Request interception and caching compatibility

docs/api.md

@@ -166,7 +166,7 @@
   * [page.setGeolocation(options)](#pagesetgeolocationoptions)
   * [page.setJavaScriptEnabled(enabled)](#pagesetjavascriptenabledenabled)
   * [page.setOfflineMode(enabled)](#pagesetofflinemodeenabled)
-  * [page.setRequestInterception(value)](#pagesetrequestinterceptionvalue)
+  * [page.setRequestInterception(value[, cacheSafe])](#pagesetrequestinterceptionvalue-cachesafe)
   * [page.setUserAgent(userAgent)](#pagesetuseragentuseragent)
   * [page.setViewport(viewport)](#pagesetviewportviewport)
   * [page.tap(selector)](#pagetapselector)
@@ -2039,8 +2039,9 @@ await page.setGeolocation({latitude: 59.95, longitude: 30.31667});
 - `enabled` <[boolean]> When `true`, enables offline mode for the page.
 - returns: <[Promise]>
 
-#### page.setRequestInterception(value)
+#### page.setRequestInterception(value[, cacheSafe])
 - `value` <[boolean]> Whether to enable request interception.
+- `cacheSafe` <[boolean]> Whether to trust browser caching. If set to false, enabling request interception disables page caching. Defaults to false.
 - returns: <[Promise]>
 
 Activating request interception enables `request.abort`, `request.continue` and

src/common/NetworkManager.ts

@@ -75,6 +75,7 @@ export class NetworkManager extends EventEmitter {
   _credentials?: Credentials = null;
   _attemptedAuthentications = new Set<string>();
   _userRequestInterceptionEnabled = false;
+  _userRequestInterceptionCacheSafe = false;
   _protocolRequestInterceptionEnabled = false;
   _userCacheDisabled = false;
   _requestIdToInterceptionId = new Map<string, string>();
@@ -189,8 +190,12 @@ export class NetworkManager extends EventEmitter {
     await this._updateProtocolCacheDisabled();
   }
 
-  async setRequestInterception(value: boolean): Promise<void> {
+  async setRequestInterception(
+    value: boolean,
+    cacheSafe = false
+  ): Promise<void> {
     this._userRequestInterceptionEnabled = value;
+    this._userRequestInterceptionCacheSafe = cacheSafe;
     await this._updateProtocolRequestInterception();
   }
 
@@ -217,7 +222,9 @@ export class NetworkManager extends EventEmitter {
   async _updateProtocolCacheDisabled(): Promise<void> {
     await this._client.send('Network.setCacheDisabled', {
       cacheDisabled:
-        this._userCacheDisabled || this._userRequestInterceptionEnabled,
+        this._userCacheDisabled ||
+        (this._userRequestInterceptionEnabled &&
+          !this._userRequestInterceptionCacheSafe),
     });
   }
 

src/common/Page.ts

@@ -688,16 +688,16 @@ export class Page extends EventEmitter {
 
   /**
    * @param value - Whether to enable request interception.
+   * @param cacheSafe - Whether to trust browser caching. If set to false,
+   * enabling request interception disables page caching. Defaults to false.
    *
    * @remarks
    * Activating request interception enables {@link HTTPRequest.abort},
    * {@link HTTPRequest.continue} and {@link HTTPRequest.respond} methods.  This
    * provides the capability to modify network requests that are made by a page.
    *
    * Once request interception is enabled, every request will stall unless it's
-   * continued, responded or aborted.
-   *
-   * **NOTE** Enabling request interception disables page caching.
+   * continued, responded or aborted; or completed using the browser cache.
    *
    * @example
    * An example of a naïve request interceptor that aborts all image requests:
@@ -719,8 +719,13 @@ export class Page extends EventEmitter {
    * })();
    * ```
    */
-  async setRequestInterception(value: boolean): Promise<void> {
-    return this._frameManager.networkManager().setRequestInterception(value);
+  async setRequestInterception(
+    value: boolean,
+    cacheSafe = false
+  ): Promise<void> {
+    return this._frameManager
+      .networkManager()
+      .setRequestInterception(value, cacheSafe);
   }
 
   /**