Creating an Input Union Type System Directive in Absinthe

In this post I will explain how to create a type system directive in Absinthe to implement Input Unions in Graphql. The code for this post can be found on Github A common issue with GraphQL is the lack of input unions. This means an input object that lets you choose between a number of potential input types. For example (taken from a spec discussion): input PetInput { cat: CatInput dog: DogInput fish: FishInput } input CatInput { name: String! »

Formatting GraphQL in Elixir projects

With the release of Elixir 1.13 it became possible to add plugins to the formatter. These plugins gives developers the option to hook into the Elixir formatter. I’ve created an Elixir formatter plugin to Absinthe to format GraphQL documents. With the release of Absinthe 1.7 this is available for everyone to use. To start, you’ll need Absinthe 1.7 or higher together with Elixir 1.13 or higher. The Absinthe project comes with Absinthe. »

Absinthe subscriptions with ReasonML and Urql

Lately I’ve been looking into ReasonML as a language to pick up. In the past I’ve dabbled with Elm and really enjoyed it but it’s lack of interoperability with javascript hampers its development. ReasonML offers a far better story in this regards, there are excellent React and React-Native libraries/bindings available as well as bindings for popular Graphql clients. That, combinated with great type-safety makes it a compelling alternative to Elm and Typescript. »

Urql graphql subscriptions with Absinthe

Many Graphql stacks use Apollo as the javascript client library. It’s well maintained, popular and has lot’s of examples. It also works together with Absinthe, the Elixir Graphql library. If you need to use graphql subscriptions in combination with Apollo and Absinthe there is the socket-apollo-link to connect the two. There’s another interesting javascript client library for Graphql on the horizon, Urql. It’s a bit more lightweight and looks really promising. »

Writing your own Absinthe DSL with macros and middleware

Absinthe is a great library to do graphql in Elixir. However, when writing your resolvers you may find that you are writing some boilerplate multiple times. So, in the spirit of keeping your code DRY, in this post I’ll show how we can leverage middleware and a macro to write your own DSL for your Graphql api. I assume some basic knowledge on how Absinthe works, most of the information can be found on in the guides »

Writing an Absinthe Phase

Absinthe does a lot when you fire a GraphQL query at it. The incoming query is parsed into an internal representation, validated and finally executed. This process is done by phases, these are individual modules chained together in a pipeline that each do a single step in processing the queries. Phases in Absinthe do a lot of work. They are the building blocks in validating and executing the GraphQL query. E. »

Absinthe Tips and Tricks

Absinthe is a great package for building GraphQL api’s in Elixir. It is fast, good DSL and overall great implementation of the GraphQL spec for servers. Working with Absinthe I’ve come across some patterns that have helped clean up code. I’d like to share some of them here. The Self function Imagine you have an image object you want to expose, and for each image you want a separate object with just the dimensions of the image. »