cloudstark / quarkus-zalando-problem-extension

Quarkus extension for application/problem+json (RFC7807)

Quarkus Problem (RFC7807) Extension

Extension to use Zalando Problem in your Quarkus JAX-RS application. The extension will register an ExceptionMapper that is responsible to map catched Exceptions into valid application/problem+json to be used as the payload of the HTTP Response.

Getting Started

The Problem extension is not available in Maven Central. For now you have to clone the repository and install the extension in your local maven repository. Then follow these steps to write and deploy a simple JAX-RS application:

Setup Project

Create a new project using the Quarkus archetype:

mvn io.quarkus:quarkus-maven-plugin:1.2.1.Final:create \
    -DprojectGroupId=org.acme.rfc7807 \
    -DprojectArtifactId=rfc7807 \
    -DclassName="org.acme.rest.json.CalcResource" \
    -Dpath="/calc" \
    -Dextensions="resteasy-jsonb"

Add the following dependency to your pom.xml:

<dependency>
      <groupId>solutions.cloudstark.quarkus</groupId>
      <artifactId>quarkus-zalando-problem</artifactId>
      <version>0.0.2-SNAPSHOT</version>
</dependency>

Define JAX-RS resource

Create a service definition in src/main/java/org/acme/rest/json/CalcResource.java

import org.zalando.problem.Problem;
import org.zalando.problem.Status;
import org.zalando.problem.violations.ConstraintViolationProblem;
import org.zalando.problem.violations.Violation;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import java.util.Arrays;

import static javax.ws.rs.core.MediaType.TEXT_PLAIN;

@Path("/calc")
public class CalcResource {

    @Context
    UriInfo uriInfo;

    @GET
    @Path("/{a: [0-9]+}:{b: [0-9]+}")
    @Produces(TEXT_PLAIN)
    public int divide(@PathParam("a") int a, @PathParam("b") int b) {
        return a / b;
    }

    @GET
    @Path("/exception")
    @Produces(TEXT_PLAIN)
    public void exception() {
        throw new RuntimeException("This is a runtime exception!");
    }

    @GET
    @Path("/problem")
    @Produces(TEXT_PLAIN)
    public void problem() {
        throw Problem.builder()
                .withStatus(Status.BAD_REQUEST)
                .withTitle("Strange problem!")
                .build();
    }

    @GET
    @Path("/violation")
    @Produces(TEXT_PLAIN)
    public void violation() {
        throw new ConstraintViolationProblem(Status.BAD_REQUEST,
                Arrays.asList(new Violation("name", "must not be null")));
    }
}

Note: You will have to adjust the generated test in src/test/java - otherwise the build will fail.

$ curl localhost:8080/calc/20:0
{
  "status": 500,
  "title": "/ by zero",
  "detail": "java.lang.ArithmeticException: / by zero",
  "instance": "/calc/20:0"
}

$ curl localhost:8080/calc/violation
{
  "type": "https://zalando.github.io/problem/constraint-violation",
  "status": 400,
  "title": "Constraint Violation",
  "violations": [
    {
      "field": "name",
      "message": "must not be null"
    }
  ]
}

Run

JVM Mode

mvn package
java -jar target/rfc7807-1.0-SNAPSHOT-runner.jar

Native Mode

mvn package -P native
./target/rfc7807-1.0-SNAPSHOT-runner

Todos

• Jackson support
• more unit tests