feat: support PLAYWRIGHT_DOWNLOAD_HOST

This patch starts respecting `PLAYWRIGHT_DOWNLOAD_HOST` env variable
in `playwright` package and it's vendored flavors (`playwright-firefox`,
`playwright-chromium` and `playwright-webkit`).

Fixes #1045

docs/api.md

@@ -3848,6 +3848,16 @@ WebKit browser instance does not expose WebKit-specific features.
 - [browser.newPage([options])](#browsernewpageoptions)
 <!-- GEN:stop -->
 
+### Environment Variables
+
+> **NOTE** [playwright-core](https://www.npmjs.com/package/playwright-core) **does not** respect environment variables.
+
+Playwright looks for certain [environment variables](https://en.wikipedia.org/wiki/Environment_variable) to aid its operations.
+If Playwright doesn't find them in the environment, a lowercased variant of these variables will be used from the [npm config](https://docs.npmjs.com/cli/config).
+
+- `PLAYWRIGHT_DOWNLOAD_HOST` - overwrite URL prefix that is used to download browsers. Note: this includes protocol and might even include path prefix. By default, Playwright uses `https://storage.googleapis.com` to download Chromium and `https://playwright.azureedge.net` to download Webkit & Firefox.
+
+
 ### Working with selectors
 
 Selector describes an element in the page. It can be used to obtain `ElementHandle` (see [page.$()](#pageselector) for example) or shortcut element operations to avoid intermediate handle (see [page.click()](#pageclickselector-options) for example).

index.js

@@ -18,5 +18,6 @@ const {Playwright} = require('./lib/server/playwright.js');
 module.exports = new Playwright({
   downloadPath: __dirname,
   browsers: ['webkit', 'chromium', 'firefox'],
+  respectEnvironmentVariables: false,
 });
 

packages/playwright-chromium/index.js

@@ -19,5 +19,6 @@ const {Playwright} = require('playwright-core/lib/server/playwright.js');
 module.exports = new Playwright({
   downloadPath: __dirname,
   browsers: ['chromium'],
+  respectEnvironmentVariables: true,
 });
 

packages/playwright-firefox/index.js

@@ -19,5 +19,6 @@ const {Playwright} = require('playwright-core/lib/server/playwright.js');
 module.exports = new Playwright({
   downloadPath: __dirname,
   browsers: ['firefox'],
+  respectEnvironmentVariables: true,
 });
 

packages/playwright-webkit/index.js

@@ -19,5 +19,6 @@ const {Playwright} = require('playwright-core/lib/server/playwright.js');
 module.exports = new Playwright({
   downloadPath: __dirname,
   browsers: ['webkit'],
+  respectEnvironmentVariables: true,
 });
 

packages/playwright/index.js

@@ -18,5 +18,6 @@ const {Playwright} = require('playwright-core/lib/server/playwright.js');
 module.exports = new Playwright({
   downloadPath: __dirname,
   browsers: ['webkit', 'chromium', 'firefox'],
+  respectEnvironmentVariables: true,
 });
 

src/server/chromium.ts

@@ -38,10 +38,12 @@ import { BrowserContext } from '../browserContext';
 
 export class Chromium implements BrowserType {
   private _downloadPath: string;
+  private _downloadHost: string;
   readonly _revision: string;
 
-  constructor(downloadPath: string, preferredRevision: string) {
+  constructor(downloadPath: string, downloadHost: (string|undefined), preferredRevision: string) {
     this._downloadPath = downloadPath;
+    this._downloadHost = downloadHost || 'https://storage.googleapis.com';
     this._revision = preferredRevision;
   }
 
@@ -221,7 +223,7 @@ export class Chromium implements BrowserType {
 
     const defaultOptions = {
       path: path.join(this._downloadPath, '.local-chromium'),
-      host: 'https://storage.googleapis.com',
+      host: this._downloadHost,
       platform: (() => {
         const platform = os.platform();
         if (platform === 'darwin')

src/server/firefox.ts

@@ -39,10 +39,12 @@ const mkdtempAsync = platform.promisify(fs.mkdtemp);
 
 export class Firefox implements BrowserType {
   private _downloadPath: string;
+  private _downloadHost: string;
   readonly _revision: string;
 
