Add tests for interim response handling

Author: Acconut

docker/nginx/nginx.conf

@@ -9,5 +9,6 @@ server {
         proxy_pass http://localhost:8000;
         proxy_cache my-cache;
         proxy_cache_revalidate on;
+        proxy_http_version 1.1;
     }
 }

package.json

@@ -11,7 +11,8 @@
   "dependencies": {
     "liquidjs": "^10.9.2",
     "marked": "^15.0.0",
-    "npm": "^11.0.0"
+    "npm": "^11.0.0",
+    "undici": "^7.4.0"
   },
   "scripts": {
     "server": "node test-engine/server/server.mjs",

test-engine/client/test.mjs

@@ -4,6 +4,7 @@ import * as utils from '../lib/utils.mjs'
 import * as config from './config.mjs'
 import * as clientUtils from './utils.mjs'
 import * as fetching from './fetching.mjs'
+import { getGlobalDispatcher } from 'undici'
 const assert = utils.assert
 const setupCheck = clientUtils.setupCheck
 
@@ -32,11 +33,19 @@ export async function makeTest (test) {
           controller.abort()
         }, config.requestTimeout * 1000)
         init.signal = controller.signal
+
+        const interimResponses = []
+        if ('expected_interim_responses' in reqConfig) {
+          const globalDispatcher = getGlobalDispatcher()
+          const dispatcher = globalDispatcher.compose(clientUtils.interimResponsesCollectingInterceptor(interimResponses))
+          init.dispatcher = dispatcher
+        }
+
         if (test.dump === true) clientUtils.logRequest(url, init, reqNum)
         return fetch(url, init)
           .then(response => {
             responses.push(response)
-            return checkResponse(test, requests, idx, response)
+            return checkResponse(test, requests, idx, response, interimResponses)
           })
           .finally(() => {
             clearTimeout(timeout)
@@ -84,7 +93,7 @@ export async function makeTest (test) {
     })
 }
 
-function checkResponse (test, requests, idx, response) {
+function checkResponse (test, requests, idx, response, interimResponses) {
   const reqNum = idx + 1
   const reqConfig = requests[idx]
   const resNum = parseInt(response.headers.get('Server-Request-Count'))
@@ -185,6 +194,37 @@ function checkResponse (test, requests, idx, response) {
       }
     })
   }
+
+  // check interim responses
+  if ('expected_interim_responses' in reqConfig) {
+    const isSetup = setupCheck(reqConfig, 'expected_interim_responses')
+
+    reqConfig.expected_interim_responses.forEach(([statusCode, headers = []], idx) => {
+      if (interimResponses[idx] == null) {
+        assert(isSetup, false, `Interim response ${idx + 1} not received`)
+      } else {
+        assert(isSetup, interimResponses[idx][0] === statusCode, `Interim response ${idx + 1} status is ${interimResponses[idx][0]}, not ${statusCode}`)
+
+        const receivedHeaders = interimResponses[idx][1]
+        headers.forEach(([header, value]) => {
+          if (typeof header === 'string') {
+            assert(isSetup, header in receivedHeaders,
+              `Interim response ${idx + 1} ${header} header not present.`)
+          } else if (header.length > 2) {
+            assert(isSetup, header in receivedHeaders,
+              `Interim response ${idx + 1} ${header} header not present.`)
+
+            const receivedValue = receivedHeaders[header]
+            assert(isSetup, value === receivedValue,
+              `Interim response ${idx + 1} header ${header} is ${receivedValue}, should ${value}`)
+          } else {
+            console.log('ERROR: Unknown header item in expected_interim_responses', header)
+          }
+        })
+      }
+    })
+  }
+
   return response.text().then(makeCheckResponseBody(test, reqConfig, response.status))
 }
 

