Set environment variable containing path to index.html

When we load index.html via a non-file: uri, electron's renderer/init.js can't find the file, so it can't set up the module search paths correctly, and require'ing dependencies from a renderer process fails.

This change sets an environment variable with the path to index.html that the renderer process can read and patch up the module search paths to be correct.

Author: Ben Demboski

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 1.2.0
+
+- Set environment variable allowing renderer process to set module search path correctly
+
 ## 1.1.0
 
 - Made indexPath accessible via options for more complex configuration

index.js

@@ -35,14 +35,20 @@ module.exports = function protocolServe({
 
   indexPath = indexPath || join(cwd, 'index.html');
 
+  const options = { cwd, name, endpoint, indexPath };
+  const handler = createHandler(options);
+
   app.on('ready', () => {
-    const options = { cwd, name, endpoint, indexPath };
-    protocol.registerFileProtocol(name, createHandler(options), error => {
+    protocol.registerFileProtocol(name, handler, error => {
       if (error) {
         console.error('Failed to register protocol');
       }
     });
   });
 
+  // Set our ELECTRON_PROTOCOL_SERVE_INDEX environment variable so the renderer
+  // process can find index.html to set it up as its main module path
+  handler({ url: `${name}://${endpoint}` }, ({ path }) => process.env.ELECTRON_PROTOCOL_SERVE_INDEX = path);
+
   return name;
 };

package.json

@@ -15,6 +15,7 @@
     "bluebird": "^3.5.0",
     "chai": "^3.5.0",
     "eslint": "^3.17.1",
+    "lodash": "^4.17.4",
     "mocha": "^3.2.0",
     "sinon": "^1.17.7"
   },

tests/unit/index-test.js

@@ -1,13 +1,17 @@
 const { assert } = require('chai');
 const mock = require('mock-require');
+const sinon = require('sinon');
 const { join } = require('path');
+const { clone } = require('lodash');
 
 describe('index', () => {
+  let env;
   let app;
   let protocol;
   let onAppReady;
   let protocolName;
   let handlerOptions;
+  let handlerStub;
 
   function register(options) {
     require('../..')(Object.assign({
@@ -17,14 +21,37 @@ describe('index', () => {
     }, options));
   }
 
-  before(() => {
-    mock('../../lib/handler', options => handlerOptions = options);
+  //
+  // Mock our handler library
+  //
+  beforeEach(() => {
+    handlerStub = sinon.stub();
+    handlerStub.callsArgWith(1, { path: '/path/to/index.html' });
+
+    mock('../../lib/handler', options => {
+      handlerOptions = options;
+      return handlerStub;
+    });
   });
 
-  after(() => {
+  afterEach(() => {
     mock.stop('../../lib/handler');
   });
 
+  //
+  // Sandbox any changes to the environment
+  //
+  beforeEach(() => {
+    env = clone(process.env);
+  });
+
+  afterEach(() => {
+    process.env = env;
+  });
+
+  //
+  // Set up our stubbed app and protocol
+  //
   beforeEach(() => {
     app = {
       on(evt, cb) {
@@ -53,6 +80,8 @@ describe('index', () => {
       endpoint: 'dist',
       indexPath: join('.', 'index.html'),
     });
+    assert.ok(handlerStub.calledWith({ url: 'serve://dist' }));
+    assert.equal(process.env.ELECTRON_PROTOCOL_SERVE_INDEX, '/path/to/index.html');
   });
 
   it('works with a custom cwd', () => {
@@ -69,6 +98,8 @@ describe('index', () => {
       endpoint: 'dist',
       indexPath: join('foo', 'bar', 'index.html'),
     });
+    assert.ok(handlerStub.calledWith({ url: 'serve://dist' }));
+    assert.equal(process.env.ELECTRON_PROTOCOL_SERVE_INDEX, '/path/to/index.html');
   });
 
   it('works with non-default arguments', () => {
@@ -88,6 +119,8 @@ describe('index', () => {
       endpoint: 'so',
       indexPath: join('we', 'meet', 'again.html'),
     });
+    assert.ok(handlerStub.calledWith({ url: 'friend://so' }));
+    assert.equal(process.env.ELECTRON_PROTOCOL_SERVE_INDEX, '/path/to/index.html');
   });
 
   it('required a cwd', () => {

yarn.lock

@@ -651,7 +651,7 @@ lodash.keys@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
-lodash@^4.0.0, lodash@^4.3.0:
+lodash@^4.0.0, lodash@^4.17.4, lodash@^4.3.0:
   version "4.17.4"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.4.tgz#78203a4d1c328ae1d86dca6460e369b57f4055ae"