RESTBindingListenerServlet.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.tuscany.sca.binding.rest.provider;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLDecoder;
import java.text.ParseException;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

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

import org.apache.tuscany.sca.assembly.Binding;
import org.apache.tuscany.sca.binding.rest.RESTBinding;
import org.apache.tuscany.sca.common.http.HTTPCacheContext;
import org.apache.tuscany.sca.common.http.HTTPContentTypeMapper;
import org.apache.tuscany.sca.common.http.HTTPContext;
import org.apache.tuscany.sca.common.http.HTTPHeader;
import org.apache.tuscany.sca.invocation.Invoker;
import org.apache.tuscany.sca.invocation.Message;
import org.apache.tuscany.sca.invocation.MessageFactory;

/**
 * Servlet responsible for dispatching HTTP requests to the
 * target component implementation.
 *
 * @version $Rev$ $Date$
 */
public class RESTBindingListenerServlet extends HttpServlet {
    private static final long serialVersionUID = 2865466417329430610L;

    transient private MessageFactory messageFactory;

    transient private RESTBinding binding;
    transient private Invoker bindingInvoker;

    private Invoker invoker;
    private Invoker getInvoker;
    private Invoker conditionalGetInvoker;
    private Invoker putInvoker;
    private Invoker conditionalPutInvoker;
    private Invoker postInvoker;
    private Invoker conditionalPostInvoker;
    private Invoker deleteInvoker;
    private Invoker conditionalDeleteInvoker;

    /**
     * Constructs a new RESTServiceListenerServlet.
     */
    public RESTBindingListenerServlet(Binding binding, Invoker bindingInvoker, MessageFactory messageFactory) {
        this.binding = (RESTBinding) binding;
        this.bindingInvoker = bindingInvoker;
        this.messageFactory = messageFactory;
    }

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        if( binding.getOperationSelector() != null || binding.getRequestWireFormat() != null) {
            HTTPContext bindingContext = new HTTPContext();
            bindingContext.setHttpRequest(request);
            bindingContext.setHttpResponse(response);

            // Dispatch the service interaction to the service invoker
            Message requestMessage = messageFactory.createMessage();
            requestMessage.setBindingContext(bindingContext);

            requestMessage.setBody(new Object[] {request.getInputStream()});

            Message responseMessage = bindingInvoker.invoke(requestMessage);

            // return response to client
            if (responseMessage.isFault()) {
                // Turn a fault into an exception
                Throwable e = (Throwable)responseMessage.getBody();
                response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.toString());
            } else {

                for(HTTPHeader header : binding.getHttpHeaders()) {
                    //treat special headers that need to be calculated
                    if(header.getName().equalsIgnoreCase("Expires")) {
                        GregorianCalendar calendar = new GregorianCalendar();
                        calendar.setTime(new Date());

                        calendar.add(Calendar.HOUR, Integer.parseInt(header.getValue()));

                        response.setHeader("Expires", HTTPCacheContext.RFC822DateFormat.format( calendar.getTime() ));
                    } else {
                        //default behaviour to pass the header value to HTTP response
                        response.setHeader(header.getName(), header.getValue());
                    }

                }

                //handle void operations
                write(response.getOutputStream(), responseMessage.getBody());
                response.getOutputStream().flush();
                response.getOutputStream().close();
            }
        } else {
            super.service(request, response);
        }


    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Get the request path
        String pathInfo = request.getPathInfo();
        if (pathInfo == null || pathInfo.length() == 0) {
            // Redirect to a URL ending with / to make relative hrefs work
            // relative to the served resource.
            response.sendRedirect(request.getRequestURL().append('/').toString());
            return;
        }
        String path = URLDecoder.decode(pathInfo, "UTF-8");

        // Invoke the get operation on the service implementation
        Message requestMessage = messageFactory.createMessage();

        String id = path.substring(1);

        Message responseMessage = null;
        HTTPCacheContext cacheContext = null;
        try {
            cacheContext = HTTPCacheContext.createCacheContextFromRequest(request);
        } catch (ParseException e) {

