1 files changed, 353 insertions, 0 deletions
diff --git a/vanilla/node_modules/undici/lib/mock/snapshot-agent.js b/vanilla/node_modules/undici/lib/mock/snapshot-agent.js
new file mode 100644
index 0000000..8028011
--- /dev/null
+++ b/vanilla/node_modules/undici/lib/mock/snapshot-agent.js
@@ -0,0 +1,353 @@
+'use strict'
+
+const Agent = require('../dispatcher/agent')
+const MockAgent = require('./mock-agent')
+const { SnapshotRecorder } = require('./snapshot-recorder')
+const WrapHandler = require('../handler/wrap-handler')
+const { InvalidArgumentError, UndiciError } = require('../core/errors')
+const { validateSnapshotMode } = require('./snapshot-utils')
+
+const kSnapshotRecorder = Symbol('kSnapshotRecorder')
+const kSnapshotMode = Symbol('kSnapshotMode')
+const kSnapshotPath = Symbol('kSnapshotPath')
+const kSnapshotLoaded = Symbol('kSnapshotLoaded')
+const kRealAgent = Symbol('kRealAgent')
+
+// Static flag to ensure warning is only emitted once per process
+let warningEmitted = false
+
+class SnapshotAgent extends MockAgent {
+  constructor (opts = {}) {
+    // Emit experimental warning only once
+    if (!warningEmitted) {
+      process.emitWarning(
+        'SnapshotAgent is experimental and subject to change',
+        'ExperimentalWarning'
+      )
+      warningEmitted = true
+    }
+
+    const {
+      mode = 'record',
+      snapshotPath = null,
+      ...mockAgentOpts
+    } = opts
+
+    super(mockAgentOpts)
+
+    validateSnapshotMode(mode)
+
+    // Validate snapshotPath is provided when required
+    if ((mode === 'playback' || mode === 'update') && !snapshotPath) {
+      throw new InvalidArgumentError(`snapshotPath is required when mode is '${mode}'`)
+    }
+
+    this[kSnapshotMode] = mode
+    this[kSnapshotPath] = snapshotPath
+
+    this[kSnapshotRecorder] = new SnapshotRecorder({
+      snapshotPath: this[kSnapshotPath],
+      mode: this[kSnapshotMode],
+      maxSnapshots: opts.maxSnapshots,
+      autoFlush: opts.autoFlush,
+      flushInterval: opts.flushInterval,
+      matchHeaders: opts.matchHeaders,
+      ignoreHeaders: opts.ignoreHeaders,
+      excludeHeaders: opts.excludeHeaders,
+      matchBody: opts.matchBody,
+      matchQuery: opts.matchQuery,
+      caseSensitive: opts.caseSensitive,
+      shouldRecord: opts.shouldRecord,
+      shouldPlayback: opts.shouldPlayback,
+      excludeUrls: opts.excludeUrls
+    })
+    this[kSnapshotLoaded] = false
+
+    // For recording/update mode, we need a real agent to make actual requests
+    // For playback mode, we need a real agent if there are excluded URLs
+    if (this[kSnapshotMode] === 'record' || this[kSnapshotMode] === 'update' ||
+        (this[kSnapshotMode] === 'playback' && opts.excludeUrls && opts.excludeUrls.length > 0)) {
+      this[kRealAgent] = new Agent(opts)
+    }
+
+    // Auto-load snapshots in playback/update mode
+    if ((this[kSnapshotMode] === 'playback' || this[kSnapshotMode] === 'update') && this[kSnapshotPath]) {
+      this.loadSnapshots().catch(() => {
+        // Ignore load errors - file might not exist yet
+      })
+    }
+  }
+
+  dispatch (opts, handler) {
+    handler = WrapHandler.wrap(handler)
+    const mode = this[kSnapshotMode]
+
+    // Check if URL should be excluded (pass through without mocking/recording)
+    if (this[kSnapshotRecorder].isUrlExcluded(opts)) {
+      // Real agent is guaranteed by constructor when excludeUrls is configured
+      return this[kRealAgent].dispatch(opts, handler)
+    }
+
+    if (mode === 'playback' || mode === 'update') {
+      // Ensure snapshots are loaded
+      if (!this[kSnapshotLoaded]) {
+        // Need to load asynchronously, delegate to async version
+        return this.#asyncDispatch(opts, handler)
+      }
+
+      // Try to find existing snapshot (synchronous)
+      const snapshot = this[kSnapshotRecorder].findSnapshot(opts)
+
+      if (snapshot) {
+        // Use recorded response (synchronous)
