Answer

Why Your Requests Might Not Be Intercepted in Playwright

You might be wondering why certain requests from a specific component aren't being intercepted by the page.route() method in Playwright. Let's dive into some possible reasons.

Service Workers

Service Workers are scripts that run in the background of your browser, separate from a web page. They can take over network requests, making them invisible to browserContext.route() and page.route(). If you're using Playwright's native browserContext.route() and page.route(), and it seems like network events are missing, you should disable Service Workers. Here's how you can do it:

const context = await browser.newContext({
  serviceWorkers: 'block'
});

Mock Tools

Mock tools like Mock Service Worker (MSW) can also interfere. MSW works great for mocking responses, but it adds its own Service Worker that takes over network requests. This makes these network requests invisible to both browserContext.route() and page.route(). If you're interested in both network testing and mocking, consider using built-in browserContext.route() and page.route() for response mocking.

Experimental Feature

Lastly, if you're interested in not only using Service Workers for testing and network mocking but also routing and listening for requests made by Service Workers themselves, there's an experimental feature available.

In conclusion, while Playwright provides powerful APIs like page.route() for monitoring or modifying HTTP/HTTPS traffic including XHRs & fetches request made by pages, certain factors like service workers or mock tools can interfere with their ability to intercept all types of request effectively. Understanding these nuances is crucial when working with Playwright's networking capabilities.