How to get a redirected url without using a Selenium in Python

If this is just an HTTP redirect, urllib.request/urllib2 in the standard library can follow redirects just fine, as can third-party HTTP client libraries like requests and PycURL. In fact, in the simplest use cases, they do so automatically.

So, just:

>>> import urllib.request
>>> original_url = 'http://registry.theknot.com/track/View?lt=RetailerGVR&r=325404419&rt=12160&a=994&st=RegistryProfile&ss=LinkedRegistries&sp=Logo'
>>> u = urllib.request.urlopen(original_url)
>>> print(u.url)
http://www.target.com/RegistryGiftGiverCmd?isPreview=false&status=completePageLink&registryType=WD&isAjax=false&listId=NjPO_i-DoIafZPZSFhaBRw&clkid=0b5XTmU%3A5WbqRETSYD20AQKOUkWXSGQgQSquVU0&lnm=Online+Tracking+Link&afid=The+Knot%2C+Inc.+and+Subsidiaries&ref=tgt_adv_xasd0002

But if you just want the data, you don't even need that:

>>> data = u.read()

That's the contents of the redirected request.

(For Python 2.x, just replace urllib.request with urllib2 and it works the same.)

The only reason you'd need to use Selenium (or another browser automation and/or JS-environment library) is if the redirect is done through in-page JavaScript. Which it usually isn't, and isn't in this case. There's no reason to go outside the standard library, talk to another app, etc. for simple things like this.