ResponseHandler.java

package net.wasdev.twelvefactorapp;

import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Entity;
import javax.ws.rs.client.Invocation;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

public class ResponseHandler {

	private Invocation.Builder invoBuild = null;
	
	public enum RequestType {
		GET, POST, PUT, DELETE
	}
	
	public ResponseHandler(String extension) throws Exception {
		CloudantCredentials cc = new CloudantCredentials(
				System.getenv("dbUsername"),
				System.getenv("dbPassword"),
				System.getenv("dbUrl"),
				System.getenv("VCAP_SERVICES")
				);
		
		String fullUrl = cc.getUrl() + extension;
		System.out.println("Found url " + fullUrl);
		
		String usernameAndPassword = cc.getUsername() + ":" + cc.getPassword();
				
		String authorizationHeaderName = "Authorization";
		String authorizationHeaderValue = "Basic " + javax.xml.bind.DatatypeConverter.printBase64Binary(usernameAndPassword.getBytes());
		
		Client client = ClientBuilder.newClient();
		WebTarget target = client.target(fullUrl);
		invoBuild  = target.request(MediaType.APPLICATION_JSON).header(authorizationHeaderName, authorizationHeaderValue);
	}
	
	public String invoke(RequestType requestType) throws Exception {
		return invoke(requestType, null);
	}
	
	public String invoke(RequestType requestType, Entity<?> ent) throws Exception {
		if (invoBuild == null) {
			throw new Exception("Database cannot be accessed at this time, invobuild is null");
		}
		Response response = invoBuild.build(requestType.toString(), ent).invoke();
		String resp = response.readEntity(String.class);
		response.close();
		checkResponse(resp);
		return resp;
	}
	
	public void checkResponse(String response) throws Exception {
		if (response.contains("error")) {
			throw new Exception("Database returned an error " + response);
		}
	}
}