title
Web Scraping with Puppeteer & Node.js: Chrome Automation

description
Join my premium 2024 bootcamp here https://learnwebcode.teachable.com/p/brads-web-developer-bootcamp?coupon_code=YOUTUBEWELCOME 0:00 Intro 1:20 Installing Puppeteer 4:29 Taking a Screenshot 7:09 Scraping Text From HTML 15:34 Saving Images to Hard Drive 21:45 Clicking a Button 25:16 Filling Out a Form 30:51 Scheduling a Task to Repeat The practice URL I'm working with in the video: https://learnwebcode.github.io/practice-requests/ My finished example code: https://gist.github.com/LearnWebCode/31f8a20ef7e4324aca322a21dbfc3d7e Follow me for updates on new videos or projects: Instagram: https://www.instagram.com/javaschiff/ Twitter: https://twitter.com/learnwebcode Facebook: https://www.facebook.com/Brad-Schiff-1542576316048470/ Twitch: https://www.twitch.tv/learnwebcode

detail
{'title': 'Web Scraping with Puppeteer & Node.js: Chrome Automation', 'heatmap': [{'end': 150.201, 'start': 81.258, 'weight': 0.713}, {'end': 338.605, 'start': 312.102, 'weight': 0.802}, {'end': 709.931, 'start': 653.974, 'weight': 1}, {'end': 1311.7, 'start': 1281.721, 'weight': 0.702}, {'end': 1526.392, 'start': 1495.048, 'weight': 0.759}], 'summary': "This tutorial covers automating browser interactions with puppeteer, setting up puppeteer for website automation, web scraping, using puppeteer's $$eval function, simulating button click and automating form submission, and automating tasks and scheduling with puppeteer and node.js.", 'chapters': [{'end': 80.778, 'segs': [{'end': 80.778, 'src': 'embed', 'start': 20.756, 'weight': 0, 'content': [{'end': 34.441, 'text': "wouldn't it be nice if we could programmatically spin up a headless version of Google Chrome through the command line or through Node.js and then simulate clicking on certain buttons or filling out certain form fields,", 'start': 20.756, 'duration': 13.685}, {'end': 37.022, 'text': 'maybe pulling text value from certain elements,', 'start': 34.441, 'duration': 2.581}, {'end': 46.105, 'text': "maybe submitting a form and then accessing data on the resulting page that's perhaps password protected or some sort of secret data on the resulting page?", 'start': 37.022, 'duration': 9.083}, {'end': 51.667, 'text': 'Well, programmatically controlling the Google Chrome browser like that is a lot easier than you might think it is.', 'start': 46.305, 'duration': 5.362}, {'end': 56.789, 'text': "And in this video, we're going to use a package called Puppeteer to make it happen.", 'start': 52.327, 'duration': 4.462}, {'end': 62.711, 'text': 'Before we jump into the action though, I just want to say that this video is sponsored by me.', 'start': 57.409, 'duration': 5.302}, {'end': 68.913, 'text': "In the description for this video, you'll find heavily discounted coupon links to all of my premium courses.", 'start': 63.211, 'duration': 5.702}, {'end': 76.516, 'text': 'They range in topics from HTML, CSS, JavaScript, Node, Express, React, WordPress and more.', 'start': 69.273, 'duration': 7.243}, {'end': 80.778, 'text': "Having said all of that, let's jump into the actual action for this video.", 'start': 76.896, 'duration': 3.882}], 'summary': 'Using puppeteer to programmatically control google chrome for automating tasks.', 'duration': 60.022, 'max_score': 20.756, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI20756.jpg'}], 'start': 0.149, 'title': 'Automating browser interactions with puppeteer', 'summary': 'Delves into programmatically controlling google chrome using puppeteer to simulate interactions, such as clicking buttons, filling forms, and accessing password-protected data. it also includes a sponsorship note for discounted premium courses.', 'chapters': [{'end': 80.778, 'start': 0.149, 'title': 'Automating browser interactions with puppeteer', 'summary': 'Discusses programmatically controlling the google chrome browser using puppeteer to simulate interactions like clicking buttons, filling forms, and accessing password-protected data, with a sponsorship note for discounted premium courses.', 'duration': 80.629, 'highlights': ['Puppeteer allows programmatically controlling Google Chrome to simulate interactions like clicking buttons, filling forms, and accessing data on password-protected pages.', 'The video is sponsored with heavily discounted coupon links to premium courses in HTML, CSS, JavaScript, Node, Express, React, WordPress, and more.', 'Developers often encounter situations where certain data or features are only accessible through the website, necessitating the need for programmatically simulating human interactions with the headless version of Google Chrome.', 'Programmatically controlling Google Chrome through Puppeteer offers an easier solution for developers in such scenarios.']}], 'duration': 80.629, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI149.jpg', 'highlights': ['Puppeteer allows programmatically controlling Google Chrome to simulate interactions like clicking buttons, filling forms, and accessing data on password-protected pages.', 'Developers often encounter situations where certain data or features are only accessible through the website, necessitating the need for programmatically simulating human interactions with the headless version of Google Chrome.', 'Programmatically controlling Google Chrome through Puppeteer offers an easier solution for developers in such scenarios.', 'The video is sponsored with heavily discounted coupon links to premium courses in HTML, CSS, JavaScript, Node, Express, React, WordPress, and more.']}, {'end': 439.809, 'segs': [{'end': 110.898, 'src': 'embed', 'start': 81.258, 'weight': 1, 'content': [{'end': 85.621, 'text': 'Okay, so I have a completely new empty folder opened up in VS Code.', 'start': 81.258, 'duration': 4.363}, {'end': 88.743, 'text': 'So I just have this folder on my desktop named Example.', 'start': 85.661, 'duration': 3.082}, {'end': 91.385, 'text': "And here's how I would start using Puppeteer.", 'start': 89.464, 'duration': 1.921}, {'end': 93.586, 'text': "So I'd open up the command line.", 'start': 92.265, 'duration': 1.321}, {'end': 95.428, 'text': "It's pointing towards my new empty folder.", 'start': 93.646, 'duration': 1.782}, {'end': 99.01, 'text': 'And I would run npm init-y.', 'start': 95.968, 'duration': 3.042}, {'end': 105.094, 'text': 'Now in order to use this command, you will need to have Node.js installed on your computer.', 'start': 99.39, 'duration': 5.704}, {'end': 110.898, 'text': "So if you don't already have that, you can go pause the lesson, visit the official website, and get that installed.", 'start': 