https://github.com/jusexton/spring-graphql-example

GraphQL example project using Kotlin and Spring Boot.
https://github.com/jusexton/spring-graphql-example

example-project graphql kotlin spring-boot

Last synced: about 2 months ago
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GraphQL example project using Kotlin and Spring Boot.

• Host: GitHub
• URL: https://github.com/jusexton/spring-graphql-example
• Owner: jusexton
• Created: 2019-07-30T03:44:37.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2019-08-12T03:43:26.000Z (almost 7 years ago)
• Last Synced: 2025-07-31T22:58:02.058Z (11 months ago)
• Topics: example-project, graphql, kotlin, spring-boot
• Language: Kotlin
• Homepage:
• Size: 597 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# Spring GraphQL Example

Small CRUD application demonstrating how to build a GraphQL API with Kotlin, MongoDB and Spring Boot.

You will need a mongo instance to connect too for this application to work.

## GraphQL Dependencies

```

implementation 'com.graphql-java:graphiql-spring-boot-starter:5.0.2'

implementation 'com.graphql-java:graphql-spring-boot-starter:5.0.2'

implementation 'com.graphql-java:graphql-java-tools:5.2.4'

```

## GraphiQL

### Adding New Users

![Alt text](screenshots/mutation-screenshot.png?raw=true "Mutation Screenshot")

```

type Mutation {

    # Used to create a new user in the system

    createUser(input: UserInput!): User!

}

```

```kotlin

fun createUser(userInput: UserInput) = userRepository.save(User(userInput.username, userInput.address))

```

### Querying Users

![Alt text](screenshots/query-screenshot.png?raw=true "Query Screenshot")

```

extend type Query {

    # Retrieves a user by their id

    userById(id: String!): User

    # Used to retrieve all users in the system.

    allUsers(filter: UserFilter): [User]!

}

```

```kotlin

fun userById(id: String) = userService.repository.findById(id).orElseThrow { UserNotFoundException(id) }

fun allUsers(filter: UserFilter?) = userService.findAll(filter)

```

### Error Messages

![Alt text](screenshots/error-screenshot.png?raw=true "Error Screenshot")

```kotlin

@Component

class ErrorHandler : GraphQLErrorHandler {

    override fun processErrors(errors: MutableList?): MutableList =

            errors?.map { getNested(it) }?.toMutableList() ?: mutableListOf()

    private fun getNested(error: GraphQLError): GraphQLError =

            if (error is ExceptionWhileDataFetching && error.exception is GraphQLError) error.exception as GraphQLError else error

}

```