Bottlecap.Net.GraphQL.Generation 1.0.2

Bottlecap.Net.GraphQL.Generation

The purpose of this is to support the generation of GraphTypes for .Net GraphQL based on existing entities.

Why does this exist?

I strive for seperation of concerns when building my applications. However, I also don't like repeating code and performing boiler plate tasks.

Therefore, I created this toolset to generate extendable GraphType objects based on defined entity/data classes.

How does it work?

Bottlecap.Net.GraphQL.Generation.Attributes

This provides attributes which are used to decorate classes that you wish to have graph types and dataloaders generated for. The aim was to support bespoke attributing at a minimum for most scenarios.

GraphType

Any class that has this attribute will have a GraphQL type generated for it. Specify IsInput if the graph type is used for input.

This will generate a GraphType field for each public property with descriptions defined using the System.ComponentModel.Description attribute.

If there are properties you don't want to expose, then there is a GraphTypeProperty attribute, which has an IsIgnored flag.

DataLoaders

This will generate an extension method for GraphQL.IDataLoaderContextAccessor for each public method in the class that returns a Task<IDictionary<,>>.

Bottlecap.Net.GraphQL.Generation

This contains the main generation logic. If you're wanting to upgrade the generator, or generate types without using attributes, then this is the assembly you will want.

GraphType Example

Below is an example of a data record defined for graph type generation

[GraphType]
public class User
{
    [Description("The id of the user")]
    public long Id { get; set; }

    [Description("The username of the user")]
    public string Username { get; set; }

    [GraphTypeProperty(IsIgnored = true)]
    [Description("The password of the user")]
    public string Password { get; set; }
}

and here is the result...

public partial class UserGraphType : ObjectGraphType<GraphQLExample.Data.User>
{
    public UserGraphType()
    {
        Name = "User";
        Field(x => x.Id, nullable: false)
        .Description("The id of the user");
        Field(x => x.Username, nullable: false)
        .Description("The username of the user");
        SetupFields();
    }

    partial void SetupFields();
}

DataLoader Example

Below is an example of a method defined for data loader generation

[DataLoaders]
public interface IUserRepository
{
    Task<IDictionary<long, User>> GetUsersByIdsAsync(IEnumerable<long> ids);
}

and here is the result...

public static class IUserRepositoryExtensions
{
     public static Task<GraphQLExample.Data.User> GetUsersByIdsAsync(this IDataLoaderContextAccessor accessor, 
      GraphQLExample.Data.IUserRepository repository,
      Func<System.Int64> keySelector)
    {
        var loader = accessor.Context.GetOrAddBatchLoader<System.Int64, GraphQLExample.Data.User>("GraphQLExample.Data.IUserRepository.GetUsersByIdsAsync", repository.GetUsersByIdsAsync);
        return loader.LoadAsync(keySelector()).GetResultAsync();
    }
}

Bottlecap.Net.GraphQL.Generation.Cli

This is the CLI that utilises Bottlecap.Net.GraphQL.Generation by taking a given dll, and looking for all classes that implement a Bottlecap.Net.GraphQL.Generation.Attributes attribute. It will then generate all GraphQL types in the specified namespace at the specified output location.

Installation

You can install the application using dotnet tool install.

e.g.

dotnet tool install Bottlecap.Net.GraphQL.Generation.Cli --version 0.3.2-alpha --tool-path "C:\Repos\Applications\ProjectX\tools"

Using

An example of running the application would look like the following.

bottlecap-graphql-gen -i <<INPUT DLL> -o <<OUTPUT>> -n GraphQLExample.Schemas