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Web scraping a stream chat in real-time (puppeteer.js)

I want to get the chat from a stream in real time with web scraping.
Attempting to create a while loop inside of the .then() function of puppeeter doesn't seem to be effective, and in some implementations breaks it all together.
I am able to get the initial scrape to happen, but in all cases the program ends and does not want to follow the while loop I implemented.
Working code WITHOUT while loop
const puppeteer = require ('puppeteer');
//initiating Puppeteer
puppeteer
.launch ()
.then (async browser => {
//opening a new page and navigating to the live stream
const page = await browser.newPage ();
await page.goto ('https://www.younow.com/Ken_Nara24');
await page.waitForSelector ('body');
//manipulating the page's content
let getComments = await page.evaluate (() => {
let comments = document.body.querySelectorAll ('.comment');
let scrapeItems = [];
comments.forEach (item => {
let commentAuthor = item.querySelector ('div.user-card__header.mini-profile-launcher').innerText;
let commentContent = '';
try {
commentContent = item.querySelector ('div.user-card__body.ng-star-inserted').innerText;
} catch (err) {}
scrapeItems.push ({
commentAuthor: commentAuthor,
commentContent: commentContent,
});
});
let items = {
"userComments": scrapeItems,
};
return items;
});
//outputting the scraped data
console.log (getComments);
//closing the browser
await browser.close ();
})
//handling any errors
.catch (function (err) {
console.error (err);
});
All attempts to get that logic looping have been for naught. I cannot find a way or past issue/example that clearly defines how or if such a thing could be done. I have made a few attempts to implement it myself, but nothing has even compiled correctly.
Am I missing something significant here? I just want to essentially listen to a web page and every 3-5 seconds re-scrape it.

If you still need help you could give this way a try.
const puppeteer = require("puppeteer");
let pageScraping = false; /* set scraping to false */
const scraper = async () => {
if (pageScraping == true) return; /* check if already scraping page */
let browser, page;
let pageUrl = 'https://www.younow.com/Ken_Nara24';
try {
pageScraping = true; /* set scraping to true */
browser = await puppeteer.launch({ headless: true });
page = await browser.newPage();
await page.goto(pageUrl, { waitUntil: 'domcontentloaded', timeout: 60000 });
/* wait for chat to be visible */
await page.waitForSelector('.chat', { visible: true, timeout: 60000 });
let getComments = await page.evaluate(() => {
let scrapeComments = [];
let comments = document.querySelectorAll('.comment');
comments.forEach(comment => {
let commentContent = '';
let commentAuthor = comment.querySelector('div[class="user-card__header mini-profile-launcher"]').innerText;
commentContent = comment.querySelector('div[class="user-card__body ng-star-inserted"]').innerText;
scrapeComments.push({
'commentAuthor': commentAuthor,
'commentContent': commentContent,
});
});
return { 'userComments': scrapeComments };
});
console.log(await getComments); /* log comments */
} catch (err) {
console.log(err.message);
} finally {
if (browser) { /* check if browser is open befor trying to close */
await browser.close();
console.log('closing browser');
}
pageScraping = false; /* set scraping to false again */
await setTimeout(scraper, 5000); /* wait 5 seconds befor re-scraping */
}
}
setTimeout(scraper, 5000); /* start scraping */

How Do I Run page.screenshot Inside page.evaluate in Puppeteer?

