Selenium wait for download?

Question

I'm trying to test the happy-path for a piece of code which takes a long time to respond, and then begins writing a file to the response output stream, which prompts a download dialog in browsers.

The problem is that this process has failed in the past, throwing an exception after this long amount of work. Is there a way in selenium to wait-for-download or equivalent?

I could throw in a Thread.sleep, but that would be inaccurate and unnecessarily slow down the test run.

What should I do, here?

Answer 1

I had the same problem. I invented something to solve the problem. A tempt file is created by Python with '.part' extension. So, if still we have the temp, python can wait for 10 second and check again if the file is downloaded or not yet.

 while True:
        if os.path.isfile('ts.csv.part'):
            sleep(10)
        elif os.path.isfile('ts.csv'):
            break
        else:
            sleep(10)
 driver.close()

Answer 2

So you have two problems here:

1. You need to cause the browser to download the file
2. You need to measure when the downloaded file is complete

Neither problemc an be directly solved by Selenium (yet - 2.0 may help), but both are solvable problems. The first problem can be solved by GUI automation toolkits, such as AutoIT. But they can also be solved by simply sending an automated keypress at the OS level that simulates the enter key (works for Firefox, a little harder on some versions of Chrome and Safari). If you're using Java, you can use Robot to do that. Other languages have similar toolkits to do such a thing.

The second issue is probably best solved with some sort of proxy solution. For example, if your browser was configured to go through a proxy and that proxy had an API, you could query the proxy with that API to ask when network activity had ended.

That's what we do at http://browsermob.com, which is a a startup I founded that uses Selenium to do load testing. We've released some of the proxy code as open source, available at http://browsermob.com/tools.

But two problems still persist:

1. You need to configure the browser to use the proxy. In Selenium 2 this is easier, but it's possible to do it with Selenium 1 as well. The key is just making sure that your browser launcher brings up the browser with the right profile/settings.
2. There currently is no API for BrowserMob proxy to tell you when network traffic has stopped! This is a big hole in the concept of the project that I want to fix as soon as I get the time. However, if you're keen to help out, join the Google Group and I can definitely point you in the right direction.

Hope that helps you identify your various options. Best of luck!