puppeteer/src/common/ExecutionContext.ts
2022-07-01 11:52:39 +00:00

443 lines
14 KiB
TypeScript

/**
* 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 {assert} from './assert.js';
import {CDPSession} from './Connection.js';
import {DOMWorld} from './DOMWorld.js';
import {ElementHandle} from './ElementHandle.js';
import {Frame} from './FrameManager.js';
import {JSHandle} from './JSHandle.js';
import {EvaluateFunc, HandleFor} from './types.js';
import {
getExceptionMessage,
isString,
valueFromRemoteObject,
createJSHandle,
} from './util.js';
/**
* @public
*/
export const EVALUATION_SCRIPT_URL = 'pptr://__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
* ```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
* {@link JSHandle} instances can be passed as arguments to the
* `executionContext.* evaluate`:
* ```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 - 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<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>
>(
pageFunction: Func | string,
...args: Params
): Promise<Awaited<ReturnType<Func>>> {
return await this.#evaluate(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
* ```ts
* 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.
*
* ```ts
* // Handle for the '3' * object.
* const aHandle = await context.evaluateHandle('1 + 2');
* ```
*
* @example
* JSHandle instances can be passed as arguments
* to the `executionContext.* evaluateHandle`:
*
* ```ts
* 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<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>
>(
pageFunction: Func | string,
...args: Params
): Promise<HandleFor<Awaited<ReturnType<Func>>>> {
return this.#evaluate(false, pageFunction, ...args);
}
async #evaluate<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>
>(
returnByValue: true,
pageFunction: Func | string,
...args: Params
): Promise<Awaited<ReturnType<Func>>>;
async #evaluate<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>
>(
returnByValue: false,
pageFunction: Func | string,
...args: Params
): Promise<HandleFor<Awaited<ReturnType<Func>>>>;
async #evaluate<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>
>(
returnByValue: boolean,
pageFunction: Func | string,
...args: Params
): Promise<HandleFor<Awaited<ReturnType<Func>>> | Awaited<ReturnType<Func>>> {
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);
}
if (typeof pageFunction !== 'function') {
throw new Error(
`Expected to get |string| or |function| as the first argument, but got "${pageFunction}" instead.`
);
}
let functionText = pageFunction.toString();
try {
new Function('(' + functionText + ')');
} catch (error) {
// This means we might have a function shorthand. Try another
// time prefixing 'function '.
if (functionText.startsWith('async ')) {
functionText =
'async function ' + functionText.substring('async '.length);
} else {
functionText = 'function ' + functionText;
}
try {
new Function('(' + functionText + ')');
} catch (error) {
// We tried hard to serialize, but there's a weird beast here.
throw new Error('Passed function is not well-serializable!');
}
}
let callFunctionOnPromise;
try {
callFunctionOnPromise = this._client.send('Runtime.callFunctionOn', {
functionDeclaration: functionText + '\n' + suffix + '\n',
executionContextId: this._contextId,
arguments: args.map(convertArgument.bind(this)),
returnByValue,
awaitPromise: true,
userGesture: true,
});
} catch (error) {
if (
error instanceof TypeError &&
error.message.startsWith('Converting circular structure to JSON')
) {
error.message += ' Recursive objects are not allowed.';
}
throw error;
}
const {exceptionDetails, result: remoteObject} =
await callFunctionOnPromise.catch(rewriteError);
if (exceptionDetails) {
throw new Error(
'Evaluation failed: ' + getExceptionMessage(exceptionDetails)
);
}
return returnByValue
? valueFromRemoteObject(remoteObject)
: createJSHandle(this, remoteObject);
function convertArgument(
this: ExecutionContext,
arg: unknown
): Protocol.Runtime.CallArgument {
if (typeof arg === 'bigint') {
// eslint-disable-line valid-typeof
return {unserializableValue: `${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
* ```ts
* // 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<Prototype>(
prototypeHandle: JSHandle<Prototype>
): Promise<HandleFor<Prototype[]>> {
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) as HandleFor<Prototype[]>;
}
/**
* @internal
*/
async _adoptBackendNodeId(
backendNodeId?: Protocol.DOM.BackendNodeId
): Promise<ElementHandle> {
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<ElementHandle> {
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);
}
}