Optional path parameter in vertx - vert.x

Question

I want to use a get request to get optional path parameters in a single end point . For example :-
if user hit below api :-
/metric/monitor/:id
or
/metric/:id
here id is path parameter than i need to route to the same function in a single end point using get request. How can i do the same ?

Answer 1

You can specify a route using regular expressions.
Assuming the id is a number:
router.getWithRegex( "\\/metric(\\/monitor)?\\/(?<ID>\\d+)" ).respond( this::monitor );
and then read the value:
long id = Long.parseLong( ctx.pathParam( "ID" ) );
This is how I usually declare the route using Vert.x Web 4.3.1:
public class MyVerticle extends AbstractVerticle {
#Override
public void start(Promise<Void> startPromise) {
Router router = Router.router( vertx );
BodyHandler bodyHandler = BodyHandler.create();
router.post().handler( bodyHandler );
router.getWithRegex( "\\/metric(\\/monitor)?\\/(?<ID>\\d+)" ).respond( this::monitor );
// Keeping track of it so that I can close it later
this.httpServer = vertx.createHttpServer();
final Future<HttpServer> startHttpServer = httpServer
.requestHandler( router )
.listen( HTTP_PORT )
.onSuccess( v -> LOG.infof( "✅ HTTP server listening on port %s", HTTP_PORT ) );
startHttpServer
.onSuccess( s -> startPromise.complete() )
.onFailure( startPromise::fail );
}
private Future<Result> monitor(RoutingContext ctx) {
long id = Long.parseLong( ctx.pathParam( "ID" ) );
Result result = ... // Do something
return Future.succeededFuture(result);
}
More details about routing with regular expressions are available in the documentation.
But, to be fair, creating two separate entry points seems easier for this case:
router.get( "/metric/monitor/:id" ).respond( this::monitor );
router.get( "/metric/:id" ).respond( this::monitor );