I am creating a screen scraper that needs to scrape the content of a page and take a screenshot of it. For that I am using Puppeteer, but I am hitting a snag. When I try to call a function that runs page.screenshot inside of page.evaulate I am getting an error that the funtion is not defined.
Here is my code:
async function getContent(clink, ce, networkidle, host, filepath) {
let browser = await puppeteer.launch();
let cpage = await browser.newPage();
await cpage.goto(clink, { waitUntil: networkidle });
let content = await cpage.evaluate((clink, ce, networkidle, host, filepath, pubDate) => {
let results = '';
let enclurl = clink;
takeScreenshot(enclurl, filepath, networkidle)
.then(() => {
console.log("Screenshot taken");
})
.catch((err) => {
console.log("Error occured!");
console.dir(err);
});
results += '<title><![CDATA[' + 'test' + ']]</title>';
results += '<description><![CDATA[' + '<img src="' + host + filepath.slice(1) + '">' + document.querySelector(ce).innerHTML + ']]</description>';
results += '<link>' + clink + '</link>';
results += '<guid>' + clink + '</guid>';
results += '<pubDate>' + pubDate + '</pubDate>';
return results;
}, clink, ce, networkidle, host, filepath, pubDate);
await cpage.close();
await browser.close();
return content;
}
That code should return items before a RSS format xml file is created. The URLs of such files will then be added to WPRobot campaigns. The end goal will be a search engine the uses Wordpress to aggregate the main content of pages with full screenshots of the sources.
The takeScreenshot function is as follows:
async function takeScreenshot(enclurl, filepath, networkidle) {
let browser = await puppeteer.launch();
let page = await browser.newPage();
await page.goto(enclurl, { waitUntil: networkidle });
let buffer = await page.screenshot({
path: filepath
});
await page.close();
await browser.close();
}
Take screenshot works just fine when called outside of page.evaluate. The exact error I get says "takeScreenshot is undefined." I have another function that parses RSS feeds and takes screenshots of their source URLs, but it does not use page.evaluate at all.
I have now added the call to takeScreenshot to an earlier part of my code right before getContent() called but now it seems getContent() always returns as undefined. My new getContent() reads:
async function getContent(clink, ce, networkidle) {
let browser = await puppeteer.launch();
let cpage = await browser.newPage();
await cpage.goto(clink, { waitUntil: networkidle });
let content = await cpage.evaluate((ce) => {
let cefc = ce.charAt(0);
if (cefc != '.') {
ce = '#' + ce;
}
console.log('ce=' + ce);
let results = document.querySelector(ce).innerHTML;
return results;
}, ce);
await cpage.close();
await browser.close();
return content;
}
I am also not seeing console.log('ce=' + ce) being written to the log. After moving the console.log out of the page.evaluate loop it logged the appropriate value for the content which is the HTML of the element with the specified class. Despite that the value of return content remains undefined.

Page.evaluate has a strange and not intuitive way to work:
the code of the function ( in you case: (clink, ce, networkidle, host, filepath, pubDate) => {...} ) is NOT executed in your script. This function in serialized, and send to the headless browser, inside puppeteer.
If you want to call a function from inside the evaluate function, usually (but not in this case) you can use one of this tricks: How to pass a function in Puppeteers .evaluate() method?
BUT in this case... there is a problem!
inside takeScreenshot there are other function that CAN'T BE inside the headless browser of puppeteer, that are puppeteer.launch(); etc. This functions require a lot of dependecies (and same executable)... and can't be passed.
To do what you need, move the screenshot part of your code out of evaluate:
async function getContent(clink, ce, networkidle, host, filepath) {
let browser = await puppeteer.launch();
let cpage = await browser.newPage();
await cpage.goto(clink, { waitUntil: networkidle });
let content = await cpage.evaluate((clink, ce, networkidle, host, filepath, pubDate) => {
let results = '';
let enclurl = clink;
results += '<title><![CDATA[' + 'test' + ']]</title>';
results += '<description><![CDATA[' + '<img src="' + host + '{REPL_ME}' + '">' + document.querySelector(ce).innerHTML + ']]</description>';
results += '<link>' + clink + '</link>';
results += '<guid>' + clink + '</guid>';
results += '<pubDate>' + pubDate + '</pubDate>';
return results;
}, clink, ce, networkidle, host, filepath, pubDate);
await takeScreenshot(enclurl, filepath, networkidle);
content = content.replace('{REPL_ME}', filepath)
await cpage.close();
await browser.close();
return content;
}