test-engine/client/utils.mjs

@@ -80,3 +80,46 @@ export function logResponse (response, reqNum) {
   })
   console.log('')
 }
+
+class InterimResponsesCollectingHandler {
+  #handler
+  #interimResponses
+
+  constructor (handler, interimResponses) {
+    this.#handler = handler
+    this.#interimResponses = interimResponses
+  }
+
+  onRequestStart (controller, context) {
+    this.#handler.onRequestStart?.(controller, context)
+  }
+
+  onRequestUpgrade (controller, statusCode, headers, socket) {
+    this.#handler.onRequestUpgrade?.(controller, statusCode, headers, socket)
+  }
+
+  onResponseStart (controller, statusCode, headers, statusMessage) {
+    if (statusCode < 200) this.#interimResponses.push([statusCode, headers])
+    this.#handler.onResponseStart?.(controller, statusCode, headers, statusMessage)
+  }
+
+  onResponseData (controller, data) {
+    this.#handler.onResponseData?.(controller, data)
+  }
+
+  onResponseEnd (controller, trailers) {
+    this.#handler.onResponseEnd?.(controller, trailers)
+  }
+
+  onResponseError (controller, err) {
+    this.#handler.onResponseError?.(controller, err)
+  }
+}
+
+export function interimResponsesCollectingInterceptor (collectInto) {
+  return (dispatch) => {
+    return (opts, handler) => {
+      return dispatch(opts, new InterimResponsesCollectingHandler(handler, collectInto))
+    }
+  }
+}

test-engine/server/handle-test.mjs

@@ -43,6 +43,17 @@ function continueHandleTest (uuid, request, response, requests, serverState) {
   const previousConfig = requests[reqNum - 2]
   const now = Date.now()
 
+  const interimResponses = reqConfig.interim_responses || []
+  for (const [status, headers = []] of interimResponses) {
+    if (status === 102) {
+      response.writeProcessing()
+    } else if (status === 103) {
+      response.writeEarlyHints(Object.fromEntries(headers))
+    } else {
+      console.log(`ERROR: Sending ${status} is not yet supported`)
+    }
+  }
+
   // Determine what the response status should be
   let httpStatus = reqConfig.response_status || [200, 'OK']
   if ('expected_type' in reqConfig && reqConfig.expected_type.endsWith('validated')) {

tests/index.mjs

@@ -22,5 +22,6 @@ import partial from './partial.mjs'
 import auth from './authorization.mjs'
 import other from './other.mjs'
 import cdncc from './cdn-cache-control.mjs'
+import interim from './interim.mjs'
 
-export default [ccFreshness, ccParse, ageParse, expires, expiresParse, ccResponse, stale, heuristic, methods, statuses, ccRequest, pragma, vary, varyParse, conditionalLm, conditionalEtag, headers, update304, updateHead, invalidation, partial, auth, other, cdncc]
+export default [ccFreshness, ccParse, ageParse, expires, expiresParse, ccResponse, stale, heuristic, methods, statuses, ccRequest, pragma, vary, varyParse, conditionalLm, conditionalEtag, headers, update304, updateHead, invalidation, partial, auth, other, cdncc, interim]

tests/interim.mjs

@@ -0,0 +1,59 @@
+export default
+
+{
+  name: 'Interim Response Handling',
+  id: 'interim',
+  description: 'These tests check how caches handle interim responses.',
+  tests: [
+    {
+      name: 'An optimal HTTP cache passes a 102 response through and caches the final response',
+      id: 'interim-102',
+      browser_skip: true, // Fetch API in browsers don't expose interim responses
+      kind: 'optimal',
+      requests: [
+        {
+          interim_responses: [[102]],
+          expected_interim_responses: [[102]],
+          response_headers: [
+            ['Cache-Control', 'max-age=100000'],
+            ['Date', 0]
+          ],
+          pause_after: true
+        },
+        {
+          expected_type: 'cached'
+        }
+      ]
+    },
+    {
+      name: 'An optimal HTTP cache passes a 103 response through and caches the final response',
+      id: 'interim-103',
+      browser_skip: true,
+      kind: 'optimal',
+      requests: [
+        {
+          interim_responses: [
+            [103, [
+              ['link', '</styles.css>; rel=preload; as=style'],
+              ['x-my-header', 'test']
+            ]]
+          ],
+          expected_interim_responses: [
+            [103, [
+              ['link', '</styles.css>; rel=preload; as=style'],
+              ['x-my-header', 'test']
+            ]]
+          ],
+          response_headers: [
+            ['Cache-Control', 'max-age=100000'],
+            ['Date', 0]
+          ],
+          pause_after: true
+        },
+        {
+          expected_type: 'cached'
+        }
+      ]
+    }
+  ]
+}