RFC: Universal Web-Native Communication Protocol (UWNCP)

1. Introduction

The Universal Web-Native Communication Protocol (UWNCP) aims to standardize the exchange of data between web content and native applications. While the protocol is designed to be framework-agnostic, it particularly addresses common practices within the React and React Native communities. UWNCP facilitates efficient, secure, and straightforward communication across the boundary between web and native environments.

2. Background

The integration of web content within native applications is widespread, combining the strengths of web development with the capabilities of native platforms. However, disparate communication methods have led to inconsistent and often insecure implementations. UWNCP proposes a standardized approach to foster better interoperability, security, and development efficiency.

3. Terminology

• Web Content: Web applications or HTML content rendered within a native application's WebView component.
• Native Application: Applications developed for specific platforms, utilizing native SDKs and frameworks.
• WebView: A component in native development frameworks for embedding web content.
• Message: The structured data exchanged between web content and a native application.

4. Communication Protocol

4.1 Message Structure

To ensure consistency and ease of parsing, messages exchanged must follow a simple JSON structure:

{
  "type": "string",
  "payload": "any"
}

• type: A descriptive string indicating the action or category of the message.
• payload: The content of the message, which can be any datatype that is serializable into JSON.

4.2 Sending Messages from Web Content

Web content sends messages to the native side using a standardized JavaScript interface. This interface must be exposed to the web content by the native application:

function sendMessage(message) {
  if (window.NativeInterface) {
    window.NativeInterface.postMessage(JSON.stringify(message));
  } else {
    console.error("Native interface not available");
  }
}

4.3 Receiving Messages in Native Applications

Native applications listen for messages by setting up a message handler within the WebView:

// Generic example that needs to be adapted to specific native framework syntax
webView.setupMessageHandler(message => {
  const { type, payload } = JSON.parse(message);
  // Process the message based on type and payload
});

4.4 Security Considerations

• Validate the structure and content of all messages to prevent code injection and other security vulnerabilities.
• Ensure the web content is loaded over HTTPS to mitigate the risk of man-in-the-middle attacks.
• Implement origin checks where applicable to ensure messages are received from trusted sources only.

5. Use Cases

UWNCP enables a variety of integrations, such as:

• Sharing authentication status or user data between web content and the native app.
• Invoking native functionality (camera, GPS, etc.) from web content.
• Synchronizing application state or data across web and native components.

6. Implementation Examples

While specific code will vary depending on the development framework, the principles of UWNCP apply universally. Implementers are encouraged to adapt the message sending and handling examples to their specific frameworks, ensuring adherence to the protocol's structure and security guidelines.

7. Conclusion

The Universal Web-Native Communication Protocol provides a standardized method for web content and native applications to communicate efficiently and securely. By adopting UWNCP, developers can ensure consistent and secure data exchange across web and native components, improving the interoperability and user experience of integrated applications. This protocol serves as a foundation for future development and optimization in the ever-evolving landscape of web and native application integration.

This final draft of the RFC reflects current best practices within the React and React Native communities for web-native communication, providing a streamlined and flexible approach to interoperability. By focusing on essential elements and security, UWNCP aims to be a robust foundation for developers bridging web content with native application environments.