## -*- coding: utf-8 -*-
############################################
## File : auth.py
## Author : Sylvain Viollon
## Email : sylvain@infrae.com
## Creation Date : Fri May 16 10:28:49 2008 CEST
## Last modification : Mon Jul 14 13:30:39 2008 CEST
############################################

__author__ ="sylvain@infrae.com"
__format__ ="plaintext"
__version__ ="$Id$"

from authkit.authenticate import middleware as AuthenticateMiddleware
from authkit.authorize import middleware as AuthorizeMiddleware
from authkit.permissions import RemoteUser

from watlabws.odbc import  ODBCConnectionPool
import csv

class FileAuthChecker(object):
    """Check the authentication using a CSV file.
    """

    def __init__(self, filename):
        self.filename = filename

    def __call__(self, environ, user, password):
        csv_file = csv.reader(open(self.filename))
        for csv_user, csv_password in csv_file:
            if (csv_user == user) and (csv_password == password):
                return True
        return False


SQL_REQUEST = """select %(login_column)s as username, %(password_column)s as password
from %(user_table)s
where %(login_column)s = '%%s'"""


class ODBCAuthChecker(object):
    """Check the authentication using a ODBC connection.
    """

    def __init__(self, dsn, user_table, login_column, password_column,
                 number_connection=1, max_request=1000):
        sql_args = dict(login_column=login_column,
                        password_column=password_column,
                        user_table=user_table)
        self.sql_request = SQL_REQUEST %  sql_args
        self.connection = ODBCConnectionPool(dsn, number_connection, max_request)

    def __call__(self, environ, user, password):
        entries = list(self.connection.execute(self.sql_request % user))
        if len(entries) != 1:
            return False
        if (entries[0]['username'] == user and
        entries[0]['password'] == password):
            return True
        return False


def authorize_filter(global_conf):
    """Create a middleware to authorize.
    """

    def filter(app):
        return AuthorizeMiddleware(app, RemoteUser())
    return filter


def buildAuthenticationMiddleware(checkAuth, conf):
    """Build a middleware checking the authentication using the given
    auth checker.
    """

    def filter(app):
        return AuthenticateMiddleware(app,
                                      setup_method=conf.get('method', 'basic'),
                                      basic_realm=conf.get('realm', 'Auth Realm'),
                                      basic_authenticate_function=checkAuth)
    return filter


def authenticate_text_filter(global_conf, passfile, **conf):
    """Create a middleware for authentication using a CSV file.
    """

    checkAuth = FileAuthChecker(passfile)
    return buildAuthenticationMiddleware(checkAuth, conf)


def authenticate_odbc_filter(global_conf, dsn, user_table, login_column,
                             password_column, number_connection=1, max_request=1000,
                             **conf):
    """Create a middleware for authentication using an mxODBC connection.
    """

    checkAuth = ODBCAuthChecker(dsn, user_table, login_column, password_column,
                                number_connection, max_request)
    return buildAuthenticationMiddleware(checkAuth, conf)