Add WebSocket traffic support to HAR generator and per-message mocking#3
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waldekmastykarz wants to merge 2 commits into
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Add WebSocket traffic support to HAR generator and per-message mocking#3waldekmastykarz wants to merge 2 commits into
waldekmastykarz wants to merge 2 commits into
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Replace raw byte WebSocket relay with frame-aware relay using WebSocket.CreateFromStream on both client and origin sides. Each relayed message is captured as a WebSocketMessageRecord and stored on the session. The HAR generator now detects WebSocket upgrade entries and embeds captured messages using the _resourceType and _webSocketMessages custom HAR fields, following the Chrome DevTools / mitmproxy convention. Changes: - Add WebSocketMessageRecord abstraction (direction, type, data, timestamp) - Add IProxySession.WebSocketMessages property - Convert WebSocketRelay from raw byte splice to message-level relay with PrefixedStream for leftover handshake bytes - Add HarWebSocketMessage model and _resourceType/_webSocketMessages fields to HarEntry - Update HarGeneratorPlugin to populate WebSocket fields - Update WebSocketRelayTests for frame-level relay and message capture verification Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Convert WebSocket mocking from full-connection takeover to per-message interception: the proxy connects to the origin and relays traffic, but each client message is offered to the interceptor first. Matched messages get mock responses; unmatched ones pass through to the origin. When the origin is unreachable but an interceptor is registered, the proxy falls back to mock-only mode — same as the old HandleWebSocket behavior. - Add InterceptWebSocketMessages to IProxySession with interceptor and onConnected callbacks - Split WebSocket relay into client-to-origin and origin-to-client tasks with thread-safe client sends via SemaphoreSlim - Add InterceptorClientConnection wrapper with send serialization and message capture for HAR - Convert WebSocketMockResponsePlugin from HandleWebSocket to InterceptWebSocketMessages - Add origin-unreachable fallback in ProxyConnectionHandler Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Summary
Adds two major WebSocket capabilities to Dev Proxy:
HAR generator captures WebSocket messages — WebSocket traffic relayed through the proxy is now recorded in HAR files following the Chrome DevTools / mitmproxy convention (
_resourceType: "websocket"+_webSocketMessagesarray on the upgrade entry).Per-message WebSocket interception — Converts the WebSocket mock plugin from full-connection takeover to per-message interception with origin passthrough, matching how HTTP mocking works: matched messages get mock responses, unmatched ones pass through to the origin.
Changes
WebSocket message capture (HAR)
WebSocketMessageRecordabstraction (direction, type, data, timestamp)WebSocketMessagesproperty toIProxySessionWebSocketRelaywithWebSocket.CreateFromStream-based frame-level relay that captures every messagePrefixedStreamto handle leftover handshake bytes_resourceTypeand_webSocketMessagesHAR extension fields (matching Chrome/mitmproxy convention)HarGeneratorPluginfor upgrade entriesPer-message interception
InterceptWebSocketMessages(interceptor, onConnected)toIProxySessionRelayClientToOriginAsyncandRelayOriginToClientAsyncwithSemaphoreSlimfor thread-safe client sendsInterceptorClientConnectionwrapper with send serialization and message captureWebSocketMockResponsePluginfromHandleWebSockettoInterceptWebSocketMessagesArchitecture
Testing
WebSocketRelayTestsrewritten for frame-level relay with message capture verificationWebSocketMockIntegrationTestspass (mock-only fallback covers the no-origin scenario)