Phoenix GraphQL Tutorial with Absinthe

I apologize for not seeing this sooner. Somehow it got past me! Pretty late but here are a few reasons why I like GraphQL.

1. One HTTP Request - GraphQL makes only one HTTP request. Using another pattern like REST you would generally have to make a number of HTTP requests to get data from different resources. With GraphQL, you send one query to the server and it sends back all the data you need without having to make multiple requests.

2. Type Checking - In GraphQL you define the fields and types that can be queried or that can be input into a mutation. As a result, you get data validation out of the box. You don’t have to do any type checking on mutation arguments because GraphQL already does it for you.

3. Querying Nested Data - Let’s say you have an app that lawyers use to manage their cases. Each lawyer can have many cases. The case has a foreign key property called lawyer_id. With GraphQL, I can set up a lawyer field that takes the lawyer_id on a case and requests the lawyer’s data. So, I could query for a case like this:

{
  case {
    lawyer {
      first_name,
      last_name
    }
}

This comes in really handy with complex schemas.

There are a quite a few more benefits but I think the best way to identify them is to build something. Let me know if you have any questions.

@ryanswapp
Why would you recommend someone to use GraphQl,
I have never used it but am wondering how could I create a login system with it etc

Ps: am a currently learning Elixir

For those interested on using Absinthe with Apollo client via Phoenix channels, I just released a custom Apollo networkInterface just for that: apollo-phoenix-websocket

can’t wait to see it man. and i wish i can contribute as well

Hey there, this is a great question. Most of the stuff you see with GraphQL is using it to power an API. However we have an experimental project we hope to release very very soon that lets you use graphql to power totally ordinary Phoenix views.

great stuff man loved it. just a noob question . can we use phoenix template with graphql?

Thanks! Will test this out

Thanks! Good question… I was just thinking about this myself. I haven’t yet tried this out but I think it would work. You could do something like this:

# Another File
defmodule MyApp.Schema.Query.User do
  object :user_queries do 
    field :users, list_of(:user) do
      resolve &MyApp.UserResolver.all/2
    end

    field :user, type: :user do
      arg :id, non_null(:id)
      resolve &MyApp.UserResolver.find/2
    end
  end
end

# Schema file
defmodule MyApp.Schema do
  import_types MyApp.Schema.Query.User
  query do
    import_fields :user_queries
  end
end

Hey Ryan, great article!

I’m trying to hack together an Absinthe app (without Phoenix) and I was wondering how you would split the Schema (into multiple files) before it becomes to big.

I’m using an Electron based client, graphiql-app, because it allow me to set custom headers (e.g. for authentication)

Seems like by default, the apollo client makes the requests to “/graphql”, Ryan instead, set it to “/api”. that was all