Unify dart:html/dart:io WebSocket interfaces.

[DartBot]

This issue was originally filed by george.moschoviti...@gmail.com

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The WbeSocket interface in dart:html is different than the one defined in dart:io.

So when you have a class that could perfectly well work on both the console and the browser (e.g. a client for a websocket protocol) you have to create and maintain two slightly different versions.

[anders-sandholm]

Added Area-IO, Triaged labels.

[sgjesse]

In the short term the WebSocket interface in dart:io and dart:html will focus on providing access to all features that each underlying platform supports. Based on these two APIs a common interface can be implemented a a separate package.

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Added this to the Later milestone.
Removed Type-Defect, Priority-Unassigned, Area-IO labels.
Added Type-Enhancement, Priority-Low, Area-Library labels.

[DartBot]

This comment was originally written by igor.ko...@mailvision.com

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Can it be used as such interface ?

import 'dart:async';

abstract class AbstractWebSocket {
  static const int CONNECTING = 0;
  static const int OPEN = 1;
  static const int CLOSING = 2;
  static const int CLOSED = 3;
  
  int readyState;
  int closeCode;
  String closeState;
  
  void close([int code, String reason]);
  void send(dynamic data); // String or List<int>
  
  Stream get onOpen;
  Stream get onMessage;
  Stream get onClose;
  Stream get onError;
}

[DartBot]

This comment was originally written by igor.ko...@mailvision.com

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Problem here is stream events !

For example html web socket version defined in dartium.dart:
@DomName('WebSocket.onclose')
  @­DocsEditable()
  Stream<CloseEvent> get onClose => closeEvent.forTarget(this);

  @­DomName('WebSocket.onerror')
  @­DocsEditable()
  Stream<Event> get onError => errorEvent.forTarget(this);

  @­DomName('WebSocket.onmessage')
  @­DocsEditable()
  Stream<MessageEvent> get onMessage => messageEvent.forTarget(this);

Event, CloseEvent, MessageEvent defined in the same file, so cannot be used in
server code (dart:io)

[DartBot]

This comment was originally written by igor.ko...@mailvision.com

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I really needed such common interface, so implemented it for dart:io and dart:html

abstract class AbstractWebSocket {
  static const int CONNECTING = 0;
  static const int OPEN = 1;
  static const int CLOSING = 2;
  static const int CLOSED = 3;

  int get readyState;
  int get closeCode;
  String get closeState;

  void close([int code, String reason]);
  void send(dynamic data); // String or List<int>

  Future<Stream<dynamic>> connect(String url);
  Stream<dynamic> get stream; // data is String or List<int>
}

The test:
 - connect to echo web socket server
 - send string message, send binary message,
 - receive messages
 - disconnect

passed for

• dart application mode
• browser mode as dart, and as js (in dartium).

Test projects in attachment.
(I only learn Future/Stream API, so sure that it can be improved)

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Attachments:
web_socket_client.zip (135.93 KB)
web_socket_server.zip (1.35 KB)

[DartBot]

This comment was originally written by igor.ko...@mailvision.com

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1. to AbstractWebSocket interface
      added optional sub-protocol (header Sec-Websocket-Protocol in http handshake)

  connect(String url, [dymamic subProtocols])

where subProtocols is String or List<String>

1. compatibility question:
   I see that "io" websocket send in handshake header: Accept-Encoding: gzip
   Can I remove the header (and use plain text) ?

[kasperl]

Removed this from the Later milestone.
Added Oldschool-Milestone-Later label.

[kasperl]

Removed Oldschool-Milestone-Later label.

[DartBot]

This comment was originally written by @stevenroose

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A unified HTTP interface would be very beneficial as well.

I'd propose a (fictional) dart:http.HttpClient interface that both dart:io.HttpClient and package:browser_client.BrowserClient can implement.

It's very cumbersome that libraries that try to implement a protocol that is specified around HTTP has to worry about whether it is run in VM or a browser.