105.474, 'duration': 5.424}], 'summary': 'Using puppeteer: open new folder in vs code, run npm init-y to start, node.js required.', 'duration': 29.64, 'max_score': 81.258, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI81258.jpg'}, {'end': 150.201, 'src': 'heatmap', 'start': 81.258, 'weight': 0.713, 'content': [{'end': 85.621, 'text': 'Okay, so I have a completely new empty folder opened up in VS Code.', 'start': 81.258, 'duration': 4.363}, {'end': 88.743, 'text': 'So I just have this folder on my desktop named Example.', 'start': 85.661, 'duration': 3.082}, {'end': 91.385, 'text': "And here's how I would start using Puppeteer.", 'start': 89.464, 'duration': 1.921}, {'end': 93.586, 'text': "So I'd open up the command line.", 'start': 92.265, 'duration': 1.321}, {'end': 95.428, 'text': "It's pointing towards my new empty folder.", 'start': 93.646, 'duration': 1.782}, {'end': 99.01, 'text': 'And I would run npm init-y.', 'start': 95.968, 'duration': 3.042}, {'end': 105.094, 'text': 'Now in order to use this command, you will need to have Node.js installed on your computer.', 'start': 99.39, 'duration': 5.704}, {'end': 110.898, 'text': "So if you don't already have that, you can go pause the lesson, visit the official website, and get that installed.", 'start': 105.474, 'duration': 5.424}, {'end': 119.864, 'text': 'Anyways though NPM and it dash why that will give us the package dot JSON file and now we can install whatever we want.', 'start': 111.658, 'duration': 8.206}, {'end': 122.246, 'text': 'So what we want to install is puppeteer.', 'start': 120.365, 'duration': 1.881}, {'end': 128.41, 'text': "So NPM install pup but here it's very easy to misspell it.", 'start': 122.846, 'duration': 5.564}, {'end': 130.192, 'text': 'At least it is for me.', 'start': 129.291, 'duration': 0.901}, {'end': 131.953, 'text': "But let's go ahead and run that command.", 'start': 130.271, 'duration': 1.682}, {'end': 141.075, 'text': 'The download could take a good minute or two or even longer on a slow connection because it needs to download a version of Google Chrome.', 'start': 133.53, 'duration': 7.545}, {'end': 143.216, 'text': "So that's a pretty sizable download.", 'start': 141.415, 'duration': 1.801}, {'end': 150.201, 'text': 'OK Once it completes to actually begin using it we just want to create a JavaScript file where we can write a bit of code.', 'start': 143.857, 'duration': 6.344}], 'summary': 'Using puppeteer in vs code: npm init-y, install puppeteer, create javascript file.', 'duration': 68.943, 'max_score': 81.258, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI81258.jpg'}, {'end': 253.3, 'src': 'embed', 'start': 218.359, 'weight': 0, 'content': [{'end': 220.199, 'text': "so we're launching the browser again.", 'start': 218.359, 'duration': 1.84}, {'end': 223.1, 'text': "we don't know how long that will take, but we're awaiting it.", 'start': 220.199, 'duration': 2.901}, {'end': 229.942, 'text': 'so maybe it takes one millisecond, maybe it takes a thousand milliseconds, but once that completes,', 'start': 223.1, 'duration': 6.842}, {'end': 233.903, 'text': 'then we want to create sort of a new page or new tab in the browser.', 'start': 229.942, 'duration': 3.961}, {'end': 238.885, 'text': "so we'd say const page equals await browser dot new page.", 'start': 233.903, 'duration': 4.982}, {'end': 244.715, 'text': "Now that we have our new page, let's tell it to actually navigate to a specific U.R.L.", 'start': 239.813, 'duration': 4.902}, {'end': 253.3, 'text': 'So I would just say await page dot go to in the go to function just give it a string of text and then paste in the U.R.L.', 'start': 245.236, 'duration': 8.064}], 'summary': 'Launching browser, creating new page, navigating to a specific url.', 'duration': 34.941, 'max_score': 218.359, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI218359.jpg'}, {'end': 338.605, 'src': 'heatmap', 'start': 304.623, 'weight': 5, 'content': [{'end': 310.388, 'text': "So just the file name node index and you can see it's taking just a moment.", 'start': 304.623, 'duration': 5.765}, {'end': 319.729, 'text': "Oops, it's actually just going to take forever until the end of time because up in the code I forgot to close the task or close the browser.", 'start': 312.102, 'duration': 7.627}, {'end': 327.755, 'text': 'So you would want to add a final line of code here that says await browser.close and just call the close method.', 'start': 320.189, 'duration': 7.566}, {'end': 329.577, 'text': 'So let me save that again.', 'start': 328.136, 'duration': 1.441}, {'end': 331.178, 'text': "Now we don't actually need to run it again.", 'start': 329.617, 'duration': 1.561}, {'end': 333.68, 'text': 'It successfully created the screenshot.', 'start': 331.198, 'duration': 2.482}, {'end': 335.042, 'text': 'Cool There it is.', 'start': 334.421, 'duration': 0.621}, {'end': 338.605, 'text': 'Amazing.png If I open it up, you get the idea.', 'start': 335.062, 'duration': 3.543}], 'summary': 'A code error caused the process to take too long, but it was fixed by adding a line of code to close the browser, resulting in successful creation of the screenshot.', 'duration': 24.954, 'max_score': 304.623, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI304623.jpg'}, {'end': 392.435, 'src': 'embed', 'start': 365.056, 'weight': 3, 'content': [{'end': 371.922, 'text': 'But what if you have a really long page? So, for example, here is the Wikipedia page for JavaScript.', 'start': 365.056, 'duration': 6.866}, {'end': 374.525, 'text': 'This page is super long.', 'start': 372.403, 'duration': 2.122}, {'end': 380.05, 'text': "So what if I wanted to take a screenshot of the entire thing? So I'll just take the URL.", 'start': 375.066, 'duration': 4.984}, {'end': 383.832, 'text': "I'll use that temporarily for my go-to URL.", 'start': 380.891, 'duration': 2.941}, {'end': 387.474, 'text': "And then when you're taking the screenshot, you can just give it another property.", 'start': 384.312, 'duration': 3.162}, {'end': 392.435, 'text': 'So comma of full page and set that to true.', 'start': 387.514, 'duration': 4.921}], 'summary': "Using the url of a long wikipedia page, take a full-page screenshot by setting the 'full page' property to true.", 'duration': 27.379, 'max_score': 365.056, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI365056.jpg'}], 'start': 81.258, 'title': 'Puppeteer setup and website automation', 'summary': 'Covers setting up puppeteer in vs code, including creating a new folder, initializing node.js, installing puppeteer, and using asynchronous functions. it also details automating