feat: Add support for running Windows Firefox from WSL

I'm assuming everyone who runs WSL wants to run the Windows version of Firefox (and not try to actually run the Linux version under WSL).

index.js

@@ -2,6 +2,8 @@
 
 var fs = require('fs')
 var path = require('path')
+var isWsl = require('is-wsl')
+var { execSync } = require('child_process')
 
 var PREFS = [
   'user_pref("browser.shell.checkDefaultBrowser", false);',
@@ -66,6 +68,59 @@ var getFirefoxExe = function (firefoxDirName) {
   return path.join('C:\\Program Files', firefoxDirNames[0], 'firefox.exe')
 }
 
+var getAllPrefixesWsl = function () {
+  var drives = []
+  // Some folks configure their wsl.conf to mount Windows drives without the
+  // /mnt prefix (e.g. see https://nickjanetakis.com/blog/setting-up-docker-for-windows-and-wsl-to-work-flawlessly)
+  //
+  // In fact, they could configure this to be any number of things. So we
+  // take each path, convert it to a Windows path, check if it looks like
+  // it starts with a drive and then record that.
+  var re = /^([A-Z]):\\/i
+  for (var pathElem of process.env.PATH.split(':')) {
+    var windowsPath = execSync('wslpath -w "' + pathElem + '"').toString()
+    var matches = windowsPath.match(re)
+    if (matches !== null && drives.indexOf(matches[1]) === -1) {
+      drives.push(matches[1])
+    }
+  }
+
+  var result = []
+  // We don't have the PROGRAMFILES or PROGRAMFILES(X86) environment variables
+  // in WSL so we just hard code them.
+  var prefixes = ['Program Files', 'Program Files (x86)']
+  for (var prefix of prefixes) {
+    for (var drive of drives) {
+      // We only have the drive, and only wslpath knows exactly what they map to
+      // in Linux, so we convert it back here.
+      var wslPath =
+        execSync('wslpath "' + drive + ':\\' + prefix + '"').toString().trim()
+      result.push(wslPath)
+    }
+  }
+
+  return result
+}
+
+var getFirefoxExeWsl = function (firefoxDirName) {
+  if (!isWsl) {
+    return null
+  }
+
+  var firefoxDirNames = Array.prototype.slice.call(arguments)
+
+  for (var prefix of getAllPrefixesWsl()) {
+    for (var dir of firefoxDirNames) {
+      var candidate = path.join(prefix, dir, 'firefox.exe')
+      if (fs.existsSync(candidate)) {
+        return candidate
+      }
+    }
+  }
+
+  return path.join('/mnt/c/Program Files/', firefoxDirNames[0], 'firefox.exe')
+}
+
 var getFirefoxWithFallbackOnOSX = function () {
   if (process.platform !== 'darwin') {
     return null
@@ -144,10 +199,12 @@ var FirefoxBrowser = function (id, baseBrowserDecorator, args) {
       })
     }
 
-    fs.writeFileSync(profilePath + '/prefs.js', this._getPrefs(args.prefs))
+    fs.writeFileSync(path.join(profilePath, 'prefs.js'), this._getPrefs(args.prefs))
+    var translatedProfilePath =
+      isWsl ? execSync('wslpath -w ' + profilePath).toString().trim() : profilePath
     self._execCommand(
       command,
-      [url, '-profile', profilePath, '-no-remote', '-wait-for-browser'].concat(flags)
+      [url, '-profile', translatedProfilePath, '-no-remote', '-wait-for-browser'].concat(flags)
     )
   }
 }
@@ -156,7 +213,7 @@ FirefoxBrowser.prototype = {
   name: 'Firefox',
 
   DEFAULT_CMD: {
-    linux: 'firefox',
+    linux: isWsl ? getFirefoxExeWsl('Mozilla Firefox') : 'firefox',
     freebsd: 'firefox',
     darwin: getFirefoxWithFallbackOnOSX('Firefox'),
     win32: getFirefoxExe('Mozilla Firefox')
@@ -175,7 +232,7 @@ var FirefoxDeveloperBrowser = function () {
 FirefoxDeveloperBrowser.prototype = {
   name: 'FirefoxDeveloper',
   DEFAULT_CMD: {
-    linux: 'firefox',
+    linux: isWsl ? getFirefoxExeWsl('Firefox Developer Edition') : 'firefox',
     darwin: getFirefoxWithFallbackOnOSX('FirefoxDeveloperEdition', 'FirefoxAurora'),
     win32: getFirefoxExe('Firefox Developer Edition')
   },
@@ -193,7 +250,7 @@ var FirefoxAuroraBrowser = function () {
 FirefoxAuroraBrowser.prototype = {
   name: 'FirefoxAurora',
   DEFAULT_CMD: {
-    linux: 'firefox',
+    linux: isWsl ? getFirefoxExeWsl('Aurora') : 'firefox',
     darwin: getFirefoxWithFallbackOnOSX('FirefoxAurora'),
     win32: getFirefoxExe('Aurora')
   },
@@ -212,7 +269,7 @@ FirefoxNightlyBrowser.prototype = {
   name: 'FirefoxNightly',
 
   DEFAULT_CMD: {
-    linux: 'firefox',
+    linux: isWsl ? getFirefoxExeWsl('Nightly', 'Firefox Nightly') : 'firefox',
     darwin: getFirefoxWithFallbackOnOSX('FirefoxNightly', 'Firefox Nightly'),
     win32: getFirefoxExe('Nightly', 'Firefox Nightly')
   },

package.json

@@ -51,5 +51,7 @@
     "Schaaf, Martin <[email protected]>",
     "Žilvinas Urbonas <[email protected]>"
   ],
-  "dependencies": {}
+  "dependencies": {
+    "is-wsl": "^2.1.0"
+  }
 }