Initializing a Puppeteer Browser Outside of Scraping Function

I am very new to puppeteer (I started today). I have some code that is working the way that I want it to except for an issue that I think is making it extremely inefficient. I have a function that links me through potentially thousands of urls that have incremental IDs to pull the name, position, and stats of each player and then inserts that data into a neDB database. Here is my code:
const puppeteer = require('puppeteer');
const Datastore = require('nedb');
const database = new Datastore('database.db');
database.loadDatabase();
async function scrapeProduct(url, id){
const browser = await puppeteer.launch();
const page = await browser.newPage();
await page.goto(url);
let attributes = [];
const [name] = await page.$x('//*[#id="ctl00_ctl00_ctl00_Main_Main_name"]');
const txt = await name.getProperty('innerText');
const playerName = await txt.jsonValue();
attributes.push(playerName);
//Make sure that there is a legitimate player profile before trying to pull a bunch of 'undefined' information.
if(playerName){
const [role] = await page.$x('//*[#id="ctl00_ctl00_ctl00_Main_Main_position"]');
const roleTxt = await role.getProperty('innerText');
const playerRole = await roleTxt.jsonValue();
attributes.push(playerRole);
//Loop through the 12 attributes and pull their values.
for(let i = 1; i < 13; i++){
let vLink = '//*[#id="ctl00_ctl00_ctl00_Main_Main_SectionTabBox"]/div/div/div/div[1]/table/tbody/tr['+i+']/td[2]';
const [e1] = await page.$x(vLink);
const val = await e1.getProperty('innerText');
const skillVal = await val.jsonValue();
attributes.push(skillVal);
}
//Create a player profile to be pushed into the database. (I realize this is very wordy and ugly code)
let player = {
Name: attributes[0],
Role: attributes[1],
Athleticism: attributes[2],
Speed: attributes[3],
Durability: attributes[4],
Work_Ethic: attributes[5],
Stamina: attributes[6],
Strength: attributes[7],
Blocking: attributes[8],
Tackling: attributes[9],
Hands: attributes[10],
Game_Instinct: attributes[11],
Elusiveness: attributes[12],
Technique: attributes[13],
_id: id,
};
database.insert(player);
console.log('player #' + id + " scraped.");
await browser.close();
} else {
console.log("Blank profile");
await browser.close();
}
}
//Making sure the first URL is scraped before moving on to the next URL. (i removed the URL because its unreasonably long and is not important for this part).
(async () => {
for(let i = 0; i <= 1000; i++){
let link = 'https://url.com/Ratings.aspx?rid='+i+'&section=Ratings';
await scrapeProduct(link, i);
}
})();
What I think is making this so inefficient is the fact that everytime scrapeProduct() is called, i create a new browser and create a new page. Instead I believe it would be more efficient to create 1 browser and 1 page and just change the pages URL with
await page.goto(url)
I believe that in order to do what I'm trying to accomplish here, i need to move:
const browser = await puppeteer.launch();
const page = await browser.newPage();
outside of my scrapeProduct() function but i cannot seem to get this to work. Anytime I try i get an error in my function saying that page is not defined. I am very new to puppeteer (started today), I would appreciate any guidance on how to accomplish this. Thank you very much!
TL;DR
How do i create 1 Browser instance and 1 Page instance that a function can use repeatedly by only changing the await page.goto(url) function.