+        return this.#replaySnapshot(snapshot, handler)
+      } else if (mode === 'update') {
+        // Make real request and record it (async required)
+        return this.#recordAndReplay(opts, handler)
+      } else {
+        // Playback mode but no snapshot found
+        const error = new UndiciError(`No snapshot found for ${opts.method || 'GET'} ${opts.path}`)
+        if (handler.onError) {
+          handler.onError(error)
+          return
+        }
+        throw error
+      }
+    } else if (mode === 'record') {
+      // Record mode - make real request and save response (async required)
+      return this.#recordAndReplay(opts, handler)
+    }
+  }
+
+  /**
+   * Async version of dispatch for when we need to load snapshots first
+   */
+  async #asyncDispatch (opts, handler) {
+    await this.loadSnapshots()
+    return this.dispatch(opts, handler)
+  }
+
+  /**
+   * Records a real request and replays the response
+   */
+  #recordAndReplay (opts, handler) {
+    const responseData = {
+      statusCode: null,
+      headers: {},
+      trailers: {},
+      body: []
+    }
+
+    const self = this // Capture 'this' context for use within nested handler callbacks
+
+    const recordingHandler = {
+      onRequestStart (controller, context) {
+        return handler.onRequestStart(controller, { ...context, history: this.history })
+      },
+
+      onRequestUpgrade (controller, statusCode, headers, socket) {
+        return handler.onRequestUpgrade(controller, statusCode, headers, socket)
+      },
+
+      onResponseStart (controller, statusCode, headers, statusMessage) {
+        responseData.statusCode = statusCode
+        responseData.headers = headers
+        return handler.onResponseStart(controller, statusCode, headers, statusMessage)
+      },
+
+      onResponseData (controller, chunk) {
+        responseData.body.push(chunk)
+        return handler.onResponseData(controller, chunk)
+      },
+
+      onResponseEnd (controller, trailers) {
+        responseData.trailers = trailers
+
+        // Record the interaction using captured 'self' context (fire and forget)
+        const responseBody = Buffer.concat(responseData.body)
+        self[kSnapshotRecorder].record(opts, {
+          statusCode: responseData.statusCode,
+          headers: responseData.headers,
+          body: responseBody,
+          trailers: responseData.trailers
+        })
+          .then(() => handler.onResponseEnd(controller, trailers))
+          .catch((error) => handler.onResponseError(controller, error))
+      }
+    }
+
+    // Use composed agent if available (includes interceptors), otherwise use real agent
+    const agent = this[kRealAgent]
+    return agent.dispatch(opts, recordingHandler)
+  }
+
+  /**
+   * Replays a recorded response
+   *
+   * @param {Object} snapshot - The recorded snapshot to replay.
+   * @param {Object} handler - The handler to call with the response data.
+   * @returns {void}
+   */
+  #replaySnapshot (snapshot, handler) {
+    try {
+      const { response } = snapshot
+
+      const controller = {
+        pause () { },
+        resume () { },
+        abort (reason) {
+          this.aborted = true
+          this.reason = reason
+        },
+
+        aborted: false,
+        paused: false
+      }
+
+      handler.onRequestStart(controller)
+
+      handler.onResponseStart(controller, response.statusCode, response.headers)
+
+      // Body is always stored as base64 string
+      const body = Buffer.from(response.body, 'base64')
+      handler.onResponseData(controller, body)
+
+      handler.onResponseEnd(controller, response.trailers)
+    } catch (error) {
+      handler.onError?.(error)
+    }
+  }
+
+  /**
+   * Loads snapshots from file
+   *
+   * @param {string} [filePath] - Optional file path to load snapshots from.
+   * @returns {Promise<void>} - Resolves when snapshots are loaded.
