Check update instead of force download

package.json

@@ -50,7 +50,8 @@
     "7zip": "0.0.6",
     "cross-unzip": "0.0.2",
     "rimraf": "^2.5.2",
-    "semver": "^5.3.0"
+    "semver": "^5.3.0",
+    "xml2js": "^0.4.17"
   },
   "babel": {
     "presets": [

src/index.js

@@ -4,6 +4,7 @@ import path from 'path';
 import semver from 'semver';
 
 import downloadChromeExtension from './downloadChromeExtension';
+import needUpdate from './needUpdate';
 import { getPath } from './utils';
 
 const { BrowserWindow } = remote || electron;
@@ -14,9 +15,9 @@ if (fs.existsSync(IDMapPath)) {
   IDMap = JSON.parse(fs.readFileSync(IDMapPath, 'utf8'));
 }
 
-const install = (extensionReference, forceDownload = false) => {
+const install = (extensionReference, checkUpdate = false) => {
   if (Array.isArray(extensionReference)) {
-    return Promise.all(extensionReference.map(extension => install(extension, forceDownload)));
+    return Promise.all(extensionReference.map(extension => install(extension, checkUpdate)));
   }
   let chromeStoreID;
   if (typeof extensionReference === 'object' && extensionReference.id) {
@@ -35,24 +36,29 @@ const install = (extensionReference, forceDownload = false) => {
   const extensionInstalled = extensionName &&
     BrowserWindow.getDevToolsExtensions &&
     BrowserWindow.getDevToolsExtensions()[extensionName];
-  if (!forceDownload && extensionInstalled) {
-    return Promise.resolve(IDMap[chromeStoreID]);
-  }
-  return downloadChromeExtension(chromeStoreID, forceDownload)
-    .then((extensionFolder) => {
-      // Use forceDownload, but already installed
-      if (extensionInstalled) {
-        BrowserWindow.removeDevToolsExtension(extensionName);
-      }
-      const name = BrowserWindow.addDevToolsExtension(extensionFolder); // eslint-disable-line
-      fs.writeFileSync(
-        IDMapPath,
-        JSON.stringify(Object.assign(IDMap, {
-          [chromeStoreID]: name,
-        })),
-      );
-      return Promise.resolve(name);
-    });
+  const promise = checkUpdate && extensionInstalled ?
+    needUpdate(chromeStoreID, extensionInstalled.version) :
+    Promise.resolve(false);
+  return promise.then((toUpdate) => {
+    if (!toUpdate && extensionInstalled) {
+      return Promise.resolve(IDMap[chromeStoreID]);
+    }
+    return downloadChromeExtension(chromeStoreID, toUpdate)
+      .then((extensionFolder) => {
+        // Use forceDownload, but already installed
+        if (extensionInstalled) {
+          BrowserWindow.removeDevToolsExtension(extensionName);
+        }
+        const name = BrowserWindow.addDevToolsExtension(extensionFolder); // eslint-disable-line
+        fs.writeFileSync(
+          IDMapPath,
+          JSON.stringify(Object.assign(IDMap, {
+            [chromeStoreID]: name,
+          })),
+        );
+        return Promise.resolve(name);
+      });
+  });
 };
 
 export default install;

src/needUpdate.js

@@ -0,0 +1,23 @@
+import { parseString } from 'xml2js';
+import { fetchData } from './utils';
+
+export default (chromeStoreID, currentVersion) => new Promise((resolve, reject) =>
+  fetchData(
+    `https://clients2.google.com/service/update2/crx?x=id%3D${chromeStoreID}%26uc&prodversion=32`,
+  ).then((res) => {
+    if (res.statusCode === 200) {
+      parseString(res.body, (err, result) => {
+        const app = result.gupdate.app[0].$;
+        if (app.status !== 'ok') return resolve(false);
+
+        const { status, version: newestVersion } = result.gupdate.app[0].updatecheck[0].$;
+        if (status !== 'ok') return resolve(false);
+
+        if (newestVersion !== currentVersion) return resolve(true);
+        return resolve(false);
+      });
+    } else {
+      reject(`Failed to check current version of ${chromeStoreID}.`);
+    }
+  }),
+);

src/utils.js

@@ -9,20 +9,34 @@ export const getPath = () => {
 };
 
 // Use https.get fallback for Electron < 1.4.5
-const { net } = (remote || electron);
+const { net } = remote || electron;
 const request = net ? net.request : https.get;
 
-export const downloadFile = (from, to) => new Promise((resolve, reject) => {
-  const req = request(from);
+const sendRequest = url => new Promise((resolve, reject) => {
+  const req = request(url);
   req.on('response', (res) => {
     // Shouldn't handle redirect with `electron.net`, this is for https.get fallback
     if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location) {
-      return downloadFile(res.headers.location, to)
-        .then(resolve)
-        .catch(reject);
+      return sendRequest(res.headers.location);
     }
-    res.pipe(fs.createWriteStream(to)).on('close', resolve);
+    resolve(res);
   });
   req.on('error', reject);
   req.end();
 });
+
+export const downloadFile = (from, to) => new Promise((resolve, reject) =>
+  sendRequest(from)
+    .then(res => res.pipe(fs.createWriteStream(to)).on('close', resolve))
+    .catch(reject),
+);
+
+export const fetchData = url => new Promise((resolve, reject) =>
+  sendRequest(url)
+    .then((res) => {
+      let body = '';
+      res.on('data', (chunk) => { body += chunk; });
+      res.on('end', () => resolve(Object.assign(res, { body })));
+    })
+    .catch(reject),
+);

test/install_spec.js

@@ -28,7 +28,7 @@ describe('Extension Installer', () => {
           .catch(() => done('Failed to resolve'));
       });
 
-      it('should upgraded the extension with forceDownload', (done) => {
+      it('should upgraded the extension with checkUpdate', (done) => {
         const extensionName = 'React Developer Tools';
         const oldVersion = '0.14.0';
         BrowserWindow.removeDevToolsExtension(extensionName);

test/update_spec.js

@@ -0,0 +1,19 @@
+// Pre-run
+import chai from 'chai';
+import chaiAsPromised from 'chai-as-promised';
+import { given } from 'mocha-testdata';
+
+// Actual Test Imports
+import needUpdate from '../src/needUpdate';
+import knownExtensions from './testdata/knownExtensions';
+
+chai.use(chaiAsPromised);
+chai.should();
+
+describe('Extension Update Checker', () => {
+  describe('when given a valid extension ID', () => {
+    given(...knownExtensions).it('should need to update (with different version)', item =>
+      needUpdate(item.id, '0.0.0').should.become(true),
+    );
+  });
+});