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channelRead() — netty Function Reference

Architecture documentation for the channelRead() function in WebSocketClientExtensionHandler.java from the netty codebase.

Function java ProtocolCodecs HTTP

Entity Profile

Dependency Diagram

graph TD
  270b7dc6_9068_5a54_fa94_d3c7d9c35c65["channelRead()"]
  9042b1fc_17ba_5cab_b9d8_edc829f68749["WebSocketClientExtensionHandler"]
  270b7dc6_9068_5a54_fa94_d3c7d9c35c65 -->|defined in| 9042b1fc_17ba_5cab_b9d8_edc829f68749
  style 270b7dc6_9068_5a54_fa94_d3c7d9c35c65 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtensionHandler.java lines 77–126

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
            throws Exception {
        if (msg instanceof HttpResponse) {
            HttpResponse response = (HttpResponse) msg;

            if (WebSocketExtensionUtil.isWebsocketUpgrade(response.headers())) {
                String extensionsHeader = response.headers().getAsString(HttpHeaderNames.SEC_WEBSOCKET_EXTENSIONS);

                if (extensionsHeader != null) {
                    List<WebSocketExtensionData> extensions =
                            WebSocketExtensionUtil.extractExtensions(extensionsHeader);
                    List<WebSocketClientExtension> validExtensions =
                            new ArrayList<WebSocketClientExtension>(extensions.size());
                    int rsv = 0;

                    for (WebSocketExtensionData extensionData : extensions) {
                        Iterator<WebSocketClientExtensionHandshaker> extensionHandshakersIterator =
                                extensionHandshakers.iterator();
                        WebSocketClientExtension validExtension = null;

                        while (validExtension == null && extensionHandshakersIterator.hasNext()) {
                            WebSocketClientExtensionHandshaker extensionHandshaker =
                                    extensionHandshakersIterator.next();
                            validExtension = extensionHandshaker.handshakeExtension(extensionData);
                        }

                        if (validExtension != null && ((validExtension.rsv() & rsv) == 0)) {
                            rsv = rsv | validExtension.rsv();
                            validExtensions.add(validExtension);
                        } else {
                            throw new CodecException(
                                    "invalid WebSocket Extension handshake for \"" + extensionsHeader + '"');
                        }
                    }

                    for (WebSocketClientExtension validExtension : validExtensions) {
                        WebSocketExtensionDecoder decoder = validExtension.newExtensionDecoder();
                        WebSocketExtensionEncoder encoder = validExtension.newExtensionEncoder();
                        ctx.pipeline().addAfter(ctx.name(), decoder.getClass().getName(), decoder);
                        ctx.pipeline().addAfter(ctx.name(), encoder.getClass().getName(), encoder);
                    }
                }

                ctx.pipeline().remove(ctx.name());
            }
        }

        super.channelRead(ctx, msg);
    }

Domain

Subdomains

Defined In

Source

Frequently Asked Questions

What does channelRead() do?
channelRead() is a function in the netty codebase, defined in codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtensionHandler.java.
Where is channelRead() defined?
channelRead() is defined in codec-http/src/main/java/io/netty/handler/codec/http/websocketx/extensions/WebSocketClientExtensionHandler.java at line 77.

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