sdks/java/basys.sdk/src/main/java/org/eclipse/basyx/vab/protocol/http/server/VABHTTPInterface.java - basyx/basyx - Git at Google

 /*******************************************************************************
  * Copyright (C) 2021 the Eclipse BaSyx Authors
  *
  * This program and the accompanying materials are made
  * available under the terms of the Eclipse Public License 2.0
  * which is available at https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  ******************************************************************************/
 package org.eclipse.basyx.vab.protocol.http.server;

 import java.io.IOException;
 import java.io.InputStream;
 import java.io.PrintWriter;
 import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.Enumeration;
 import java.util.List;
 import java.util.StringJoiner;

 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import org.eclipse.basyx.vab.coder.json.provider.JSONProvider;
 import org.eclipse.basyx.vab.exception.provider.MalformedRequestException;
 import org.eclipse.basyx.vab.exception.provider.ProviderException;
 import org.eclipse.basyx.vab.modelprovider.VABPathTools;
 import org.eclipse.basyx.vab.modelprovider.api.IModelProvider;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

 import com.google.common.base.Charsets;
 import com.google.common.io.ByteSource;


 /**
  * VAB provider class that enables access to an IModelProvider via HTTP REST
  * interface<br />
  * <br />
  * REST http interface is as following: <br />
  * - GET /aas/submodels/{subModelId} Retrieves submodel with ID {subModelId}
  * <br />
  * - GET /aas/submodels/{subModelId}/properties/a Retrieve property a of
  * submodel {subModelId}<br />
  * - GET /aas/submodels/{subModelId}/properties/a/b Retrieve property a/b of
  * submodel {subModelId} <br />
  * - POST /aas/submodels/{subModelId}/operations/a Invoke operation a of
  * submodel {subModelId}<br />
  * - POST /aas/submodels/{subModelId}/operations/a/b Invoke operation a/b of
  * submodel {subModelId}
  *
  * @author kuhn
  *
  */
 public class VABHTTPInterface<ModelProvider extends IModelProvider> extends BasysHTTPServlet {

 	private static Logger logger = LoggerFactory.getLogger(VABHTTPInterface.class);

 	/**
 	 * Version information to identify the version of serialized instances
 	 */
 	private static final long serialVersionUID = 1L;


 	/**
 	 * Reference to IModelProvider backend
 	 */
 	protected JSONProvider<ModelProvider> providerBackend = null;


 	/**
 	 * Constructor
 	 */
 	public VABHTTPInterface(ModelProvider provider) {
 		// Store provider reference
 		providerBackend = new JSONProvider<ModelProvider>(provider);
 	}


 	/**
 	 * Access model provider
 	 */
 	public ModelProvider getModelProvider() {
 		return providerBackend.getBackendReference();
 	}

 	/**
 	 * Send JSON encoded response
 	 */
 	protected void sendJSONResponse(String path, PrintWriter outputStream, Object jsonValue) {
 		// Output result
 		outputStream.write(jsonValue.toString()); // FIXME throws nullpointer exception if jsonValue is null
 		outputStream.flush();
 	}


 	/**
 	 * Implement "Get" operation
 	 *
 	 * Process HTTP get request - get sub model property value
 	 */
 	@Override
 	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 		try {
 			String path = extractPath(req);

 			// Setup HTML response header
 			resp.setContentType("application/json");
 			resp.setCharacterEncoding("UTF-8");

 			resp.setStatus(200);

 			// Process get request
 			providerBackend.processBaSysGet(path, resp.getOutputStream());
 		} catch(ProviderException e) {
 			int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
 			resp.setStatus(httpCode);
 			logger.debug("Exception in HTTP-GET. Response-code: " + httpCode, e);
 		}

 	}


 	/**
 	 * Implement "Set" operation
 	 */
 	@Override
 	protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 		try {
 			String path = extractPath(req);
 			String serValue = extractSerializedValue(req);
 			logger.trace("DoPut: {}", serValue);

 			resp.setContentType("application/json");
 			resp.setCharacterEncoding("UTF-8");
 			resp.setStatus(200);

 			providerBackend.processBaSysSet(path, serValue.toString(), resp.getOutputStream());
 		} catch(ProviderException e) {
 			int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
 			resp.setStatus(httpCode);
 			logger.debug("Exception in HTTP-PUT. Response-code: " + httpCode, e);
 		}
 	}


