Getting started with GraphQLize in Kotlin Spring-Boot is simple and straight forward.
As we typically do, let's go to Spring Initializr and create a Kotlin project with Web & JPA as dependencies. This documentation uses this Spring Initializr Template.
The first step is to add the
graphqlize-java & the JDBC driver dependencies.
The next step is initializing
GraphQLizeResolver. To do it, let's a create new file GraphQLizeResolverProvider.kt and add the following code to expose the
GraphQLizeResolver spring-boot bean.
During initialization (via
GraphQLizeResolver reads the metadata of the database using the JDBC metadata APIs and keeps an in-memory representation of them.
Currently, it takes around 8 to 12 seconds to initialize. I am planning to work on it in a future release.
To configure the
DataSource, let's add the following properties in the application.properties file
Make sure you are changing the above values to refer your database connection. The above example assumes that you are using the sakila database created from this JOOQ's example repository.
Adding GraphQL Endpoint
The final step is exposing an API endpoint for handling the GraphQL request. To do it, let's create a new file GraphQLController.kt and do the following
- Create a data class
GraphQLRequestfor deserializing GraphQL request from the client.
- Create a Controller class with a
- Create a method inside this class to handle the GraphQL request.
Handling the GraphQL request is as simple as highlighted above.
Get the query & the variables from the request and invoke the
resolve method on the initialized instance of
It returns the
result as stringified JSON, and we are sending it as response body with the content type as
To a test drive of this implementation, start the server and hit the endpoint via curl.
You'll get a response like below.
GraphQL Playground and Voyager
With the GraphQL endpoint up and running, the next step is introspecting the GraphQL schema and try out some more queries.
To introspect, we are going to make use of Voyager, a tool to visualize GraphQL API as an interactive graph. Adding it to our project is easy thanks to static content serve capability of Spring Boot.
All you need to do is download this voyager.html file and put it under the src/main/resources/static directory.
When you restart the server, the Voyager will be available at http://localhost:8080/voyager.html. A sample output would look like this.
Then to interact with the GraphQL API, let's add the GraphQL Playground. Like Voyager, download this playground.html file and put in the static directory.
This GraphQL playground will be available at http://localhost:8080/playground.html after server restart.
Congrats! You are on course to build impressive applications using GraphQLize in less time. To save yourself some more time, do refer this documentation to know more about how GraphQLize generates the GraphQL schema and the queries.
The sample code is available in this GitHub Repository.
You can also customize certain default behaviours of GraphQLize in future releases.