lj-ditrapani / scala-graphql-client

Scala GraphQL Client tutorial

Project creation

This project was created with:

sbt new scala/scala3.g8

GraphQL Schema

We are going query GraphqlZero which is a free, online GraphQL API we can use to get fake data.

The GraphQL schema in this project was downloaded from GraphqlZero API and saved as: src/main/graphql/graphqlzero.graphql

GraphQL Client

This project is configured with Caliban GraphQL Client.

Dependencies

The build.sbt contains the necessary dependencies:

"com.github.ghostdogpr" %% "caliban-client" % "1.2.1"

The build.sbt also enables the CalibanPlugin:

.enablePlugins(CalibanPlugin)

The project/plugins.sbt contains the CalibanPlugin:

addSbtPlugin("com.github.ghostdogpr" % "caliban-codegen-sbt" % "1.3.0")

Code Generation

CalibanPlugin allows you to generate the client code from a schema file or from a server URL.

Run this sbt command to translate src/main/graphql/graphqlzero.graphql into a Caliban-generated client library saved in src/main/scala/graphqlzero/Client.scala:

calibanGenClient src/main/graphql/graphqlzero.graphql src/main/scala/graphqlzero/Client.scala --genView true

Running the Application

The run sbt command is going to run the main definition from src/main/scala/Main.scala:

run

The application is going to output a simple query equivalent to the following GraphQL query against GraphqlZero API:

query {
    album(id: 1) {
        id
        title
    }
}