WebSocket

class WebSocket extends EventTarget

Annotations: @SupportedBrowser.new(SupportedBrowser.CHROME), @SupportedBrowser.new(SupportedBrowser.FIREFOX), @SupportedBrowser.new(SupportedBrowser.IE, '10'), @SupportedBrowser.new(SupportedBrowser.SAFARI), @Unstable.new(), @Native.new("WebSocket")

Use the WebSocket interface to connect to a WebSocket, and to send and receive data on that WebSocket.

To use a WebSocket in your web app, first create a WebSocket object, passing the WebSocket URL as an argument to the constructor.

var webSocket = new WebSocket('ws://127.0.0.1:1337/ws');

To send data on the WebSocket, use the send method.

if (webSocket != null && webSocket.readyState == WebSocket.OPEN) {
  webSocket.send(data);
} else {
  print('WebSocket not connected, message $data not sent');
}

To receive data on the WebSocket, register a listener for message events.

webSocket.onMessage.listen((MessageEvent e) {
  receivedData(e.data);
});

The message event handler receives a MessageEvent object as its sole argument. You can also define open, close, and error handlers, as specified by Events.

For more information, see the WebSockets section of the library tour and Introducing WebSockets, an HTML5Rocks.com tutorial.

Inheritance

Object → EventTarget → WebSocket

Constructors

WebSocket() factory

factory WebSocket(String url, [Object? protocols])

Implementation

factory WebSocket(String url, [Object? protocols]) {
  if (protocols != null) {
    return WebSocket._create_1(url, protocols);
  }
  return WebSocket._create_2(url);
}

Properties

binaryType read / write

String? get binaryType

Implementation

String? get binaryType native;

set binaryType(String? value) native;

bufferedAmount no setter

int? get bufferedAmount

Implementation

int? get bufferedAmount native;

extensions no setter

String? get extensions

Implementation

String? get extensions native;

hashCode no setter inherited

int get hashCode

Inherited from Interceptor.

Implementation

int get hashCode => Primitives.objectHashCode(this);

on no setter inherited

Events get on

This is an ease-of-use accessor for event streams which should only be used when an explicit accessor is not available.

Inherited from EventTarget.

Implementation

Events get on => new Events(this);

onClose no setter

Stream<CloseEvent> get onClose

Stream of close events handled by this WebSocket.

Implementation

Stream<CloseEvent> get onClose => closeEvent.forTarget(this);

onError no setter

Stream<Event> get onError

Stream of error events handled by this WebSocket.

Implementation

Stream<Event> get onError => errorEvent.forTarget(this);

onMessage no setter

Stream<MessageEvent> get onMessage

Stream of message events handled by this WebSocket.

Implementation

Stream<MessageEvent> get onMessage => messageEvent.forTarget(this);

onOpen no setter

Stream<Event> get onOpen

Stream of open events handled by this WebSocket.

Implementation

Stream<Event> get onOpen => openEvent.forTarget(this);

protocol no setter

String? get protocol

Implementation

String? get protocol native;

readyState no setter

int get readyState

Implementation

int get readyState native;

runtimeType no setter inherited

Type get runtimeType

Inherited from Interceptor.

Implementation

Type get runtimeType =>
    getRuntimeTypeOfInterceptorNotArray(getInterceptor(this), this);

url no setter

String? get url

Implementation

String? get url native;

Methods

addEventListener() inherited

void addEventListener(
  String type,
  (dynamic Function(Event event))? listener, [
  bool? useCapture,
])

Inherited from EventTarget.

Implementation

void addEventListener(
  String type,
  EventListener? listener, [
  bool? useCapture,
]) {
  // TODO(leafp): This check is avoid a bug in our dispatch code when
  // listener is null.  The browser treats this call as a no-op in this
  // case, so it's fine to short-circuit it, but we should not have to.
  if (listener != null) {
    _addEventListener(type, listener, useCapture);
  }
}

close()

void close([int? code, String? reason])

Implementation

void close([int? code, String? reason]) native;

dispatchEvent() inherited

bool dispatchEvent(Event event)

Inherited from EventTarget.

Implementation

bool dispatchEvent(Event event) native;

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Interceptor.

Implementation

dynamic noSuchMethod(Invocation invocation) {
  throw NoSuchMethodError.withInvocation(this, invocation);
}

removeEventListener() inherited

void removeEventListener(
  String type,
  (dynamic Function(Event event))? listener, [
  bool? useCapture,
])

Inherited from EventTarget.

Implementation

void removeEventListener(
  String type,
  EventListener? listener, [
  bool? useCapture,
]) {
  // TODO(leafp): This check is avoid a bug in our dispatch code when
  // listener is null.  The browser treats this call as a no-op in this
  // case, so it's fine to short-circuit it, but we should not have to.
  if (listener != null) {
    _removeEventListener(type, listener, useCapture);
  }
}

send()

void send(dynamic data)

Transmit data to the server over this connection.

