I have the following code :
what = re.match("get|post|put|head\s+(\S+) ",data,re.IGNORECASE)and in the data variable let's say I have this line :
GET some-site.com HTTP/1.0 ...
If I stop the script in the debugger, and inspect the what variable, I can see it only matched GET. Why doesn't it match some-site.com ?
Regex language operator precedence puts head\s+(\S+) as the 4th alternative. The parenthesis in @Mykola Kharechko's answer arrange for head as the 4th alternative, and \s+(\S+) is appended to whatever alternative matched the group.
>>> re.match("(get|post|put|head)\s+(\S+) ",'GET some-site.com HTTP/1.0 ...',re.IGNORECASE).groups()
('GET', 'some-site.com')
>>>
+1 Mykola's answer and gimel's explanation. In addition, do you really want to use regex for this? As you've found out, they are not as straightforward as they look. Here's a non-regex-based method:
def splitandpad(s, find, limit):
seq= s.split(find, limit)
return seq+['']*(limit-len(seq)+1)
method, path, protocol= splitandpad(data, ' ', 2)
if method.lower() not in ('get', 'head', 'post', 'put'):
# complain, unknown method
if protocol.lower() not in ('http/1.0', 'http/1.1'):
# complain, unknown protocol
