Viaduct Jetty Starter App

A minimal Viaduct GraphQL application using Eclipse Jetty servlet container. This example demonstrates how to integrate Viaduct with a lightweight HTTP server using servlets.

Requirements

• Java JDK 21 is installed
• JAVA_HOME environment variable is set correctly or java is in the classpath

Quick Start

Check out the Getting Started docs.

Start the Viaduct Jetty Starter App

./gradlew run

The server will start on http://localhost:8080.

Test the GraphQL endpoint

curl

With the server running, you can use the following curl command to send GraphQL queries:

curl 'http://localhost:8080/graphql' -H 'content-type: application/json' --data-raw '{"query":"{ greeting }"}'

You should see the following output:

{"data":{"greeting":"Hello from Jetty + Viaduct!"}}

Query multiple fields

curl 'http://localhost:8080/graphql' -H 'content-type: application/json' --data-raw '{"query":"query HelloWorld { greeting author }"}'

Response:

{
  "data": {
    "greeting": "Hello from Jetty + Viaduct!",
    "author": "Viaduct GraphQL with Jetty"
  }
}

GET requests

The servlet also supports GET requests with query parameters:

curl 'http://localhost:8080/graphql?query=%7B%20greeting%20%7D'

GraphiQL

With the server running, navigate to the following URL in your browser to bring up the GraphiQL interface:

http://localhost:8080/graphiql

Then, run the following query:

query HelloWorld {
  greeting
  author
}

You should see this response:

{
  "data": {
    "greeting": "Hello from Jetty + Viaduct!",
    "author": "Viaduct GraphQL with Jetty"
  }
}

Running Tests

Run the integration tests with:

./gradlew test

The tests start an embedded Jetty server and verify the GraphQL endpoint behavior.

Project Structure

jetty-starter/
├── src/main/kotlin/com/example/viadapp/
│   ├── JettyViaductApplication.kt  # Main application entry point
│   └── ViaductServlet.kt           # GraphQL servlet implementation
├── resolvers/                       # GraphQL resolver module
│   └── src/main/
│       ├── kotlin/com/example/viadapp/resolvers/
│       │   └── HelloWorldResolvers.kt
│       └── viaduct/schema/
│           └── schema.graphqls      # GraphQL schema definition
└── src/test/kotlin/                 # Integration tests

How It Works

This example demonstrates:

1. BasicViaductFactory: Creates a Viaduct engine with automatic module discovery
2. Custom Servlet: Implements a GraphQL-over-HTTP servlet that handles POST and GET requests
3. Jetty Server: Lightweight embedded HTTP server
4. Module-based Architecture: Resolvers are organized as a Viaduct module with automatic schema generation

The servlet supports:

• POST requests with JSON body (application/json)
• POST requests with GraphQL query body (application/graphql)
• GET requests with query parameters
• Proper error handling and status codes