84 lines
2.9 KiB
TypeScript
84 lines
2.9 KiB
TypeScript
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// Copyright (c) Microsoft Corporation.
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// Licensed under the MIT license.
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import * as fs from 'fs';
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import { Page } from './Page';
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import { assert, helper, debugError } from '../helper';
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import { Protocol } from './protocol';
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import * as dom from '../dom';
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import * as types from '../types';
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const writeFileAsync = helper.promisify(fs.writeFile);
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export class Screenshotter {
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private _queue = new TaskQueue();
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async screenshotPage(page: Page, options: types.ScreenshotOptions = {}): Promise<Buffer | string> {
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const format = helper.validateScreeshotOptions(options);
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assert(format === 'png', 'Only png format is supported');
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return this._queue.postTask(async () => {
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const params: Protocol.Page.snapshotRectParameters = { x: 0, y: 0, width: 800, height: 600, coordinateSystem: 'Page' };
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if (options.fullPage) {
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const pageSize = await page.evaluate(() =>
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({
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width: document.body.scrollWidth,
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height: document.body.scrollHeight
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}));
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Object.assign(params, pageSize);
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} else if (options.clip) {
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Object.assign(params, options.clip);
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} else if (page.viewport()) {
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Object.assign(params, page.viewport());
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}
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const [, result] = await Promise.all([
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page.browser()._activatePage(page),
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page._session.send('Page.snapshotRect', params),
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]).catch(e => {
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debugError('Failed to take screenshot: ' + e);
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throw e;
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});
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const prefix = 'data:image/png;base64,';
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const buffer = Buffer.from(result.dataURL.substr(prefix.length), 'base64');
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if (options.path)
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await writeFileAsync(options.path, buffer);
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return buffer;
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});
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}
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async screenshotElement(page: Page, handle: dom.ElementHandle, options: types.ScreenshotOptions = {}): Promise<string | Buffer> {
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const format = helper.validateScreeshotOptions(options);
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assert(format === 'png', 'Only png format is supported');
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return this._queue.postTask(async () => {
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const objectId = (handle._remoteObject as Protocol.Runtime.RemoteObject).objectId;
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page._session.send('DOM.getDocument');
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const {nodeId} = await page._session.send('DOM.requestNode', {objectId});
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const [, result] = await Promise.all([
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page.browser()._activatePage(page),
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page._session.send('Page.snapshotNode', {nodeId})
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]).catch(e => {
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debugError('Failed to take screenshot: ' + e);
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throw e;
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});
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const prefix = 'data:image/png;base64,';
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const buffer = Buffer.from(result.dataURL.substr(prefix.length), 'base64');
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if (options.path)
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await writeFileAsync(options.path, buffer);
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return buffer;
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});
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}
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}
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class TaskQueue {
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private _chain: Promise<any>;
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constructor() {
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this._chain = Promise.resolve();
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}
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postTask(task: () => any): Promise<any> {
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const result = this._chain.then(task);
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this._chain = result.catch(() => {});
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return result;
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}
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}
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