About a year ago I tried to a make an React Native Pokemon Go helper app. Since there wasn't an api for pokemon nest and pokestops I created a server that scraped thesilphroad.com and I found the need to implement something like #Arkan said.
I wanted the server to be able to take multiple request, so I decided to initialize the browser when the server is booted up. When a request is received, the server checks to see if MAX_TABS have been reached. If reached, it waits, if not a new tab is opened and the scrape is performed
Here's the scraper.js
const puppeteer = require ('puppeteer')
const fs = require('fs')
const Page = require('./Page')
const exec = require('child_process').exec
const execSync = require('util').promisify(exec)
module.exports = class scraper {
constructor(){
this.browser = null
this.getPages = null
this.getTotalPages = null
this.isRunning = false
//browser permissions
this.permissions = ['geolocation']
this.MAX_TABS = 5
//when puppeteer launches
this.useFirstTab = true
}
async init(config={}){
let headless = config.headless != undefined ? config.headless : true
this.permissions = this.permissions.concat(config.permissions || [])
//get local chromium location
let browserPath = await getBrowserPath('firefox') || await getBrowserPath('chrome')
this.browser = await puppeteer.launch({
headless:headless,
executablePath:browserPath,
defaultViewport:null,
args:[
'--start-maximized',
]
})
this.getPages = this.browser.pages
this.getTotalPages = ()=>{
return this.getPages().then(pages=>pages.length).catch(err=>0)
}
this.isRunning = true
}
async waitForTab(){
let time = Date.now()
let cycles = 1
await new Promise(resolve=>{
let interval = setInterval(async()=>{
let totalPages = await this.getTotalPages()
if(totalPages < this.MAX_TABS){
clearInterval(interval)
resolve()
}
if(Date.now() - time > 100)
console.log('Waiting...')
if(Date.now() - time > 20*1000){
console.log('... ...\n'.repeat(cycle)+'Still waiting...')
cycle++
time = Date.now()
}
},500)
})
}
//open new tab and go to page
async openPage(url,waitSelector,lat,long){
await this.waitForTab()
let pg
//puppeteer launches with a blank tab, use this
// if(this.useFirstTab){
// let pages = await this.browser.pages()
// pg = pages.pop()
// this.useFirstTab = false
// }
// else
pg = await this.browser.newPage()
if(lat && long){
await this.setPermissions(url)
}
let page = await new Page()
await page.init(pg,url,waitSelector,lat,long)
return page
}
async setPermissions(url){
const context = this.browser.defaultBrowserContext();
await context.overridePermissions(url,this.permissions)
}
}
// assumes that the browser is in path
async function getBrowserPath(browserName){
return execSync('command -v chromium').then(({stdout,stderr})=>{
if(stdout.includes('not found'))
return null
return stdout
}).catch(err=>null)
}
The scraper imports Page.js, which is just wrapper for a puppeteer Page object with the functions I used most made available
const path = require('path')
const fs = require('fs')
const userAgents = require('./staticData/userAgents.json')
const cookiesPath = path.normalize('./cookies.json')
// a wrapper for a puppeteer page with pre-made functions
module.exports = class Page{
constuctor(useCookies=false){
this.page = null
this.useCookies = useCookies
this.previousSession = this.useCookies && fs.existsSync(cookiesPath)
}
async close (){
await this.page.close()
}
async init(page,url,waitSelector,lat,long){
this.page = page
let userAgent = userAgents[Math.floor(Math.random()*userAgents.length)]
await this.page.setUserAgent(userAgent)
await this.restoredSession()
if(lat && long)
await this.page.setGeolocation({
latitude: lat || 59.95, longitude:long || 30.31667, accuracy:40
})
await this.page.goto(url)
await this.wait(waitSelector)
}
async screenshotElement(selector='body',directory='./screenshots',padding=0,offset={}) {
const rect = await this.page.evaluate(selector => {
const el = document.querySelector(selector)
const {x, y, width, height} = el.getBoundingClientRect()
return {
left: x,
top: y,
width,
height,
id: el.id
}
}, selector)
let ext = 'jpeg'
let filename = path.normalize(directory+'/'+Date.now())
return await this.page.screenshot({
type:ext,
path:filename+' - '+selector.substring(5)+'.'+ext,
clip: {
x: rect.left - padding+(offset.left || 0),
y: rect.top - padding+(offset.right || 0),
width: rect.width + padding * 2+(offset.width||0),
height: rect.height + padding * 2+ (offset.height||0)
},
encoding:'base64'
})
}
async restoredSession(){
if(!this.previousSession)
return false
let cookies = require(cookiesPath)
for(let cookie of cookies){
await this.page.setCookie(cookie)
}
console.log('Loaded previous session')
return true
}
async saveSession(){
//write cookie to file
if(!this.useCookies)
return
const cookies = await this.page.cookies()
fs.writeFileSync(cookiesPath,JSON.stringify(cookies,null,2))
console.log('Wrote cookies to file')
}
//wait for text input elment and type text
async type(selector,text,options={delay:150}){
await this.wait(selector)
await this.page.type(selector,text,options)
}
//click and waits
async click(clickSelector,waitSelector=500){
await this.page.click(clickSelector)
await this.wait(waitSelector)
}
//hovers over element and waits
async hover(selector,waitSelector=500){
await this.page.hover(selector)
await this.wait(1000)
await this.wait(waitSelector)
}
//waits and suppresses timeout errors
async wait(selector=500, waitForNav=false){
try{
//waitForNav is a puppeteer's waitForNavigation function
//which for me does nothing but timeouts after 30s
waitForNav && await this.page.waitForNavigation()
await this.page.waitFor(selector)
} catch (err){
//print everything but timeout errors
if(err.name != 'Timeout Error'){
console.log('error name:',err.name)
console.log(err)
console.log('- - - '.repeat(4))
}
this.close()
}
}
}
``

