Semi-generic Python Rest Client, assuming a DjangoRestFramework back-end (and using TokenAuthentication)

djangorestframework-client.py

__author__ = 'dkarchmer'

"""
See https://gist.github.com/dkarchmer/d85e55f9ed5450ba58cb
This API generically supports DjangoRestFramework based APIs
It is based on https://github.com/samgiles/slumber, but customized for
Django Rest Frameworks, and the use of TokenAuthentication.
Usage:
    # Assuming
    # v1_api_router.register(r'some_model', SomeModelViewSet)
    api = Api('http://127.0.0.1:8000')
    api.login(email='user1@test.com', password='user1')
    obj_list = api.some_model.get()
    logger.debug('Found {0} groups'.format(obj_list['count']))
    obj_one = api.some_model(1).get()
    api.logout()
"""
import json
import requests
import logging
from .exceptions import *

DOMAIN_NAME = 'https://example.com'
API_PREFIX = 'api/v1'
DEFAULT_HEADERS = {'Content-Type': 'application/json'}

logger = logging.getLogger(__name__)


class RestResource(object):
    """
    Resource provides the main functionality behind a Django Rest Framework based API. It handles the
    attribute -> url, kwarg -> query param, and other related behind the scenes
    python to HTTP transformations. It's goal is to represent a single resource
    which may or may not have children.
    """

    def __init__(self, *args, **kwargs):
        self._store = kwargs
        if 'use_token' not in self._store:
            self._store['use_token'] = False

    def __call__(self, id=None, action=None):
        """
        Returns a new instance of self modified by one or more of the available
        parameters. These allows us to do things like override format for a
        specific request, and enables the api.resource(ID).get() syntax to get
        a specific resource by it's ID.
        """

        kwargs = {
            'token': self._store['token'],
            'base_url': self._store['base_url']
        }

        if id is not None:
            kwargs['base_url'] = '{0}/{1}'.format(self._store['base_url'], id)

        if action is not None:
            # http://www.django-rest-framework.org/api-guide/viewsets/#marking-extra-actions-for-routing
            kwargs['base_url'] = '{0}/{1}'.format(self._store['base_url'], action)

        return self.__class__(**kwargs)

    def _check_for_errors(self, resp, url):

        if 400 <= resp.status_code <= 499:
            exception_class = HttpNotFoundError if resp.status_code == 404 else HttpClientError
            raise exception_class("Client Error %s: %s" % (resp.status_code, url), response=resp, content=resp.content)
        elif 500 <= resp.status_code <= 599:
            raise HttpServerError("Server Error %s: %s" % (resp.status_code, url), response=resp, content=resp.content)

    def _handle_redirect(self, resp, **kwargs):
        # @@@ Hacky, see description in __call__
        resource_obj = self(url_override=resp.headers["location"])
        return resource_obj.get(**kwargs)

    def _try_to_serialize_response(self, resp):
        if resp.status_code in [204, 205]:
            return

        if resp.content:
            if type(resp.content) == bytes:
                try:
                    encoding = requests.utils.guess_json_utf(resp.content)
                    return json.loads(resp.content.decode(encoding))
                except Exception:
                    return resp.content
            return json.loads(resp.content)
        else:
            return resp.content

    def _process_response(self, resp):

        self._check_for_errors(resp, self.url())

        if 200 <= resp.status_code <= 299:
            return self._try_to_serialize_response(resp)
        else:
            return  # @@@ We should probably do some sort of error here? (Is this even possible?)

    def url(self):
        url = self._store["base_url"]
        return url

    def _get_header(self):
        headers = DEFAULT_HEADERS
        if self._store['use_token']:
            if not "token" in self._store:
                raise RestBaseException('No Token')
            authorization_str = 'token %s' % self._store["token"]
            headers['Authorization'] = authorization_str

        return headers

    def get(self, **kwargs):
        resp = requests.get(self.url(), headers=self._get_header())
        return self._process_response(resp)

    def post(self, data=None, **kwargs):
        if data:
            payload = json.dumps(data)
        else:
            payload = None

        resp = requests.post(self.url(), data=payload, headers=self._get_header())
        return self._process_response(resp)

    def patch(self, data=None, **kwargs):
        if data:
            payload = json.dumps(data)
        else:
            payload = None

        resp = requests.patch(self.url(), data=payload, headers=self._get_header())
        return self._process_response(resp)

    def put(self, data=None, **kwargs):
        if data:
            payload = json.dumps(data)
        else:
            payload = None

        resp = requests.put(self.url(), data=payload, headers=self._get_header())
        return self._process_response(resp)

    def delete(self, **kwargs):
        resp = requests.delete(self.url(), headers=self._get_header())
        if 200 <= resp.status_code <= 299:
            if resp.status_code == 204:
                return True
            else:
                return True  # @@@ Should this really be True?
        else:
            return False


class Api(object):

    token = None
    domain = DOMAIN_NAME
    resource_class = RestResource

    def __init__(self, domain=None):
        if domain:
            self.domain = domain
        self.base_url = '{0}/{1}'.format(self.domain, API_PREFIX)
        self.use_token = True
        
    def set_token(self, token):
        self.token = token

    def login(self, password, email):
        data = {'email': email, 'password': password}
        url = '{0}/{1}'.format(self.base_url, 'auth/login')

        payload = json.dumps(data)
        r = requests.post(url, data=payload, headers = DEFAULT_HEADERS)
        if r.status_code == 200:
            content = json.loads(r.content.decode())
            self.token = content['token']
            self.username = content['username']
            logger.info('Welcome @{0} (token: {1})'.format(self.username, self.token))
            return True
        else:
            logger.error('Login failed: ' + str(r.status_code) + ' ' + r.content.decode())
            return False

    def logout(self):
        url = '{0}/{1}'.format(self.base_url, 'auth/logout')
        headers = DEFAULT_HEADERS
        headers['Authorization'] = 'token {0}'.format(self.token)

        r = requests.post(url, headers=headers)
        if r.status_code == 204:
            logger.info('Goodbye @{0}'.format(self.username))
            self.username = None
            self.token = None
        else:
            logger.error('Logout failed: ' + str(r.status_code) + ' ' + r.content.decode())

    def __getattr__(self, item):
        """
        Instead of raising an attribute error, the undefined attribute will
        return a Resource Instance which can be used to make calls to the
        resource identified by the attribute.
        """

        # Don't allow access to 'private' by convention attributes.
        if item.startswith("_"):
            raise AttributeError(item)

        kwargs = {
            'token': self.token,
            'base_url': self.base_url,
            'use_token': self.use_token
        }
        kwargs.update({'base_url': '{0}/{1}'.format(kwargs['base_url'], item)})

        return self._get_resource(**kwargs)

    def _get_resource(self, **kwargs):
        return self.resource_class(**kwargs)