@nzz/q-server/plugins/cdn/keycdn/index.js

**Maintainer**: [Franco Gervasi](https://github.com/fgervasi)

const KeyCDN = require("keycdn");
const Hoek = require("@hapi/hoek");

function getCacheTagForId(id) {
  return `q-item-id-${id}`;
}

module.exports = {
  name: "q-cdn-keycdn",
  dependencies: ["q-base"],
  register: async function(server, options) {
    Hoek.assert(
      typeof options.zoneId === "string",
      "options.zoneId must be a string"
    );
    Hoek.assert(
      typeof options.apiKey === "string",
      "options.apiKey must be a string"
    );

    if (!options.xPullKey) {
      options.xPullKey = "KeyCDN"; // this is the default at keycdn
    }

    server.ext("onPreResponse", async (request, h) => {
      const response = request.response;

      // if the request is not coming from keycdn: continue
      if (
        !request.headers.hasOwnProperty("x-pull") ||
        request.headers["x-pull"] !== options.xPullKey
      ) {
        return h.continue;
      }

      // if the response has no headers or response.headers is not an object with hasOwnProperty: continue
      if (!response.headers || !response.headers.hasOwnProperty) {
        return h.continue;
      }

      // if no cache-control header is present: continue
      if (!response.headers.hasOwnProperty("cache-control")) {
        return h.continue;
      }

      // if cache-control is set to no-cache: continue
      if (response.headers["cache-control"] === "no-cache") {
        return h.continue;
      }

      // if there is no id property in the route params: continue
      if (!request.params.hasOwnProperty("id")) {
        return h.continue;
      }

      // if all prerequisites are given, actually add the cache-tag header
      return h
        .response(response)
        .header("cache-tag", getCacheTagForId(request.params.id));
    });

    const keycdn = new KeyCDN(options.apiKey);
    server.events.on("item.update", item => {
      const tagsToPurge = [getCacheTagForId(item._id)];
      // dryRun is set for testing to not actually send the request to keycdn
      /* $lab:coverage:off$ */
      if (options.dryRun) {
        return;
      }
      keycdn.del(
        `zones/purgeurl/${options.zoneId}.json`,
        { tags: tagsToPurge },
        (err, res) => {
          if (err) {
            server.log(["error"], err);
          } else {
            server.log(["info"], res);
          }
        }
      );
      /* $lab:coverage:on$ */
    });
  }
};