ObjectTypes¶

An ObjectType is the single, definitive source of information about your data. It contains the essential fields and behaviors of the data you’re querying.

The basics:

Each ObjectType is a Python class that inherits from graphene.ObjectType.
Each attribute of the ObjectType represents a Field.

Quick example¶

This example model defines a Person, with a first and a last name:

import graphene

class Person(graphene.ObjectType):
    first_name = graphene.String()
    last_name = graphene.String()
    full_name = graphene.String()

    def resolve_full_name(self, args, context, info):
        return '{} {}'.format(self.first_name, self.last_name)

first_name and last_name are fields of the ObjectType. Each field is specified as a class attribute, and each attribute maps to a Field.

The above Person ObjectType has the following schema representation:

type Person {
  firstName: String
  lastName: String
  fullName: String
}

Resolvers¶

A resolver is a method that resolves certain fields within a ObjectType. If not specififed otherwise, the resolver of a field is the resolve_{field_name} method on the ObjectType.

By default resolvers take the arguments args, context and info.

NOTE: The resolvers on a ObjectType are always treated as staticmethod``s, so the first argument to the resolver method ``self (or root) need not be an actual instance of the ObjectType.

Quick example¶

This example model defines a Query type, which has a reverse field that reverses the given word argument using the resolve_reverse method in the class.

import graphene

class Query(graphene.ObjectType):
    reverse = graphene.String(word=graphene.String())

    def resolve_reverse(self, args, context, info):
        word = args.get('word')
        return word[::-1]

Resolvers outside the class¶

A field can use a custom resolver from outside the class:

import graphene

def reverse(root, args, context, info):
    word = args.get('word')
    return word[::-1]

class Query(graphene.ObjectType):
    reverse = graphene.String(word=graphene.String(), resolver=reverse)

Instances as data containers¶

Graphene ObjectTypes can act as containers too. So with the previous example you could do:

peter = Person(first_name='Peter', last_name='Griffin')

peter.first_name # prints "Peter"
peter.last_name # prints "Griffin"

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