Скачать или смотреть Resolving the DISPLAY Environment Variable Error in Selenium with Firefox

Learn how to troubleshoot the `no DISPLAY environment variable specified` error in Selenium when using Firefox on Ubuntu. Follow our step-by-step guide to resolve this issue effectively.
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This video is based on the question https://stackoverflow.com/q/70979924/ asked by the user 'Jamie Chang' ( https://stackoverflow.com/u/10343160/ ) and on the answer https://stackoverflow.com/a/70980441/ provided by the user 'Jamie Chang' ( https://stackoverflow.com/u/10343160/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting the no DISPLAY environment variable specified Error in Selenium with Firefox

If you are using Selenium with Firefox on Ubuntu and encountering the frustrating error message:

[[See Video to Reveal this Text or Code Snippet]]

you are not alone. This common issue arises particularly in headless browser testing when the required display settings aren't configured properly. Fortunately, there's a straightforward solution that will allow you to run your Selenium tests smoothly. In this guide, we'll guide you step-by-step through resolving this error.

Understanding the Problem

When running Selenium tests with Firefox in headless mode, you might come across the error indicating that the DISPLAY environment variable is not specified. This can be perplexing, especially when you have set the --headless arguments in your code. The main reason behind this error is that Selenium, while trying to execute the Firefox driver, doesn't find a display setting, which is crucial for rendering the browser in headless mode.

Example of the Problem

Here's a simplified version of the code you might be using:

[[See Video to Reveal this Text or Code Snippet]]

You notice the following error in your logs:

[[See Video to Reveal this Text or Code Snippet]]

Upon digging deeper, the logs will reveal that Firefox is trying to run commands but fails because it cannot find the display settings.

Implementing the Solution

The solution to this error is quite simple. The underlying cause stems from how you are instantiating the webdriver.Firefox. In your provided code, there is a small yet crucial error in the parameters being passed to the webdriver.Firefox() method.

Correcting the Parameters

Instead of using firefox_options=opt, you should use options=opt. Here's the corrected version of your code:

[[See Video to Reveal this Text or Code Snippet]]

Key Takeaway

Change firefox_options=opt to options=opt: This small correction in your code is essential for the proper initialization of the Firefox driver in headless mode.

Confirm Your Geckodriver Path: Ensure that the path you are providing to the Service is correct: "/usr/local/bin/firefox/geckodriver" should point directly to your Geckodriver executable.

Conclusion

With these adjustments, you should now be able to run your Selenium tests using Firefox without encountering the no DISPLAY environment variable specified error. Just remember to always check the way you're initializing the driver when troubleshooting similar issues in the future.

If you found this guide helpful, don't hesitate to share it with others who might be facing the same problem. Happy testing!