ClientRestTemplate.java

/*
 * Copyright 2013, 2014, 2015 EnergyOS.org
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package org.energyos.espi.thirdparty.web;

import java.io.IOException;

import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.AuthState;
import org.apache.http.auth.Credentials;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.client.protocol.ClientContext;
import org.apache.http.impl.auth.BasicScheme;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.ExecutionContext;
import org.apache.http.protocol.HttpContext;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

public class ClientRestTemplate extends RestTemplate {

	public ClientRestTemplate() {
	}

	public ClientRestTemplate(String username, String password) {
		DefaultHttpClient httpClient = new DefaultHttpClient();
		BasicCredentialsProvider credentialsProvider = new BasicCredentialsProvider();
		credentialsProvider.setCredentials(new AuthScope(AuthScope.ANY_HOST,
				AuthScope.ANY_PORT), new UsernamePasswordCredentials(username,
				password));
		httpClient.setCredentialsProvider(credentialsProvider);
		httpClient.addRequestInterceptor(new PreemptiveAuthInterceptor(), 0);
		ClientHttpRequestFactory rf = new HttpComponentsClientHttpRequestFactory(
				httpClient);

		this.setRequestFactory(rf);
	}

	static class PreemptiveAuthInterceptor implements HttpRequestInterceptor {

		@SuppressWarnings("deprecation")
		// TODO there are two deprecated calls here ...
		public void process(final HttpRequest request, final HttpContext context)
				throws HttpException, IOException {
			AuthState authState = (AuthState) context
					.getAttribute(ClientContext.TARGET_AUTH_STATE);

			if (authState.getAuthScheme() == null) {
				CredentialsProvider credsProvider = (CredentialsProvider) context
						.getAttribute(ClientContext.CREDS_PROVIDER);
				HttpHost targetHost = (HttpHost) context
						.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
				Credentials creds = credsProvider.getCredentials(new AuthScope(
						targetHost.getHostName(), targetHost.getPort()));
				if (creds == null)
					throw new HttpException(
							"No credentials for preemptive authentication");
				authState.setAuthScheme(new BasicScheme());
				authState.setCredentials(creds);
			}
		}
	}
}