-  constructor(downloadPath: string, preferredRevision: string) {
+  constructor(downloadPath: string, downloadHost: (string|undefined), preferredRevision: string) {
     this._downloadPath = downloadPath;
+    this._downloadHost = downloadHost || 'https://playwright.azureedge.net';
     this._revision = preferredRevision;
   }
 
@@ -219,7 +221,7 @@ export class Firefox implements BrowserType {
 
     const defaultOptions = {
       path: path.join(this._downloadPath, '.local-firefox'),
-      host: 'https://playwright.azureedge.net',
+      host: this._downloadHost,
       platform: (() => {
         const platform = os.platform();
         if (platform === 'darwin')

src/server/playwright.ts

@@ -30,6 +30,12 @@ for (const className in api) {
     helper.installApiHooks(className[0].toLowerCase() + className.substring(1), (api as any)[className]);
 }
 
+type PlaywrightOptions = {
+  downloadPath: string,
+  browsers: Array<('firefox'|'webkit'|'chromium')>,
+  respectEnvironmentVariables: boolean,
+};
+
 export class Playwright {
   readonly selectors = api.Selectors._instance();
   readonly devices: types.Devices;
@@ -38,18 +44,27 @@ export class Playwright {
   readonly firefox: (Firefox|undefined);
   readonly webkit: (WebKit|undefined);
 
-  constructor(options: {downloadPath: string, browsers: Array<('firefox'|'webkit'|'chromium')>}) {
+  constructor(options: PlaywrightOptions) {
     const {
       downloadPath,
       browsers,
+      respectEnvironmentVariables,
     } = options;
     this.devices = DeviceDescriptors;
     this.errors = { TimeoutError };
+    const downloadHost = respectEnvironmentVariables ? getFromENV('PLAYWRIGHT_DOWNLOAD_HOST') : undefined;
     if (browsers.includes('chromium'))
-      this.chromium = new Chromium(downloadPath, packageJSON.playwright.chromium_revision);
+      this.chromium = new Chromium(downloadPath, downloadHost, packageJSON.playwright.chromium_revision);
     if (browsers.includes('webkit'))
-      this.webkit = new WebKit(downloadPath, packageJSON.playwright.webkit_revision);
+      this.webkit = new WebKit(downloadPath, downloadHost, packageJSON.playwright.webkit_revision);
     if (browsers.includes('firefox'))
-      this.firefox = new Firefox(downloadPath, packageJSON.playwright.firefox_revision);
+      this.firefox = new Firefox(downloadPath, downloadHost, packageJSON.playwright.firefox_revision);
   }
 }
+
+function getFromENV(name: string): (string|undefined) {
+  let value = process.env[name];
+  value = value || process.env[`npm_config_${name.toLowerCase()}`];
+  value = value || process.env[`npm_package_config_${name.toLowerCase()}`];
+  return value;
+}

src/server/webkit.ts

@@ -41,10 +41,12 @@ import { BrowserContext } from '../browserContext';
 
 export class WebKit implements BrowserType {
   private _downloadPath: string;
+  private _downloadHost: string;
   readonly _revision: string;
 
-  constructor(downloadPath: string, preferredRevision: string) {
+  constructor(downloadPath: string, downloadHost: (string|undefined), preferredRevision: string) {
     this._downloadPath = downloadPath;
+    this._downloadHost = downloadHost || 'https://playwright.azureedge.net';
     this._revision = preferredRevision;
   }
 
@@ -203,7 +205,7 @@ export class WebKit implements BrowserType {
 
     const defaultOptions = {
       path: path.join(this._downloadPath, '.local-webkit'),
-      host: 'https://playwright.azureedge.net',
+      host: this._downloadHost,
       platform: (() => {
         const platform = os.platform();
         if (platform === 'darwin')