        }

        if (path == null || path.length() == 0 || path.equals("/")) {

        }

        // Route message based on availability of cache info and cache methods
        if (( cacheContext != null ) && (cacheContext.isEnabled()) && (conditionalGetInvoker != null )) {
            if(id != null && id.length() > 0) {
                requestMessage.setBody(new Object[] {id, cacheContext});
            } else {
                requestMessage.setBody(new Object[] {cacheContext});
            }

            responseMessage = conditionalGetInvoker.invoke(requestMessage);
        } else {
            if(id != null && id.length() > 0) {
                requestMessage.setBody(new Object[] {id});
            } else {
                //requestMessage.setBody(new Object[] {id});
            }

            responseMessage = getInvoker.invoke(requestMessage);
        }

        if (responseMessage.isFault()) {
            Object body = responseMessage.getBody();

            int index = -1;
            if ( -1 < (index = body.getClass().getName().indexOf( "NotModifiedException")) ) {
                if ( index > -1 ) {
                    response.sendError( HttpServletResponse.SC_NOT_MODIFIED, body.toString().substring( index ));
                } else {
                    response.sendError( HttpServletResponse.SC_NOT_MODIFIED );
                }
                return;
            } else if ( -1 < (index = body.getClass().getName().indexOf( "PreconditionFailedException")) ) {
                if ( index > -1 ) {
                    response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED, body.toString().substring( index ));
                } else {
                    response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED );
                }
                return;
            }

            throw new ServletException((Throwable)responseMessage.getBody());
        }

        if(response.getContentType() == null || response.getContentType().length() == 0){
            // Calculate content-type based on extension
            String contentType = HTTPContentTypeMapper.getContentType(id);
            if(contentType != null && contentType.length() >0) {
                response.setContentType(contentType);
            }
        }

        // Write the response from the service implementation to the response
        // output stream
        InputStream is = (InputStream)responseMessage.getBody();
        OutputStream os = response.getOutputStream();
        byte[] buffer = new byte[2048];
        for (;;) {
            int n = is.read(buffer);
            if (n <= 0)
                break;
            os.write(buffer, 0, n);
        }
        os.flush();
        os.close();
    }

    @Override
    protected void doDelete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Get the request path
        String path = URLDecoder.decode(request.getRequestURI().substring(request.getServletPath().length()), "UTF-8");
        if (path.length() ==0) {
            // Redirect to a URL ending with / to make relative hrefs work
            // relative to the served resource.
            response.sendRedirect(request.getRequestURL().append('/').toString());
            return;
        }

        // Invoke the get operation on the service implementation
        Message requestMessage = messageFactory.createMessage();
        String id = path.substring(1);

        Message responseMessage = null;
        HTTPCacheContext cacheContext = null;
        try {
            cacheContext = HTTPCacheContext.createCacheContextFromRequest(request);
        } catch (ParseException e) {
        }

        // Route message based on availability of cache info and cache methods
        if (( cacheContext != null ) && (cacheContext.isEnabled()) && (conditionalDeleteInvoker != null )) {
            requestMessage.setBody(new Object[] {id, cacheContext});
            responseMessage = conditionalDeleteInvoker.invoke(requestMessage);
        } else {
            requestMessage.setBody(new Object[] {id});
            responseMessage = deleteInvoker.invoke(requestMessage);
        }
        if (responseMessage.isFault()) {
            Object body = responseMessage.getBody();

            int index = -1;
            if ( -1 < (index = body.getClass().getName().indexOf( "NotModifiedException")) ) {
                if ( index > -1 ) {
                    response.sendError( HttpServletResponse.SC_NOT_MODIFIED, body.toString().substring( index ));
                } else {
                    response.sendError( HttpServletResponse.SC_NOT_MODIFIED );
                }
                return;
            } else if ( -1 < (index = body.getClass().getName().indexOf( "PreconditionFailedException")) ) {
                if ( index > -1 ) {
                    response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED, body.toString().substring( index ));
                } else {
                    response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED );
                }
                return;
            }

            throw new ServletException((Throwable)responseMessage.getBody());
        }

        // Write the response from the service implementation to the response
        // output stream
        InputStream is = (InputStream)responseMessage.getBody();
        OutputStream os = response.getOutputStream();
        byte[] buffer = new byte[2048];
        for (;;) {
            int n = is.read(buffer);
            if (n <= 0)
                break;
            os.write(buffer, 0, n);
        }
        os.flush();
        os.close();
    }

