POST request not passed

Question

I tried to send POST query with this code:

def open(self, url, params): 
 self.__opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookielib.CookieJar()))
 c = self.__opener.open(
 urllib2.Request(
 url,
 urllib.urlencode(params),
 {"User-agent": "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"}
 )
 )
Class.open('http://example.com', {'username': 'test'});

But server say to me that username field is empty.

urllib.Request('http://example.com?username=test');

it works perfectly. How to fix it?

• abarnert: This isn't Python 3. There is no urllib2 in Python 3. And, while there is a urllib, it's just a package with modules in it, not a module with a class called Request. So, first tell us which version you're actually using.
• qwerty: @abarnert, sorry. I tried to interpret it in Python 2.7.5.
• abarnert: OK, next problem. In the first version, you're passing username=test (www-form-encoded) as the body. In the second version (I'm assuming you actually used urllib2.Request there, because there's no such thing as urllib.Request?), you're passing it in the query string. While many web services will treat the two as the same thing, there's no requirement that they do so.

Answer 1

You are sending the data in the request body; this is perfectly normal in a POST request. However, http://example.com?username=test is not a POST request; that's a GET instead.

You can do the same with urlencode(); just add it to the URL with ?:

c = self.__opener.open(
 urllib2.Request(
 url + '?' + urllib.urlencode(params),
 {"User-agent": "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"}
 )
)

• abarnert: You could also use urlparse.urlunparse or a similarly higher-level function instead of string manipulation, which would work if you, e.g., got a URL that already had a query string.
• qwerty: It's so strangely. Form action param is post. Please, see this repo: github.com/Ejz/Common/blob/master/carnage-bot/bot.py (urlopen method) I think it works, but why my code doesn't work?
• Martijn Pieters: @qwerty: that depends on the server; if the server accepts your GET request but rejects the POST, then stick with GET.