;
      // Fields that might contain useful information
      const summary = md.summary || [];
      const genre = md.genre || [];
      const subject = md.subject || [];
      const description = md.description || md.group_md.description || [];
      // Check each field for map or maps
      for (let field of [summary, genre, subject, description]) {
        for (let value of field) {
          if (regexp.test(value)) {
            console.log("It's a map!");
            isMap = true;
            break;
          }
        }
        if (isMap === true) {
          break;
        }
      }
      if (isMap === true) {
        checkAllmaps(ieID);
      }
    }
  });
}

// Get the IE identifier from the url
const ieID = location.href.match(/entity=(IE\d+)/)[1];
let isMap = false;


// Wait for the page to load
waitForKeyElements("div.cell.summaryCell.small-12.medium-8", (summaryDiv) => {
  getMetadata(ieID);
});

SLV/AllMaps

Installation

If you haven't already, add a userscript manager such as ViolentMonkey or TamperMonkey to your browser. These are browser extensions or add-ons that are installed from standard web stores – just follow the instructions for your preferred browser. Note that if you're using TamperMonkey with Chrome you might need to explicitly give it permission to run userscripts.

Once your userscript manager is installed, click on the Raw button at the top of the code box. Your userscript manager will display a window with details of the userscript, and ask you to confirm that you want to proceed. Click 'install' to complete the installation.

More information

See this page for full documentation.