JSR340 Multi Filters

This tutorial we'll modify the demo that has been described in previous tutorial to write multi filters in zero system, in this kind of situation we could manage all the filters before your API, this feature is more useful and powerful.

Demo projects:

• Standalone - 6084: up-tethys

1. Source Code

1.1. API

package up.god.micro.filter;

import io.vertx.core.json.JsonObject;
import io.vertx.up.annotations.Address;
import io.vertx.up.annotations.EndPoint;

import jakarta.ws.rs.BodyParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;

@EndPoint
@Path("/api")
public interface FilterApi {

    @POST
    @Path("/jsr340/worker")
    @Address("ZERO://JSR340/WORKER")
    JsonObject filter(@BodyParam final JsonObject data);
}

1.2. Consumer

package up.god.micro.filter;

import io.vertx.core.Future;
import io.vertx.core.json.JsonObject;
import io.vertx.up.annotations.Address;
import io.vertx.up.annotations.Queue;
import io.vertx.up.commune.Envelop;

@Queue
public class FilterWorker {

    @Address("ZERO://JSR340/WORKER")
    public Future<JsonObject> work(final Envelop envelop) {
        final String key = envelop.context("key", String.class);
        final String key1 = envelop.context("key1", String.class);
        return Future.succeededFuture(new JsonObject().put("key", key).put("key1", key1));
    }
}

1.3. Filters

Here are two filters in this example, we'll manage all the filters by io.vertx.up.annotations.Ordered, The default order value is 0, it means that all the filters will be triggered in sequence by order.

FirstFilter

package up.god.micro.filter;

import io.vertx.core.VertxException;
import io.vertx.core.http.HttpServerRequest;
import io.vertx.core.http.HttpServerResponse;
import io.vertx.up.uca.web.filter.HttpFilter;

import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter("/api/jsr340/*")
public class FirstFilter extends HttpFilter {

    @Override
    public void doFilter(final HttpServerRequest request,
                         final HttpServerResponse response)
            throws IOException, VertxException {
        System.out.println("First Filter");
        this.put("key", "First Filter");
    }
}

SecondFilter

package up.god.micro.filter;

import io.vertx.core.VertxException;
import io.vertx.core.http.HttpServerRequest;
import io.vertx.core.http.HttpServerResponse;
import io.vertx.up.annotations.Ordered;
import io.vertx.up.uca.web.filter.HttpFilter;

import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter("/api/jsr340/*")
@Ordered(2)
public class SecondFilter extends HttpFilter {

    @Override
    public void doFilter(final HttpServerRequest request,
                         final HttpServerResponse response)
            throws IOException, VertxException {
        System.out.println("Second Filter");
        this.put("key1", "Second Filter");
    }
}

2. Testing

Then you can test this demo:

URL : http://localhost:6084/api/jsr340/worker

Method: POST

Request :

{
    "username":"Filter"
}

Response :

{
    "data": {
        "key": "First Filter",
        "key1": "Second Filter"
    }
}

3. Summary

In this demo we defined 2 filters in sequence to implement the whole Chain of Responsibility pattern. In zero system, please be careful about the whole filter chain:

• All the filters could be managed by io.vertx.up.annotations.Ordered.
• The data could be passed by RoutingContext instead of other form, you can put the data into RoutingContext by put.
• In Sender, you should extract data by @ContextParam or get RoutingContext reference to process it by yourself.
• In Consumer, you can call Envelop.context api to get the data from RoutingContext.