To achieve this, you'll just need to separate the browser from your requests, like in a class, for example:
class PuppeteerScraper {
async launch(options = {}) {
this.browser = await puppeteer.launch(options);
// you could reuse the page instance if it was defined here
}
/**
* Pass the address and the function that will scrape your data,
* in order to mantain the page inside this object
*/
async goto(url, callback) {
const page = await this.browser.newPage();
await page.goto(url);
/**evaluate its content */
await callback(page);
await page.close();
}
async close() {
await this.browser.close();
}
}
and, to implement it:
/**
* scrape function, takes the page instance as its parameters
*/
async function evaluate_page(page) {
const titles = await page.$$eval('.col-xs-6 .star-rating ~ h3 a', (itens) => {
const text_titles = [];
for (const item of itens) {
if (item && item.textContent) {
text_titles.push(item.textContent);
}
}
return text_titles;
});
console.log('titles', titles);
}
(async () => {
const scraper = new PuppeteerScraper();
await scraper.launch({ headless: false });
for (let i = 1; i <= 6; i++) {
let link = `https://books.toscrape.com/catalogue/page-${i}.html`;
await scraper.goto(link, evaluate_page);
}
scraper.close();
})();
altho, if you want something more complex, you could take a look how they done at Apify project.

puppeteer only scraping around 200 pages and don't continue

for some reason that I don't understand my node app stops scraping after few minutes without any errors while only scraping, btw its an infinity scroll website...
this is the code:
const fs = require('fs');
(async() => {
// start the browser
const browser = await puppeteer.launch({ args: ['--no-sandbox'] });
// open a new page
const page = await browser.newPage();
const pageURL = 'http://www.yad4.co.il/dogs//////////////#1';
try {
// try to go to URL
await page.goto(pageURL);
console.log(`opened the page: ${pageURL}`);
await page.setViewport({
width: 1200,
height: 800
});
await autoScroll(page);
} catch (error) {
console.log(`failed to open the page: ${pageURL} with the error: ${error}`);
}
// Find all links to dogs
const postsSelector = '.yd-search-page .container .row .col-md-9 .yd-gallery .search-handler-yd .col-xs-12 #dogs_more .col-md-4 .yd-dog-img .yd-mask a';
await page.waitForSelector(postsSelector);
const postUrls = await page.$$eval(postsSelector, postLinks => postLinks.map(link => link.href));
// Visit each page one by one
for (let postUrl of postUrls) {
// open the page
try {
await page.goto(postUrl);
console.log('opened the page: ', postUrl);
} catch (error) {
console.log(error);
console.log('failed to open the page: ', postUrl);
}
// get the name of the dog
const dogSelector = '.adopt.yd-amuta .container .yd-dog-cont .col-xs-12 .adopt-head .row .col-sm-6 .adopt-breadcrumb-title h2 span';
// await page.waitForSelector(dogSelector);
const dogName = await page.$eval(dogSelector, dogSelector => dogSelector.innerHTML);
// Writing the news inside a json file
fs.appendFile("dogtest4.json", JSON.stringify({dogName},), function(err) {
if (err) throw err;
console.log("Saved!");
});
}
// all done, close the browser
await browser.close();
async function autoScroll(page){
await page.evaluate(async () => {
await new Promise((resolve, reject) => {
var totalHeight = 0;
var distance = 100;
var timer = setInterval(() => {
var scrollHeight = document.body.scrollHeight;
window.scrollBy(0, distance);
totalHeight += distance;
if(totalHeight >= scrollHeight){
clearInterval(timer);
resolve();
}
}, 100);
});
});
}
process.exit()
})();
so it gives me information but randomly, I mean sometimes it gives me 115 pages sometimes 300 pages and some times barely 90 pages and I don't understand why,
please help me.
Thank you.

