/** * 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 {Protocol} from 'devtools-protocol'; import {CDPSession} from './Connection.js'; import {IsolatedWorld} from './IsolatedWorld.js'; import {JSHandle} from './JSHandle.js'; import {LazyArg} from './LazyArg.js'; import {EvaluateFunc, HandleFor} from './types.js'; import { createJSHandle, getExceptionMessage, isString, valueFromRemoteObject, } from './util.js'; /** * @public */ export const EVALUATION_SCRIPT_URL = 'pptr://__puppeteer_evaluation_script__'; const SOURCE_URL_REGEX = /^[\040\t]*\/\/[@#] sourceURL=\s*(\S*?)\s*$/m; /** * Represents a context for JavaScript execution. * * @example * A {@link Page} can have several execution contexts: * * - Each {@link Frame} of a {@link Page | page} has a "default" execution * context that is always created after frame is attached to DOM. This context * is returned by the {@link Frame.executionContext} method. * - Each {@link https://developer.chrome.com/extensions | Chrome extensions} * creates additional execution contexts to isolate their code. * * @remarks * By definition, each context is isolated from one another, however they are * all able to manipulate non-JavaScript resources (such as DOM). * * @remarks * Besides pages, execution contexts can be found in * {@link WebWorker | workers}. * * @internal */ export class ExecutionContext { /** * @internal */ _client: CDPSession; /** * @internal */ _world?: IsolatedWorld; /** * @internal */ _contextId: number; /** * @internal */ _contextName: string; /** * @internal */ constructor( client: CDPSession, contextPayload: Protocol.Runtime.ExecutionContextDescription, world?: IsolatedWorld ) { this._client = client; this._world = world; this._contextId = contextPayload.id; this._contextName = contextPayload.name; } /** * Evaluates the given function. * * @example * * ```ts * 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: * * ```ts * console.log(await executionContext.evaluate('1 + 2')); // prints "3" * ``` * * @example * Handles can also be passed as `args`. They resolve to their referenced object: * * ```ts * 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 - The function to evaluate. * @param args - Additional arguments to pass into the function. * @returns The result of evaluating the function. If the result is an object, * a vanilla object containing the serializable properties of the result is * returned. */ async evaluate< Params extends unknown[], Func extends EvaluateFunc = EvaluateFunc >( pageFunction: Func | string, ...args: Params ): Promise>> { return await this.#evaluate(true, pageFunction, ...args); } /** * Evaluates the given function. * * Unlike {@link ExecutionContext.evaluate | evaluate}, this method returns a * handle to the result of the function. * * This method may be better suited if the object cannot be serialized (e.g. * `Map`) and requires further manipulation. * * @example * * ```ts * const context = await page.mainFrame().executionContext(); * const handle: JSHandle = await context.evaluateHandle( * () => Promise.resolve(self) * ); * ``` * * @example * A string can also be passed in instead of a function. * * ```ts * const handle: JSHandle = await context.evaluateHandle('1 + 2'); * ``` * * @example * Handles can also be passed as `args`. They resolve to their referenced object: * * ```ts * const bodyHandle: ElementHandle = * await context.evaluateHandle(() => { * return document.body; * }); * const stringHandle: JSHandle = await context.evaluateHandle( * body => body.innerHTML, * body * ); * console.log(await stringHandle.jsonValue()); // prints body's innerHTML * // Always dispose your garbage! :) * await bodyHandle.dispose(); * await stringHandle.dispose(); * ``` * * @param pageFunction - The function to evaluate. * @param args - Additional arguments to pass into the function. * @returns A {@link JSHandle | handle} to the result of evaluating the * function. If the result is a `Node`, then this will return an * {@link ElementHandle | element handle}. */ async evaluateHandle< Params extends unknown[], Func extends EvaluateFunc = EvaluateFunc >( pageFunction: Func | string, ...args: Params ): Promise>>> { return this.#evaluate(false, pageFunction, ...args); } async #evaluate< Params extends unknown[], Func extends EvaluateFunc = EvaluateFunc >( returnByValue: true, pageFunction: Func | string, ...args: Params ): Promise>>; async #evaluate< Params extends unknown[], Func extends EvaluateFunc = EvaluateFunc >( returnByValue: false, pageFunction: Func | string, ...args: Params ): Promise>>>; async #evaluate< Params extends unknown[], Func extends EvaluateFunc = EvaluateFunc >( returnByValue: boolean, pageFunction: Func | string, ...args: Params ): Promise>> | Awaited>> { const suffix = `//# sourceURL=${EVALUATION_SCRIPT_URL}`; if (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: ' + getExceptionMessage(exceptionDetails) ); } return returnByValue ? valueFromRemoteObject(remoteObject) : createJSHandle(this, remoteObject); } 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: await Promise.all(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 += ' Recursive objects are not allowed.'; } throw error; } const {exceptionDetails, result: remoteObject} = await callFunctionOnPromise.catch(rewriteError); if (exceptionDetails) { throw new Error( 'Evaluation failed: ' + getExceptionMessage(exceptionDetails) ); } return returnByValue ? valueFromRemoteObject(remoteObject) : createJSHandle(this, remoteObject); async function convertArgument( this: ExecutionContext, arg: unknown ): Promise { if (arg instanceof LazyArg) { arg = await arg.get(); } 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.executionContext() !== 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}; } } } const 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; };