Golang GrahpQL Automatic Schema Generation

This repository contains a library to auto generate a GraphQL schemas based on golang structs.

It based on github.com/lab259/go-graphql-struct and github.com/graphql-go/graphql.

Usually, building the schema is a one time task, and it is done statically. So, this library does not degrade the performance, not even a little, but in that one-time initialization.

Usage

type Person struct {
	Name    string   `graphql:"!name"`
	Age     int      `graphql:"age"`
	Friends []Person `graphql:"friends"`
}

Custom Types

The default data types of the GraphQL can be count in one hand, which is not a bad thing. However, that means that you may need to implement some scalar types (or event complexes types) yourself.

In order to provide custom types for the fields the GraphqlTyped interface was defined:

type GraphqlTyped interface {
    GraphqlType() graphql.Type
}

An example:

type TypeA string

func (*TypeA) GraphqlType() graphql.Type {
    return graphql.Int
}

Remember, this library is all about declaring the schema. If you need marshalling/unmarshaling a custom type to another, use the implementation of the github.com/graphql-go/graphql library (check on the graphql.NewScalar and graphql.ScalarConfig).

Resolver

To implement resolvers over a Custom Type, you will implement the interface GraphqlResolver:

type GraphqlResolver interface {
    GraphqlResolve(p graphql.ResolveParams) (interface{}, error)
}

IMPORTANT: Although the method GraphqlResolve is a member of a struct, it is called statically. So, do not make any references of the struct itself, inside of this method.

An example:

type TypeA string

func (*TypeA) GraphqlType() graphql.Type {
    return graphql.Int
}

License

MIT