OS X: Use app.setAsDefaultProtocolClient

- OS X: Register as default handler for "magnet" on startup

Also:

- Log errors in the renderer process, like the rest of errors in the
main process
- Windows: Less chance of registry write race condition

Fix #285

main/handlers.js

@@ -7,85 +7,38 @@ var path = require('path')
 var log = require('./log')
 
 function init () {
+  if (process.platform === 'darwin') {
+    initDarwin()
+  }
   if (process.platform === 'win32') {
-    initWindows()
+    initWin32()
   }
   if (process.platform === 'linux') {
     initLinux()
   }
 }
 
-function initWindows () {
+function initDarwin () {
+  var electron = require('electron')
+  var app = electron.app
+
+  // On OS X, only protocols that are listed in Info.plist can be set as the default
+  // handler at runtime.
+  app.setAsDefaultProtocolClient('magnet')
+
+  // File handlers are registered in the Info.plist.
+}
+
+function initWin32 () {
+  var Registry = require('winreg')
+
   var iconPath = path.join(process.resourcesPath, 'app.asar.unpacked', 'static', 'WebTorrentFile.ico')
+
   registerProtocolHandlerWin32('magnet', 'URL:BitTorrent Magnet URL', iconPath, process.execPath)
   registerFileHandlerWin32('.torrent', 'io.webtorrent.torrent', 'BitTorrent Document', iconPath, process.execPath)
-}
-
-function initLinux () {
-  var config = require('../config')
-  var fs = require('fs')
-  var mkdirp = require('mkdirp')
-  var os = require('os')
-  var path = require('path')
-
-  installDesktopFile()
-  installIconFile()
-
-  function installDesktopFile () {
-    var templatePath = path.join(config.STATIC_PATH, 'webtorrent.desktop')
-    fs.readFile(templatePath, 'utf8', writeDesktopFile)
-  }
-
-  function writeDesktopFile (err, desktopFile) {
-    if (err) return console.error(err.message)
-
-    var appPath = config.IS_PRODUCTION ? path.dirname(process.execPath) : config.ROOT_PATH
-    var execPath = process.execPath + (config.IS_PRODUCTION ? '' : ' \.')
-    var tryExecPath = process.execPath
-
-    desktopFile = desktopFile.replace(/\$APP_NAME/g, config.APP_NAME)
-    desktopFile = desktopFile.replace(/\$APP_PATH/g, appPath)
-    desktopFile = desktopFile.replace(/\$EXEC_PATH/g, execPath)
-    desktopFile = desktopFile.replace(/\$TRY_EXEC_PATH/g, tryExecPath)
-
-    var desktopFilePath = path.join(
-      os.homedir(),
-      '.local',
-      'share',
-      'applications',
-      'webtorrent.desktop'
-    )
-    mkdirp(path.dirname(desktopFilePath))
-    fs.writeFile(desktopFilePath, desktopFile, function (err) {
-      if (err) return console.error(err.message)
-    })
-  }
-
-  function installIconFile () {
-    var iconStaticPath = path.join(config.STATIC_PATH, 'WebTorrent.png')
-    fs.readFile(iconStaticPath, writeIconFile)
-  }
-
-  function writeIconFile (err, iconFile) {
-    if (err) return console.error(err.message)
-
-    var iconFilePath = path.join(
-      os.homedir(),
-      '.local',
-      'share',
-      'icons',
-      'webtorrent.png'
-    )
-    mkdirp(path.dirname(iconFilePath))
-    fs.writeFile(iconFilePath, iconFile, function (err) {
-      if (err) return console.error(err.message)
-    })
-  }
-}
 
   /**
- * To add a protocol handler on Windows, the following keys must be added to the Windows
+   * To add a protocol handler, the following keys must be added to the Windows registry:
- * registry:
    *
    * HKEY_CLASSES_ROOT
    *   $PROTOCOL
@@ -106,60 +59,168 @@ function initLinux () {
    */
 
   function registerProtocolHandlerWin32 (protocol, name, icon, command) {
-  var Registry = require('winreg')
+    setProtocol()
 
     var protocolKey = new Registry({
       hive: Registry.HKCU, // HKEY_CURRENT_USER
       key: '\\Software\\Classes\\' + protocol
     })
-  protocolKey.set('', Registry.REG_SZ, name, callback)
+
-  protocolKey.set('URL Protocol', Registry.REG_SZ, '', callback)
+    function setProtocol (err) {
+      if (err) log.error(err.message)
+      protocolKey.set('', Registry.REG_SZ, name, setURLProtocol)
+    }
+
+    function setURLProtocol (err) {
+      if (err) log.error(err.message)
+      protocolKey.set('URL Protocol', Registry.REG_SZ, '', setIcon)
+    }
+
+    function setIcon (err) {
+      if (err) log.error(err.message)
 
       var iconKey = new Registry({
         hive: Registry.HKCU,
         key: '\\Software\\Classes\\' + protocol + '\\DefaultIcon'
       })
-  iconKey.set('', Registry.REG_SZ, icon, callback)
+      iconKey.set('', Registry.REG_SZ, icon, setCommand)
+    }
+
+    function setCommand (err) {
+      if (err) log.error(err.message)
 
       var commandKey = new Registry({
         hive: Registry.HKCU,
         key: '\\Software\\Classes\\' + protocol + '\\shell\\open\\command'
       })
-  commandKey.set('', Registry.REG_SZ, '"' + command + '" "%1"', callback)
+      commandKey.set('', Registry.REG_SZ, '"' + command + '" "%1"', done)
+    }
 
