feat(Network): implement request.redirectChain() api (#2194)

The request.redirectChain() returns all the requests issued to fetch
the resource.

Fixes #1816.

docs/api.md

@@ -208,6 +208,7 @@
   * [request.headers()](#requestheaders)
   * [request.method()](#requestmethod)
   * [request.postData()](#requestpostdata)
+  * [request.redirectChain()](#requestredirectchain)
   * [request.resourceType()](#requestresourcetype)
   * [request.respond(response)](#requestrespondresponse)
   * [request.response()](#requestresponse)
@@ -2379,6 +2380,33 @@ page.on('requestfailed', request => {
 #### request.postData()
 - returns: <[string]> Request's post body, if any.
 
+#### request.redirectChain()
+- returns: <[Array]<[Request]>>
+
+A `redirectChain` is a chain of requests initiated to fetch a resource.
+- If there are no redirects and the request was successful, the chain will be empty.
+- If a server responds with at least a single redirect, then the chain will
+contain all the requests that were redirected.
+
+`redirectChain` is shared between all the requests of the same chain.
+
+For example, if the website `http://example.com` has a single redirect to
+`https://example.com`, then the chain will contain one request:
+
+```js
+const response = await page.goto('http://example.com');
+const chain = response.request().redirectChain();
+console.log(chain.length); // 1
+console.log(chain[0].url()); // 'http://example.com'
+```
+
+If the website `https://google.com` has no redirects, then the chain will be empty:
+```js
+const response = await page.goto('https://google.com');
+const chain = response.request().redirectChain();
+console.log(chain.length); // 0
+```
+
 #### request.resourceType()
 - returns: <[string]>
 

lib/NetworkManager.js

@@ -154,7 +154,7 @@ class NetworkManager extends EventEmitter {
       const request = this._interceptionIdToRequest.get(event.interceptionId);
       if (request) {
         this._handleRequestRedirect(request, event.responseStatusCode, event.responseHeaders, false /* fromDiskCache */, false /* fromServiceWorker */, null /* securityDetails */);
-        this._handleRequestStart(request._requestId, event.interceptionId, event.redirectUrl, event.resourceType, event.request, event.frameId);
+        this._handleRequestStart(request._requestId, event.interceptionId, event.redirectUrl, event.resourceType, event.request, event.frameId, request._redirectChain);
       }
       return;
     }
@@ -162,10 +162,10 @@ class NetworkManager extends EventEmitter {
     const requestId = this._requestHashToRequestIds.firstValue(requestHash);
     if (requestId) {
       this._requestHashToRequestIds.delete(requestHash, requestId);
-      this._handleRequestStart(requestId, event.interceptionId, event.request.url, event.resourceType, event.request, event.frameId);
+      this._handleRequestStart(requestId, event.interceptionId, event.request.url, event.resourceType, event.request, event.frameId, []);
     } else {
       this._requestHashToInterceptionIds.set(requestHash, event.interceptionId);
-      this._handleRequestStart(null, event.interceptionId, event.request.url, event.resourceType, event.request, event.frameId);
+      this._handleRequestStart(null, event.interceptionId, event.request.url, event.resourceType, event.request, event.frameId, []);
     }
   }
 
