load auto-update sctipt dynamically

modules/io/cloud.js

@@ -0,0 +1,139 @@
+"use strict";
+
+/*
+Cloud provider implementations (Dropbox only as now)
+
+provider Interface:
+
+name: name of the provider
+async auth(): authenticate and get access tokens from provider
+async save(filename): save map file to provider as filename
+async load(filename): load filename from provider
+async list(): list available filenames at provider
+async getLink(filePath): get shareable link for file
+restore(): restore access tokens from storage if possible
+
+*/
+
+window.Cloud = (function () {
+  // helpers to use in providers for token handling
+  const lSKey = x => `auth-${x}`;
+  const setToken = (prov, key) => localStorage.setItem(lSKey(prov), key);
+  const getToken = prov => localStorage.getItem(lSKey(prov));
+
+  /**********************************************************/
+  /* Dropbox provider                                       */
+  /**********************************************************/
+
+  const DBP = {
+    name: "dropbox",
+    clientId: "pdr9ae64ip0qno4",
+    authWindow: undefined,
+    token: null, // Access token
+    api: null,
+
+    restore() {
+      this.token = getToken(this.name);
+      if (this.token) this.connect(this.token);
+    },
+
+    async call(name, param) {
+      try {
+        return await this.api[name](param);
+      } catch (e) {
+        if (e.name !== "DropboxResponseError") throw e;
+        // retry with auth
+        await this.auth();
+        return await this.api[name](param);
+      }
+    },
+
+    connect(token) {
+      const clientId = this.clientId;
+      const auth = new Dropbox.DropboxAuth({clientId});
+      auth.setAccessToken(token);
+      this.api = new Dropbox.Dropbox({auth});
+    },
+
+    async save(fileName, contents) {
+      if (!this.api) await this.auth();
+      const resp = this.call("filesUpload", {path: "/" + fileName, contents});
+      DEBUG && console.log("Dropbox response:", resp);
+      return true;
+    },
+
+    async load(path) {
+      if (!this.api) await this.auth();
+      const resp = await this.call("filesDownload", {path});
+      const blob = resp.result.fileBlob;
+      if (!blob) throw new Error("Invalid response from dropbox.");
+      return blob;
+    },
+
+    async list() {
+      if (!this.api) return null;
+      const resp = await this.call("filesListFolder", {path: ""});
+      return resp.result.entries.map(e => ({name: e.name, path: e.path_lower}));
+    },
+
+    auth() {
+      const url = window.location.origin + window.location.pathname + "dropbox.html";
+      this.authWindow = window.open(url, "auth", "width=640,height=480");
+      // child window expected to call
+      // window.opener.Cloud.providers.dropbox.setDropBoxToken (see below)
+      return new Promise((resolve, reject) => {
+        const watchDog = () => {
+          this.authWindow.close();
+          reject(new Error("Timeout. No auth for dropbox."));
+        };
+        setTimeout(watchDog, 120 * 1000);
+        window.addEventListener("dropboxauth", e => {
+          clearTimeout(watchDog);
+          resolve();
+        });
+      });
+    },
+
+    // Callback function for auth window.
+    setDropBoxToken(token) {
+      DEBUG && console.log("Access token:", token);
+      setToken(this.name, token);
+      this.connect(token);
+      this.authWindow.close();
+      window.dispatchEvent(new Event("dropboxauth"));
+    },
+
+    async getLink(path) {
+      if (!this.api) await this.auth();
+      let resp;
+
+      // already exists?
+      resp = await this.call("sharingListSharedLinks", {path});
+      if (resp.result.links.length) return resp.result.links[0].url;
+
+      // create new
+      resp = await this.call("sharingCreateSharedLinkWithSettings", {
+        path,
+        settings: {
+          require_password: false,
+          audience: "public",
+          access: "viewer",
+          requested_visibility: "public",
+          allow_download: true
+        }
+      });
+      DEBUG && console.log("Dropbox link object:", resp.result);
+      return resp.result.url;
+    }
+  };
+
+  // register providers here:
+  const providers = {
+    dropbox: DBP
+  };
+
+  // restore all providers at startup
+  for (const p of Object.values(providers)) p.restore();
+
+  return {providers};
+})();