feat: handle absolute URIs in PUBLIC_PATH (openedx#568)

Webpack allows `publicPath` to be an absolute URI (https://webpack.js.org/configuration/output/#outputpublicpath), in order to support deployments to a CDN.  However, the browser history module expects a relative path for `basename` but uses the same environment variable (`PUBLIC_PATH`) to configure it.  Since the path is always expected to be be suffixed to the absolute URI, we avoid introducing another configuration variable (thus maintaining full backwards compatibility) by extracting it at initialization time.

src/index.js

@@ -5,6 +5,8 @@ export {
   convertKeyNames,
   getQueryParameters,
   ensureDefinedConfig,
+  parseURL,
+  getPath,
 } from './utils';
 export {
   APP_TOPIC,

src/initialize.js

@@ -54,7 +54,7 @@ Note that the env.config.js file in frontend-platform's root directory is NOT us
 initialization code, it's just there for the test suite and example application.
 */
 import envConfig from 'env.config'; // eslint-disable-line import/no-unresolved
-
+import { getPath } from './utils';
 import {
   publish,
 } from './pubSub';
@@ -99,7 +99,7 @@ import configureCache from './auth/LocalForageCache';
  */
 export const history = (typeof window !== 'undefined')
   ? createBrowserHistory({
-    basename: getConfig().PUBLIC_PATH,
+    basename: getPath(getConfig().PUBLIC_PATH),
   }) : createMemoryHistory();
 
 /**

src/initialize.test.js

@@ -1,4 +1,5 @@
 import PubSub from 'pubsub-js';
+import { createBrowserHistory } from 'history';
 import {
   APP_PUBSUB_INITIALIZED,
   APP_CONFIG_INITIALIZED,
@@ -37,6 +38,7 @@ jest.mock('./auth');
 jest.mock('./analytics');
 jest.mock('./i18n');
 jest.mock('./auth/LocalForageCache');
+jest.mock('history');
 
 let config = null;
 const newConfig = {
@@ -351,3 +353,12 @@ describe('initialize', () => {
     expect(logError).not.toHaveBeenCalled();
   });
 });
+
+describe('history', () => {
+  it('browser history called by default path', async () => {
+    // import history from initialize;
+    expect(createBrowserHistory).toHaveBeenCalledWith({
+      basename: '/',
+    });
+  });
+});

src/utils.js

@@ -122,6 +122,38 @@ export function convertKeyNames(object, nameMap) {
   return modifyObjectKeys(object, transformer);
 }
 
+/**
+ * Given a string URL return an element that has been parsed via href.
+ * This element has the possibility to return different part of the URL.
+  parser.protocol; // => "http:"
+  parser.hostname; // => "example.com"
+  parser.port;     // => "3000"
+  parser.pathname; // => "/pathname/"
+  parser.search;   // => "?search=test"
+  parser.hash;     // => "#hash"
+  parser.host;     // => "example.com:3000"
+ * https://gist.github.com/jlong/2428561
+ *
+ * @param {string}
+ * @returns {Object}
+ */
+export function parseURL(url) {
+  const parser = document.createElement('a');
+  parser.href = url;
+  return parser;
+}
+
+/**
+ * Given a string URL return the path of the URL
+ *
+ *
+ * @param {string}
+ * @returns {string}
+ */
+export function getPath(url) {
+  return parseURL(url).pathname;
+}
+
 /**
  * *Deprecated*: A method which converts the supplied query string into an object of
  * key-value pairs and returns it.  Defaults to the current query string - should perform like

src/utils.test.js

@@ -3,6 +3,8 @@ import {
   camelCaseObject,
   snakeCaseObject,
   convertKeyNames,
+  parseURL,
+  getPath,
   getQueryParameters,
 } from '.';
 
@@ -113,3 +115,79 @@ describe('getQueryParameters', () => {
     });
   });
 });
+
+describe('ParseURL', () => {
+  const testURL = 'http://example.com:3000/pathname/?search=test#hash';
+  const parsedURL = parseURL(testURL);
+  it('String URL is correctly parsed', () => {
+    expect(parsedURL.toString()).toEqual(testURL);
+    expect(parsedURL.href).toEqual(testURL);
+    expect(typeof (parsedURL)).toEqual('object');
+  });
+
+  it('should return protocol from URL', () => {
+    expect(parsedURL.protocol).toEqual('http:');
+  });
+
+  it('should return hostname from URL', () => {
+    expect(parsedURL.hostname).toEqual('example.com');
+  });
+
+  it('should return port from URL', () => {
+    expect(parsedURL.port).toEqual('3000');
+  });
+
+  it('should return pathname from URL', () => {
+    expect(parsedURL.pathname).toEqual('/pathname/');
+  });
+
+  it('should return search rom URL', () => {
+    expect(parsedURL.search).toEqual('?search=test');
+  });
+
+  it('should return hash from URL', () => {
+    expect(parsedURL.hash).toEqual('#hash');
+  });
+
+  it('should return host from URL', () => {
+    expect(parsedURL.host).toEqual('example.com:3000');
+  });
+});
+
+describe('getPath', () => {
+  it('Path is retrieved with full url', () => {
+    const testURL = 'http://example.com:3000/pathname/?search=test#hash';
+
+    expect(getPath(testURL)).toEqual('/pathname/');
+  });
+
+  it('Path is retrieved with only path', () => {
+    const testURL = '/learning/';
+
+    expect(getPath(testURL)).toEqual('/learning/');
+  });
+
+  it('Path is retrieved without protocol', () => {
+    const testURL = '//example.com:3000/accounts/';
+
+    expect(getPath(testURL)).toEqual('/accounts/');
+  });
+
+  it('Path is retrieved with base `/`', () => {
+    const testURL = '/';
+
+    expect(getPath(testURL)).toEqual('/');
+  });
+
+  it('Path is retrieved without port', () => {
+    const testURL = 'https://example.com/accounts/';
+
+    expect(getPath(testURL)).toEqual('/accounts/');
+  });
+
+  it('Path is retrieved without CDN shape', () => {
+    const testURL = 'https://d20blt6w1kfasr.cloudfront.net/learning/';
+
+    expect(getPath(testURL)).toEqual('/learning/');
+  });
+});