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Use CDP Page.setDownloadBehavior and headless for demo
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| /** | ||
| * Copyright 2018 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. | ||
| * | ||
| * @author ebidel@ (Eric Bidelman) | ||
| */ | ||
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| /** | ||
| * Note: this approach only works in headful Chrome. | ||
| * Another approach to verifying a file gets downloaded. Shows how to click a | ||
| * file download link and verify that the file gets downloaded in the | ||
| * chrome:downloads page. | ||
| * | ||
| * Install: | ||
| * npm i puppeteer | ||
| * Run: | ||
| * node verify_download2.js | ||
| */ | ||
|
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| const puppeteer = require('puppeteer'); | ||
| const fs = require('fs'); | ||
| const path = require('path'); | ||
| const os = require('os'); | ||
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| const DOWNLOADS_FOLDER = `${os.homedir()}/Downloads`; | ||
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| /** | ||
| * From @xprudhomme. | ||
| * Check if file exists, watching containing directory meanwhile. | ||
| * Resolve if the file exists, or if the file is created before the timeout | ||
| * occurs. | ||
| * @param {string} filePath | ||
| * @param {integer} timeout | ||
| * @returns {!Promise<undefined>} Resolves when file has been created. Rejects | ||
| * if timout is reached. | ||
| */ | ||
| function checkFileExists(filePath, timeout=15000) { | ||
| return new Promise((resolve, reject) => { | ||
| const dir = path.dirname(filePath); | ||
| const basename = path.basename(filePath); | ||
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| const watcher = fs.watch(dir, (eventType, filename) => { | ||
| if (eventType === 'rename' && filename === basename) { | ||
| clearTimeout(timer); | ||
| watcher.close(); | ||
| resolve(); | ||
| } | ||
| }); | ||
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| const timer = setTimeout(() => { | ||
| watcher.close(); | ||
| reject(new Error(' [checkFileExists] File does not exist, and was not created during the timeout delay.')); | ||
| }, timeout); | ||
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| fs.access(filePath, fs.constants.R_OK, err => { | ||
| if (!err) { | ||
| clearTimeout(timer); | ||
| watcher.close(); | ||
| resolve(); | ||
| } | ||
| }); | ||
| }); | ||
| } | ||
|
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| /** | ||
| * @param {!Browser} browser | ||
| * @param {string} url The URL of the download file to wait for. | ||
| * @returns {!Promise<!Object>} Metadata about the latest file in Download Manager. | ||
| */ | ||
| async function waitForFileToDownload(browser, url) { | ||
| const downloadPage = await browser.newPage(); | ||
| // Note: navigating to this page only works in headful chrome. | ||
| await downloadPage.goto('chrome://downloads/'); | ||
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| // Wait for our download to show up in the list by matching on its url. | ||
| const jsHandle = await downloadPage.waitForFunction(downloadUrl => { | ||
| const manager = document.querySelector('downloads-manager'); | ||
| const downloads = manager.items_.length; | ||
| const lastDownload = manager.items_[0]; | ||
| if (downloads && lastDownload.url === downloadUrl && | ||
| lastDownload.state === 'COMPLETE') { | ||
| return manager.items_[0]; | ||
| } | ||
| }, {polling: 100}, url); | ||
|
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| const fileMeta = await jsHandle.jsonValue(); | ||
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| await downloadPage.close(); | ||
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| return fileMeta; | ||
| } | ||
|
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| /** | ||
| * @param {!Browser} browser | ||
| * @param {string} url The url of the page to navigate to. | ||
| * @param {string} text The link with this text to find and click on the page. | ||
| * @returns {!Promise<?string>} The download resource's url. | ||
| */ | ||
| async function clickDownloadLink(browser, url, text) { | ||
| const page = await browser.newPage(); | ||
| await page.goto(url, {waitUntil: 'networkidle2'}); | ||
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| const downloadUrl = await page.evaluate((text) => { | ||
| const link = document.evaluate(`//a[text()="${text}"]`, document, | ||
| null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue; | ||
| if (link) { | ||
| link.click(); | ||
| return link.href; | ||
| } | ||
| return null; | ||
| }, text); | ||
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| await page.close(); | ||
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| return downloadUrl; | ||
| } | ||
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| (async() => { | ||
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| const browser = await puppeteer.launch({ | ||
| headless: false, | ||
| // dumpio: true, | ||
| }); | ||
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| // TODO: setDownloadBehavior would be a good approach, as we could check | ||
| // that the file shows up in the location specified by downloadPath. However, | ||
| // that arg doesn't currently work. | ||
| // const client = await page.target().createCDPSession(); | ||
| // await client.send('Page.setDownloadBehavior', { | ||
| // behavior: 'allow', | ||
| // downloadPath: path.resolve(__dirname, 'downloads'), | ||
| // }); | ||
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| // await client.detach(); | ||
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| // 1. navigate to a page with a bunch links to download. | ||
| // 2. click the "Short Selling (csv)" link on the page. The browser force downloads the file. | ||
| const url = 'https://www.nseindia.com/products/content/equities/equities/homepage_eq.htm'; | ||
| const downloadUrl = await clickDownloadLink(browser, url, 'Short Selling (csv)'); | ||
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| if (!downloadUrl) { | ||
| console.error('Did not find download link!'); | ||
| return; | ||
| } | ||
|
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| // 3. Open chrome:downloads and wait for the file to be downloaded. | ||
| const fileMeta = await waitForFileToDownload(browser, downloadUrl); | ||
| console.log(`"${fileMeta.file_name}" was downloaded`); | ||
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| // 4. Optionally check that the file really ends up in the expected location | ||
| // on the filesystem. | ||
| const exists = await checkFileExists(`${DOWNLOADS_FOLDER}/${fileMeta.file_name}`); | ||
| console.assert(exists, `${fileMeta.file_name} was not downloaded to correct location.`); | ||
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| await browser.close(); | ||
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| })(); |