graphene/docs/pages/docs/middleware.md

title	description
Middleware	Walkthrough Middleware

Middleware

You can use middleware to affect the evaluation of fields in your schema.

A middleware is any object that responds to resolve(*args, next_middleware). Inside that method, it should either:

• Send resolve to the next middleware to continue the evaluation; or
• Return a value to end the evaluation early.

Middlewares' resolve is invoked with several arguments:

• next represents the execution chain. Call next to continue evalution.
• root is the root value object passed throughout the query
• args is the hash of arguments passed to the field
• context is the context object passed throughout the query
• info is the resolver info

Add a middleware to a schema by adding to the middlewares list.

Example: Authorization

This middleware only continues evaluation if the field_name is not 'user':

class AuthorizationMiddleware(object):

    def resolve(self, next, root, args, context, info):
        if info.field_name == 'user':
            return None
        return next(root, args, context, info)

Then, add the middleware to your schema:

schema = Schema(middlewares=[AuthorizationMiddleware])