website navigation, taking customized screenshots, and emphasizing the importance of closing the browser.', 'chapters': [{'end': 238.885, 'start': 81.258, 'title': 'Setting up puppeteer in vs code', 'summary': 'Demonstrates setting up puppeteer in vs code by creating a new empty folder, initializing node.js, installing puppeteer, creating a javascript file, and using asynchronous functions to launch a browser and create a new page.', 'duration': 157.627, 'highlights': ["Creating a new empty folder and initializing Node.js To initiate the process, a new empty folder is created in VS Code and Node.js is initialized using the command 'npm init -y'.", "Installing Puppeteer and creating a JavaScript file The process involves installing Puppeteer using 'npm install puppeteer' and creating a new JavaScript file to write code for Puppeteer.", "Using asynchronous functions to launch a browser and create a new page Asynchronous functions are utilized to launch a browser and create a new page in the browser, requiring the use of 'await' inside an 'async' function."]}, {'end': 439.809, 'start': 239.813, 'title': 'Automating website navigation and screenshots', 'summary': 'Explains how to navigate to a specific url, take screenshots using puppeteer, and customize the screenshot size, emphasizing the importance of closing the browser to avoid indefinite running tasks.', 'duration': 199.996, 'highlights': ["The chapter emphasizes the process of navigating to a specific URL and taking screenshots using Puppeteer, providing practical examples and encouraging the usage of provided URLs for demonstration. It explains the process of using 'await page.goto' to navigate to a specific URL and 'await page.screenshot' to take a screenshot, with an emphasis on using practical examples and provided URLs for demonstration.", "It highlights the importance of closing the browser to avoid indefinite running tasks, providing a specific code snippet for closing the browser using 'await browser.close'. It emphasizes the necessity of closing the browser to avoid indefinite running tasks, providing a specific code snippet for closing the browser using 'await browser.close'.", "The chapter demonstrates customizing the screenshot size to capture an entire page by setting 'fullPage' property to true, showcasing the practicality and benefits of this feature. It showcases the process of customizing the screenshot size to capture an entire page by setting 'fullPage' property to true, emphasizing the practicality and benefits of this feature."]}], 'duration': 358.551, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI81258.jpg', 'highlights': ['Using asynchronous functions to launch a browser and create a new page', 'Installing Puppeteer and creating a JavaScript file', 'Creating a new empty folder and initializing Node.js', 'The chapter emphasizes the process of navigating to a specific URL and taking screenshots using Puppeteer', "The chapter demonstrates customizing the screenshot size to capture an entire page by setting 'fullPage' property to true", 'It highlights the importance of closing the browser to avoid indefinite running tasks']}, {'end': 963.193, 'segs': [{'end': 535.944, 'src': 'embed', 'start': 508.362, 'weight': 1, 'content': [{'end': 511.425, 'text': 'So up at the very top of this file, I would pull in something.', 'start': 508.362, 'duration': 3.063}, {'end': 522.494, 'text': 'So const fs equals and then just require in now instead of just using the default file system module, I would actually use fs slash promises.', 'start': 511.445, 'duration': 11.049}, {'end': 525.497, 'text': "So this way we don't have to write messy callback code.", 'start': 523.255, 'duration': 2.242}, {'end': 527.098, 'text': 'It will just give us a promise.', 'start': 525.657, 'duration': 1.441}, {'end': 529.3, 'text': 'So now we can go leverage this.', 'start': 527.879, 'duration': 1.421}, {'end': 535.944, 'text': 'So right below our made up array, I would just await and then I would use that FS file system module.', 'start': 529.54, 'duration': 6.404}], 'summary': 'Using fs.promises to avoid messy callback code for file system operations.', 'duration': 27.582, 'max_score': 508.362, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI508362.jpg'}, {'end': 628.361, 'src': 'embed', 'start': 554.106, 'weight': 0, 'content': [{'end': 556.307, 'text': 'So I would just take our array of names.', 'start': 554.106, 'duration': 2.201}, {'end': 557.287, 'text': 'So names.', 'start': 556.467, 'duration': 0.82}, {'end': 559.488, 'text': "It's an array in JavaScript.", 'start': 557.847, 'duration': 1.641}, {'end': 562.69, 'text': 'Every array has access to a method called join.', 'start': 559.628, 'duration': 3.062}, {'end': 564.11, 'text': 'right sort of.', 'start': 563.63, 'duration': 0.48}, {'end': 568.293, 'text': 'how do you want to glue together the different items in the array into a string?', 'start': 564.11, 'duration': 4.183}, {'end': 578.261, 'text': 'and i would just want to sort of glue them together with a backslash r, backslash n, in other words a return and a new line.', 'start': 568.293, 'duration': 9.968}, {'end': 583.284, 'text': "so let's go ahead and save this and test it out so down in the command line node index.", 'start': 578.261, 'duration': 5.023}, {'end': 583.965, 'text': 'give that a run.', 'start': 583.284, 'duration': 0.681}, {'end': 591.31, 'text': 'You can see that created a new file in the sidebar named names dot txt, and if we open it up, perfect.', 'start': 585.342, 'duration': 5.968}, {'end': 602.303, 'text': "So now just instead of these made up imaginary values in my array let's actually use puppeteer to find all of the names on the Web page.", 'start': 591.75, 'duration': 10.553}, {'end': 607.487, 'text': "Now every website will be different and we'll use a different HTML structure,", 'start': 603.104, 'duration': 4.383}, {'end': 612.371, 'text': "but a good place to start is to just right click on the piece of text you're interested in.", 'start': 607.487, 'duration': 4.884}, {'end': 616.093, 'text': 'choose, inspect and look at the HTML structure.', 'start': 612.371, 'duration': 3.722}, {'end': 623.078, 'text': 'So here you can see that name is wrapped inside a strong tag and that lives inside a div with a class of info.', 'start': 616.674, 'duration': 6.404}, {'end': 628.361, 'text': 'So it would be very easy to just write a CSS selector right, of .', 'start': 623.478, 'duration': 4.883}], 'summary': 'Using javascript, a method called join was used to glue together the items in an array into a string with a return and a new