puppeteer/lib/ExecutionContext.js
Andrey Lushnikov e8bb26eb95
refactor: split out classes into files (#3773)
New files:
- LifecycleWatcher
- JSHandle
2019-01-14 20:34:50 -08:00

182 lines
6.5 KiB
JavaScript

/**
* 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.
*/
const {helper, assert} = require('./helper');
const {createJSHandle, JSHandle} = require('./JSHandle');
const EVALUATION_SCRIPT_URL = '__puppeteer_evaluation_script__';
const SOURCE_URL_REGEX = /^[\040\t]*\/\/[@#] sourceURL=\s*(\S*?)\s*$/m;
class ExecutionContext {
/**
* @param {!Puppeteer.CDPSession} client
* @param {!Protocol.Runtime.ExecutionContextDescription} contextPayload
* @param {?Puppeteer.Frame} frame
*/
constructor(client, contextPayload, frame) {
this._client = client;
this._frame = frame;
this._contextId = contextPayload.id;
this._isDefault = contextPayload.auxData ? !!contextPayload.auxData['isDefault'] : false;
}
/**
* @return {?Puppeteer.Frame}
*/
frame() {
return this._frame;
}
/**
* @param {Function|string} pageFunction
* @param {...*} args
* @return {!Promise<(!Object|undefined)>}
*/
async evaluate(pageFunction, ...args) {
const handle = await this.evaluateHandle(pageFunction, ...args);
const result = await handle.jsonValue().catch(error => {
if (error.message.includes('Object reference chain is too long'))
return;
if (error.message.includes('Object couldn\'t be returned by value'))
return;
throw error;
});
await handle.dispose();
return result;
}
/**
* @param {Function|string} pageFunction
* @param {...*} args
* @return {!Promise<!JSHandle>}
*/
async evaluateHandle(pageFunction, ...args) {
const suffix = `//# sourceURL=${EVALUATION_SCRIPT_URL}`;
if (helper.isString(pageFunction)) {
const contextId = this._contextId;
const expression = /** @type {string} */ (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: false,
awaitPromise: true,
userGesture: true
}).catch(rewriteError);
if (exceptionDetails)
throw new Error('Evaluation failed: ' + helper.getExceptionMessage(exceptionDetails));
return createJSHandle(this, remoteObject);
}
if (typeof pageFunction !== 'function')
throw new Error('The following is not a function: ' + pageFunction);
let functionText = pageFunction.toString();
try {
new Function('(' + functionText + ')');
} catch (e1) {
// 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 (e2) {
// 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: false,
awaitPromise: true,
userGesture: true
});
} catch (err) {
if (err instanceof TypeError && err.message === 'Converting circular structure to JSON')
err.message += ' Are you passing a nested JSHandle?';
throw err;
}
const { exceptionDetails, result: remoteObject } = await callFunctionOnPromise.catch(rewriteError);
if (exceptionDetails)
throw new Error('Evaluation failed: ' + helper.getExceptionMessage(exceptionDetails));
return createJSHandle(this, remoteObject);
/**
* @param {*} arg
* @return {*}
* @this {ExecutionContext}
*/
function convertArgument(arg) {
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 };
}
/**
* @param {!Error} error
* @return {!Protocol.Runtime.evaluateReturnValue}
*/
function rewriteError(error) {
if (error.message.endsWith('Cannot find context with specified id'))
throw new Error('Execution context was destroyed, most likely because of a navigation.');
throw error;
}
}
/**
* @param {!JSHandle} prototypeHandle
* @return {!Promise<!JSHandle>}
*/
async queryObjects(prototypeHandle) {
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);
}
}
helper.tracePublicAPI(ExecutionContext);
module.exports = {ExecutionContext, EVALUATION_SCRIPT_URL};