How to change the header of connect request with okhttp

Question

I installed an interceptor, which sets the custom useragent string on my java okhttp4 client.

public class UserAgentInterceptor implements Interceptor {
    @Override
    public Response intercept(Interceptor.Chain chain) throws IOException {
        return chain.proceed(chain.request().newBuilder()
                .removeHeader("User-Agent")
                .addHeader("User-Agent", MYUSERAGENT);
    }
}

client = new OkHttpClient.Builder()
                .addNetworkInterceptor(new UserAgentInterceptor())
                .build();

I checked it with Fiddler and it seems to work with the request (GET/POST) itself. However, there is a CONNECT request beforehand which still has the okhttp header. How can I change the CONNECT User-Agent header?

Answer 1

I finally solved my problem by adding a custom proxy authenticator

new OkHttpClient.Builder()
                .proxyAuthenticator(new MyProxyAuthenticator())
                .addNetworkInterceptor(new UserAgentInterceptor());

public class MyProxyAuthenticator implements Authenticator {

    @Nullable
    @Override
    public Request authenticate(@Nullable Route route, @NotNull Response response) throws IOException {
        Request request = new JavaNetAuthenticator().authenticate(route, response);

        if (request == null) {
            request = new Request.Builder()
                    .url(route.address().url())
                    .method("CONNECT", null)
                    .header("Host", toHostHeader(route.address().url(), true))
                    .header("Proxy-Connection", "Keep-Alive")
                    .build();
        }

        return request.newBuilder()
                .header("User-Agent", MYUSERAGENT)
                .build();
    }
}