line, resulting in the creation of a new file named names.txt. additionally, the process of using puppeteer to find names on a webpage was discussed, emphasizing the importance of understanding the html structure for selecting specific elements.', 'duration': 74.255, 'max_score': 554.106, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI554106.jpg'}, {'end': 716.675, 'src': 'heatmap', 'start': 653.974, 'weight': 4, 'content': [{'end': 659.937, 'text': "and then let me pull this up a little bit so you can see choose copy, and there's one called copy selector.", 'start': 653.974, 'duration': 5.963}, {'end': 666.142, 'text': 'And then with that in your clipboard, if you paste it in, you see you have a CSS like selector.', 'start': 660.938, 'duration': 5.204}, {'end': 670.485, 'text': "Now it's specific to just that one element that you right clicked on.", 'start': 666.542, 'duration': 3.943}, {'end': 674.127, 'text': 'So in other words, it has this pseudo selector of nth child one.', 'start': 670.525, 'duration': 3.602}, {'end': 676.249, 'text': 'So that would only select meows a lot.', 'start': 674.207, 'duration': 2.042}, {'end': 679.554, 'text': 'But you could very easily adapt this right.', 'start': 677.213, 'duration': 2.341}, {'end': 683.096, 'text': 'Just get rid of that pseudo selector and now that would work for all of them.', 'start': 679.574, 'duration': 3.522}, {'end': 685.917, 'text': "You don't have to use that copy selector feature.", 'start': 683.676, 'duration': 2.241}, {'end': 689.339, 'text': 'You can write your own selectors but on more complicated websites.', 'start': 685.957, 'duration': 3.382}, {'end': 691.54, 'text': "That's a nice trick to have up your sleeve.", 'start': 689.739, 'duration': 1.801}, {'end': 696.983, 'text': "Anyways the idea is we're just going to write a selector for the elements we're interested in.", 'start': 692.261, 'duration': 4.722}, {'end': 700.165, 'text': 'So how do we actually do this within puppeteer though.', 'start': 697.623, 'duration': 2.542}, {'end': 709.931, 'text': "Well let's get rid of the fake hard coded array and instead say const names equals a weight page dot.", 'start': 700.825, 'duration': 9.106}, {'end': 714.994, 'text': "And then we're going to use a method called evaluate inside evaluate.", 'start': 709.991, 'duration': 5.003}, {'end': 716.675, 'text': 'We give it a function that we want to run.', 'start': 715.054, 'duration': 1.621}], 'summary': "Demonstrates using css selectors to target elements and discusses using puppeteer's 'evaluate' method for automation.", 'duration': 24.414, 'max_score': 653.974, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI653974.jpg'}, {'end': 924.657, 'src': 'embed', 'start': 894.746, 'weight': 5, 'content': [{'end': 898.767, 'text': 'I do want to stress one thing, though, because this confused me at first,', 'start': 894.746, 'duration': 4.021}, {'end': 904.808, 'text': 'and that is that if you tried to test something out within this function by using console dot log,', 'start': 898.767, 'duration': 6.041}, {'end': 907.808, 'text': 'you would not be logging to the node JS command line.', 'start': 904.808, 'duration': 3}, {'end': 911.409, 'text': 'You would be logging to the Chrome browser console.', 'start': 908.248, 'duration': 3.161}, {'end': 915.011, 'text': "Right So that's something to definitely be aware of within this function.", 'start': 911.869, 'duration': 3.142}, {'end': 918.974, 'text': 'You are in browser land, not node JS land.', 'start': 915.451, 'duration': 3.523}, {'end': 924.657, 'text': "So keep that in mind in terms of scope and which variables are and aren't available to you.", 'start': 919.514, 'duration': 5.143}], 'summary': 'When testing within a function, log to the chrome browser console, not the node.js command line.', 'duration': 29.911, 'max_score': 894.746, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI894746.jpg'}], 'start': 440.289, 'title': 'Puppeteer for web scraping', 'summary': 'Covers using puppeteer to extract names from a web page, saving them to a text file, utilizing the fs module, and the process of inspecting html structure, writing css selectors, and the limitations of running client-side javascript.', 'chapters': [{'end': 602.303, 'start': 440.289, 'title': 'Extracting and saving names with puppeteer', 'summary': 'Discusses using puppeteer to extract names from a web page, saving them to a text file on the hard drive, and utilizing the fs module to accomplish this with promises and avoiding messy callback code.', 'duration': 162.014, 'highlights': ['Using Puppeteer to extract names from a web page The chapter highlights the process of using Puppeteer to extract names from a web page, demonstrating the potential use case with 100 or 500 different names for extraction.', 'Utilizing fs module with promises It explains the usage of the fs module with promises to avoid writing messy callback code, providing a smoother and more manageable approach to file system operations.', 'Saving extracted names to a text file The chapter explains the process of saving the extracted names to a text file on the hard drive, showcasing the method of joining array elements and gluing them together with a return and a new line.']}, {'end': 963.193, 'start': 603.104, 'title': 'Web scraping with puppeteer', 'summary': "Covers the process of inspecting html structure, writing css selectors, using puppeteer's evaluate method to extract data, and the limitations and scope of running client-side javascript within the evaluate function.", 'duration': 360.089, 'highlights': ["The chapter covers the process of inspecting HTML structure and writing CSS selectors. The speaker explains the process of right-clicking on the text of interest, choosing 'inspect' to view the HTML structure, and writing a CSS selector to extract the desired content.", "Using Puppeteer's evaluate method to extract data from the web page. The speaker demonstrates using Puppeteer's evaluate method to run client-side JavaScript and extract specific elements from the web page, such as using document.querySelector to select elements based on CSS selectors.", 'Limitations and scope of running client-side JavaScript within the evaluate function. The speaker discusses the limitations of running client-side JavaScript within the evaluate function, such as the inability to log to the Node.js command line and the need to return values to Node.js from the browser environment.']