Zaptools #

A toolkit for Event-Driven websocket management

Getting started #

Zaptools provides tools for building event-driven websocket integration. It is built on top websocket.

Usage #

Server

  final app = ZapServer();

  app.onConnected((context) {
    // when a new client joined
    print("client connected");
  });

  app.onDisconnected((context) {
    // when a client left
    print("client disconnected!");
  });

  app.onEvent("myEvent", (context) {
    // When the event "myEvent" is received
    print("fire!");
   });

  final server = await app.start();
  print("listen on -> ${server.port}");

Client (based on callbacks)

  Uri uri = Uri.parse("ws://127.0.0.1:8000/");
  final zapClient = ClientConnector.connect(uri);

  zapClient.onConnected((eventData) {
    print("Connected");
   });

  zapClient.onDisconnected((eventData) {
    print("disconnected");
  });

  zapClient.sendEvent("myEvent", "payload");

  zapClient.onEvent("Hello", (eventData){
    print("event received");
  });

Client (based on streams)

  Uri uri = Uri.parse("ws://127.0.0.1:8000/");
  final zapClient = ClientConnector.attach(uri);

  zapClient.connectionState.listen((event) {
    if (event case ConnectionState.online) {
      print("connected!");
    }
    if (event case ConnectionState.offline) {
      print("disconnected!");
    }
  });

  zapClient.subscribeToEvent("myEVent").listen((eventData){
    print("event received!");
  });

attach method returns a subscriber, it is a client based on streams

Integrating with other frameworks (Server Side) #

Zaptools can integrate with other frameworks that exposes the HttpRequest object of the Dart:io library, like Alfred framework.

Alfred

  final app = Alfred();

  final reg = EventRegister();

  reg.onConnected((contexts) {
    // when a new client joined
    print("client connected");
  });

  reg.onDisconnected((context) {
    // when a client left
    print("client disconnected!");
  });

  reg.onEvent("myEvent", (context) {
    // When a event the event "myEvent" is received
    print("fire!");
   });

  app.get("/ws", (HttpRequest req, HttpResponse res) {
    plugAndStartWithIO(req, reg);
  });

Alfred is a great framework to make server side apps with dart.

EventRegister has responsability to create events. plugAndStartWithIO connect the HttpRequest with the EventRegister instance and upgrade the connection to websocket.

It planning to add Shelf and Frog support in the future.

EventContext

The EventContext object has the information about the current event, the EventData and the WebSocketConnection it is invoking the event.

    context.eventData; // EventData
    context.connection; // WebSocketConnection

EventData has the properties like payload, name (event name), headers.

    context.eventData.name; // name of the event
    context.eventData.payload; // payload of this event invoking
    context.eventData.headers; // headers of this event invoking

connection property is a instance of WebSocketConnection it has an id and is able to send and close the connection with the client.

    context.connection.id; //connection identifier
    context.connection.send("eventName", "payload"); // send to client
    context.connection.close(); // close the connection

Executing send or close method in onDisconnected event it will throw an Unhandled Error

Contributions are wellcome! #

What's Next?

• ✅ event management.
• ❌ comunication between clients.