    @Override
    protected void doPut(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Get the request path
        String path = URLDecoder.decode(request.getRequestURI().substring(request.getServletPath().length()), "UTF-8");
        if (path.length() ==0) {
            // Redirect to a URL ending with / to make relative hrefs work
            // relative to the served resource.
            response.sendRedirect(request.getRequestURL().append('/').toString());
            return;
        }

        // Invoke the get operation on the service implementation
        Message requestMessage = messageFactory.createMessage();
        String id = path.substring(1);

        Message responseMessage = null;
        HTTPCacheContext cacheContext = null;
        try {
            cacheContext = HTTPCacheContext.createCacheContextFromRequest(request);
        } catch (ParseException e) {
        }

        // Route message based on availability of cache info and cache methods
        if (( cacheContext != null ) && (cacheContext.isEnabled()) && (conditionalPutInvoker != null )) {
            requestMessage.setBody(new Object[] {id, cacheContext});
            responseMessage = conditionalPutInvoker.invoke(requestMessage);
        } else {
            requestMessage.setBody(new Object[] {id});
            responseMessage = putInvoker.invoke(requestMessage);
        }
        if (responseMessage.isFault()) {
            Object body = responseMessage.getBody();

            int index = -1;
            if ( -1 < (index = body.getClass().getName().indexOf( "NotModifiedException")) ) {
                if ( index > -1 ) {
                    response.sendError( HttpServletResponse.SC_NOT_MODIFIED, body.toString().substring( index ));
                } else {
                    response.sendError( HttpServletResponse.SC_NOT_MODIFIED );
                }
                return;
            } else if ( -1 < (index = body.getClass().getName().indexOf( "PreconditionFailedException")) ) {
                if ( index > -1 ) {
                    response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED, body.toString().substring( index ));
                } else {
                    response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED );
                }
                return;
            }

            throw new ServletException((Throwable)responseMessage.getBody());
        }

        // Write the response from the service implementation to the response
        // output stream
        InputStream is = (InputStream)responseMessage.getBody();
        OutputStream os = response.getOutputStream();
        byte[] buffer = new byte[2048];
        for (;;) {
            int n = is.read(buffer);
            if (n <= 0)
                break;
            os.write(buffer, 0, n);
        }
        os.flush();
        os.close();
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Get the request path
        String path = URLDecoder.decode(request.getRequestURI().substring(request.getServletPath().length()), "UTF-8");
        if (path.length() ==0) {
            // Redirect to a URL ending with / to make relative hrefs work
            // relative to the served resource.
            response.sendRedirect(request.getRequestURL().append('/').toString());
            return;
        }

        // Invoke the get operation on the service implementation
        Message requestMessage = messageFactory.createMessage();
        // String id = path.substring(1);

        Message responseMessage = null;
        HTTPCacheContext cacheContext = null;
        try {
           cacheContext = HTTPCacheContext.createCacheContextFromRequest(request);
        } catch (ParseException e) {
        }

        // Route message based on availability of cache info and cache methods
        if (( cacheContext != null ) && (cacheContext.isEnabled()) && (conditionalPostInvoker != null )) {
        	requestMessage.setBody(new Object[] {cacheContext});
        	responseMessage = conditionalPostInvoker.invoke(requestMessage);
        } else {
        	requestMessage.setBody(new Object[] {});
        	responseMessage = postInvoker.invoke(requestMessage);
        }
        if (responseMessage.isFault()) {
        	Object body = responseMessage.getBody();

        	int index = -1;
        	if ( -1 < (index = body.getClass().getName().indexOf( "NotModifiedException")) ) {
        		if ( index > -1 )
            		response.sendError( HttpServletResponse.SC_NOT_MODIFIED, body.toString().substring( index ));
        		else
            		response.sendError( HttpServletResponse.SC_NOT_MODIFIED );
        		return;
        	} else if ( -1 < (index = body.getClass().getName().indexOf( "PreconditionFailedException")) ) {
        		if ( index > -1 )
            		response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED, body.toString().substring( index ));
        		else
            		response.sendError( HttpServletResponse.SC_PRECONDITION_FAILED );
        		return;
            }

