How to Retrieve HTTP Status Codes
Intro
There are times when you are testing a page (or numerous pages) and you want to verify that it responded correctly. A great way to handle this is by checking the HTTP Status Code that the browser received. However, this functionality is not available in Selenium WebDriver.
A Solution
The tried and true approach that Selenium practitioners used to recommend was a proxy server (e.g., BrowserMob Proxy), which watches the network traffic between the browser and the application. It works, but it is one more thing to download, start, configure, and keep up to date.
Nowadays the browser can tell us itself. The Navigation Timing API
keeps an entry for the page that was loaded, and its responseStatus property is the HTTP status code of the
response. So we can read it with a small piece of JavaScript executed through Selenium:
return performance.getEntriesByType('navigation')[0].responseStatus
It works in all modern browsers, with no proxy and no extra libraries.
NOTE: It gives us the status code of the page we navigated to. If you need the status codes of other requests (e.g., images, scripts, or API calls), have a look at the network features of WebDriver BiDi.
Example
NOTE: We are using a status codes example found on
the-internet. It has a page that returns each of these status codes:
200, 301, 404, and 500.
We add a small helper that executes the script above and returns the status code. Then, for each of the status codes, we visit its page and check that the helper returns the code we expect.
Expected Behavior
- Browser opens
- Visit the page that returns the status code
- Retrieve the status code with the Navigation Timing API
- Assert that it is the status code we expect
- Browser closes
Summary
Hopefully this tip will help you add a quick check of the HTTP status codes to your tests.
The original version of this tip was inspired by Jim Evans' multi-part blog post series on doing the same thing in C# with Fiddler (1, 2, 3), which was in response to Selenium Issue 141. Thanks, Jim!
Happy Testing!
Authors
