Here is how to accept custom protocol links like dat://LINK in an @electronjs app, in osx. For this to work you need to properly package the app into a `.app`, and place the CFBundleURLTypes spec into it's Info.plist. Then, move the app into another directory using Finder (!). Here we're using electron-packager.

extend.plist

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLName</key>
    <string>Dat Link</string>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>dat</string>
    </array>
  </dict>
</array>

index.js

// ...

app.on('will-finish-launching', () => {
  app.on('open-url', (ev, url) => {
    ev.preventDefault();
    // send the url to the renderer process via rpc
  });
});

// ...

package.json

{
  "scripts": {
    "package": "electron-packager . --all --extend-info extend.plist"
  }
}