graphql-dotnet / conventions

GraphQL Conventions Library for .NET

GraphQL Conventions Library for .NET

Introduction

GraphQL .NET has been around for a while. This library is a complementary layer on top that allows you to automatically wrap your .NET classes into GraphQL schema definitions using existing property getters and methods as field resolvers.

In short, this project builds on top of the following components:

• The GraphQL library written by Joe McBride (MIT licence)
• The GraphQL lexer/parser originally written by Marek Magdziak (MIT licence)

Disclaimer: I am providing code in this repository to you under an open source licence (MIT). Because this is my personal repository, the licence you receive to my code is from me and not my employer (Facebook).

Installation

Download and install the package from NuGet:

PS> Install-Package GraphQL.Conventions

This project targets .NET Standard 2.0.

Getting Started

Implement your query type:

[ImplementViewer(OperationType.Query)]
public class Query
{
    [Description("Retrieve book by its globally unique ID.")]
    public Task<Book> Book(UserContext context, Id id) =>
        context.Get<Book>(id);

    [Description("Retrieve author by his/her globally unique ID.")]
    public Task<Author> Author(UserContext context, Id id) =>
        context.Get<Author>(id);

    [Description("Search for books and authors.")]
    public Connection<SearchResult> Search(
        UserContext context,
        [Description("Title or last name.")] NonNull<string> forString,
        [Description("Only return search results after given cursor.")] Cursor? after,
        [Description("Return the first N results.")] int? first)
    {
        return context
            .Search(forString.Value)
            .Select(node => new SearchResult { Instance = node })
            .ToConnection(first ?? 5, after);
    }
}

Construct your schema and run your query:

using GraphQL.Conventions;

var engine = GraphQLEngine.New<Query>();
var result = await engine
    .NewExecutor()
    .WithUserContext(userContext)
    .WithDependencyInjector(dependencyInjector)
    .WithRequest(requestBody)
    .Execute();

Examples

More detailed examples can be found in the unit tests.