Enable use of download mirrors (#28)

* Allow setting chromium revision from .npmrc

* Allow the download host URL to be overriden

* Update tests to allow multiple installs

* Update readme with download host option

* Address PR feedback

* Refactor tests to use a helper
* Document the expected download mirror structure

* Allow configuration via .npmrc

This builds on the work in #27, providing an alternative to env vars
via the .npmrc.
I have also bolstered the unit testing significantly and allowed the
environment to be mocked out.

* Address PR feedback

1. Move tests to test/ directory
2. Remove experimental config._setEnv mocking method and update tests
3. Refactor new config.getEnvVar method
4. Refactor confusing ALT_URL variable in utils test

Also:

* removed now superfluous "install from mirror" test
* Updated target NodeJS versions on CI, the specified ones were ancient
  I have changed it to LTS and Latest which will never age.

Co-authored-by: psociety <[email protected]>

Author: ricksbrown

.travis.yml

@@ -4,7 +4,5 @@ os:
   - linux
   - osx
 node_js:
-  - "7"
-  - "8"
-  - "9"
+  - "lts/*"
   - "node"

README.MD

@@ -41,11 +41,39 @@ npm config set no-proxy localhost,127.0.0.1,example.org
 Additionally proxy settings found in the environment variables `HTTP_PROXY`, `HTTPS_PROXY` and `NO_PROXY` will be used if they are not defined in the `.npmrc` file. 
 
 ### Install a concrete revision
-If you want to specify the revision of Chromium to be installed, just set the environment variable CHROMIUM_REVISION to the number of the revision you want to install, as in:
+If you want to specify the revision of Chromium to be installed, just set the environment variable `CHROMIUM_REVISION` to the number of the revision you want to install, as in:
 ```shell script
 export CHROMIUM_REVISION=729994
 ```
 
+Note - may also be set in .npmrc like so:
+
+```ini
+chromium_revision=729994
+```
+
+### Use a Download Mirror
+You may download a specific revision from an alternate download host using the environment variable `CHROMIUM_DOWNLOAD_HOST`, for example:
+
+```bash
+export CHROMIUM_REVISION=737027
+export CHROMIUM_DOWNLOAD_HOST=https://npm.taobao.org/mirrors/chromium-browser-snapshots/
+
+# If running on Linux x64 this will download binary from:
+# https://npm.taobao.org/mirrors/chromium-browser-snapshots/Linux_x64/737027/chrome-linux.zip?alt=media
+```
+
+Notes on `CHROMIUM_DOWNLOAD_HOST`:
+
+* The default download host is `https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/`
+* Mirrors are expected to host binaries in the structure: `<CHROMIUM_DOWNLOAD_HOST>/<PLATFORM_ARCHITECTURE>/<REVISION>/<OS_CHROMIUM_FILE_NAME>.zip?alt=media` for example see the taobao mirror [chromium-browser-snapshots](https://npm.taobao.org/mirrors/chromium-browser-snapshots/).
+* May also be set in .npmrc like so:
+
+```ini
+chromium_download_host=https://npm.taobao.org/mirrors/chromium-browser-snapshots/
+chromium_revision=737027
+```
+
 ## Selenium WebDriver Headless (without UI) tests
 It's extremely easy to use **node-chromium** with **selenium-webdriver** to perform e2e tests without spawning browser UI.
 First, install all dependencies

config.js

@@ -3,5 +3,25 @@
 const path = require('path');
 
 module.exports = {
-    BIN_OUT_PATH: path.join(__dirname, 'lib', 'chromium')
+    /**
+     * The default CDN URL, used if not overridden by user
+     */
+    CDN_URL: 'https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/',
+    /**
+     * The default filesystem path where chromium will be installed.
+     */
+    BIN_OUT_PATH: path.join(__dirname, 'lib', 'chromium'),
+    /**
+     * Gets a configuration parameter from the environment.
+     * Will first check for a lowercase variant set via npm config in the format: `npm_config_${name.toLowerCase()}`.
+     * If not set then will check the environment for the variable, as provided.
+     * @param {string} name The name of the environment variable, case sensitive, conventionally uppercase.
+     * @returns {string} The value of the environment variable.
+     */
+    getEnvVar: name => {
+        if (!name) {
+            return '';
+        }
+        return process.env[`npm_config_${name.toLowerCase()}`] || process.env[name] || '';
+    }
 };

install.js

@@ -9,8 +9,6 @@ const debug = require('debug')('node-chromium');
 const config = require('./config');
 const utils = require('./utils');
 
-const chromiumRevision =  process.env.npm_config_chromium_revision || process.env.CHROMIUM_REVISION;
-
 function createTempFile() {
     return new Promise((resolve, reject) => {
         tmp.file((error, path) => {
@@ -68,8 +66,9 @@ function unzipArchive(archivePath, outputFolder) {
 }
 
 async function install() {
+    const chromiumRevision = config.getEnvVar('CHROMIUM_REVISION');
     try {
-        console.info('Step 1. Retrieving Chromium latest revision number');
+        console.info('Step 1. Retrieving Chromium revision number');
         const revision = chromiumRevision || await utils.getLatestRevisionNumber();
 
         console.info(`Step 2. Downloading Chromium (this might take a while). Revision number: ${revision}`);
@@ -84,4 +83,9 @@ async function install() {
     }
 }
 
