How to detect when Selenium loads a browser's error page
Is there a universal way to detect when a selenium browser opens an error page? For example, disable your internet connection and do
driver.get("http://google.com")
In Firefox, Selenium will load the 'Try Again' error page containing text like "Firefox can't establish a connection to the server at www.google.com." Selenium will NOT throw any errors.
Is there a browser-independent way to detect these cases? For firefox (python), I can do
if "errorPageContainer" in [ elem.get_attribute("id") for elem in driver.find_elements_by_css_selector("body > div") ]
But (1) this seems like computational overkill (see next point below) and (2) I must create custom code for every browser.
If you disable your internet and use htmlunit as the browser you will get a page with the following html
<html>
<head></head>
<body>Unknown host</body>
</html>
How can I detect this without doing
if driver.find_element_by_css_selector("body").text == "Unknown host"
It seems like this would be very expensive to check on every single page load since there would usually be a ton of text in the body.
Bonus points if you also know of a way to detect the type of load problem, for example no internet connection, unreachable host, etc.
Answer
WebDriver API doesnot expose HTTP status codes , so if you want to detect/manage HTTP errors, you should use a debugging proxy.
See Jim's excellent post Implementing WebDriver HTTP Status on how to do exactly that.