reading-notes

Differences between scraping static and dynamic websites:

• Static websites: Static websites are composed of HTML files that are served as-is from the server to the client. The content of a static website does not change dynamically, and the entire page can be obtained with a single HTTP request. Scraping static websites typically involves parsing the HTML structure and extracting the desired data directly.
• Dynamic websites: Dynamic websites generate content on the client-side using JavaScript or other scripting languages. The initial HTML response from the server may contain only a skeleton structure, and the actual content is loaded and rendered dynamically using JavaScript. Scraping dynamic websites requires executing JavaScript code to interact with the page, simulate user actions, and extract the data.

Techniques to avoid getting blocked while scraping websites:

• Respect the website’s terms of service: Always review the website’s terms of service and make sure your scraping activities comply with them. Some websites explicitly prohibit scraping or have specific guidelines you need to follow.
• Use request headers: Set appropriate user-agent headers to mimic a real browser and include other relevant headers such as referer and accept-language. This helps make your requests look more like legitimate traffic.
• Implement rate limiting and delays: Avoid sending a large number of requests in a short period. Introduce delays between requests to simulate human behavior. Respect robots.txt directives and avoid scraping too frequently.

Playwright and its benefits in web scraping:

Playwright is a tool developed by Microsoft that allows automation and scraping of web pages. It provides a high-level API for interacting with web browsers programmatically. Playwright supports multiple browsers like Chrome, Firefox, and WebKit, and it can emulate user interactions like clicks, form submissions, and scrolling. Playwright is particularly beneficial for web scraping tasks because it handles the rendering and execution of JavaScript on the page, making it easier to scrape dynamic websites. It also provides features like headless and proxy support, cookies and sessions management, and capturing screenshots or videos of the browsing session.

Example use case:

Suppose you need to scrape an e-commerce website that heavily relies on JavaScript to load product details and images. Using Playwright, you can automate the process of navigating to product pages, interacting with elements, and extracting the necessary data. Playwright’s ability to render JavaScript ensures that you retrieve the complete and up-to-date content of the website.

Purpose of using Xpath in web scraping:

XPath (XML Path Language) is a query language used to navigate and select elements in an XML or HTML document. In web scraping, XPath is commonly used to locate specific elements within the HTML structure for extraction. XPath expressions provide a concise and flexible way to identify elements based on their attributes, position, or hierarchical relationships. It allows you to traverse the document tree and select elements using various criteria.

Example XPath expression:

Suppose you want to select all the links ( tags) with the class attribute set to “external” from an HTML page. The corresponding XPath expression would be:

//a[@class='external']

This expression selects all elements anywhere in the document that have the class attribute set to “external”. You can modify the XPath expression to target different elements or add additional conditions based on your scraping requirements.