{"id":6514,"date":"2023-10-18T14:47:43","date_gmt":"2023-10-18T14:47:43","guid":{"rendered":"https:\/\/royadata.io\/blog\/?p=6514"},"modified":"2023-10-18T14:47:43","modified_gmt":"2023-10-18T14:47:43","slug":"how-to-build-a-web-crawler-using-selenium-proxies","status":"publish","type":"post","link":"http:\/\/royadata.io\/blog\/how-to-build-a-web-crawler-using-selenium-proxies\/","title":{"rendered":"Building a Web Crawler Using Selenium and Proxies"},"content":{"rendered":"

\"Web\n<\/picture>\n

Once upon a time, people looking for information had to physically walk into a brick-and-mortar library, find the right books, and read through them intently.<\/p>\n

Today, it seems a given that whatever data you\u2019re looking for exists on the Internet. There are over a billion websites on the World Wide Web at any given moment, containing enough information to take up out 305 billion printed sheets of paper.<\/p>\n

The good news is that no matter what kind of data you\u2019re looking for, you can be sure to find it online. The bad news is that there is so much data online that personally sifting through it borders on the physically impossible.<\/p>\n

\"World\n<\/picture>\n

Add in the fact that most websites have different scopes, formats, and frameworks. About 30% of websites use WordPress<\/a><\/strong>, for instance, and the rest use a variety of other platforms like Joomla, Drupal, Magento, etc.<\/p>\n

Enter web crawling. Web crawlers are automated data-gathering tools that interact with websites on their owners\u2019 behalf. This lets you access reams of data ready for output to a local database or spreadsheet for further analysis.<\/p>\n

Although it may sound complicated, the truth is that building a web crawler using Selenium<\/a> is a pretty straightforward process. Let\u2019s dive in and find out exactly what you need to get started.<\/p>\n

\"Two\n<\/picture>\n

<\/span>There are Two Ways to Crawl Web Data<\/span><\/h2>\n

One of the first obstacles you\u2019ll encounter when learning how to build a web crawler using Selenium is the fact that websites don\u2019t seem to like it. Web crawlers generate a lot of tra\ufb03c, and website administrators tend to feel like web crawlers abuse the server resources they make available to the public.<\/p>\n

But major Internet companies like Google crawl data all the time. The only di\ufb00erence is that they ask permission and offer something in return (in Google\u2019s case, placement on the world\u2019s number-one search engine). What do you do if you need access to data and don\u2019t have the convenient backing of a powerful economic incentive on your side?<\/p>\n

You can use Selenium to collect data from websites through a browser \u2013 just like a regular user would. But since web administrators don\u2019t like it, you\u2019ll need the proxy to hide your identity<\/strong> behind so that they can\u2019t trace the activity back to you.<\/p>\n

Depending on your jurisdiction and the jurisdiction of the website you want to access, using a proxy could be a life-saver. In 2011, a court in British Columbia<\/strong><\/a> punished a company for scraping content from a real estate website, but more recent cases allow crawling of publicly-accessible content.<\/p>\n

Journalists, data analysts, and programmers generally don\u2019t have the resources Google brings to the table when it asks for web crawler access.<\/p>\n\n

<\/span>Selenium \u2013 How it Works and Why You Should Use It<\/span><\/h2>\n

There are lots of tools and platforms you can use to scrape web data, but most have limitations. For instance, if you use the Python module Scrapy<\/strong><\/a>, you can only access websites that don\u2019t feature JavaScript-heavy user interfaces.<\/p>\n

Selenium is a simple tool for automating browsers. With Selenium, you can automate a web browser like Google Chrome or Safari so that any website is crawl-compatible.<\/p>\n

The first step is downloading and setting up Selenium. You will need to download a version of Selenium specifically tailored to your browser. For Google Chrome, for instance, this is called ChromeDriver<\/a><\/strong>.<\/p>\n

When you extract the file (ChromeDriver.exe, for instance), make sure to remember where you put it, because you\u2019ll need it later.<\/p>\n

In order to use Selenium to build a web crawler, you\u2019ll need some extra Java modules. This requires a little bit of coding, but it\u2019s not that complicated. First, install Maven<\/a><\/strong>, which is what you\u2019re going to use to build the Java program.<\/p>\n

\"Use\n<\/picture>\n

Once Maven is ready, you must add this dependency to POM.xml:<\/p>\n

Now just run the build process and you\u2019re ready to take your first steps with Selenium.<\/p>\n\n

<\/span>Basic Introduction to Using Selenium<\/strong><\/span><\/h2>\n

\"Basic\n<\/picture>\n

Let\u2019s start with something simple. First, create an instance of ChromeDriver:<\/p>\n

\n

WebDriver driver = new ChromeDriver();<\/p>\n<\/blockquote>\n

Now you\u2019ll have a Google Chrome window open. To navigate to a web page, use this command (using example.com as an example):<\/p>\n

\n

driver.get(\u201chttp:\/\/www.example.com\u201d);<\/p>\n<\/blockquote>\n

To locate HTML elements on a page, use WebDriver.findElement()<\/strong>. To get the page title, your command should look like this:<\/p>\n

\n

System.out.println(\u201cTitle: \u201d +
\ndriver.getTitle());<\/p>\n<\/blockquote>\n

This is how Selenium works. It assigns a coding matrix to the browser so that you can automate the things you would normally do by hand. It\u2019s a simple, and powerful way to complete a broad variety of time-intensive tasks. To close out the session, use this command:<\/p>\n

driver.quit();<\/p>\n

And that\u2019s it. You\u2019ve successfully controlled a browser session using Java in Selenium.<\/p>\n

To learn more about using Selenium as a web crawler, use this GitHub tutorial<\/a><\/strong>. Once you know the commands and understand the methodology, the entire Internet is open to you.<\/p>\n