 	/**
 	 * <pre>
 	 * Handle HTTP POST operation. Creates a new Property, Operation, Event,
 	 * Submodel or AAS or invokes an operation.
 	 */
 	@Override
 	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 		try {
 			String path = extractPath(req);
 			String serValue = extractSerializedValue(req);

 			logger.trace("DoPost: {}", serValue);

 			// Setup HTML response header
 			resp.setStatus(201);
 			resp.setContentType("application/json");
 			resp.setCharacterEncoding("UTF-8");

 			// Check if request is for property creation or operation invoke
 			if (VABPathTools.isOperationInvokationPath(path)) {
 			// Invoke BaSys VAB 'invoke' primitive

 				providerBackend.processBaSysInvoke(path, serValue, resp.getOutputStream());

 			} else {
 			// Invoke the BaSys 'create' primitive
 				providerBackend.processBaSysCreate(path, serValue, resp.getOutputStream());
 			}
 		} catch (ProviderException e) {
 			int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
 			resp.setStatus(httpCode);
 			logger.debug("Exception in HTTP-POST. Response-code: " + httpCode, e);
 		}
 	}


 	/**
 	 * Handle a HTTP PATCH operation. Updates a map or collection
 	 *
 	 */
 	@Override
 	protected void doPatch(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 		try {
 			String path = extractPath(req);
 			String serValue = extractSerializedValue(req);
 			logger.trace("DoPatch: {}", serValue);

 			resp.setStatus(200);

 			providerBackend.processBaSysDelete(path, serValue, resp.getOutputStream());
 		} catch(ProviderException e) {
 			int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
 			resp.setStatus(httpCode);
 			logger.debug("Exception in HTTP-PATCH. Response-code: " + httpCode, e);
 		}
 	}


 	/**
 	 * Implement "Delete" operation. Deletes any resource under the given path.
 	 */
 	@Override
 	protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 		try {
 			String path = extractPath(req);

 			// No parameter to read! Provide serialized null
 			String nullParam = "";

 			resp.setStatus(200);


 			providerBackend.processBaSysDelete(path, nullParam, resp.getOutputStream());
 		} catch(ProviderException e) {
 			int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
 			resp.setStatus(httpCode);
 			logger.debug("Exception in HTTP-DELETE. Response-code: " + httpCode, e);
 		}
 	}


 	private String extractPath(HttpServletRequest req) throws UnsupportedEncodingException {
 		// Extract path
 		String uri = req.getRequestURI();

 		// Normalizes URI
 		String nUri = "/" + VABPathTools.stripSlashes(uri);
 		String contextPath = req.getContextPath();
 		if (nUri.startsWith(contextPath) && nUri.length() > getEnvironmentPathSize(req) - 1) {
 			String path = nUri.substring(getEnvironmentPathSize(req));
 			String extractedParameters = extractParameters(req);

 			path = VABPathTools.stripSlashes(path);

 			if (extractedParameters.isEmpty()) {
 				path += "/";
 			} else {
 				path += extractedParameters;
 			}
 			return path;
 		}
 		throw new MalformedRequestException("The passed path " + uri + " is not a possbile path for this server.");
 	}

 	/**
 	 * Extracts request parameters from the request
 	 *
 	 * @param req
 	 * @return
 	 */
 	private String extractParameters(HttpServletRequest req) {
 		Enumeration<String> parameterNames = req.getParameterNames();

 		// Collect list of parameters
 		List<String> parameters = new ArrayList<>();
 		while (parameterNames.hasMoreElements()) {

 			StringBuilder ret = new StringBuilder();
 			String paramName = parameterNames.nextElement();
 			ret.append(paramName);
 			ret.append("=");

 			String[] paramValues = req.getParameterValues(paramName);
 			for (int i = 0; i < paramValues.length; i++) {
 				ret.append(paramValues[i]);
 			}
 			parameters.add(ret.toString());

 		}

 		// If no parameter is existing, return an empty string. Else join the parameters
 		// and return them prefixed with a ?
 		if (parameters.isEmpty()) {
 			return "";
 		} else {
 			StringJoiner joiner = new StringJoiner("&");
 			parameters.stream().forEach(s -> joiner.add(s));
 			return "?" + joiner.toString();
 		}
 	}

 	private int getEnvironmentPathSize(HttpServletRequest req) {
 		return req.getContextPath().length() + req.getServletPath().length();
 	}


