django-proxy-server 0.1.7

This is a django application to use django as a proxy server between a frontend device/server and a backend server inside a DMZ

django_proxy_server
===================
This is a django application to use django as a proxy server between a frontend device/server and a backend server inside a militarized zone. Services are exposed using Django REST Framework. To identify itself, django-proxy-server uses the SECRET_KEY variable defined in settings as its API KEY.

Quick start
-----------
Install using pip or easy_install

$ pip install django-proxy-server

$ easy_install django-proxy-server

Add "proxy_server" to your INSTALLED_APPS setting like this:

INSTALLED_APPS = (
...
'proxy_server',
)

Add the following options to the settings.py file to configure:

PROXY_API_KEYS = [
# Add the API KEYS you wish to allow consuming services
# API KEYS are required. Services cannot be consumed without an API KEY
]

# Write the route to the service you wish to use as token validation.
# If you don't wish to have a token validation, skip this setting
PROXY_TOKEN_VALIDATION_SERVICE = 'project.services.token_service'

# The IP or domain address of the backend services to be consumed
BACKEND_HOST = '127.0.0.1'

# The port through which the backend services will be consumed
BACKEND_PORT = '8000'

Usage
-----------
To expose a service using Django, simply decorate a view with

# The option methods is a list of HTTP methods that can be exposed.
# For example: GET, POST, PUT, DELETE
# The option public indicates that the service will be exposed as public,
# thus it doesn't require for the header to include a USER_TOKEN value
@expose_service([ methods ], public=True)

There are two ways of invoking backend services, from a traditional Django view or from an external device that uses Django as a proxy server. The functions to invoke backend services relies on the helper function generate_service_url.

The function generate_service_url allows appending parameters to a URL, as well as encrypting them if the kwarg encrypted is set to True (by default, it is False).

When using traditional Django views, invoke services as follows:

from proxy_server.backend_services import invoke_backend_service
from proxy_server.helpers import generate_service_url

def function(request):
...
response = invoke_backend_service('GET', generate_service_url('/get_user', params={ 'username':'proxy_server_admin' }, encrypted=True), request=request)
...

The invoke_backend_service receives the following parameters:
* method: The method of the service to be invoked
* function_path: The path of the service URL
* json_data: A dictionary with the body content of the service. Default value: empty dict.
* request: The request of the Django view with the information of the user and headers
* response_token: Boolean argument that indicates if a response token is expected. By default, the service expects a token on response.
* public: Boolean argument that indicates if the accessed service is public. By default, the invoked services are not public.
* secure: Boolean argument that indicates if the web service connection must be stablished over HTTPS. By default, the connection is created using HTTP.

When using Django as a proxy server, invoke services as follows:

from proxy_server.decorators import expose_service
from proxy_server.helpers import generate_service_url
from proxy_server.backend_services import invoke_backend_service_as_proxy
import proxy_server

@expose_service(['GET'])
def home(request):
...
response = invoke_backend_service_as_proxy('GET', generate_service_url('/get_user', params={ 'username':'proxy_server_admin' }, encrypted=True), secure=True)
...

The invoke_backend_service_as_proxy receives the following parameters:
* method: The method of the service to be invoked
* function_path: The path of the service URL
* json_data: A dictionary with the body content of the service. Default value: empty dict.
* request: The request of the Django view with the information of the user and headers
* response_token: Boolean argument that indicates if a response token is expected. By default, the service expects a token on response.
* secure: Boolean argument that indicates if the web service connection must be stablished over HTTPS. By default, the connection is created using HTTP.

Considerations
--------------
The previous annotation and functions depend on the following response structure:

For response.status_code = 200

{
'user-token':'abc', # If the server returns it
'expiration-date':'2014-09-09 10:41:54', # Expiration date of the user token.
# If the user token is not present, this is not represent either
'response':{
# Content of the response. This content can also be an array
}
}

For response.status_code != 200

{
'user-token':'abc', # If the server returns it
'expiration-date':'2014-09-09 10:41:54', # Expiration date of the user token.
# If the user token is not present, this is not represent either
'error': {
'code': 500, # Or any other code sent by the server. This is specific to the server
'type': 'ErrorType', # Type of the error. This is specific to the server
'message': 'Error message'
}
}