+   */
+  async loadSnapshots (filePath) {
+    await this[kSnapshotRecorder].loadSnapshots(filePath || this[kSnapshotPath])
+    this[kSnapshotLoaded] = true
+
+    // In playback mode, set up MockAgent interceptors for all snapshots
+    if (this[kSnapshotMode] === 'playback') {
+      this.#setupMockInterceptors()
+    }
+  }
+
+  /**
+   * Saves snapshots to file
+   *
+   * @param {string} [filePath] - Optional file path to save snapshots to.
+   * @returns {Promise<void>} - Resolves when snapshots are saved.
+   */
+  async saveSnapshots (filePath) {
+    return this[kSnapshotRecorder].saveSnapshots(filePath || this[kSnapshotPath])
+  }
+
+  /**
+   * Sets up MockAgent interceptors based on recorded snapshots.
+   *
+   * This method creates MockAgent interceptors for each recorded snapshot,
+   * allowing the SnapshotAgent to fall back to MockAgent's standard intercept
+   * mechanism in playback mode. Each interceptor is configured to persist
+   * (remain active for multiple requests) and responds with the recorded
+   * response data.
+   *
+   * Called automatically when loading snapshots in playback mode.
+   *
+   * @returns {void}
+   */
+  #setupMockInterceptors () {
+    for (const snapshot of this[kSnapshotRecorder].getSnapshots()) {
+      const { request, responses, response } = snapshot
+      const url = new URL(request.url)
+
+      const mockPool = this.get(url.origin)
+
+      // Handle both new format (responses array) and legacy format (response object)
+      const responseData = responses ? responses[0] : response
+      if (!responseData) continue
+
+      mockPool.intercept({
+        path: url.pathname + url.search,
+        method: request.method,
+        headers: request.headers,
+        body: request.body
+      }).reply(responseData.statusCode, responseData.body, {
+        headers: responseData.headers,
+        trailers: responseData.trailers
+      }).persist()
+    }
+  }
+
+  /**
+   * Gets the snapshot recorder
+   * @return {SnapshotRecorder} - The snapshot recorder instance
+   */
+  getRecorder () {
+    return this[kSnapshotRecorder]
+  }
+
+  /**
+   * Gets the current mode
+   * @return {import('./snapshot-utils').SnapshotMode} - The current snapshot mode
+   */
+  getMode () {
+    return this[kSnapshotMode]
+  }
+
+  /**
+   * Clears all snapshots
+   * @returns {void}
+   */
+  clearSnapshots () {
+    this[kSnapshotRecorder].clear()
+  }
+
+  /**
+   * Resets call counts for all snapshots (useful for test cleanup)
+   * @returns {void}
+   */
+  resetCallCounts () {
+    this[kSnapshotRecorder].resetCallCounts()
+  }
+
+  /**
+   * Deletes a specific snapshot by request options
+   * @param {import('./snapshot-recorder').SnapshotRequestOptions} requestOpts - Request options to identify the snapshot
+   * @return {Promise<boolean>} - Returns true if the snapshot was deleted, false if not found
+   */
+  deleteSnapshot (requestOpts) {
+    return this[kSnapshotRecorder].deleteSnapshot(requestOpts)
+  }
+
+  /**
+   * Gets information about a specific snapshot
+   * @returns {import('./snapshot-recorder').SnapshotInfo|null} - Snapshot information or null if not found
+   */
+  getSnapshotInfo (requestOpts) {
+    return this[kSnapshotRecorder].getSnapshotInfo(requestOpts)
+  }
+
+  /**
+   * Replaces all snapshots with new data (full replacement)
+   * @param {Array<{hash: string; snapshot: import('./snapshot-recorder').SnapshotEntryshotEntry}>|Record<string, import('./snapshot-recorder').SnapshotEntry>} snapshotData - New snapshot data to replace existing snapshots
+   * @returns {void}
+   */
+  replaceSnapshots (snapshotData) {
+    this[kSnapshotRecorder].replaceSnapshots(snapshotData)
+  }
+
+  /**
+   * Closes the agent, saving snapshots and cleaning up resources.
+   *
+   * @returns {Promise<void>}
+   */
+  async close () {
+    await this[kSnapshotRecorder].close()
+    await this[kRealAgent]?.close()
+    await super.close()
+  }
+}
+
+module.exports = SnapshotAgent