 	/**
 	 * Read serialized value
 	 * @param req
 	 * @return
 	 * @throws IOException
 	 */
 	private String extractSerializedValue(HttpServletRequest req) throws IOException {
 		// https://www.baeldung.com/convert-input-stream-to-string#guava
 		ByteSource byteSource = new ByteSource() {
 	        @Override
 	        public InputStream openStream() throws IOException {
 	            return req.getInputStream();
 	        }
 	    };

 	    return byteSource.asCharSource(Charsets.UTF_8).read();
 	}
 }
	/*******************************************************************************
	* Copyright (C) 2021 the Eclipse BaSyx Authors
	*
	* This program and the accompanying materials are made
	* available under the terms of the Eclipse Public License 2.0
	* which is available at https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	******************************************************************************/
	package org.eclipse.basyx.vab.protocol.http.server;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.PrintWriter;
	import java.io.UnsupportedEncodingException;
	import java.util.ArrayList;
	import java.util.Enumeration;
	import java.util.List;
	import java.util.StringJoiner;

	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	import org.eclipse.basyx.vab.coder.json.provider.JSONProvider;
	import org.eclipse.basyx.vab.exception.provider.MalformedRequestException;
	import org.eclipse.basyx.vab.exception.provider.ProviderException;
	import org.eclipse.basyx.vab.modelprovider.VABPathTools;
	import org.eclipse.basyx.vab.modelprovider.api.IModelProvider;
	import org.slf4j.Logger;
	import org.slf4j.LoggerFactory;

	import com.google.common.base.Charsets;
	import com.google.common.io.ByteSource;


	/**
	* VAB provider class that enables access to an IModelProvider via HTTP REST
	* interface<br />
	* <br />
	* REST http interface is as following: <br />
	* - GET /aas/submodels/{subModelId} Retrieves submodel with ID {subModelId}
	* <br />
	* - GET /aas/submodels/{subModelId}/properties/a Retrieve property a of
	* submodel {subModelId}<br />
	* - GET /aas/submodels/{subModelId}/properties/a/b Retrieve property a/b of
	* submodel {subModelId} <br />
	* - POST /aas/submodels/{subModelId}/operations/a Invoke operation a of
	* submodel {subModelId}<br />
	* - POST /aas/submodels/{subModelId}/operations/a/b Invoke operation a/b of
	* submodel {subModelId}
	*
	* @author kuhn
	*
	*/
	public class VABHTTPInterface<ModelProvider extends IModelProvider> extends BasysHTTPServlet {

	private static Logger logger = LoggerFactory.getLogger(VABHTTPInterface.class);

	/**
	* Version information to identify the version of serialized instances
	*/
	private static final long serialVersionUID = 1L;


	/**
	* Reference to IModelProvider backend
	*/
	protected JSONProvider<ModelProvider> providerBackend = null;



	/**
	* Constructor
	*/
	public VABHTTPInterface(ModelProvider provider) {
	// Store provider reference
	providerBackend = new JSONProvider<ModelProvider>(provider);
	}


	/**
	* Access model provider
	*/
	public ModelProvider getModelProvider() {
	return providerBackend.getBackendReference();
	}

	/**
	* Send JSON encoded response
	*/
	protected void sendJSONResponse(String path, PrintWriter outputStream, Object jsonValue) {
	// Output result
	outputStream.write(jsonValue.toString()); // FIXME throws nullpointer exception if jsonValue is null
	outputStream.flush();
	}


	/**
	* Implement "Get" operation
	*
	* Process HTTP get request - get sub model property value
	*/
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	try {
	String path = extractPath(req);

	// Setup HTML response header
	resp.setContentType("application/json");
	resp.setCharacterEncoding("UTF-8");

	resp.setStatus(200);

	// Process get request
	providerBackend.processBaSysGet(path, resp.getOutputStream());
	} catch(ProviderException e) {
	int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
	resp.setStatus(httpCode);
	logger.debug("Exception in HTTP-GET. Response-code: " + httpCode, e);
	}

	}


	/**
	* Implement "Set" operation
	*/
	@Override
	protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	try {
	String path = extractPath(req);
	String serValue = extractSerializedValue(req);
	logger.trace("DoPut: {}", serValue);

	resp.setContentType("application/json");
	resp.setCharacterEncoding("UTF-8");
	resp.setStatus(200);

	providerBackend.processBaSysSet(path, serValue.toString(), resp.getOutputStream());
	} catch(ProviderException e) {
	int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
	resp.setStatus(httpCode);
	logger.debug("Exception in HTTP-PUT. Response-code: " + httpCode, e);
	}
	}


