authorization-client/src/main/java/org/gcube/common/authorization/client/proxy/DefaultAuthorizationProxy.java

package org.gcube.common.authorization.client.proxy;

import static org.gcube.common.authorization.client.Constants.CLIENT_ID_PARAM;
import static org.gcube.common.authorization.client.Constants.CONTEXT_PARAM;
import static org.gcube.common.authorization.client.Constants.ROLES_PARAM;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.gcube.common.authorization.client.Binder;
import org.gcube.common.authorization.client.Constants;
import org.gcube.common.authorization.client.exceptions.ObjectNotFound;
import org.gcube.common.authorization.library.AuthorizationEntry;
import org.gcube.common.authorization.library.enpoints.AuthorizationEndpoint;
import org.gcube.common.authorization.library.enpoints.AuthorizationEndpointScanner;
import org.gcube.common.encryption.StringEncrypter;
import org.gcube.common.scope.api.ScopeProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DefaultAuthorizationProxy implements AuthorizationProxy {

	private static Logger log = LoggerFactory.getLogger(AuthorizationProxy.class);
	
	private static Map<String, AuthorizationEntryCache> cache = new HashMap<String, AuthorizationEntryCache>();


	private List<AuthorizationEndpoint> endpoints;

	public DefaultAuthorizationProxy() {
				
		endpoints = AuthorizationEndpointScanner.endpoints();
		AuthorizationEndpoint ae = endpoints.get(0);
		try{
			InetAddress addr = InetAddress.getByName(ae.getHost());
			if (addr.isAnyLocalAddress() || addr.isLoopbackAddress()){
				ae.setHost("localhost");
				this.setEndpoint(ae);
			}
			log.debug("endpoint set to localhost");
		}catch(UnknownHostException e){
			log.warn("unknown host", e);
		}
	}

	private String getInternalEnpoint(){
		StringBuilder endpoint = new StringBuilder("http://").append(getEndpoint().getHost()).append(":")
				.append(getEndpoint().getPort()).append("/authorization-service/gcube/service");
		return endpoint.toString();

	}

	@Deprecated
	@Override
	public String generate(String clientId, List<String> roles) throws Exception {
		final String context = ScopeProvider.instance.get();
		return this.generate(clientId, context , roles);

	}

	@Override
	public String generate(String clientId, String context,  List<String> roles) throws Exception {
		final String methodPath = "/generate/token/"; 

		StringBuilder rolesQueryString = new StringBuilder(); 
		if (roles.size()>0){
			for (String role: roles)
				rolesQueryString.append(role).append(",");
			rolesQueryString.deleteCharAt(rolesQueryString.lastIndexOf(","));
		}
		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath).append("?")
				.append(CLIENT_ID_PARAM).append("=").append(clientId).append("&")
				.append(ROLES_PARAM).append("=").append(rolesQueryString).append("&")
				.append(CONTEXT_PARAM).append("=").append(context);

		URL url = new URL(callUrl.toString());
		HttpURLConnection connection = (HttpURLConnection)url.openConnection();
		connection.setRequestMethod("POST");


		if (connection.getResponseCode()!=200) throw new Exception("error contacting authorization service");
		String encryptedToken= "";
		try(BufferedReader reader = new BufferedReader(new InputStreamReader((InputStream)connection.getContent()));){
			StringBuilder result = new StringBuilder();
			String line;
			while((line = reader.readLine()) != null) 
				result.append(line);
			encryptedToken =  result.toString();
		}

		return StringEncrypter.getEncrypter().decrypt(encryptedToken, context);

	}

	@Override
	public AuthorizationEntry get(final String token) throws ObjectNotFound, Exception{
		final String methodPath = "/retrieve/"; 

		StringBuilder callUrl = new StringBuilder(getInternalEnpoint()).append(methodPath).append(token);

		log.debug("call uri "+callUrl.toString());
		
		URL url = new URL(callUrl.toString());
		HttpURLConnection connection = makeRequest(url, "GET");
		log.debug("response code is "+connection.getResponseCode());
		log.debug("response message is "+connection.getResponseMessage());
		
		if (connection.getResponseCode()==404) throw new ObjectNotFound("token "+token+" not found");
		if (connection.getResponseCode()!=200) throw new Exception("error contacting authorization service");
		if (connection.getContentLengthLong()<=0) return null;

		try(InputStream stream = (InputStream)connection.getContent();){
			AuthorizationEntry entry = (AuthorizationEntry)Binder.getContext().createUnmarshaller().unmarshal(stream);
			cache.put(token, new AuthorizationEntryCache(entry));
			return entry;
		}

	}

	/*
	@Override
	public BannedService deny(final String userName,  final  String serviceClass, final String serviceName) throws Exception {

		URL url = new URL(endpoint+"/deny/"+userName+"/"+serviceClass+"/"+serviceName);
		HttpURLConnection connection = makeRequest(url, "POST");

		if (connection.getResponseCode()!=200 && connection.getResponseCode()!=200) throw new Exception("error contacting authorization service");
		if (connection.getContentLengthLong()<=0) return null;

		try(InputStream stream = (InputStream)connection.getContent();){
			BannedService service = (BannedService)Binder.getContext().createUnmarshaller().unmarshal(stream);
			return service;
		}
	}

	@Override
	public void allow(final String userName, final  String serviceClass, final String serviceName) throws Exception{
		URL url = new URL(endpoint+"/deny/"+userName+"/"+serviceClass+"/"+serviceName);
		HttpURLConnection connection = makeRequest(url, "DELETE");
		if (!(connection.getResponseCode()>=200 && connection.getResponseCode()<=206)) 
			throw new Exception("error contacting authorization service");
	}


	@Override
	public List<BannedService> getBannedServices(final String userName) throws Exception{

		URL url = new URL(endpoint+"/deny/"+userName);

		HttpURLConnection connection = makeRequest(url, "GET");
		if (connection.getResponseCode()!=200) throw new Exception("error contacting authorization service");
		if (connection.getContentLengthLong()<=0) return Collections.emptyList();

		try(InputStream stream = (InputStream)connection.getContent();){
			BannedServices services = (BannedServices)Binder.getContext().createUnmarshaller().unmarshal(stream);
			if (services.get()==null) return Collections.emptyList();
			else return services.get();
		}

	}

	 */

	private HttpURLConnection makeRequest(URL url, String method) throws Exception{
		HttpURLConnection connection = (HttpURLConnection)url.openConnection();
		connection.setRequestProperty(Constants.SCOPE_HEADER_ENTRY, ScopeProvider.instance.get());
		connection.setRequestMethod(method);
		return connection;
	}

	@Override
	public AuthorizationEndpoint getEndpoint() {
		return this.endpoints.get(0);
	}

	@Override
	public void setEndpoint(AuthorizationEndpoint authEndpoint) {
		this.endpoints = Collections.singletonList(authEndpoint);		
	}
}