bindings.py

# -*- coding: utf-8 -*-

# Copyright (c) 2008 Alberto García Hierro <fiam@rm-fr.net>

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

"""Different bindings for Wapi. This version only includes ReST"""

from copy import copy

from django.http import Http404
from django.conf import settings

from wapi.responses import get_response
from wapi.formatters import UnknownFormat
from wapi.exceptions import ApiError, ApiLoginRequired
from wapi.function import ApiFunction
from wapi.utils import api_iterate, get_instance

class Binding(object):
    """Base class for all Wapi bindings"""
    def __init__(self, api):
        self.api = get_instance(api)
        self.registry = {
            'read': {},
            'write': {},
        }
        for func in api_iterate(api):
            registered_name = self.mangle_name(func.func_name)
            apifunc = ApiFunction(func)
            if settings.DEBUG or apifunc.is_read:
                self.registry['read'][registered_name] = apifunc
            if settings.DEBUG or apifunc.is_write:
                self.registry['write'][registered_name] = apifunc

    def mangle_name(self, name):
        """Modifies the function name which gets exposed"""
        return name

    def get_method(self, read_or_write, method_name):
        try:
            return self.registry[read_or_write][method_name]
        except KeyError:
            raise Http404('Method "%s" not found' % method_name)

class RestBinding(Binding):
    """Exposes an API trough ResT"""
    PATTERN = '(?P<method_name>.*)\.(?P<format>\w+)'
    READ_WRITE_MAPPING = {
        'GET': 'read',
        'POST': 'write',
    }
    def __init__(self, api, auth=None):
        super(RestBinding, self).__init__(api)
        self.auth = get_instance(auth)

    def mangle_name(self, name):
        return name.replace('__', '/')

    def __call__(self, request, method_name, format):
        """Searchs the method, calls it and transforms the response
            into a serialized format"""
        if self.auth:
            response = self.auth.login(request)
            if response:
                return response

        try:
            response_cls = get_response(format)
        except UnknownFormat:
            raise Http404('No registered serializer for format "%s"' % format)

        try:
            method = self.get_method(self.READ_WRITE_MAPPING[request.method],
                method_name)
        except KeyError:
            raise Http404('Method "%s" not found' % method_name)

        try:
            if request.method == 'POST':
                response = method(request, copy(request.POST))
            else:
                response = method(request, copy(request.GET))
        except ApiLoginRequired:
            return self.auth.login_required(request)
        except ApiError, e:
            return e.get_response()

        response.kwargs['request'] = request
        return response.transform(response_cls)