-  function callback (err) {
+    function done (err) {
-    if (err) log.error(err.message || err)
+      if (err) log.error(err.message)
     }
   }
 
+  /**
+   * To add a file handler, the following keys must be added to the Windows registry:
+   *
+   * HKEY_CLASSES_ROOT
+   *   $EXTENSION
+   *     (Default) = "$EXTENSION_ID"
+   *   $EXTENSION_ID
+   *     (Default) = "$NAME"
+   *     DefaultIcon
+   *       (Default) = "$ICON"
+   *     shell
+   *       open
+   *         command
+   *           (Default) = "$COMMAND" "%1"
+   */
   function registerFileHandlerWin32 (ext, id, name, icon, command) {
-  var Registry = require('winreg')
+    setExt()
 
+    function setExt () {
       var extKey = new Registry({
         hive: Registry.HKCU, // HKEY_CURRENT_USER
         key: '\\Software\\Classes\\' + ext
       })
-  extKey.set('', Registry.REG_SZ, id, callback)
+      extKey.set('', Registry.REG_SZ, id, setId)
+    }
+
+    function setId (err) {
+      if (err) log.error(err.message)
 
       var idKey = new Registry({
         hive: Registry.HKCU,
         key: '\\Software\\Classes\\' + id
       })
-  idKey.set('', Registry.REG_SZ, name, callback)
+      idKey.set('', Registry.REG_SZ, name, setIcon)
+    }
+
+    function setIcon (err) {
+      if (err) log.error(err.message)
 
       var iconKey = new Registry({
         hive: Registry.HKCU,
         key: '\\Software\\Classes\\' + id + '\\DefaultIcon'
       })
-  iconKey.set('', Registry.REG_SZ, icon, callback)
+      iconKey.set('', Registry.REG_SZ, icon, setCommand)
+    }
+
+    function setCommand (err) {
+      if (err) log.error(err.message)
 
       var commandKey = new Registry({
         hive: Registry.HKCU,
         key: '\\Software\\Classes\\' + id + '\\shell\\open\\command'
       })
-  commandKey.set('', Registry.REG_SZ, '"' + command + '" "%1"', callback)
+      commandKey.set('', Registry.REG_SZ, '"' + command + '" "%1"', done)
+    }
 
-  function callback (err) {
+    function done (err) {
-    if (err) log.error(err.message || err)
+      if (err) log.error(err.message)
+    }
+  }
+}
+
+function initLinux () {
+  var config = require('../config')
+  var fs = require('fs')
+  var mkdirp = require('mkdirp')
+  var os = require('os')
+  var path = require('path')
+
+  installDesktopFile()
+  installIconFile()
+
+  function installDesktopFile () {
+    var templatePath = path.join(config.STATIC_PATH, 'webtorrent.desktop')
+    fs.readFile(templatePath, 'utf8', writeDesktopFile)
+  }
+
+  function writeDesktopFile (err, desktopFile) {
+    if (err) return log.error(err.message)
+
+    var appPath = config.IS_PRODUCTION ? path.dirname(process.execPath) : config.ROOT_PATH
+    var execPath = process.execPath + (config.IS_PRODUCTION ? '' : ' \.')
+    var tryExecPath = process.execPath
+
+    desktopFile = desktopFile.replace(/\$APP_NAME/g, config.APP_NAME)
+    desktopFile = desktopFile.replace(/\$APP_PATH/g, appPath)
+    desktopFile = desktopFile.replace(/\$EXEC_PATH/g, execPath)
+    desktopFile = desktopFile.replace(/\$TRY_EXEC_PATH/g, tryExecPath)
+
+    var desktopFilePath = path.join(
+      os.homedir(),
+      '.local',
+      'share',
+      'applications',
+      'webtorrent.desktop'
+    )
+    mkdirp(path.dirname(desktopFilePath))
+    fs.writeFile(desktopFilePath, desktopFile, function (err) {
+      if (err) return log.error(err.message)
+    })
+  }
+
+  function installIconFile () {
+    var iconStaticPath = path.join(config.STATIC_PATH, 'WebTorrent.png')
+    fs.readFile(iconStaticPath, writeIconFile)
+  }
+
+  function writeIconFile (err, iconFile) {
+    if (err) return log.error(err.message)
+
+    var iconFilePath = path.join(
+      os.homedir(),
+      '.local',
+      'share',
+      'icons',
+      'webtorrent.png'
+    )
+    mkdirp(path.dirname(iconFilePath))
+    fs.writeFile(iconFilePath, iconFile, function (err) {
+      if (err) return log.error(err.message)
+    })
   }
 }