from rfc3986 import uri_reference

example = uri_reference('http://example.com')
email = uri_reference('mailto:user@domain.com')
ssh = uri_reference('ssh://user@git.openstack.org:29418/openstack/keystone.git')

With a parsed URI you can access data about the components:

print(example.scheme)  # => http
print(email.path)  # => user@domain.com
print(ssh.userinfo)  # => user
print(ssh.host)  # => git.openstack.org
print(ssh.port)  # => 29418

It can also parse URIs with unicode present:

uni = uri_reference(b'http://httpbin.org/get?utf8=\xe2\x98\x83')  # ☃
print(uni.query)  # utf8=%E2%98%83

With a parsed URI you can also validate it:

if ssh.is_valid():
    subprocess.call(['git', 'clone', ssh.unsplit()])

You can also take a parsed URI and normalize it:

mangled = uri_reference('hTTp://exAMPLe.COM')
print(mangled.scheme)  # => hTTp
print(mangled.authority)  # => exAMPLe.COM

normal = mangled.normalize()
print(normal.scheme)  # => http
print(mangled.authority)  # => example.com

But these two URIs are (functionally) equivalent:

if normal == mangled:
    webbrowser.open(normal.unsplit())

Your paths, queries, and fragments are safe with us though:

mangled = uri_reference('hTTp://exAMPLe.COM/Some/reallY/biZZare/pAth')
normal = mangled.normalize()
assert normal == 'hTTp://exAMPLe.COM/Some/reallY/biZZare/pAth'
assert normal == 'http://example.com/Some/reallY/biZZare/pAth'
assert normal != 'http://example.com/some/really/bizzare/path'

If you do not actually need a real reference object and just want to normalize your URI:

from rfc3986 import normalize_uri

assert (normalize_uri('hTTp://exAMPLe.COM/Some/reallY/biZZare/pAth') ==
        'http://example.com/Some/reallY/biZZare/pAth')

You can also very simply validate a URI:

from rfc3986 import is_valid_uri

assert is_valid_uri('hTTp://exAMPLe.COM/Some/reallY/biZZare/pAth')