add: example to create secure fiware header

CHANGELOG.md

@@ -1,3 +1,6 @@
+### v0.6.X
+- add: Tutorial for connecting with secured endpoints ([#319](https://github.com/RWTH-EBC/FiLiP/pull/319))
+
 ### v0.5.0
 - update: allow duplicated name in device, check uniqueness of object_id ([#279](https://github.com/RWTH-EBC/FiLiP/pull/279))
 - update: upgrade dependency of `paho-mqtt` to v2 ([#273](https://github.com/RWTH-EBC/FiLiP/pull/273/))

examples/ngsi_v2/e13_ngsi_v2_secure_fiware_headers.py

@@ -0,0 +1,121 @@
+"""
+# This example shows how to generate an access token from an authnetication srever in order to access Fiware services
+# which are protected behind an authentication/authorisation layer.
+"""
+import os
+
+import requests
+import urllib3
+
+from filip.clients.ngsi_v2 import ContextBrokerClient
+from filip.config import settings
+from filip.models.base import FiwareHeaderSecure
+
+urllib3.disable_warnings()
+session = requests.Session()
+CB_URL = settings.CB_URL
+# FIWARE-Service
+SERVICE = 'filip'
+# FIWARE-Servicepath
+SERVICE_PATH = '/'
+# Provide client credentials which are used when generating access token from authentication server
+CLIENT_ID = 'client_id'
+CLIENT_SECRET = 'client_secret'
+# TODO: Please adapt it according to your authentication server which is generating access token for the service
+KEYCLOAK_HOST = 'https://keycloak.example.com'
+
+
+class KeycloakPython:
+    def __init__(self, keycloak_host=None, client_id=None, client_secret=None):
+        """
+        - Initialze the Keycloak Host , Client ID and Client secret.
+        - If no parameters are passed .env file is used
+        - Priority : function parameters > Class Instatiation > .env file
+        """
+        # if keycloak_host == None:
+        #     self.keycloak_host = os.getenv('KEYCLOAK_HOST')
+        # else:
+        #     self.keycloak_host = keycloak_host
+        self.keycloak_host = os.getenv('KEYCLOAK_HOST') if keycloak_host == None else keycloak_host
+        self.client_id = os.getenv('CLIENT_ID') if client_id == None else client_id
+        self.client_secret = os.getenv('CLIENT_SECRET') if client_secret == None else client_secret
+
+    def get_access_token(self, keycloak_host=None, client_id=None, client_secret=None):
+        """
+        - Get access token for a given client id and client secret.
+        """
+        self.keycloak_host = keycloak_host if keycloak_host != None else self.keycloak_host
+        self.client_id = client_id if client_id != None else self.client_id
+        self.client_secret = client_secret if client_secret != None else self.client_secret
+        self.data = {'client_id': self.client_id,
+                     'client_secret': self.client_secret,
+                     'scope': 'email',
+                     'grant_type': 'client_credentials',
+                     }
+        try:
+            headers = {"content-type": "application/x-www-form-urlencoded"}
+            access_data = requests.post(self.keycloak_host, data=self.data, headers=headers)
+            expires_in = access_data.json()['expires_in']
+            access_token = access_data.json()['access_token']
+            return access_token, expires_in
+        except requests.exceptions.RequestException as err:
+            raise KeycloakPythonException(err.args[0])
+
+    def get_data(self, client_host, headers={}, keycloak_host=None, client_id=None, client_secret=None):
+        """
+        - Get data for a given api.
+        - Mandatory input - Target api, fiware-service and fiware-servicepath headers
+        - Optional Inmput - Keycloak host, Client ID, Client Secret
+        """
+        access_token, expires_in = self.get_access_token(keycloak_host=keycloak_host, client_id=client_id,
+                                                         client_secret=client_secret)
+        headers['Authorization'] = 'Bearer %s' % (access_token)
+        response = requests.get(client_host, headers=headers)
+        return response.text
+
+    def post_data(self, client_host, data, headers={}, keycloak_host=None, client_id=None, client_secret=None):
+        """
+        - Post data for a given api.
+        - Mandatory input - Target api, headers, request body.
+        - Optional Inmput - Keycloak host, Client ID, Client Secret.
+        """
+        access_token, expires_in = self.get_access_token(keycloak_host=keycloak_host, client_id=client_id,
+                                                         client_secret=client_secret)
+        headers['Content-Type'] = 'application/json'
+        headers['Authorization'] = 'Bearer %s' % (access_token)
+        response = requests.post(client_host, data=data, headers=headers)
+        return response
+
+    def patch_data(self, client_host, json, headers={}, keycloak_host=None, client_id=None, client_secret=None):
+        """
+        - Patch data for a given api.
+        - Mandatory input - Target api, headers, request body.
+        - Optional Inmput - Keycloak host, Client ID, Client Secret.
+        """
+        access_token, expires_in = self.get_access_token(keycloak_host=keycloak_host, client_id=client_id,
+                                                         client_secret=client_secret)
+        headers['Content-Type'] = 'application/json'
+        headers['Authorization'] = 'Bearer %s' % (access_token)
+        response = requests.patch(url=client_host, json=json, headers=headers)
+        return response
+
+
+class KeycloakPythonException(Exception):
+    def __init__(self, message):
+        self.message = message
+        super().__init__(self.message)
+
+
+if __name__ == "__main__":
+    # get token from keycloak
+    token, in_sec = KeycloakPython(KEYCLOAK_HOST, CLIENT_ID, CLIENT_SECRET).get_access_token()
+
+    # create secure fiware header with authorisation token
+    fiware_header = FiwareHeaderSecure(service=SERVICE,
+                                       service_path=SERVICE_PATH,
+                                       authorization='Bearer %s' % token)
+
+    # create a context broker client
+    cb_client = ContextBrokerClient(url=CB_URL, fiware_header=fiware_header, session=session)
+    # you don't need to set any extra parameter for requesting the service besides setting session in the client object
+    entity_list = cb_client.get_entity_list()