tartiflette-middleware 1.0.2

Framework for middleware for Tartiflette, with context data assignment

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.

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']()