}], 'duration': 522.904, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI440289.jpg', 'highlights': ['Using Puppeteer to extract names from a web page with 100 or 500 different names for extraction', 'Utilizing fs module with promises for smoother and more manageable file system operations', 'Saving extracted names to a text file by joining array elements and gluing them together with a return and a new line', "Inspecting HTML structure and writing CSS selectors by right-clicking on the text of interest and choosing 'inspect'", "Using Puppeteer's evaluate method to extract data from the web page, such as using document.querySelector", 'Limitations and scope of running client-side JavaScript within the evaluate function, including the inability to log to the Node.js command line']}, {'end': 1303.718, 'segs': [{'end': 1014.985, 'src': 'embed', 'start': 988.493, 'weight': 0, 'content': [{'end': 994.035, 'text': 'But in this case, since we have a very specific task in hand, right, we want to select a collection of elements.', 'start': 988.493, 'duration': 5.542}, {'end': 996.497, 'text': 'Puppeteer actually gives us a function.', 'start': 994.796, 'duration': 1.701}, {'end': 1001.559, 'text': 'So page dot function called dollar sign, dollar sign, a vowel.', 'start': 996.517, 'duration': 5.042}, {'end': 1006.721, 'text': 'This function is specifically designed for the purpose of selecting multiple elements.', 'start': 1002.199, 'duration': 4.522}, {'end': 1012.043, 'text': "In other words, we won't have to do this awkward thing of saying array dot from.", 'start': 1007.161, 'duration': 4.882}, {'end': 1014.985, 'text': 'Instead, Puppeteer will just sort of do that for us.', 'start': 1012.564, 'duration': 2.421}], 'summary': 'Puppeteer provides a function to select multiple elements effortlessly.', 'duration': 26.492, 'max_score': 988.493, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI988493.jpg'}, {'end': 1062.138, 'src': 'embed', 'start': 1033.892, 'weight': 1, 'content': [{'end': 1036.173, 'text': 'OK And then the second argument is just a function.', 'start': 1033.892, 'duration': 2.281}, {'end': 1038.053, 'text': "So I'll use an arrow function.", 'start': 1036.733, 'duration': 1.32}, {'end': 1041.655, 'text': 'So parentheses arrow symbol curly brackets.', 'start': 1039.094, 'duration': 2.561}, {'end': 1051.306, 'text': "And the way that $$eval works is it's going to pass this collection of elements that it finds into our function.", 'start': 1042.454, 'duration': 8.852}, {'end': 1052.887, 'text': "So let's have a parameter.", 'start': 1051.806, 'duration': 1.081}, {'end': 1054.049, 'text': 'You could name it anything.', 'start': 1052.948, 'duration': 1.101}, {'end': 1057.373, 'text': "Let's name it maybe just imgs, short for images.", 'start': 1054.289, 'duration': 3.084}, {'end': 1060.977, 'text': 'And now the cool part is that it is an actual array.', 'start': 1058.114, 'duration': 2.863}, {'end': 1062.138, 'text': "It's not a node list.", 'start': 1061.017, 'duration': 1.121}], 'summary': 'Using $$eval with arrow function to manipulate elements in an array', 'duration': 28.246, 'max_score': 1033.892, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1033892.jpg'}, {'end': 1150.398, 'src': 'embed', 'start': 1081.952, 'weight': 3, 'content': [{'end': 1085.516, 'text': 'So, inside of map I would just have an arrow function with one parameter,', 'start': 1081.952, 'duration': 3.564}, {'end': 1092.064, 'text': "so x for the current image that's been looped to and then we would just wanna return x.src.", 'start': 1085.516, 'duration': 6.548}, {'end': 1096.349, 'text': "If you're new to HTML and JavaScript, let me show you how that works in the browser.", 'start': 1092.785, 'duration': 3.564}, {'end': 1102.253, 'text': 'So if you open up your console, And you just select the very first element, the first image on the page.', 'start': 1096.389, 'duration': 5.864}, {'end': 1106.554, 'text': 'So document query selector, give us the first image.', 'start': 1102.313, 'duration': 4.241}, {'end': 1114.958, 'text': 'Well, then you can look inside that for its SRC property and you can see that gives you the full web address for that image.', 'start': 1107.115, 'duration': 7.843}, {'end': 1122.645, 'text': 'So in other words we will now have this constant named photos that is just an array with those different image you are else.', 'start': 1115.638, 'duration': 7.007}, {'end': 1128.73, 'text': 'So now below this code we just want to loop through that array and just save them to our hard drive.', 'start': 1123.165, 'duration': 5.565}, {'end': 1138.319, 'text': "So we know that this is an array but instead of looping through it with a for each I'm going to use a four of because it allows for the await syntax.", 'start': 1129.451, 'duration': 8.868}, {'end': 1144.408, 'text': 'So I would just say for parentheses const photo of photos.', 'start': 1138.659, 'duration': 5.749}, {'end': 1148.395, 'text': 'Right Our array of those image paths curly brackets.', 'start': 1144.468, 'duration': 3.927}, {'end': 1150.398, 'text': 'So I just made up this name.', 'start': 1149.156, 'duration': 1.242}], 'summary': 'Using javascript to loop through images and save them to the hard drive.', 'duration': 68.446, 'max_score': 1081.952, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1081952.jpg'}, {'end': 1266.571, 'src': 'embed', 'start': 1238.121, 'weight': 6, 'content': [{'end': 1244.623, 'text': 'OK, and then the second argument instead of the B placeholder, this is the contents of the file that we want to save to our hard drive.', 'start': 1238.121, 'duration': 6.502}, {'end': 1250.985, 'text': "So we would just say await image page, write that new page that's pointing towards the image.", 'start': 1244.783, 'duration': 6.202}, {'end': 1255.927, 'text': 'And then we can just say dot and call a buffer function that puppeteer offers.', 'start': 1251.365, 'duration': 4.562}, {'end': 1259.448, 'text': "Let's go ahead and save this and test it out.", 'start': 1256.727, 'duration': 2.721}, {'end': 1266.571, 'text': 'So if I call node index and open up my sidebar we should see a few new images appear.', 'start': 1259.528, 'duration': 7.043}], 'summary': "Using puppeteer to save image files to hard drive and test the functionality by running 'node index' to see new images appear.", 'duration': 28.45, 'max_score': 1238.121, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1238121.jpg'}], 'start': 964.353, 'title': "Puppeteer's $$eval function and javascript image scraping", 'summary': "Explores using puppeteer's $$eval function for selecting multiple elements, simplifying the process of selecting a collection of elements on a web page, and demonstrates how to scrape image urls using javascript, resulting in three new jpeg images being successfully saved.", 'chapters': [{'end': 1057.373, 'start': 964.353, 'title': "Using puppeteer's $$eval function", 'summary': "Explores how to use puppeteer's $$eval function to select multiple elements, providing a more focused method than the generic evaluate, ultimately simplifying the process of selecting a collection of elements on a web page.", 'duration': 93.02, 'highlights': ["Puppeteer's $$eval function is specifically designed for the purpose of selecting multiple elements, simplifying the process by avoiding the need for array manipulation.", 'The $$eval function takes a CSS-like selector as the first argument and a function as the second argument, making it versatile for selecting various types of elements on a web page.', 'Using the $$eval function eliminates the need for the awkward array manipulation using array.from, providing a more streamlined approach to selecting multiple elements on a web page.']