This method accepts data of type Blob, ByteBuffer, String, or TypedData. Named variants sendBlob, sendByteBuffer, sendString, or sendTypedData, in contrast, only accept data of the specified type.

Implementation

void send(data) native;

sendBlob()

void sendBlob(Blob data)

Transmit data to the server over this connection.

This method accepts data of type Blob, ByteBuffer, String, or TypedData. Named variants sendBlob, sendByteBuffer, sendString, or sendTypedData, in contrast, only accept data of the specified type.

Implementation

@JSName('send')
/**
 * Transmit data to the server over this connection.
 *
 * This method accepts data of type [Blob], [ByteBuffer], [String], or
 * [TypedData]. Named variants [sendBlob], [sendByteBuffer], [sendString],
 * or [sendTypedData], in contrast, only accept data of the specified type.
 */
void sendBlob(Blob data) native;

sendByteBuffer()

void sendByteBuffer(ByteBuffer data)

Transmit data to the server over this connection.

This method accepts data of type Blob, ByteBuffer, String, or TypedData. Named variants sendBlob, sendByteBuffer, sendString, or sendTypedData, in contrast, only accept data of the specified type.

Implementation

@JSName('send')
/**
 * Transmit data to the server over this connection.
 *
 * This method accepts data of type [Blob], [ByteBuffer], [String], or
 * [TypedData]. Named variants [sendBlob], [sendByteBuffer], [sendString],
 * or [sendTypedData], in contrast, only accept data of the specified type.
 */
void sendByteBuffer(ByteBuffer data) native;

sendString()

void sendString(String data)

Transmit data to the server over this connection.

This method accepts data of type Blob, ByteBuffer, String, or TypedData. Named variants sendBlob, sendByteBuffer, sendString, or sendTypedData, in contrast, only accept data of the specified type.

Implementation

@JSName('send')
/**
 * Transmit data to the server over this connection.
 *
 * This method accepts data of type [Blob], [ByteBuffer], [String], or
 * [TypedData]. Named variants [sendBlob], [sendByteBuffer], [sendString],
 * or [sendTypedData], in contrast, only accept data of the specified type.
 */
void sendString(String data) native;

sendTypedData()

void sendTypedData(TypedData data)

Transmit data to the server over this connection.

This method accepts data of type Blob, ByteBuffer, String, or TypedData. Named variants sendBlob, sendByteBuffer, sendString, or sendTypedData, in contrast, only accept data of the specified type.

Implementation

@JSName('send')
/**
 * Transmit data to the server over this connection.
 *
 * This method accepts data of type [Blob], [ByteBuffer], [String], or
 * [TypedData]. Named variants [sendBlob], [sendByteBuffer], [sendString],
 * or [sendTypedData], in contrast, only accept data of the specified type.
 */
void sendTypedData(TypedData data) native;

toString() inherited

String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Interceptor.

Implementation

String toString() => Primitives.objectToHumanReadableString(this);

Operators

operator ==() inherited

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

• Total: It must return a boolean for all arguments. It should never throw.

• Reflexive: For all objects o, o == o must be true.

• Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

• Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Interceptor.

Implementation

bool operator ==(Object other) => identical(this, other);

Static Properties

supported no setter

bool get supported

Checks if this type is supported on the current platform.

Implementation

static bool get supported =>
    JS('bool', 'typeof window.WebSocket != "undefined"');

Constants

CLOSED

const int CLOSED

Implementation

static const int CLOSED = 3;

closeEvent

const EventStreamProvider<CloseEvent> closeEvent

Static factory designed to expose close events to event handlers that are not necessarily instances of WebSocket.

See EventStreamProvider for usage information.

Implementation

static const EventStreamProvider<CloseEvent> closeEvent =
    const EventStreamProvider<CloseEvent>('close');

CLOSING

const int CLOSING

Implementation

static const int CLOSING = 2;

CONNECTING

const int CONNECTING

Implementation

static const int CONNECTING = 0;

errorEvent

const EventStreamProvider<Event> errorEvent

Static factory designed to expose error events to event handlers that are not necessarily instances of WebSocket.

See EventStreamProvider for usage information.

Implementation

static const EventStreamProvider<Event> errorEvent =
    const EventStreamProvider<Event>('error');

messageEvent

const EventStreamProvider<MessageEvent> messageEvent

Static factory designed to expose message events to event handlers that are not necessarily instances of WebSocket.

See EventStreamProvider for usage information.

Implementation

static const EventStreamProvider<MessageEvent> messageEvent =
    const EventStreamProvider<MessageEvent>('message');

OPEN

const int OPEN

Implementation

static const int OPEN = 1;

openEvent

const EventStreamProvider<Event> openEvent

Static factory designed to expose open events to event handlers that are not necessarily instances of WebSocket.

See EventStreamProvider for usage information.

Implementation

static const EventStreamProvider<Event> openEvent =
    const EventStreamProvider<Event>('open');