Tartiflette Middleware

Framework to facilitate the creation of middleware for Tartiflette with resolver context variable assignment using python context managers.

Allows for processing of request/response headers, dependent on the http server you're using.

Installation

pip install tartiflette-middleware

Usage

This requires:

1. Creation of your middleware.
2. Configuration of your middleware in your application.
3. Update your resolvers to access your data.

1 - Creation of your middleware

Create a context manager to run on each request.

Example:

from tartiflette_middleware import BaseMiddleware

class MyMiddleware(BaseMiddleware):
    # required short arbitrary unique middleware label
    label = 'MyMware'

    def __init__(self, my_middleware_params):
        BaseMiddleware.__init__(self)
        # do things necessary for repeated use across all of the requests, e.g.
        # configure factories

    async def __aenter__(self):
        # provide the data or method to be used in all queries for a single
        # request. 
        your_method_or_data = ...
        # store the data/method to be reused for this request
        await self.store_request_data(your_method_or_data)

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        # optional: for if you need to do something when the request is
        # completed
        data = await self.get_request_data()
        data.close_or_whatever()

There are more examples in the examples directory including one with access to AIOHTTP request headers.

You can set the response http status using something like:

async def __aenter__(self):
    self.status = 401

2 - Configuration of your middleware in your app

Currently only AIOHTTP is supported but the library is extensible if others would like to submit a pull request to support other servers that Tartiflette supports.

Limited AIOHTTP setup example, imports and configuration kept to middleware specific details:

from tartiflette_middleware import Middleware, server
import MyMiddleware     # your Middleware as defined earlier

my_middleware = Middleware(
    context_manager=MyMiddleware(
        my_middleware_params={},
    ),
    server_middleware=server.aiohttp
)

app = web.Application(middlewares=[
    my_middleware.middleware
])
ctx = {
    'my_session_service': my_middleware.service,
}
web.run_app(
    register_graphql_handlers(
        # your configuration
        executor_context=ctx,
    )
)

3 - Access data in your resolvers' context

Works in queries, mutations, and subscriptions.

@Resolver('Query.whatever')
async def resolve_query_user_login(parent, args, ctx, info):
    my_data = await ctx['my_session_service']()