chore: abstract http message parser

Author: kettanaito

src/interceptors/Socket/SocketInterceptor.ts

@@ -85,8 +85,6 @@ export class SocketInterceptor extends Interceptor<SocketEventMap> {
         // Otherwise, listen to the original response
         // and forward it to the interceptor.
         controller.onResponse = (response, isMockedResponse) => {
-          console.log('onResponse callback')
-
           self.emitter.emit('response', {
             requestId,
             request,
@@ -130,9 +128,7 @@ class SocketController {
   private shouldSuppressEvents = false
   private suppressedEvents: Array<[event: string, ...args: Array<unknown>]> = []
   private request: Request
-  private requestParser: typeof HTTPParser
   private requestStream?: Readable
-  private responseParser: typeof HTTPParser
   private responseStream?: Readable
 
   constructor(
@@ -142,58 +138,35 @@ class SocketController {
   ) {
     this.url = parseSocketConnectionUrl(normalizedOptions)
 
-    // Create the parser later on because a single
-    // socket can be *reused* for multiple requests.
-    // The same way, don't free the parser.
-    this.requestParser = new HTTPParser()
-    this.requestParser[HTTPParser.kOnHeadersComplete] = (
-      verionMajor: number,
-      versionMinor: number,
-      headers: Array<string>,
-      idk: number,
-      path: string,
-      idk2: undefined,
-      idk3: undefined,
-      idk4: boolean
-    ) => {
-      this.onRequestStart(path, headers)
-    }
-    this.requestParser[HTTPParser.kOnBody] = (chunk: Buffer) => {
-      this.onRequestData(chunk)
-    }
-    this.requestParser[HTTPParser.kOnMessageComplete] = () => {
-      this.onRequestEnd()
-    }
-    this.requestParser.initialize(HTTPParser.REQUEST, {})
-
-    this.responseParser = new HTTPParser()
-    this.responseParser[HTTPParser.kOnHeadersComplete] = (
-      verionMajor: number,
-      versionMinor: number,
-      headers: Array<string>,
-      method: string | undefined,
-      url: string | undefined,
-      status: number,
-      statusText: string,
-      upgrade: boolean,
-      shouldKeepAlive: boolean
-    ) => {
-      this.onResponseStart(status, statusText, headers)
-    }
-    this.responseParser[HTTPParser.kOnBody] = (chunk: Buffer) => {
-      this.onResponseData(chunk)
-    }
-    this.responseParser[HTTPParser.kOnMessageComplete] = () => {
-      this.onResponseEnd()
-    }
-    this.responseParser.initialize(
-      HTTPParser.RESPONSE,
-      // Don't create any async resources here.
-      // This has to be "HTTPINCOMINGMESSAGE" in practice.
-      // @see https://github.com/nodejs/llhttp/issues/44#issuecomment-582499320
-      // new HTTPServerAsyncResource('INTERCEPTORINCOMINGMESSAGE', socket)
-      {}
-    )
+    const requestParser = new HttpMessageParser('request', {
+      onHeadersComplete: (major, minor, headers, _, path) => {
+        this.onRequestStart(path, headers)
+      },
+      onBody: (chunk) => {
+        this.onRequestData(chunk)
+      },
+      onMessageComplete: this.onRequestEnd.bind(this),
+    })
+
+    const responseParser = new HttpMessageParser('response', {
+      onHeadersComplete: (
+        versionMajor,
+        versionMinor,
+        headers,
+        method,
+        url,
+        status,
+        statusText,
+        upgrade,
+        keepalive
+      ) => {
+        this.onResponseStart(status, statusText, headers)
+      },
+      onBody: (chunk) => {
+        this.onResponseData(chunk)
+      },
+      onMessageComplete: this.onResponseEnd.bind(this),
+    })
 
     socket.emit = new Proxy(socket.emit, {
       apply: (target, thisArg, args) => {
@@ -209,13 +182,13 @@ class SocketController {
         if (this.shouldSuppressEvents) {
           if (args[0] === 'error') {
             Reflect.set(this.socket, '_hadError', false)
-            this.suppressedEvents.push(['error', args.slice(1)])
+            this.suppressedEvents.push(['error', ...args.slice(1)])
             return true
           }
 
           // Suppress close events for errored mocked connections.
           if (args[0] === 'close') {
-            this.suppressedEvents.push(['close', args.slice(1)])
+            this.suppressedEvents.push(['close', ...args.slice(1)])
             return true
           }
         }
@@ -224,7 +197,7 @@ class SocketController {
       },
     })
 