@@ -189,6 +189,7 @@ class NetworkManager extends EventEmitter {
   _handleRequestRedirect(request, redirectStatus, redirectHeaders, fromDiskCache, fromServiceWorker, securityDetails) {
     const response = new Response(this._client, request, redirectStatus, redirectHeaders, fromDiskCache, fromServiceWorker, securityDetails);
     request._response = response;
+    request._redirectChain.push(request);
     this._requestIdToRequest.delete(request._requestId);
     this._interceptionIdToRequest.delete(request._interceptionId);
     this._attemptedAuthentications.delete(request._interceptionId);
@@ -203,12 +204,13 @@ class NetworkManager extends EventEmitter {
    * @param {string} resourceType
    * @param {!Object} requestPayload
    * @param {?string} frameId
+   * @param {!Array<!Request>} redirectChain
    */
-  _handleRequestStart(requestId, interceptionId, url, resourceType, requestPayload, frameId) {
+  _handleRequestStart(requestId, interceptionId, url, resourceType, requestPayload, frameId, redirectChain) {
     let frame = null;
     if (frameId)
       frame = this._frameManager.frame(frameId);
-    const request = new Request(this._client, requestId, interceptionId, this._userRequestInterceptionEnabled, url, resourceType, requestPayload, frame);
+    const request = new Request(this._client, requestId, interceptionId, this._userRequestInterceptionEnabled, url, resourceType, requestPayload, frame, redirectChain);
     if (requestId)
       this._requestIdToRequest.set(requestId, request);
     if (interceptionId)
@@ -236,13 +238,16 @@ class NetworkManager extends EventEmitter {
       }
       return;
     }
+    let redirectChain = [];
     if (event.redirectResponse) {
       const request = this._requestIdToRequest.get(event.requestId);
       // If we connect late to the target, we could have missed the requestWillBeSent event.
-      if (request)
+      if (request) {
         this._handleRequestRedirect(request, event.redirectResponse.status, event.redirectResponse.headers, event.redirectResponse.fromDiskCache, event.redirectResponse.fromServiceWorker, event.redirectResponse.securityDetails);
+        redirectChain = request._redirectChain;
+      }
     }
-    this._handleRequestStart(event.requestId, null, event.request.url, event.type, event.request, event.frameId);
+    this._handleRequestStart(event.requestId, null, event.request.url, event.type, event.request, event.frameId, redirectChain);
   }
 
   /**
@@ -303,8 +308,9 @@ class Request {
    * @param {string} resourceType
    * @param {!Object} payload
    * @param {?Puppeteer.Frame} frame
+   * @param {!Array<!Request>} redirectChain
    */
-  constructor(client, requestId, interceptionId, allowInterception, url, resourceType, payload, frame) {
+  constructor(client, requestId, interceptionId, allowInterception, url, resourceType, payload, frame, redirectChain) {
     this._client = client;
     this._requestId = requestId;
     this._interceptionId = interceptionId;
@@ -322,6 +328,7 @@ class Request {
     this._postData = payload.postData;
     this._headers = {};
     this._frame = frame;
+    this._redirectChain = redirectChain;
     for (const key of Object.keys(payload.headers))
       this._headers[key.toLowerCase()] = payload.headers[key];
 
@@ -377,6 +384,13 @@ class Request {
     return this._frame;
   }
 
+  /**
+   * @return {!Array<!Request>}
+   */
+  redirectChain() {
+    return this._redirectChain.slice();
+  }
+
   /**
    * @return {?{errorText: string}}
    */

test/test.js

@@ -1646,6 +1646,15 @@ describe('Page', function() {
       expect(response.url()).toContain('empty.html');
       expect(requests.length).toBe(5);
       expect(requests[2].resourceType()).toBe('document');
+      // Check redirect chain
+      const redirectChain = response.request().redirectChain();
+      expect(redirectChain.length).toBe(4);
+      expect(redirectChain[0].url()).toContain('/non-existing-page.html');
+      expect(redirectChain[2].url()).toContain('/non-existing-page-3.html');
+      for (let i = 0; i < redirectChain.length; ++i) {
+        const request = redirectChain[i];
+        expect(request.redirectChain().indexOf(request)).toBe(i);
+      }
     });
     it('should be able to abort redirects', async({page, server}) => {
       await page.setRequestInterception(true);
@@ -2948,7 +2957,7 @@ describe('Page', function() {
       page.on('requestfailed', request => events.push(`FAIL ${request.url()}`));
       server.setRedirect('/foo.html', '/empty.html');
       const FOO_URL = server.PREFIX + '/foo.html';
-      await page.goto(FOO_URL);
+      const response = await page.goto(FOO_URL);
       expect(events).toEqual([
         `GET ${FOO_URL}`,
         `302 ${FOO_URL}`,
@@ -2957,6 +2966,11 @@ describe('Page', function() {
         `200 ${server.EMPTY_PAGE}`,
         `DONE ${server.EMPTY_PAGE}`
       ]);
+
+      // Check redirect chain
+      const redirectChain = response.request().redirectChain();
+      expect(redirectChain.length).toBe(1);
+      expect(redirectChain[0].url()).toContain('/foo.html');
     });
   });