bpel-rest-extensions/src/main/java/org/apache/ode/bpel/extension/bpel4restlight/http/HighLevelRestApi.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.ode.bpel.extension.bpel4restlight.http;

import java.io.UnsupportedEncodingException;

import org.apache.commons.httpclient.HttpMethodBase;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.DeleteMethod;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.PutMethod;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.ode.bpel.common.FaultException;
import org.apache.ode.bpel.extension.bpel4restlight.Bpel4RestLightExtensionBundle;

/**
 * This class wraps HTTP method functionality and thereby abstracts from low
 * level library-specific code to simplify its usage.
 * 
 * @author Michael Hahn (mhahn.dev@gmail.com)
 */
public class HighLevelRestApi {

	/**
	 * This method implements the HTTP PUT Method
	 * 
	 * @param uri
	 *            The URI of the target resource
	 * @param requestPayload
	 *            The payload of the request message
	 * @param acceptHeaderValue
	 *            The value of the accept header field to be set
	 * @return A HttpResponseMessage providing the response message payload and
	 *         status code.
	 * 
	 * @exception FaultException
	 */
	public static HttpResponseMessage Put(String uri, String requestPayload, String acceptHeaderValue)
			throws FaultException {

		PutMethod method = new PutMethod(uri);

		HighLevelRestApi.setAcceptHeader(method, acceptHeaderValue);
		try {
			method.setRequestEntity(new StringRequestEntity(requestPayload, "application/xml", "UTF-8"));
		} catch (UnsupportedEncodingException e) {
			throw new FaultException(Bpel4RestLightExtensionBundle.FAULT_QNAME,
					"BPEL4REST: Execution of HTTP method '" + method.getName() + "' caused an exception.", e);
		}

		HttpResponseMessage responseMessage = LowLevelRestApi.executeHttpMethod(method);
		// Remove <?xml... in front of response
		HighLevelRestApi.cleanResponseBody(responseMessage);

		return responseMessage;
	}

	/**
	 * This method implements the HTTP POST Method
	 * 
	 * @param uri
	 *            The URI of the target resource
	 * @param requestPayload
	 *            The payload of the request message
	 * @param acceptHeaderValue
	 *            The value of the accept header field to be set
	 * @return A HttpResponseMessage providing the response message payload and
	 *         status code.
	 * 
	 * @exception FaultException
	 */
	public static HttpResponseMessage Post(String uri, String requestPayload, String acceptHeaderValue)
			throws FaultException {

		PostMethod method = null;
		if (uri.contains("?")) {
			String[] split = uri.split("\\?");
			method = new PostMethod(split[0]);
			method.setQueryString(HighLevelRestApi.createNameValuePairArrayFromQuery(split[1]));
		} else {
			method = new PostMethod(uri);
		}

		try {
			method.setRequestEntity(new StringRequestEntity(requestPayload, "application/xml", "UTF-8"));
		} catch (UnsupportedEncodingException e) {
			throw new FaultException(Bpel4RestLightExtensionBundle.FAULT_QNAME,
					"BPEL4REST: Execution of HTTP method '" + method.getName() + "' caused an exception.", e);
		}

		HighLevelRestApi.setAcceptHeader(method, acceptHeaderValue);
		HttpResponseMessage responseMessage = LowLevelRestApi.executeHttpMethod(method);
		// Remove <?xml... in front of response
		HighLevelRestApi.cleanResponseBody(responseMessage);

		return responseMessage;
	}

	/**
	 * This method implements the HTTP GET Method
	 * 
	 * @param uri
	 *            The URI of the target resource
	 * @param acceptHeaderValue
	 *            The value of the accept header field to be set
	 * @return A HttpResponseMessage providing the response message payload and
	 *         status code.
	 * 
	 * @exception FaultException
	 */
	public static HttpResponseMessage Get(String uri, String acceptHeaderValue) throws FaultException {
		GetMethod method = null;
		if (uri.contains("?")) {
			String[] split = uri.split("\\?");
			method = new GetMethod(split[0]);
			method.setQueryString(HighLevelRestApi.createNameValuePairArrayFromQuery(split[1]));
		} else {
			method = new GetMethod(uri);
		}
		HighLevelRestApi.setAcceptHeader(method, acceptHeaderValue);
		HttpResponseMessage responseMessage = LowLevelRestApi.executeHttpMethod(method);
		HighLevelRestApi.cleanResponseBody(responseMessage);
		return responseMessage;
	}

	/**
	 * This method implements the HTTP DELETE Method
	 * 
	 * @param uri
	 *            The URI of the target resource
	 * @param acceptHeaderValue
	 *            The value of the accept header field to be set
	 * @return A HttpResponseMessage providing the response message payload and
	 *         status code.
	 * 
	 * @exception FaultException
	 */
	public static HttpResponseMessage Delete(String uri, String acceptHeaderValue) throws FaultException {

		DeleteMethod method = new DeleteMethod(uri);
		HighLevelRestApi.setAcceptHeader(method, acceptHeaderValue);
		HttpResponseMessage responseMessage = LowLevelRestApi.executeHttpMethod(method);
		HighLevelRestApi.cleanResponseBody(responseMessage);
		return responseMessage;
	}

	private static NameValuePair[] createNameValuePairArrayFromQuery(String query) {
		// example:
		// csarID=Moodle.csar&serviceTemplateID={http://www.example.com/tosca/ServiceTemplates/Moodle}Moodle&nodeTemplateID={http://www.example.com/tosca/ServiceTemplates/Moodle}VmApache
		String[] pairs = query.trim().split("&");
		NameValuePair[] nameValuePairArray = new NameValuePair[pairs.length];
		int count = 0;
		for (String pair : pairs) {
			String[] keyValue = pair.split("=");
			NameValuePair nameValuePair = new NameValuePair();
			nameValuePair.setName(keyValue[0]);
			nameValuePair.setValue(keyValue[1]);
			nameValuePairArray[count] = nameValuePair;
			count++;
		}
		return nameValuePairArray;
	}

	private static void setAcceptHeader(HttpMethodBase method, String value) {
		if (!value.equals("")) {
			method.setRequestHeader("Accept", value);
		} else {
			method.setRequestHeader("Accept", "application/xml");
		}
	}

	private static void cleanResponseBody(HttpResponseMessage responseMessage) {
		if (responseMessage.getResponseBody() != null) {
			String temp = responseMessage.getResponseBody()
					.replace("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>", "");
			responseMessage.setResponseBody(temp);
		}
	}
}