Exception Handling and Validation Handler in Vertx applications

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  • onComplete will in invoked when the execution is completed, either it is succeeded or failed.
  • onSuccess handles the successful result.
  • onFailure catches the exception thrown in the execution.
public class PostNotFoundException extends RuntimeException {
public PostNotFoundException(UUID id) {
super("Post id: " + id + " was not found. ");
}
}
public Future<Post> findById(UUID id) {
Objects.requireNonNull(id, "id can not be null");
return client.preparedQuery("SELECT * FROM posts WHERE id=$1")
.execute(Tuple.of(id))
.map(RowSet::iterator)
.map(iterator -> {
if (iterator.hasNext()) {
return MAPPER.apply(iterator.next());
}
throw new PostNotFoundException(id);
});
}
public void get(RoutingContext rc) {
var params = rc.pathParams();
var id = params.get("id");
this.posts.findById(UUID.fromString(id))
.onSuccess(
post -> rc.response().end(Json.encode(post))
)
.onFailure(
throwable -> rc.fail(throwable)
);
}
router.get("/posts/:id")
.produces("application/json")
.handler(handlers::get)
.failureHandler(frc -> {
Throwable failure = frc.failure();
if (failure instanceof PostNotFoundException) {
frc.response().setStatusCode(404).end();
}
frc.response().setStatusCode(500).setStatusMessage("Server internal error:" + failure.getMessage()).end();
});
router.post("/posts").consumes("application/json")
.handler(BodyHandler.create())
.handler(validation)
.handler(handlers::save)
.failureHandler(validationFailureHandler);
<dependency>
<groupId>io.vertx</groupId>
<artifactId>vertx-json-schema</artifactId>
</dependency>
SchemaRouter schemaRouter = SchemaRouter.create(vertx, new SchemaRouterOptions());
SchemaParser schemaParser = SchemaParser.createDraft201909SchemaParser(schemaRouter);
ObjectSchemaBuilder bodySchemaBuilder = objectSchema()
.requiredProperty("title", stringSchema().with(minLength(5)).with(maxLength(100)))
.requiredProperty("content", stringSchema().with(minLength(10)).with(maxLength(2000)));
ValidationHandler validation = ValidationHandler.newInstance(
ValidationHandler
.builder(schemaParser)
//.queryParameter(param("parameterName", intSchema()))
//.pathParameter(param("pathParam", numberSchema()))
.body(Bodies.json(bodySchemaBuilder))
//.body(Bodies.formUrlEncoded(bodySchemaBuilder))
.predicate(RequestPredicate.BODY_REQUIRED)
.build()
);
Handler<RoutingContext> validationFailureHandler = (RoutingContext rc) -> {
if (rc.failure() instanceof BodyProcessorException exception) {
rc.response()
.setStatusCode(400)
.end("validation failed.");
//.end(exception.toJson().encode());
}
};

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Self-employed technical consultant, solution architect and full-stack developer, open source contributor, freelancer and remote worker

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Hantsy

Hantsy

Self-employed technical consultant, solution architect and full-stack developer, open source contributor, freelancer and remote worker

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