	/**
	* <pre>
	* Handle HTTP POST operation. Creates a new Property, Operation, Event,
	* Submodel or AAS or invokes an operation.
	*/
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	try {
	String path = extractPath(req);
	String serValue = extractSerializedValue(req);

	logger.trace("DoPost: {}", serValue);

	// Setup HTML response header
	resp.setStatus(201);
	resp.setContentType("application/json");
	resp.setCharacterEncoding("UTF-8");

	// Check if request is for property creation or operation invoke
	if (VABPathTools.isOperationInvokationPath(path)) {
	// Invoke BaSys VAB 'invoke' primitive

	providerBackend.processBaSysInvoke(path, serValue, resp.getOutputStream());

	} else {
	// Invoke the BaSys 'create' primitive
	providerBackend.processBaSysCreate(path, serValue, resp.getOutputStream());
	}
	} catch (ProviderException e) {
	int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
	resp.setStatus(httpCode);
	logger.debug("Exception in HTTP-POST. Response-code: " + httpCode, e);
	}
	}


	/**
	* Handle a HTTP PATCH operation. Updates a map or collection
	*
	*/
	@Override
	protected void doPatch(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	try {
	String path = extractPath(req);
	String serValue = extractSerializedValue(req);
	logger.trace("DoPatch: {}", serValue);

	resp.setStatus(200);

	providerBackend.processBaSysDelete(path, serValue, resp.getOutputStream());
	} catch(ProviderException e) {
	int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
	resp.setStatus(httpCode);
	logger.debug("Exception in HTTP-PATCH. Response-code: " + httpCode, e);
	}
	}


	/**
	* Implement "Delete" operation. Deletes any resource under the given path.
	*/
	@Override
	protected void doDelete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	try {
	String path = extractPath(req);

	// No parameter to read! Provide serialized null
	String nullParam = "";

	resp.setStatus(200);


	providerBackend.processBaSysDelete(path, nullParam, resp.getOutputStream());
	} catch(ProviderException e) {
	int httpCode = ExceptionToHTTPCodeMapper.mapFromException(e);
	resp.setStatus(httpCode);
	logger.debug("Exception in HTTP-DELETE. Response-code: " + httpCode, e);
	}
	}


	private String extractPath(HttpServletRequest req) throws UnsupportedEncodingException {
	// Extract path
	String uri = req.getRequestURI();

	// Normalizes URI
	String nUri = "/" + VABPathTools.stripSlashes(uri);
	String contextPath = req.getContextPath();
	if (nUri.startsWith(contextPath) && nUri.length() > getEnvironmentPathSize(req) - 1) {
	String path = nUri.substring(getEnvironmentPathSize(req));
	String extractedParameters = extractParameters(req);

	path = VABPathTools.stripSlashes(path);

	if (extractedParameters.isEmpty()) {
	path += "/";
	} else {
	path += extractedParameters;
	}
	return path;
	}
	throw new MalformedRequestException("The passed path " + uri + " is not a possbile path for this server.");
	}

	/**
	* Extracts request parameters from the request
	*
	* @param req
	* @return
	*/
	private String extractParameters(HttpServletRequest req) {
	Enumeration<String> parameterNames = req.getParameterNames();

	// Collect list of parameters
	List<String> parameters = new ArrayList<>();
	while (parameterNames.hasMoreElements()) {

	StringBuilder ret = new StringBuilder();
	String paramName = parameterNames.nextElement();
	ret.append(paramName);
	ret.append("=");

	String[] paramValues = req.getParameterValues(paramName);
	for (int i = 0; i < paramValues.length; i++) {
	ret.append(paramValues[i]);
	}
	parameters.add(ret.toString());

	}

	// If no parameter is existing, return an empty string. Else join the parameters
	// and return them prefixed with a ?
	if (parameters.isEmpty()) {
	return "";
	} else {
	StringJoiner joiner = new StringJoiner("&");
	parameters.stream().forEach(s -> joiner.add(s));
	return "?" + joiner.toString();
	}
	}

	private int getEnvironmentPathSize(HttpServletRequest req) {
	return req.getContextPath().length() + req.getServletPath().length();
	}


	/**
	* Read serialized value
	* @param req
	* @return
	* @throws IOException
	*/
	private String extractSerializedValue(HttpServletRequest req) throws IOException {
	// https://www.baeldung.com/convert-input-stream-to-string#guava
	ByteSource byteSource = new ByteSource() {
	@Override
	public InputStream openStream() throws IOException {
	return req.getInputStream();
	}
	};

	return byteSource.asCharSource(Charsets.UTF_8).read();
	}
	}