. Generic "command servlet" implementation

- Replaces specific command servlets, such as the WorkflowActionServlet with a generic CommandServlet

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@2618 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/web/app/servlet/CommandServlet.java

@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2005 Alfresco, Inc.
+ *
+ * Licensed under the Mozilla Public License version 1.1 
+ * with a permitted attribution clause. You may obtain a
+ * copy of the License at
+ *
+ *   http://www.alfresco.org/legal/license.txt
+ *
+ * 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.alfresco.web.app.servlet;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.StringTokenizer;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.transaction.UserTransaction;
+
+import org.alfresco.config.Config;
+import org.alfresco.error.AlfrescoRuntimeException;
+import org.alfresco.service.ServiceRegistry;
+import org.alfresco.web.app.Application;
+import org.alfresco.web.app.servlet.command.CommandFactory;
+import org.alfresco.web.app.servlet.command.CommandProcessor;
+import org.alfresco.web.config.CommandServletConfigElement;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Servlet responsible for executing commands upon node(s).
+ * <p>
+ * The URL to the servlet should be generated thus:
+ * <pre>/alfresco/command/processor-name/command-name/args/...</pre>
+ * <p>
+ * The 'processor-name' identifies the command processor to execute the command. For example the
+ * 'workflow' processor will execute workflow commands upon a node (e.g. "approve" or "reject").
+ * For example:
+ * <pre>/alfresco/command/workflow/approve/workspace/SpacesStore/0000-0000-0000-0000
+ * The store protocol, followed by the store ID, followed by the content Node Id used to
+ * identify the node to execute the workflow action upon.
+ * <p>
+ * A 'return-page' URL argument can be specified as the redirect page to navigate too after processing.
+ * <p>
+ * Like most Alfresco servlets, the URL may be followed by a valid 'ticket' argument for authentication:
+ * ?ticket=1234567890
+ * <p>
+ * And/or also followed by the "?guest=true" argument to force guest access login for the URL. 
+ * 
+ * @author Kevin Roast
+ */
+public class CommandServlet extends BaseServlet
+{
+   private static final long serialVersionUID = -5432407921038376133L;
+   
+   private static Log logger = LogFactory.getLog(CommandServlet.class);
+   
+   private static CommandFactory commandfactory = CommandFactory.getInstance();
+   
+   public static final String ARG_RETURNPAGE = "return-page";
+   
+   /**
+    * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
+    */
+   protected void doGet(HttpServletRequest req, HttpServletResponse res)
+      throws ServletException, IOException
+   {
+      String uri = req.getRequestURI();
+      
+      if (logger.isDebugEnabled())
+         logger.debug("Processing URL: " + uri + (req.getQueryString() != null ? ("?" + req.getQueryString()) : ""));
+      
+      AuthenticationStatus status = servletAuthenticate(req, res);
+      if (status == AuthenticationStatus.Failure)
+      {
+         return;
+      }
+      
+      StringTokenizer t = new StringTokenizer(uri, "/");
+      int tokenCount = t.countTokens();
+      if (tokenCount < 4)
+      {
+         throw new IllegalArgumentException("Command Servlet URL did not contain all required args: " + uri); 
+      }
+      
+      t.nextToken();    // skip web app name
+      t.nextToken();    // skip servlet name
+      
+      // get the command processor to execute the command e.g. "workflow"
+      String procName = t.nextToken();
+      
+      // get the command to perform
+      String command = t.nextToken();
+      
+      // get any remaining uri elements to pass to the processor
+      String[] args = new String[tokenCount - 4];
+      for (int i=0; i<tokenCount-4; i++)
+      {
+         args[i] = t.nextToken();
+      }
+      
+      try
+      {
+         // get configured command processor by name from Config Service
+         CommandProcessor processor = createCommandProcessor(procName);
+         
+         // validate that the processor has everything it needs to run the command
+         ServiceRegistry serviceRegistry = getServiceRegistry(getServletContext());
+         if (processor.validateArguments(serviceRegistry, args) == false)
+         {
+            redirectToLoginPage(req, res, getServletContext());
+            return;
+         }
+         
+         UserTransaction txn = null;
+         try
+         {
+            txn = serviceRegistry.getTransactionService().getUserTransaction();
+            txn.begin();
+            
+            // inform the processor to execute the specified command
+            processor.process(serviceRegistry, command);
+            
+            // commit the transaction
+            txn.commit();
+         }
+         catch (Throwable txnErr)
+         {
+            try { if (txn != null) {txn.rollback();} } catch (Exception tex) {}
+            throw txnErr;
+         }
+         
+         String returnPage = req.getParameter(ARG_RETURNPAGE);
+         if (returnPage != null && returnPage.length() != 0)
+         {
+            if (logger.isDebugEnabled())
+               logger.debug("Redirecting to specified return page: " + returnPage);
+            
+            res.sendRedirect(returnPage);
+         }
+         else
+         {
+            if (logger.isDebugEnabled())
+               logger.debug("No return page specified, displaying status output.");
+            
+            res.setContentType("text/html");
+            
+            // request that the processor output a useful status message
+            PrintWriter out = res.getWriter();
+            processor.outputStatus(out);
+            out.close();
+         }
+      }
+      catch (Throwable err)
+      {
+         throw new AlfrescoRuntimeException("Error during command servlet processing: " + err.getMessage(), err);
+      }
+   }
+
+   /**
+    * @param procName
+    * @throws InstantiationException
+    * @throws IllegalAccessException
+    */
+   private CommandProcessor createCommandProcessor(String procName) throws InstantiationException, IllegalAccessException
+   {
+      Config config = Application.getConfigService(getServletContext()).getConfig("Command Servlet");
+      if (config == null)
+      {
+         throw new AlfrescoRuntimeException("No command processors configured - unable to process any commands.");
+      }
+      
+      CommandServletConfigElement configElement = (CommandServletConfigElement)
+         config.getConfigElement(CommandServletConfigElement.CONFIG_ELEMENT_ID);
+      if (configElement == null)
+      {
+         throw new AlfrescoRuntimeException("No command processors configured - unable to process any commands.");
+      }
+      
+      Class clazz = configElement.getCommandProcessor(procName);
+      Object obj = clazz.newInstance();
+      if (obj instanceof CommandProcessor == false)
+      {
+         throw new AlfrescoRuntimeException("Configured command processor '" + procName + "' is does not implement interface CommandProcessor!"); 
+      }
+      
+      return (CommandProcessor)obj;
+   }
+}