/** * Copyright 2017 Google Inc. All rights reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import { assert } from './assert.js'; import { helper } from './helper.js'; import { createJSHandle, JSHandle, ElementHandle } from './JSHandle.js'; import { CDPSession } from './Connection.js'; import { DOMWorld } from './DOMWorld.js'; import { Frame } from './FrameManager.js'; import { Protocol } from 'devtools-protocol'; import { EvaluateHandleFn, SerializableOrJSHandle } from './EvalTypes.js'; /** * @public */ export const EVALUATION_SCRIPT_URL = '__puppeteer_evaluation_script__'; const SOURCE_URL_REGEX = /^[\040\t]*\/\/[@#] sourceURL=\s*(\S*?)\s*$/m; /** * This class represents a context for JavaScript execution. A [Page] might have * many execution contexts: * - each * {@link https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe | * frame } has "default" execution context that is always created after frame is * attached to DOM. This context is returned by the * {@link frame.executionContext()} method. * - {@link https://developer.chrome.com/extensions | Extension}'s content scripts * create additional execution contexts. * * Besides pages, execution contexts can be found in * {@link https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API | * workers }. * * @public */ export class ExecutionContext { /** * @internal */ _client: CDPSession; /** * @internal */ _world: DOMWorld; /** * @internal */ _contextId: number; /** * @internal */ _contextName: string; /** * @internal */ constructor( client: CDPSession, contextPayload: Protocol.Runtime.ExecutionContextDescription, world: DOMWorld ) { this._client = client; this._world = world; this._contextId = contextPayload.id; this._contextName = contextPayload.name; } /** * @remarks * * Not every execution context is associated with a frame. For * example, workers and extensions have execution contexts that are not * associated with frames. * * @returns The frame associated with this execution context. */ frame(): Frame | null { return this._world ? this._world.frame() : null; } /** * @remarks * If the function passed to the `executionContext.evaluate` returns a * Promise, then `executionContext.evaluate` would wait for the promise to * resolve and return its value. If the function passed to the * `executionContext.evaluate` returns a non-serializable value, then * `executionContext.evaluate` resolves to `undefined`. DevTools Protocol also * supports transferring some additional values that are not serializable by * `JSON`: `-0`, `NaN`, `Infinity`, `-Infinity`, and bigint literals. * * * @example * ```js * const executionContext = await page.mainFrame().executionContext(); * const result = await executionContext.evaluate(() => Promise.resolve(8 * 7))* ; * console.log(result); // prints "56" * ``` * * @example * A string can also be passed in instead of a function. * * ```js * console.log(await executionContext.evaluate('1 + 2')); // prints "3" * ``` * * @example * {@link JSHandle} instances can be passed as arguments to the * `executionContext.* evaluate`: * ```js * const oneHandle = await executionContext.evaluateHandle(() => 1); * const twoHandle = await executionContext.evaluateHandle(() => 2); * const result = await executionContext.evaluate( * (a, b) => a + b, oneHandle, * twoHandle * ); * await oneHandle.dispose(); * await twoHandle.dispose(); * console.log(result); // prints '3'. * ``` * @param pageFunction - a function to be evaluated in the `executionContext` * @param args - argument to pass to the page function * * @returns A promise that resolves to the return value of the given function. */ async evaluate( pageFunction: Function | string, ...args: unknown[] ): Promise { return await this._evaluateInternal( true, pageFunction, ...args ); } /** * @remarks * The only difference between `executionContext.evaluate` and * `executionContext.evaluateHandle` is that `executionContext.evaluateHandle` * returns an in-page object (a {@link JSHandle}). * If the function passed to the `executionContext.evaluateHandle` returns a * Promise, then `executionContext.evaluateHandle` would wait for the * promise to resolve and return its value. * * @example * ```js * const context = await page.mainFrame().executionContext(); * const aHandle = await context.evaluateHandle(() => Promise.resolve(self)); * aHandle; // Handle for the global object. * ``` * * @example * A string can also be passed in instead of a function. * * ```js * // Handle for the '3' * object. * const aHandle = await context.evaluateHandle('1 + 2'); * ``` * * @example * JSHandle instances can be passed as arguments * to the `executionContext.* evaluateHandle`: * * ```js * const aHandle = await context.evaluateHandle(() => document.body); * const resultHandle = await context.evaluateHandle(body => body.innerHTML, * aHandle); * console.log(await resultHandle.jsonValue()); // prints body's innerHTML * await aHandle.dispose(); * await resultHandle.dispose(); * ``` * * @param pageFunction - a function to be evaluated in the `executionContext` * @param args - argument to pass to the page function * * @returns A promise that resolves to the return value of the given function * as an in-page object (a {@link JSHandle}). */ async evaluateHandle( pageFunction: EvaluateHandleFn, ...args: SerializableOrJSHandle[] ): Promise { return this._evaluateInternal(false, pageFunction, ...args); } private async _evaluateInternal( returnByValue: boolean, pageFunction: Function | string, ...args: unknown[] ): Promise { const suffix = `//# sourceURL=${EVALUATION_SCRIPT_URL}`; if (helper.isString(pageFunction)) { const contextId = this._contextId; const expression = pageFunction; const expressionWithSourceUrl = SOURCE_URL_REGEX.test(expression) ? expression : expression + '\n' + suffix; const { exceptionDetails, result: remoteObject } = await this._client .send('Runtime.evaluate', { expression: expressionWithSourceUrl, contextId, returnByValue, awaitPromise: true, userGesture: true, }) .catch(rewriteError); if (exceptionDetails) throw new Error( 'Evaluation failed: ' + helper.getExceptionMessage(exceptionDetails) ); return returnByValue ? helper.valueFromRemoteObject(remoteObject) : createJSHandle(this, remoteObject); } if (typeof pageFunction !