            throw new ServletException((Throwable)responseMessage.getBody());
        }


        // Test if the ETag and LastModified are returned as a cache context.
    	Object body = responseMessage.getBody();
    	if ( body.getClass() == HTTPCacheContext.class ) {
    		// Transfer to header if so.
    		HTTPCacheContext cc = (HTTPCacheContext)responseMessage.getBody();
    		if (( cc != null ) && ( cc.isEnabled() )) {
    		    String eTag = cc.getETag();
    		    if ( eTag != null ) {
    		        response.setHeader( "ETag", cc.getETag() );
    		    }
    		    String lastModified = cc.getLastModified();
    		    if ( lastModified != null) {
    		        response.setHeader( "LastModified", cc.getLastModified() );
    		    }
    		}
    	}
    }


    public void setInvoker(Invoker invoker) {
        this.invoker = invoker;
    }

    public Invoker getInvoker() {
        return invoker;
    }


    /**
     * @return the getInvoker
     */
    public Invoker getGetInvoker() {
        return getInvoker;
    }

    /**
     * @param getInvoker the getInvoker to set
     */
    public void setGetInvoker(Invoker getInvoker) {
        this.getInvoker = getInvoker;
    }

    /**
     * @return the conditionalGetInvoker
     */
    public Invoker getConditionalGetInvoker() {
        return conditionalGetInvoker;
    }

    /**
     * @param conditionalGetInvoker the conditionalGetInvoker to set
     */
    public void setConditionalGetInvoker(Invoker conditionalGetInvoker) {
        this.conditionalGetInvoker = conditionalGetInvoker;
    }

    /**
     * @return the putInvoker
     */
    public Invoker getPutInvoker() {
        return putInvoker;
    }

    /**
     * @param putInvoker the putInvoker to set
     */
    public void setPutInvoker(Invoker putInvoker) {
        this.putInvoker = putInvoker;
    }

    /**
     * @return the conditionalPutInvoker
     */
    public Invoker getConditionalPutInvoker() {
        return conditionalPutInvoker;
    }

    /**
     * @param conditionalPutInvoker the conditionalPutInvoker to set
     */
    public void setConditionalPutInvoker(Invoker conditionalPutInvoker) {
        this.conditionalPutInvoker = conditionalPutInvoker;
    }

    /**
     * @return the postInvoker
     */
    public Invoker getPostInvoker() {
        return postInvoker;
    }

    /**
     * @param postInvoker the postInvoker to set
     */
    public void setPostInvoker(Invoker postInvoker) {
        this.postInvoker = postInvoker;
    }

    /**
     * @return the conditionalPostInvoker
     */
    public Invoker getConditionalPostInvoker() {
        return conditionalPostInvoker;
    }

    /**
     * @param conditionalPostInvoker the conditionalPostInvoker to set
     */
    public void setConditionalPostInvoker(Invoker conditionalPostInvoker) {
        this.conditionalPostInvoker = conditionalPostInvoker;
    }

    /**
     * @return the deleteInvoker
     */
    public Invoker getDeleteInvoker() {
        return deleteInvoker;
    }

    /**
     * @param deleteInvoker the deleteInvoker to set
     */
    public void setDeleteInvoker(Invoker deleteInvoker) {
        this.deleteInvoker = deleteInvoker;
    }

    /**
     * @return the conditionalDeleteInvoker
     */
    public Invoker getConditionalDeleteInvoker() {
        return conditionalDeleteInvoker;
    }

    /**
     * @param conditionalDeleteInvoker the conditionalDeleteInvoker to set
     */
    public void setConditionalDeleteInvoker(Invoker conditionalDeleteInvoker) {
        this.conditionalDeleteInvoker = conditionalDeleteInvoker;
    }

    /**
     *
     * Utility methods
     *
     */



    private void write(OutputStream out, Object obj) throws IOException {
        if (obj == null) {
            return;
        }
        if (obj instanceof String) {
            out.write(((String)obj).getBytes("UTF-8"));
        } else if (obj instanceof byte[]) {
            out.write((byte[])obj);
        } else if (obj instanceof InputStream) {
            byte[] buf = new byte[8192];
            InputStream in = (InputStream)obj;
            while (true) {
                int size = in.read(buf);
                if (size < 0) {
                    break;
                }
                out.write(buf, 0, size);
            }
        } else {
            out.write(obj.toString().getBytes("UTF-8"));
        }
    }


}