Python and urllib2: how to make a GET request with parameters

I'm building an "API API", it's basically a wrapper for a in house REST web service that the web app will be making a lot of requests to. Some of the web service calls need to be GET rather than post, but passing parameters.

Is there a "best practice" way to encode a dictionary into a query string? e.g.: ?foo=bar&bla=blah

I'm looking at the urllib2 docs, and it looks like it dec开发者_C百科ides by itself wether to use POST or GET based on if you pass params or not, but maybe someone knows how to make it transform the params dictionary into a GET request.

Maybe there's a package for something like this out there? It would be great if it supported keep-alive, as the web server will be constantly requesting things from the REST service.

Ideally something that would also transform the XML into some kind of traversable python object.

Thanks!

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Is urllib.urlencode() not enough?

>>> import urllib
>>> urllib.urlencode({'foo': 'bar', 'bla': 'blah'})
foo=bar&bla=blah

EDIT:

You can also update the existing url:

  >>> import urlparse, urlencode
  >>> url_dict = urlparse.parse_qs('a=b&c=d')
  >>> url_dict
  {'a': ['b'], 'c': ['d']}
  >>> url_dict['a'].append('x')
  >>> url_dict
  {'a': ['b', 'x'], 'c': ['d']}
  >>> urllib.urlencode(url_dict, True)
  'a=b&a=x&c=d'

Note that parse_qs function was in cgi package before Python 2.6

EDIT 23/04/2012:

You can also take a look at python-requests - it should kill urllibs eventually :)

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urllib.urlencode

And yes, the urllib / urllib2 division of labor is a little confusing in Python 2.x.

---

import urllib
data = {}
data["val1"] = "VALUE1"
data["val2"] = "VALUE2"
data["val3"] = "VALUE3"
url_values = urllib.urlencode(data)
url = "https://www.python.org"
print url + "?" + url_values

The url_values is an encoded values and can be used to post to the server along with url as a query string(url+"?"+url_values).