I can't comment, but I suppose it could be something to do with memory limit being reached and that slows things down.
you can try adding "await" in front of fs.appendFile(...) like here explained, might work for you

puppeteer stream playing <video> to node.js buffer

using Puppeteer I'm able to navigate to a certain video src URL, and the MP4 (using a custom build of chronium) plays fine.
NOW: I want to be able to get the video data that's playing and send it to some kind of buffer in node.js that can be saved as a file or sent to a client via a websocket or sent as a response etc.... but I'm not sure how to do it, all I have is the video playing.
I'm not able to just send the URL over to node.js, because in order to view the video file you have to go through the whole puppeteer crawling process (it's not just a static URL, it's dependent on that browser session only, so only puppeteer can view it).
SO: what can I do to get a src URL to a file (or buffer) in nodeJS? this is my current code, if it helps:
var puppeteer = require("puppeteer-core");
var http=require("https");
var fs=require("fs");
var fetch=require("fetch-node");
(async() => {
var browser = await puppeteer.launch({
executablePath:"./cobchrome/chrome.exe"
});
console.log("Got browser", browser);
var page = await browser.newPage();
console.log(page,"got page");
var agentStr = `Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0`;
var agent = await page.setUserAgent(agentStr);
console.log(agent, "Set the user agent");
// await page.goto("https://drive.google.com/file/d/17tkL8jPlBIh5XtcX_tNhyDV5nSX8v7f8/preview");
await page.goto("https://docs.google.com/file/d/1Cyuh41yNfYZU_zL-MHLf_EPJCYnlT7oJ/preview?enablejsapi=1&playerapiid=player4");
console.log("went to page..");
await page._client.send('Page.setDownloadBehavior', {behavior: 'allow', downloadPath: './downloadscob/'})
await page.screenshot({path:"shots/onopen.png"});
// var btn = await page.$(".ndfHFb-c4YZDc ndfHFb-c4YZDc-AHmuwe-Hr88gd-OWB6Me ndfHFb-c4YZDc-vyDMJf-aZ2wEe ndfHFb-c4YZDc-i5oIFb ndfHFb-c4YZDc-e1YmVc ndfHFb-c4YZDc-TSZdd");
// var tst = await page.$("#start-of-content");
var clickEl = ".ndfHFb-c4YZDc-aTv5jf-bVEB4e-RJLb9c";
var newClickID = ".ndfHFb-c4YZDc-aTv5jf-NziyQe-LgbsSe";
var clicker = await page.waitForSelector(newClickID);
console.log(clicker,"got clicker");
await page.screenshot({path:"shots/ongotclicker.png"});
await page.click(clickEl);
console.log("clicked")
await page.screenshot({path:"shots/onclicked.png"});
var frame = await page.waitForSelector("iframe[id=drive-viewer-video-player-object-0]");
console.log(frame, "got video frame");
await page.screenshot({path:"shots/ongotframe.png"});
var cf = await frame.contentFrame();
await page.screenshot({path:"shots/oncf.png"});
console.log(cf, "got content frame");
await cf.waitFor(() => !!document.querySelector("video"))
await page.screenshot({path:"shots/videoappeared.png"});
//await cf.waitFor(30000);
// var videos = await cf.$("video");
// console.log(videos, videos.length, "all videos");
var video = await cf.$("video");
await page.screenshot({path:"shots/selectedvideo.png"});
var videoEl = await cf.evaluate(
v =>{
var result = {};
for(var k in v) {
result[k] = v[k];
}
return result;
},
video
);
var src = videoEl.src;
var file = fs.createWriteStream("down.mp4");
console.log("starting to stream");
var req = http.get(src, r => {
console.log("finished pipin");
r.pipe(file); //I REALLY thought this would work but it doesn't do anything
});
var start = Date.now();
await page.screenshot({path:"shots/evalled_vido.png"});
console.log("$$###VIDEO SOURCE::", "time it took", src);
await page.goto(src);
await page.screenshot({path:"shots/wentToNewPage.png"});
// await page.waitFor(5000);
await page.screenshot({path:"shots/maybeItsPlayingNow.png"});
console.log("ABOUT t oFETHC wit H SOURCE", src)
var content = await page.content();
fs.writeFile("outputagain.txt", content, (re) => {
console.log("saved it?");
})
console.log(content);
// await browser.close();
})();
currently the page.content() at the end just gets the HTML content of the page, not any binary data................