-module.exports = install();
+if (require.main === module) {
+    // Module called directly, not via "require", so execute install...
+    install();
+}
+
+module.exports = install;

test/test-config.js

@@ -0,0 +1,44 @@
+'use strict';
+
+import test from 'ava';
+
+const config = require('../config');
+
+/* eslint camelcase: ["error", {properties: "never"}] */
+
+test.serial('getEnvVar returns string always', t => {
+    delete process.env.FOO_BAR;  // Make sure this doesn't exist
+    t.is('', config.getEnvVar('FOO_BAR'));
+});
+
+test.serial('getEnvVar basic test', t => {
+    const expected = Date.now().toString();
+    try {
+        process.env.FOO_BAR = expected;
+        t.is(expected, config.getEnvVar('FOO_BAR'));
+    } finally {
+        delete process.env.FOO_BAR;
+    }
+});
+
+test.serial('getEnvVar looks for npm_config version', t => {
+    const expected = Date.now().toString();
+    try {
+        process.env.npm_config_foo_bar = expected;
+        t.is(expected, config.getEnvVar('FOO_BAR'));
+    } finally {
+        delete process.env.npm_config_foo_bar;
+    }
+});
+
+test.serial('getEnvVar prefers npm_config version', t => {
+    const expected = Date.now().toString();
+    try {
+        process.env.FOO_BAR = 'foobar';
+        process.env.npm_config_foo_bar = expected;
+        t.is(expected, config.getEnvVar('FOO_BAR'), 'npm_config_ variant should trump raw env var');
+    } finally {
+        delete process.env.FOO_BAR;
+        delete process.env.npm_config_foo_bar;
+    }
+});

test-install.js renamed to test/test-install.js

@@ -7,12 +7,9 @@ const rimraf = require('rimraf');
 const got = require('got');
 const debug = require('debug')('node-chromium');
 
-const utils = require('./utils');
-const config = require('./config');
-
-const install = async () => {
-    await require('./install');
-};
+const utils = require('../utils');
+const config = require('../config');
+const install = require('../install');
 
 test.before(t => {
     // Deleting output folder
@@ -29,12 +26,12 @@ test.serial('Canary Test', t => {
     t.pass();
 });
 
-test('Before Install Process', t => {
+test.serial('Before Install Process', t => {
     const binPath = utils.getOsChromiumBinPath();
     t.false(fs.existsSync(binPath), `Chromium binary is found in: [${binPath}]`);
 });
 
-test('Chromium Install', async t => {
+test.serial('Chromium Install', async t => {
     await install();
 
     const binPath = utils.getOsChromiumBinPath();
@@ -48,6 +45,7 @@ test.serial('Different OS support', async t => {
 
     const originalPlatform = process.platform;
 
+    /* eslint-disable no-await-in-loop */
     for (const platform of supportedPlatforms) {
         mockPlatform(platform);
 
@@ -56,6 +54,7 @@ test.serial('Different OS support', async t => {
         const url = utils.getDownloadUrl(revision);
         t.true(await isUrlAccessible(url));
     }
+    /* eslint-enable no-await-in-loop */
 
     for (const platform of notSupportedPlatforms) {
         mockPlatform(platform);

test/test-utils.js

@@ -0,0 +1,40 @@
+'use strict';
+
+import test from 'ava';
+
+const config = require('../config');
+const utils = require('../utils');
+
+const OVERRIDE_URL = 'http://example.com/chromium-browser-snapshots/';
+
+/* eslint camelcase: ["error", {properties: "never"}] */
+
+test.beforeEach(t => {
+    process.env = {};  // Prevent the real environment from interfering with these tests
+    t.pass();
+});
+
+test.serial('getDownloadUrl uses default', t => {
+    const url = utils.getDownloadUrl('737027');
+    t.true(url.indexOf(config.CDN_URL) === 0, `By default the URL should download from ${config.CDN_URL} but got ${url}`);
+});
+
+test.serial('getDownloadUrl contains revision', t => {
+    const revision = '737027';
+    const url = utils.getDownloadUrl(revision);
+    t.true(url.indexOf(revision) > 0, `Expected revision ${revision} in ${url}`);
+});
+
+test.serial('getDownloadUrl honors environment variable', t => {
+    process.env.CHROMIUM_DOWNLOAD_HOST = OVERRIDE_URL;
+
+    const url = utils.getDownloadUrl('737027');
+    t.true(url.indexOf(OVERRIDE_URL) === 0, `Download URL should honor environment variable ${OVERRIDE_URL} but got ${url}`);
+});
+
+test.serial('getDownloadUrl honors npm config', t => {
+    process.env.npm_config_chromium_download_host = OVERRIDE_URL;
+
+    const url = utils.getDownloadUrl('737027');
+    t.true(url.indexOf(OVERRIDE_URL) === 0, `Download URL should honor npm config ${OVERRIDE_URL} but got ${url}`);
+});

utils.js

@@ -7,8 +7,6 @@ const tunnel = require('tunnel');
 
 const config = require('./config');
 
-const CDN_URL = 'https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/';
-
 module.exports = {
     /**
      * Returns chromium output folder name for current OS
@@ -60,16 +58,21 @@ module.exports = {
      * @returns {string}
      */
     getDownloadUrl(revision) {
-        return `${this.getOsCdnUrl()}%2F${revision}%2F${this.getOsChromiumFolderName()}.zip?alt=media`;
+        const altUrl = config.getEnvVar('CHROMIUM_DOWNLOAD_HOST');
+        let revisionPath = `/${revision}/${this.getOsChromiumFolderName()}`;
+        if (!altUrl) {
+            revisionPath = encodeURIComponent(revisionPath);  // Needed for googleapis.com
+        }
+        return `${this.getOsCdnUrl()}${revisionPath}.zip?alt=media`;
     },
 
     /**
-     * Returns CDN Url according to current OS
+     * Returns download Url according to current OS
      *
      * @returns {string}
      */
     getOsCdnUrl() {
-        let url = CDN_URL;
+        let url = config.getEnvVar('CHROMIUM_DOWNLOAD_HOST') || config.CDN_URL;
 
         const platform = process.platform;