migrating from charon 3 to 4

[Annemarie-dw]

Hi all,

I'm working on a Spring Boot project that uses charon 3.x which is configured through application.properties,
Took a stab at migrating but cannot get the proxy forwarding working.

Doing a basic test of forwarding the url
http://localhost:8090/search?q=hello

to
https://google.com/
I receive the google 404 page.

Log output:
2021-05-28 08:00:08.543 INFO 24456 --- [nio-8090-exec-2] c.g.m.c.f.i.log.ForwardingLogger : Forwarding: GET http://localhost:8090/search?q=hello -> 'test mapping' -> GET https://google.com/search?q=hello 404

I think I'm misunderstanding some fundamental setup.
I'm not familiar with Spring Boot either so there is a whole lot of unknowns for me :)

My setup:

build.gradle:
dependencies {
	compile (group: 'com.github.mkopylec', name: 'charon-spring-webmvc', version: '4.9.0');
	implementation 'org.springframework.boot:spring-boot-starter-jersey'
	implementation 'org.springframework.boot:spring-boot-starter-web'
	providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'
}

Charon:

@Configuration
class CharonConfiguration {

    @Bean
    public CharonConfigurer charonConfigurer() {

        CharonConfigurer configurer = charonConfiguration()
                .add( requestMapping( "test mapping" )
                                .set( requestServerNameRewriter().outgoingServers( "https://google.com" ) )
                );
        return configurer;

    }
}

Any ideas where I'm going off the rails?

Kind regards
Anna

[mkopylec]

Hi, please try with http://example.com/ instead of https://google.com.
Google may block suspicious traffic like the one from your localhost.
IMO the example domain should not block any trafiic.

[Annemarie-dw]

Yay, I got it working by adding:

set( RequestHostHeaderRewriterConfigurer.requestHostHeaderRewriter() )

The previous team also rewrite the response body like so:

public class StripHateoas implements ReceivedResponseInterceptor {
public void intercept( ResponseData response, MappingProperties mapping ) {
String str = response.getBodyAsString();

Is it possible to retrieve the response body as a string in v4?

I tried this:

HttpResponse response = execution.execute( request );
byte[] bytes = response.getBodyAsBytes();
String body = new String( bytes, "utf8");

But the string body is raw bytes, where v3 was the response' JSON string

[Annemarie-dw]

Looking at migrating again, and trying to rewrite the response body...

I figured out that this call:
byte[] bytes = response.getBodyAsBytes();
returned gzip compressed bytes.
Or rather Charon V4 passes the response as-is to the interceptor.

Does that mean Charon V3 tweaked headers to ensure the response wasn't compressed?
Because in V3 getBody returned the JSON I expect.

Should I write a interceptor to remove the accept-encoding header or something along those lines?

[mkopylec]

I don't how this worked in v3 but I guess it should work as you wrote: pass the response as-is to the interceptors and to the client.