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27 Oct, 4 tweets, 2 min read
New post! Web #Scraping: Intercepting XHR Requests.

Take advantage of XHR requests and scrape websites content without any effort. No need for fickle HTML or CSS selectors, API endpoints tend to remain stable.…
@playwrightweb and other headless browsers allow response/request interception. We can take advantage and inspect them easily.

Those responses usually come already formatted and structured.
We covered,, and as examples, but the opportunities are infinite.

And not just for the first load, but from any subsequent browsing. The same rules apply.
To detect those cases, browse with the DevTools Network tab open and watch for XHR requests. Check the HTML (view page source) in case of doubt, and look for relevant data points (product name, price, whatever). If they're not there, search each request for the data. Image

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More from @AnderRV_

29 Dec
3 days to finish the year, and I decided to do a countdown with the TOP 3 blog posts I've written in 2021. And some context. 🧵

Direct to #3: DOs and DON'Ts of Web #Scraping…
Published December 21, the last one of the year, and straight to #3! No way we could have seen it coming.

SEO wasn't relevant here, no time for it to work either. #GoogleDiscover launched us there in our official blog. But even in other sites we publish, it has great numbers.
Coming in at #2 is Web Scraping with #Javascript and #NodeJS

Probably the longest and with more code in the whole lot. Published on September 1, the primary source in Google through SEO. Many interesting keywords in high positions.…
Read 7 tweets
21 Dec
New post! DOs and DON'Ts of Web #Scraping

Learn how to create better web scrapers by following best practices and avoiding common mistakes. Choose the right approach for the job thanks to these tips.…
1. DO Rotate IPs

The most common anti-scraping solution is to ban by IP. By using proxies, you'll avoid showing the same IP in every request and thus increasing your chances of success. You can code your own or use a Rotating Proxy like
2. DO Use Custom User-Agent

Overwrite your client's User-Agent, or you'll risk sending something like "curl/7.74.0".

But always sending the same UA might be suspicious, too, so you need a vast and updated list.
Read 10 tweets
30 Nov
New post! Web Scraping with Selenium in Python.

Learn how to navigate and scrape websites using @SeleniumHQ in #Python, even dynamic content, thanks to Javascript Rendering and other available features.…
After installing and launching the basics, we will start selecting elements using several ways. That will allow us to interact with them to click or fill in forms.

For the particular case of infinite scroll or lazy loaded content, we'll take advantage of sending keyboard inputs.
Another typical use case is to wait for an element to be present. That might happen in dynamic pages loaded via XHR. The initial HTML is just a skeleton with no actual content.

We can wait for the content to be present before starting the data extraction.
Read 8 tweets
29 Sep
New post! Blocking Resources in Playwright 🚧

Save time and money by downloading only the essential resources while web scraping or testing.…
Learn how to use @playwrightweb in #python to avoid CSS files, images, or Javascript from loading and executing.

You can use glob ("**/*.svg") or #regex (r"\.(jpg|png|svg)$").
For more general use, you can access requests resource type, for example image:
route.request.resource_type == "image"

And being even more aggressive, allow only documents:
route.request.resource_type != "document"…
Read 7 tweets
1 Sep
New post! Web Scraping with #Javascript and #NodeJs.
Learn how to build a web scraper, add anti-blocking techniques, a headless browser, and parallelize requests with a queue.…
You'll first build a web scraper using Axios and Cheerio, then a headless browser - Playwright.
Start by getting the HTML and parsing the content for new links to follow, applying Cheerio and CSS Selectors. Extract also content similarly.
Follow the gathered links and start a loop that will iterate over all links we find.
To avoid problems, set a maximum limit and store a list with the already visited URLs to prevent duplicates.
Read 7 tweets
29 Jul
New post! Stealth Web Scraping in #Python: Avoid Blocking Like a Ninja. We share the best techniques for massive scale scraping.
From the basic, such as avoiding rate limits or adding proxies, to more complex as full set of headers or behavioral patterns.…
For the basic defensive protections, rotating proxies with the correct headers should be enough.

For a bit more complex ones, maybe residential IPs are necessary.

Captchas can be solved nowadays, but it is best to bypass them. The same applies to login or paywalls.
Sending real-world User-Agents is important. But not enough, since there are other headers involved, i.e. sec-ch-ua or sec-fetch-dest.

They all should be used together, to avoid suspicion.
Read 8 tweets

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