CODEWITHSUNDEEP
javaakkaakka-http
Sergey Karpushin
Sergey Karpushin

Reputation: 874

How to perform simple http request with akka-http_2.12 v10.0.6

I'm trying to learn akka by making simple example that queries urls. I was trying to use example from Akka HTTP official docs, but "surprisingly" official doc is outdated.

I was trying to make use of this answer here on StackOverflow, but again - it's referring to outdated API.

My code is:

import java.util.concurrent.CompletionStage;

import static akka.pattern.Patterns.pipe;

import akka.actor.AbstractActor;
import akka.http.javadsl.Http;
import akka.http.javadsl.model.HttpRequest;
import akka.http.javadsl.model.HttpResponse;
import akka.japi.pf.FI.UnitApply;
import akka.japi.pf.ReceiveBuilder;
import akka.stream.ActorMaterializer;
import akka.stream.Materializer;
import scala.concurrent.ExecutionContextExecutor;

public class RequestForPageActor extends AbstractActor {
    final Http http = Http.get(context().system());
    final ExecutionContextExecutor dispatcher = context().dispatcher();
    final Materializer materializer = ActorMaterializer.create(context());

    @Override
    public Receive createReceive() {
        return receiveBuilder().match(RequestForPage.class, onRequestForPage()).build();
        // TODO: Handle page response
    }

    private UnitApply<RequestForPage> onRequestForPage() {
        return request -> {
            pipe(fetch(request.getUrl()), dispatcher).to(self());
        };
    }

    CompletionStage<HttpResponse> fetch(String url) {
        return http.singleRequest(HttpRequest.create(url), materializer);
    }
}

The problem is that API has changed. And now compiler's complaint is: The method pipe(Future<T>, ExecutionContext) in the type Patterns is not applicable for the arguments (CompletionStage<HttpResponse>, ExecutionContextExecutor)

Question: So, how do I perform this simple task of querying url and processing results?

Upvotes: 0

Views: 455

Answers (1)

Stefano Bonetti
Stefano Bonetti

Reputation: 9023

The documentation is not outdated. You're just importing the wrong static method.

Replace 

import static akka.pattern.Patterns.pipe;

with 

import static akka.pattern.PatternsCS.pipe;

PatternsCS contains a bunch of patterns implementations which work with CompletionStage instead Future. A few usage examples can be found in this docs page.

Upvotes: 2

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