}, {'end': 1303.718, 'start': 1058.114, 'title': 'Javascript image scraping', 'summary': 'Explains how to scrape image urls from a webpage using javascript, demonstrating the process of extracting image source urls and saving the images to the hard drive, resulting in three new jpeg images being successfully saved.', 'duration': 245.604, 'highlights': ['The chapter explains how to scrape image URLs from a webpage using JavaScript Demonstrates the process of extracting image source URLs and saving the images to the hard drive', 'Resulting in three new JPEG images being successfully saved Successfully saved three new JPEG images to the hard drive', 'Demonstrates the use of map and arrow functions to extract image source URLs Utilizes map and arrow functions to extract image source URLs from the webpage', "Utilizes the 'await' syntax and 'for...of' loop for asynchronous operations Utilizes 'await' syntax and 'for...of' loop for asynchronous operations to save images to the hard drive", 'Includes error handling and awaiting asynchronous operations Includes error handling and awaiting asynchronous operations to ensure successful image scraping and saving']}], 'duration': 339.365, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI964353.jpg', 'highlights': ["Puppeteer's $$eval function simplifies selecting multiple elements, avoiding array manipulation.", 'The $$eval function is versatile for selecting various types of elements on a web page.', 'Using $$eval eliminates awkward array manipulation using array.from, streamlining element selection.', 'Demonstrates scraping image URLs from a webpage using JavaScript and saving three new JPEG images.', 'Utilizes map and arrow functions to extract image source URLs from the webpage.', "Utilizes 'await' syntax and 'for...of' loop for asynchronous operations to save images.", 'Includes error handling and awaiting asynchronous operations for successful image scraping and saving.']}, {'end': 1851.05, 'segs': [{'end': 1338.221, 'src': 'embed', 'start': 1304.198, 'weight': 3, 'content': [{'end': 1308.217, 'text': "Perfect OK, let's change gears and move on to the next example.", 'start': 1304.198, 'duration': 4.019}, {'end': 1311.7, 'text': 'So now see this button here that says click me on the page.', 'start': 1308.617, 'duration': 3.083}, {'end': 1316.063, 'text': 'Well, if you actually click it, it inserts a bit of new text.', 'start': 1312.24, 'duration': 3.823}, {'end': 1325.371, 'text': "So imagine from a Node.js perspective, we want to be able to access this content that only exists once you've clicked the button.", 'start': 1316.264, 'duration': 9.107}, {'end': 1329.955, 'text': "Right When you first visit the page, that text doesn't exist in the DOM.", 'start': 1326.051, 'duration': 3.904}, {'end': 1338.221, 'text': 'Now sure you could hunt through the client-side JavaScript file and search for that text, but imagine if it came from a network request right?', 'start': 1330.675, 'duration': 7.546}], 'summary': 'Demonstrating dynamic content insertion through button click in node.js perspective.', 'duration': 34.023, 'max_score': 1304.198, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1304198.jpg'}, {'end': 1395.686, 'src': 'embed', 'start': 1368.703, 'weight': 2, 'content': [{'end': 1373.726, 'text': 'Cool So from within Node.js, we want to simulate clicking on this button.', 'start': 1368.703, 'duration': 5.023}, {'end': 1378.069, 'text': 'And only then do we want to try to select the text that will be in this div.', 'start': 1373.826, 'duration': 4.243}, {'end': 1380.231, 'text': "So let's jump back into our code.", 'start': 1378.709, 'duration': 1.522}, {'end': 1390.2, 'text': 'And just a quick note, we want to be sure to write this code before this code, because this code is changing the page that Chrome is pointing towards.', 'start': 1380.871, 'duration': 9.329}, {'end': 1395.686, 'text': 'Right This code is looping through the images and actually visiting the URLs for the images.', 'start': 1390.28, 'duration': 5.406}], 'summary': 'Simulate clicking on a button in node.js before selecting text in a div.', 'duration': 26.983, 'max_score': 1368.703, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1368703.jpg'}, {'end': 1526.392, 'src': 'heatmap', 'start': 1495.048, 'weight': 0.759, 'content': [{'end': 1500.792, 'text': "So just for a quick test to make sure that we actually have it right below it, let's log it to the Node.js console.", 'start': 1495.048, 'duration': 5.744}, {'end': 1502.994, 'text': 'So clicked data.', 'start': 1500.852, 'duration': 2.142}, {'end': 1505.016, 'text': "Let's give that a save and test it out.", 'start': 1503.014, 'duration': 2.002}, {'end': 1506.417, 'text': 'So node index.', 'start': 1505.076, 'duration': 1.341}, {'end': 1512.266, 'text': 'Awesome Down in our terminal we see dogs bark and cats meow.', 'start': 1508.985, 'duration': 3.281}, {'end': 1515.788, 'text': "Cool So it's that easy to simulate clicking on an element.", 'start': 1513.027, 'duration': 2.761}, {'end': 1517.469, 'text': "Let's move on to the next task.", 'start': 1516.068, 'duration': 1.401}, {'end': 1518.969, 'text': 'Actually the final task.', 'start': 1517.649, 'duration': 1.32}, {'end': 1526.392, 'text': "And what we want to do here is we have this form and you can see it's asking what color is the sky on a clear and sunny day.", 'start': 1519.549, 'duration': 6.843}], 'summary': 'Simulated clicking on element successfully in node.js console.', 'duration': 31.344, 'max_score': 1495.048, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1495048.jpg'}, {'end': 1558.281, 'src': 'embed', 