-    socket.once('ready', () => {
+    socket.once('connect', () => {
       // Notify the interceptor once the socket is ready.
       // The HTTP parser triggers BEFORE that.
       this.onRequest(this.request)
@@ -234,7 +207,7 @@ class SocketController {
     socket.write = new Proxy(socket.write, {
       apply: (target, thisArg, args) => {
         if (args[0] !== null) {
-          this.requestParser.execute(
+          requestParser.push(
             Buffer.isBuffer(args[0]) ? args[0] : Buffer.from(args[0])
           )
         }
@@ -246,7 +219,7 @@ class SocketController {
     socket.push = new Proxy(socket.push, {
       apply: (target, thisArg, args) => {
         if (args[0] !== null) {
-          this.responseParser.execute(
+          responseParser.push(
             Buffer.isBuffer(args[0]) ? args[0] : Buffer.from(args[0])
           )
         }
@@ -304,11 +277,15 @@ class SocketController {
   }
 
   private replayErrors() {
+    console.log('replay errors...', this.suppressedEvents)
+
     if (this.suppressedEvents.length === 0) {
       return
     }
 
     for (const [event, ...args] of this.suppressedEvents) {
+      console.log('replaying event', event, ...args)
+
       if (event === 'error') {
         Reflect.set(this.socket, '_hadError', true)
       }
@@ -342,6 +319,7 @@ class SocketController {
       method,
       headers,
       body: methodWithBody ? Readable.toWeb(this.requestStream) : null,
+      // @ts-expect-error Not documented fetch property.
       duplex: methodWithBody ? 'half' : undefined,
       credentials: 'same-origin',
     })
@@ -356,8 +334,6 @@ class SocketController {
   }
 
   private onRequestEnd() {
-    this.requestParser.free()
-
     invariant(
       this.requestStream,
       'Failed to handle the request end: request stream is missing'
@@ -376,7 +352,7 @@ class SocketController {
       statusText,
       headers: parseRawHeaders(rawHeaders),
     })
-    this.onResponse(response)
+    this.onResponse(response, false)
   }
 
   private onResponseData(chunk: Buffer) {
@@ -388,8 +364,6 @@ class SocketController {
   }
 
   private onResponseEnd() {
-    this.responseParser.free()
-
     invariant(
       this.responseStream,
       'Failed to handle the response end: response stream is missing'
@@ -398,6 +372,57 @@ class SocketController {
   }
 }
 
+type HttpMessageParserMessageType = 'request' | 'response'
+interface HttpMessageParserCallbacks<T extends HttpMessageParserMessageType> {
+  onHeadersComplete?: T extends 'request'
+    ? (
+        versionMajor: number,
+        versionMinor: number,
+        headers: Array<string>,
+        idk: number,
+        path: string
+      ) => void
+    : (
+        versionMajor: number,
+        versionMinor: number,
+        headers: Array<string>,
+        method: string | undefined,
+        url: string | undefined,
+        status: number,
+        statusText: string,
+        upgrade: boolean,
+        shouldKeepAlive: boolean
+      ) => void
+  onBody?: (chunk: Buffer) => void
+  onMessageComplete?: () => void
+}
+
+class HttpMessageParser<T extends HttpMessageParserMessageType> {
+  private parser: HTTPParser
+
+  constructor(messageType: T, callbacks: HttpMessageParserCallbacks<T>) {
+    this.parser = new HTTPParser()
+    this.parser.initialize(
+      messageType === 'request' ? HTTPParser.REQUEST : HTTPParser.RESPONSE,
+      // Don't create any async resources here.
+      // This has to be "HTTPINCOMINGMESSAGE" in practice.
+      // @see https://github.com/nodejs/llhttp/issues/44#issuecomment-582499320
+      // new HTTPServerAsyncResource('INTERCEPTORINCOMINGMESSAGE', socket)
+      {}
+    )
+    this.parser[HTTPParser.kOnHeadersComplete] = callbacks.onHeadersComplete
+    this.parser[HTTPParser.kOnMessageComplete] = callbacks.onMessageComplete
+  }
+
+  public push(chunk: Buffer): void {
+    this.parser.execute(chunk)
+  }
+
+  public destroy(): void {
+    this.parser.free()
+  }
+}
+
 function parseSocketConnectionUrl(
   options: NormalizedSocketConnectOptions
 ): URL {
@@ -429,21 +454,3 @@ function parseRawHeaders(rawHeaders: Array<string>): Headers {
   }
   return headers
 }
-
-// MOCKED REQUEST:
-// 1. lookup // mock that's OK
-// 2. connect
-// 3. ready
-// HAS MOCK?
-// -> Y: data -> close
-// -> N (no response, non-existing host):
-//   -> replayErrors()
-//     -> lookup (error), error, close
-
-// BYPASSED REQUEST TO EXISTING HOST:
-// 1. lookup (no errors)
-// 2. (skip mockConnect), forward all socket events.
-// 3. emit "request" on the interceptor.
-// 4. HAS MOCK?
-//  -> Y: respondWith: data -> close
-//  -> N: do nothing