== 'function') throw new Error( `Expected to get |string| or |function| as the first argument, but got "${pageFunction}" instead.` ); let functionText = pageFunction.toString(); try { new Function('(' + functionText + ')'); } catch (error) { // This means we might have a function shorthand. Try another // time prefixing 'function '. if (functionText.startsWith('async ')) functionText = 'async function ' + functionText.substring('async '.length); else functionText = 'function ' + functionText; try { new Function('(' + functionText + ')'); } catch (error) { // We tried hard to serialize, but there's a weird beast here. throw new Error('Passed function is not well-serializable!'); } } let callFunctionOnPromise; try { callFunctionOnPromise = this._client.send('Runtime.callFunctionOn', { functionDeclaration: functionText + '\n' + suffix + '\n', executionContextId: this._contextId, arguments: args.map(convertArgument.bind(this)), returnByValue, awaitPromise: true, userGesture: true, }); } catch (error) { if ( error instanceof TypeError && error.message.startsWith('Converting circular structure to JSON') ) error.message += ' Are you passing a nested JSHandle?'; throw error; } const { exceptionDetails, result: remoteObject, } = await callFunctionOnPromise.catch(rewriteError); if (exceptionDetails) throw new Error( 'Evaluation failed: ' + helper.getExceptionMessage(exceptionDetails) ); return returnByValue ? helper.valueFromRemoteObject(remoteObject) : createJSHandle(this, remoteObject); /** * @param {*} arg * @returns {*} * @this {ExecutionContext} */ function convertArgument(this: ExecutionContext, arg: unknown): unknown { if (typeof arg === 'bigint') // eslint-disable-line valid-typeof return { unserializableValue: `${arg.toString()}n` }; if (Object.is(arg, -0)) return { unserializableValue: '-0' }; if (Object.is(arg, Infinity)) return { unserializableValue: 'Infinity' }; if (Object.is(arg, -Infinity)) return { unserializableValue: '-Infinity' }; if (Object.is(arg, NaN)) return { unserializableValue: 'NaN' }; const objectHandle = arg && arg instanceof JSHandle ? arg : null; if (objectHandle) { if (objectHandle._context !== this) throw new Error( 'JSHandles can be evaluated only in the context they were created!' ); if (objectHandle._disposed) throw new Error('JSHandle is disposed!'); if (objectHandle._remoteObject.unserializableValue) return { unserializableValue: objectHandle._remoteObject.unserializableValue, }; if (!objectHandle._remoteObject.objectId) return { value: objectHandle._remoteObject.value }; return { objectId: objectHandle._remoteObject.objectId }; } return { value: arg }; } function rewriteError(error: Error): Protocol.Runtime.EvaluateResponse { if (error.message.includes('Object reference chain is too long')) return { result: { type: 'undefined' } }; if (error.message.includes("Object couldn't be returned by value")) return { result: { type: 'undefined' } }; if ( error.message.endsWith('Cannot find context with specified id') || error.message.endsWith('Inspected target navigated or closed') ) throw new Error( 'Execution context was destroyed, most likely because of a navigation.' ); throw error; } } /** * This method iterates the JavaScript heap and finds all the objects with the * given prototype. * @remarks * @example * ```js * // Create a Map object * await page.evaluate(() => window.map = new Map()); * // Get a handle to the Map object prototype * const mapPrototype = await page.evaluateHandle(() => Map.prototype); * // Query all map instances into an array * const mapInstances = await page.queryObjects(mapPrototype); * // Count amount of map objects in heap * const count = await page.evaluate(maps => maps.length, mapInstances); * await mapInstances.dispose(); * await mapPrototype.dispose(); * ``` * * @param prototypeHandle - a handle to the object prototype * * @returns A handle to an array of objects with the given prototype. */ async queryObjects(prototypeHandle: JSHandle): Promise { assert(!prototypeHandle._disposed, 'Prototype JSHandle is disposed!'); assert( prototypeHandle._remoteObject.objectId, 'Prototype JSHandle must not be referencing primitive value' ); const response = await this._client.send('Runtime.queryObjects', { prototypeObjectId: prototypeHandle._remoteObject.objectId, }); return createJSHandle(this, response.objects); } /** * @internal */ async _adoptBackendNodeId( backendNodeId: Protocol.DOM.BackendNodeId ): Promise { const { object } = await this._client.send('DOM.resolveNode', { backendNodeId: backendNodeId, executionContextId: this._contextId, }); return createJSHandle(this, object) as ElementHandle; } /** * @internal */ async _adoptElementHandle( elementHandle: ElementHandle ): Promise { assert( elementHandle.executionContext() !== this, 'Cannot adopt handle that already belongs to this execution context' ); assert(this._world, 'Cannot adopt handle without DOMWorld'); const nodeInfo = await this._client.send('DOM.describeNode', { objectId: elementHandle._remoteObject.objectId, }); return this._adoptBackendNodeId(nodeInfo.node.backendNodeId); } }