'start': 1534.315, 'weight': 0, 'content': [{'end': 1540.417, 'text': 'But if I go back And I type in the correct answer of blue and submit the form we see.', 'start': 1534.315, 'duration': 6.102}, {'end': 1542.277, 'text': 'Congrats And let me zoom in a little bit.', 'start': 1540.497, 'duration': 1.78}, {'end': 1544.718, 'text': 'This is top secret text.', 'start': 1542.938, 'duration': 1.78}, {'end': 1554.94, 'text': 'And the idea is imagine that this was some sort of sensitive information that you only have access to if you submit a form with correct values,', 'start': 1545.278, 'duration': 9.662}, {'end': 1556.141, 'text': 'so you can use your imagination.', 'start': 1554.94, 'duration': 1.201}, {'end': 1558.281, 'text': 'This could be any sort of sensitive information.', 'start': 1556.161, 'duration': 2.12}], 'summary': 'Sensitive information accessed by submitting correct form values', 'duration': 23.966, 'max_score': 1534.315, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1534315.jpg'}, {'end': 1699.125, 'src': 'embed', 'start': 1671.428, 'weight': 1, 'content': [{'end': 1677.814, 'text': "In the real world, for most websites that you're going to use Puppeteer with, you could just actually use JavaScript to submit the form.", 'start': 1671.428, 'duration': 6.386}, {'end': 1683.82, 'text': 'But to simulate clicking on that button, I would just say await page dot click.', 'start': 1678.334, 'duration': 5.486}, {'end': 1689.158, 'text': 'And the selector for that button is just our form, the ID, our form.', 'start': 1684.875, 'duration': 4.283}, {'end': 1691.66, 'text': 'Look inside it for a button element.', 'start': 1689.778, 'duration': 1.882}, {'end': 1699.125, 'text': "Right after that, let's await the page transition, the network request to actually navigate to the new URL.", 'start': 1692.54, 'duration': 6.585}], 'summary': 'Puppeteer can simulate clicking a button using javascript, await page.click, and navigate to a new url.', 'duration': 27.697, 'max_score': 1671.428, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1671428.jpg'}], 'start': 1304.198, 'title': 'Simulating button click and automating form submission in puppeteer', 'summary': "Demonstrates simulating button click and automating form submission in puppeteer using css selectors, methods like page.click, and node.js. it also highlights successfully retrieving top secret text by entering the value 'blue'.", 'chapters': [{'end': 1487.983, 'start': 1304.198, 'title': 'Simulating button click in puppeteer', 'summary': 'Demonstrates how to simulate a button click in puppeteer to access dynamically generated content, using css selectors and methods like page.click and page.evaluate, before explaining the code execution order and providing a practical example.', 'duration': 183.785, 'highlights': ['Simulating a button click using page.click and accessing dynamically generated content using page.evaluate The chapter demonstrates how to simulate a button click in Puppeteer using page.click to access dynamically generated content and then use page.evaluate with a CSS selector to retrieve the text content of the targeted element.', 'Explanation of code execution order and practical example The chapter explains the importance of writing code in the correct order before providing a practical example and demonstrating the use of CSS selectors and methods like page.click and page.evaluate.']}, {'end': 1851.05, 'start': 1488.763, 'title': 'Automating form submission and data retrieval', 'summary': "Demonstrates the use of node.js and puppeteer to simulate clicking on an element, submitting a form with a specific value, waiting for page navigation change, and selecting sensitive data, successfully retrieving top secret text by entering the value 'blue' and navigating to the new page.", 'duration': 362.287, 'highlights': ["Successfully retrieving top secret text by entering the value 'blue' and navigating to the new page The chapter demonstrates the successful retrieval of sensitive information by submitting a form with the value 'blue', waiting for page navigation change, and selecting the top secret text, showcasing the effectiveness of the automation process.", 'Simulating clicking on an element and logging data to the Node.js console The process involves simulating the click on an element to log data to the Node.js console, providing a quick test to ensure the correct data is being captured and logged, showcasing the ease of simulating user interactions.', "Using Puppeteer to automate form submission and wait for network requests The demonstration involves using Puppeteer to automate form submission with the value 'blue', waiting for network requests, and utilizing the 'wait for navigation' method to ensure successful navigation to the new page, exemplifying the practical application of Puppeteer for automation."]}], 'duration': 546.852, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1304198.jpg', 'highlights': ["Demonstrates successfully retrieving top secret text by entering the value 'blue' and navigating to the new page", 'Using Puppeteer to automate form submission and wait for network requests', 'Simulating a button click using page.click and accessing dynamically generated content using page.evaluate', 'Explanation of code execution order and practical example', 'Simulating clicking on an element and logging data to the Node.js console']}, {'end': 2098.042, 'segs': [{'end': 1900.84, 'src': 'embed', 'start': 1874.534, 'weight': 2, 'content': [{'end': 1879.076, 'text': 'So in terms of scheduling or repeating this task you have a few different options.', 'start': 1874.534, 'duration': 4.542}, {'end': 1884.359, 'text': "So first of all let's get rid of this code at the bottom where we actually call our start function.", 'start': 1879.797, 'duration': 4.562}, {'end': 1887.621, 'text': 'Instead what if we wanted to call it every five seconds.', 'start': 1884.8, 'duration': 2.821}, {'end': 1891.023, 'text': 'You could just use a set interval.', 'start': 1888.221, 'duration': 2.802}, {'end': 1893.51, 'text': 'You give that two arguments.', 'start': 1892.369, 'duration': 1.141}, {'end': 1895.573, 'text': 'The first is the function you want to run.', 'start': 1893.53, 'duration': 2.043}, {'end': 1896.795, 'text': 'So we named it start.', 'start': 1895.733, 'duration': 1.062}, {'end': 1899.057, 'text': 'Second is how long you want to wait.', 'start': 1897.435, 'duration': 1.622}, {'end': 1900.84, 'text': 'So 5000 milliseconds.', 'start': 1899.158, 'duration': 1.682}], 'summary': 'To schedule the task to run every 5 seconds, use setinterval with