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JSON-RPC

pyramid_rpc supports JSON-RPC 2.0 Specification .

from pyramid.config import Configurator
from pyramic_rpc import jsonrpc_method

@jsonrpc_method(endpoint='api')
def say_hello(request, name):
    return 'hello, %s!' % name

def main(global_conf, **settings):
    config = Configurator(settings=settings)
    config.include('pyramid_rpc.jsonrpc')
    config.add_jsonrpc_endpoint('api', '/api')
    config.scan(__name__)
    return config.make_wsgi_app()

if __name__ == '__main__':
    from paste.httpserver import serve
    app = main({})
    serve(app, 'localhost', 8080)

Setup

Use the includeme via pyramid.config.Configurator.include:

config.include('pyramid_rpc.jsonrpc')

Once activated, the following happens:

  1. The pyramid_rpc.jsonrpc.add_jsonrpc_endpoint directive is added to the config instance.
  2. The pyramid_rpc.jsonrpc.add_jsonrpc_method directive is added to the config instance.
  3. An exception view is registered for pyramid_rpc.jsonrpc.JsonRpcError exceptions.

Usage

After including the pyramid_rpc.jsonrpc package in your project, you can add an endpoint for handling incoming requests. After that, attach several methods to the endpoint to handle specific functions within your api.

Adding a JSON-RPC Endpoint

An endpoint is added via the ~pyramid_rpc.jsonrpc.add_jsonrpc_endpoint directive on the config instance.

Example:

config = Configurator()
config.include('pyramid_rpc.jsonrpc')
config.add_jsonrpc_endpoint('api', '/api/jsonrpc')

It is possible to add multiple endpoints as well as pass extra arguments to ~pyramid_rpc.jsonrpc.add_jsonrpc_endpoint to handle traversal, which can assist in adding security to your RPC API.

Exposing JSON-RPC Methods

Methods on your API are exposed by attaching views to an endpoint. Methods may be attached via the ~pyramid_rpc.jsonrpc.add_jsonrpc_method which is a thin wrapper around pyramid.config.Configurator.add_view method.

Example:

def say_hello(request, name):
    return 'Hello, ' + name

config.add_jsonrpc_method(say_hello, endpoint='api', method='say_hello')

If you prefer, you can use the ~pyramid_rpc.jsonrpc.jsonrpc_method view decorator to declare your methods closer to your actual code. Remember when using this lazy configuration technique, it's always necessary to call pyramid.config.Configurator.scan from within your setup code.

from pyramid_rpc.jsonrpc import jsonrpc_method

@jsonrpc_method(endpoint='api')
def say_hello(request, name):
    return 'Hello, ' + name

config.scan()

To set the RPC method to something other than the name of the view, specify the method parameter:

from pyramid_rpc.jsonrpc import jsonrpc_method

@jsonrpc_method(method='say_hello', endpoint='api')
def say_hello_view(request, name):
    return 'Hello, ' + name

config.scan()

Because methods are a thin layer around Pyramid's views, it is possible to add extra view predicates to the method, as well as permission requirements.

Custom Renderers

By default, responses are rendered using the Python standard library's json.dumps. This can be changed the same way any renderer is changed in Pyramid. See the Pyramid Renderers chapter for extra details. As an example, let's update an endpoint to use Pyramid 1.4's cool new pyramid.renderers.JSON renderer which supports custom adapters.

from pyramid.renderers import JSON

json_renderer = JSON()
json_renderer.add_adapter(datetime.datetime, lambda v: v.isoformat())
config.add_renderer('myjson', json_renderer)

config.add_jsonrpc_endpoint('api', '/api', default_renderer='myjson')

A default_renderer can be specified on an endpoint, which will propagate to all methods attached to the endpoint. Optionally, an individual method can also override the renderer.

View Mappers

A view mapper is registered for JSON-RPC methods by default which will match the arguments from request.rpc_args to the parameters of the view. Optional arguments are allowed and an error will be returned if too many or too few arguments are supplied to the view.

This default view mapper may be overridden by setting the default_mapper option on ~pyramid_rpc.jsonrpc.add_jsonrpc_endpoint or the mapper option when using ~pyramid_rpc.jsonrpc.jsonrpc_method or ~pyramid_rpc.jsonrpc.add_jsonrpc_method.

HTTP GET and POST Support

As of pyramid_rpc version 0.5, JSON-RPC requests can be made using HTTP GET. By default, an endpoint will accept requests from both GET and POST methods. This can be controlled on either the endpoint or on an individual method by using the request_method predicate. For example, to limit requests to only POST requests:

config.add_jsonrpc_endpoint('api', '/api', request_method='POST')

Handling JSONP Requests

Pyramid comes with a pyramid.renderers.JSONP which can be registered for the endpoint, using the method described within jsonrpc_custom_renderers.

API

pyramid_rpc.jsonrpc

includeme

add_jsonrpc_endpoint

add_jsonrpc_method

jsonrpc_method

Exceptions

JsonRpcError

JsonRpcParseError

JsonRpcRequestInvalid

JsonRpcMethodNotFound

JsonRpcParamsInvalid

JsonRpcInternalError