# -*- test-case-name: twisted.test.test_strcred -*-
#
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Cred plugin for ssh key login
"""

from zope.interface import implements

from twisted import plugin
from twisted.cred.strcred import ICheckerFactory
from twisted.cred.credentials import ISSHPrivateKey


sshKeyCheckerFactoryHelp = """
This allows SSH public key authentication, based on public keys listed in
authorized_keys and authorized_keys2 files in user .ssh/ directories.
"""


try:
from twisted.conch.checkers import SSHPublicKeyDatabase

class SSHKeyCheckerFactory(object):
"""
Generates checkers that will authenticate a SSH public key
"""
implements(ICheckerFactory, plugin.IPlugin)
authType = 'sshkey'
authHelp = sshKeyCheckerFactoryHelp
argStringFormat = 'No argstring required.'
credentialInterfaces = SSHPublicKeyDatabase.credentialInterfaces


def generateChecker(self, argstring=''):
"""
This checker factory ignores the argument string. Everything
needed to authenticate users is pulled out of the public keys
listed in user .ssh/ directories.
"""
return SSHPublicKeyDatabase()



theSSHKeyCheckerFactory = SSHKeyCheckerFactory()

except ImportError:
# if checkers can't be imported, then there should be no SSH cred plugin
pass