Python Regular Expression for SIP URI variables?

Question

I am using this regular expression for SIP (Session Initiation Protocol) URIs to extract the different internal variables.

_syntax = re.compile('^(?P<scheme>[a-zA-Z][a-zA-Z0-9\+\-\.]*):'  # scheme
        + '(?:(?:(?P<user>[a-zA-Z0-9\-\_\.\!\~\*\'\(\)&=\+\$,;\?\/\%]+)' # user
        + '(?::(?P<password>[^:@;\?]+))?)@)?' # password
        + '(?:(?:(?P<host>[^;\?:]*)(?::(?P<port>[\d]+))?))'  # host, port
        + '(?:;(?P<params>[^\?]*))?' # parameters
        + '(?:\?(?P<headers>.*))?$') # headers

m = URI._syntax.match(value)
    if m: 
        self.scheme, self.user, self.password, self.host, self.port, params, headers = m.groups()

I need to modify this expression to support IPv6 and match all the different types of SIP URIs. The basic idea is that IPv4 shows the form 192.168.0.1 and IPv6 2620:0:2ef0:7070:250:60ff:fe03:32b7. Beacause the port number is after :, the IPv6 is between brakets in the SIP URI.

Its general form is:

sip:user:password@host:port;uri-parameters?headers

These are some examples:

uriList = [
   'sip:192.1.2.3',
   'sip:[email protected]',
   'sip:192.1.2.3:5060',
   'sips:123@[2620:0:2ef0:7070:250:60ff:fe03:32b7]',
   'sip:[2620:0:2ef0:7070:250:60ff:fe03:32b7]',
   'sip:[2620:0:2ef0:7070:250:60ff:fe03:32b7]:5060',
   'sips:[email protected]',
   'sip:[email protected]:6000',
   'sip:thks.ashwin:[email protected]',
   ]

Output

Scheme: sip, User: , Host: 192.1.2.3, Port: 
Scheme: sip, User: 123, Host: 192.1.2.3, Port: 
Scheme: sip, User: , Host: 192.1.2.3, Port: 5060
Scheme: sips, User: 123, Host: 2620:0:2ef0:7070:250:60ff:fe03:32b7, Port: 
Scheme: sip, User: , Host: 2620:0:2ef0:7070:250:60ff:fe03:32b7, Port: 
Scheme: sip, User: , Host: 2620:0:2ef0:7070:250:60ff:fe03:32b7, Port: 5060
Scheme: sips, User:support , Host: voip.example.com
Scheme: sip, User:22444032 , Host: voip.example.com, Port: 6000
Scheme: sip, User:thks.ashwin, Password:pass ,Host: 212.123.1.213

I tried to modify the host expression to match both [IPv6] and IPv4 expression but without luck =´(

I've been using https://pythex.org/ to test the results.

Answer 1

There are no headers and params in your example, so I dont know how they show up. But you can use the following code to match your example strings:

[EDIT1 - Added regex to match hostname strings and support for user:password, based on OPs new example URIs]

[EDIT2 - Added the params and headers regex and commented more on the 'OR' part of the regex]

import re

uriList = [
        'sip:192.1.2.3',
        'sip:[email protected]',
        'sip:192.1.2.3:5060',
        'sip:123@[2620:0:2ef0:7070:250:60ff:fe03:32b7]',
        'sip:[2620:0:2ef0:7070:250:60ff:fe03:32b7]',
        'sip:[2620:0:2ef0:7070:250:60ff:fe03:32b7]:5060',
        'sips:[email protected]',
        'sip:[email protected]:6000',
        'sip:support:[email protected]',
        'sip:support:[email protected];urlparams=test',
        'sip:support:[email protected]?auth=basic',
        'sip:support:[email protected];urlparams=test?auth=basic',
        ]

mPattern = re.compile(
                        '(?P<scheme>\w+):' #Scheme
                        +'(?:(?P<user>[\w\.]+):?(?P<password>[\w\.]+)?@)?' #User:Password
                        +'\[?(?P<host>' #Begin group host
                            +'(?:\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})|' #IPv4 address Host Or
                            +'(?:(?:[0-9a-fA-F]{1,4}):){7}[0-9a-fA-F]{1,4}|' #IPv6 address Host Or
                            +'(?:(?:[0-9A-Za-z]+\.)+[0-9A-Za-z]+)'#Hostname string
                        +')\]?:?' #End group host
                        +'(?P<port>\d{1,6})?' #port
                        +'(?:\;(?P<params>[^\?]*))?' # parameters
                        +'(?:\?(?P<headers>.*))?' # headers
                        )
groupNamesList = ['scheme', 'user', 'password', 'host', 'port', 'params', 'headers'] #List of group Names

for uri in uriList: #iterate through the list of uri
    mObject = mPattern.search(uri) #pattern search
    if mObject: #if you find a match
        groupStrings = [mObject.group(groupName) if mObject.group(groupName) else '' for groupName in groupNamesList] #extract your groupStrings
        print('Scheme: {0}, User: {1}, Password: {2}, Host: {3}, Port: {4}, Params: {5}, Headers: {6}'.format(*groupStrings)) #print groupStrings

The Output I get it:

Scheme: sip, User: , Password: , Host: 192.1.2.3, Port: , Params: , Headers: 
Scheme: sip, User: 123, Password: , Host: 192.1.2.3, Port: , Params: , Headers: 
Scheme: sip, User: , Password: , Host: 192.1.2.3, Port: 5060, Params: , Headers: 
Scheme: sip, User: 123, Password: , Host: 2620:0:2ef0:7070:250:60ff:fe03:32b7, Port: , Params: , Headers: 
Scheme: sip, User: , Password: , Host: 2620:0:2ef0:7070:250:60ff:fe03:32b7, Port: , Params: , Headers: 
Scheme: sip, User: , Password: , Host: 2620:0:2ef0:7070:250:60ff:fe03:32b7, Port: 5060, Params: , Headers: 
Scheme: sips, User: support, Password: , Host: voip.example.com, Port: , Params: , Headers: 
Scheme: sip, User: 22444032, Password: , Host: voip.example.com, Port: 6000, Params: , Headers: 
Scheme: sip, User: support, Password: pass, Host: 212.123.1.213, Port: , Params: , Headers: 
Scheme: sip, User: support, Password: pass, Host: 212.123.1.213, Port: , Params: urlparams=test, Headers: 
Scheme: sip, User: support, Password: pass, Host: 212.123.1.213, Port: , Params: , Headers: auth=basic
Scheme: sip, User: support, Password: pass, Host: 212.123.1.213, Port: , Params: urlparams=test, Headers: auth=basic

Try this out and see if it works for you