Add pingInterval pass through param (#16)

Configures the construction of the WebSocketChannel.

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.2.3
+
+* Add `pingInterval` argument to `webSocketHandler`, to be passed through
+  to the created channel.
+
 ## 0.2.2+5
 
 * Allow `stream_channel` version 2.x

lib/shelf_web_socket.dart

@@ -37,8 +37,14 @@ typedef _BinaryFunction = void Function(Null, Null);
 /// See also the WebSocket spec's discussion of [origin considerations][].
 ///
 /// [origin considerations]: https://tools.ietf.org/html/rfc6455#section-10.2
+///
+/// If [pingInterval] is specified, it will get passed to the created
+/// channel instance, enabling round-trip disconnect detection.
+/// See [WebSocketChannel] for more details.
 Handler webSocketHandler(Function onConnection,
-    {Iterable<String> protocols, Iterable<String> allowedOrigins}) {
+    {Iterable<String> protocols,
+    Iterable<String> allowedOrigins,
+    Duration pingInterval}) {
   if (protocols != null) protocols = protocols.toSet();
   if (allowedOrigins != null) {
     allowedOrigins =
@@ -55,5 +61,7 @@ Handler webSocketHandler(Function onConnection,
     onConnection = (webSocket, _) => innerOnConnection(webSocket);
   }
 
-  return new WebSocketHandler(onConnection, protocols, allowedOrigins).handle;
+  return new WebSocketHandler(
+          onConnection, protocols, allowedOrigins, pingInterval)
+      .handle;
 }

lib/src/web_socket_handler.dart

@@ -18,7 +18,11 @@ class WebSocketHandler {
   /// The set of allowed browser origin connections, or `null`..
   final Set<String> _allowedOrigins;
 
-  WebSocketHandler(this._onConnection, this._protocols, this._allowedOrigins);
+  /// The ping interval used for verifying connection, or `null`.
+  final Duration _pingInterval;
+
+  WebSocketHandler(this._onConnection, this._protocols, this._allowedOrigins,
+      this._pingInterval);
 
   /// The [Handler].
   Response handle(Request request) {
@@ -74,7 +78,8 @@ class WebSocketHandler {
       if (protocol != null) sink.add("Sec-WebSocket-Protocol: $protocol\r\n");
       sink.add("\r\n");
 
-      _onConnection(new WebSocketChannel(channel), protocol);
+      _onConnection(
+          new WebSocketChannel(channel, pingInterval: _pingInterval), protocol);
     });
 
     // [request.hijack] is guaranteed to throw a [HijackException], so we'll

pubspec.yaml

@@ -1,5 +1,5 @@
 name: shelf_web_socket
-version: 0.2.2+5
+version: 0.2.3
 
 description: >-
   A shelf handler that wires up a listener for every connection.