the start function and a 5000-millisecond interval.', 'duration': 26.306, 'max_score': 1874.534, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1874534.jpg'}, {'end': 1972.86, 'src': 'embed', 'start': 1945.167, 'weight': 0, 'content': [{'end': 1948.65, 'text': 'First of all, let me show you the Node.js way of doing something like that.', 'start': 1945.167, 'duration': 3.483}, {'end': 1950.971, 'text': 'So I would install, let me clear this out.', 'start': 1948.89, 'duration': 2.081}, {'end': 1952.112, 'text': 'I would install a package.', 'start': 1951.051, 'duration': 1.061}, {'end': 1956.515, 'text': 'So npm install called node-cron.', 'start': 1952.152, 'duration': 4.363}, {'end': 1958.856, 'text': 'Okay, so install that.', 'start': 1956.535, 'duration': 2.321}, {'end': 1961.438, 'text': 'And then up at the very top, just include it in.', 'start': 1958.936, 'duration': 2.502}, {'end': 1967.521, 'text': 'So const cron equals require in node-cron.', 'start': 1961.518, 'duration': 6.003}, {'end': 1972.86, 'text': "And then down at the very bottom here, I'll just paste this in, but you can type it out.", 'start': 1968.122, 'duration': 4.738}], 'summary': 'Using node.js, install node-cron package for scheduling tasks.', 'duration': 27.693, 'max_score': 1945.167, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1945167.jpg'}, {'end': 2061.174, 'src': 'embed', 'start': 2021.631, 'weight': 1, 'content': [{'end': 2030.576, 'text': "task up and running forever and perhaps node runs into some unexpected error and then it doesn't know to restart itself to keep it up and running.", 'start': 2021.631, 'duration': 8.945}, {'end': 2036.639, 'text': 'So probably the most robust way of doing this of scheduling an automated task would be at the operating system level.', 'start': 2030.716, 'duration': 5.923}, {'end': 2038.54, 'text': 'This is where it gets a bit tricky though.', 'start': 2037.159, 'duration': 1.381}, {'end': 2041.341, 'text': "On Windows, I don't believe Windows has crontab.", 'start': 2038.68, 'duration': 2.661}, {'end': 2046.523, 'text': 'Mac has crontab, but Mac has so many security permission issues,', 'start': 2041.801, 'duration': 4.722}, {'end': 2051.065, 'text': 'you would need to explicitly give permission to like five different tasks in order to get it to work.', 'start': 2046.523, 'duration': 4.542}, {'end': 2061.174, 'text': "However, on Linux which, let's be real, that's what a server is 99% of the time going to be running it's very easy to set up a cron job using crontab.", 'start': 2051.465, 'duration': 9.709}], 'summary': 'Automated task scheduling may be best at os level, linux is easy to set up cron job', 'duration': 39.543, 'max_score': 2021.631, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI2021631.jpg'}], 'start': 1852.05, 'title': 'Automating tasks and scheduling with puppeteer and node.js', 'summary': 'Covers automating tasks with puppeteer, including running a task every 5 seconds, and scheduling automated tasks using node.js and cron jobs with node-cron installation, crontab syntax usage, and robustness at the operating system level.', 'chapters': [{'end': 1921.234, 'start': 1852.05, 'title': 'Automating tasks with puppeteer', 'summary': 'Discusses automating tasks with puppeteer, including using set interval to run a task every 5 seconds and the concept of automation continuing to run.', 'duration': 69.184, 'highlights': ['Using set interval to automate a task to run every 5 seconds, demonstrated by waiting for 5 seconds and observing the task running continuously.', 'The concept of automation is that it continues to run, providing continuous execution of tasks.']}, {'end': 2098.042, 'start': 1921.254, 'title': 'Scheduling automated tasks with node.js and cron jobs', 'summary': 'Discusses scheduling automated tasks using node.js and cron jobs, highlighting the installation of node-cron, the usage of crontab syntax for scheduling, and the robustness of scheduling tasks at the operating system level.', 'duration': 176.788, 'highlights': ["Installing 'node-cron' package to enable more controlled scheduling of automated tasks, as demonstrated by the usage of crontab syntax for scheduling, providing an alternative approach to running tasks at the operating system level which is considered the most robust way of handling scheduling.", 'Explaining the usage of crontab syntax for scheduling, utilizing the example of running a task only on the 14th hour of every day or a certain day of the month, and suggesting to explore further details on crontab or cronjob if interested in learning more about the syntax.', "Highlighting the robustness of scheduling tasks at the operating system level, particularly on Linux, and recommending a YouTube search for 'cron job' or 'crontab' for those interested in setting up automated tasks on a VPS, while emphasizing that calling the function once and leaving the scheduling to the operating system is the most robust way of handling tasks."]}], 'duration': 245.992, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/lgyszZhAZOI/pics/lgyszZhAZOI1852050.jpg', 'highlights': ["Installing 'node-cron' package for controlled scheduling of tasks using crontab syntax.", 'Utilizing crontab syntax for scheduling tasks at the operating system level.', 'Using set interval to automate a task to run every 5 seconds.', 'Highlighting the robustness of scheduling tasks at the operating system level.']}], 'highlights': ['Puppeteer allows programmatically controlling Google Chrome to simulate interactions like clicking buttons, filling forms, and accessing data on password-protected pages.', 'Developers often encounter situations where certain data or features are only accessible through the website, necessitating the need for programmatically simulating human interactions with the headless version of Google Chrome.', 'Programmatically controlling Google Chrome through Puppeteer offers an easier solution for developers in such scenarios.', 'Using asynchronous functions to launch a browser and create a new page', 'Installing Puppeteer and creating a JavaScript file', 'The chapter emphasizes the process of navigating to a specific URL and taking screenshots using Puppeteer', 'Using Puppeteer to extract names from a web page with 100 or 500 different names for extraction', "Puppeteer's $$eval function simplifies selecting multiple elements, avoiding array manipulation.", "Demonstrates successfully retrieving top secret text by entering the value 'blue' and navigating to the new page", "Installing 'node-cron' package for controlled scheduling of tasks using crontab syntax."]}