Introducing new ResponseValues subclass for serving File downloads, mainly for Visualizations. Also modified FreemarkerHttpServlet & BaseResponseValues to handle the new methods pertaining to file download response.

webapp/src/edu/cornell/mannlib/vitro/webapp/controller/freemarker/FreemarkerHttpServlet.java

@@ -26,6 +26,7 @@ import edu.cornell.mannlib.vitro.webapp.controller.VitroHttpServlet;
 import edu.cornell.mannlib.vitro.webapp.controller.VitroRequest;
 import edu.cornell.mannlib.vitro.webapp.controller.freemarker.UrlBuilder.Route;
 import edu.cornell.mannlib.vitro.webapp.controller.freemarker.responsevalues.ExceptionResponseValues;
+import edu.cornell.mannlib.vitro.webapp.controller.freemarker.responsevalues.FileResponseValues;
 import edu.cornell.mannlib.vitro.webapp.controller.freemarker.responsevalues.ForwardResponseValues;
 import edu.cornell.mannlib.vitro.webapp.controller.freemarker.responsevalues.RdfResponseValues;
 import edu.cornell.mannlib.vitro.webapp.controller.freemarker.responsevalues.RedirectResponseValues;
@@ -153,6 +154,8 @@ public class FreemarkerHttpServlet extends VitroHttpServlet {
                 doForward(vreq, response, values);
             } else if (values instanceof RdfResponseValues) {
                 doRdf(vreq, response, values);
+            } else if (values instanceof FileResponseValues) {
+                doFile(vreq, response, values);
             }
         } catch (ServletException e) {
             log.error("ServletException in doResponse()", e);
@@ -239,6 +242,26 @@ public class FreemarkerHttpServlet extends VitroHttpServlet {
         
         values.getModel().write( response.getOutputStream(), format );      
     }
+    
+    protected void doFile(HttpServletRequest request, HttpServletResponse response, ResponseValues values) 
+        throws IOException {
+        
+        String mediaType = values.getContentType().getMediaType();
+        response.setContentType(mediaType);
+        
+        Map<String, String> headerKeyToValue = values.getHeader();
+        
+        for (Map.Entry<String, String> currentHeaderPair : headerKeyToValue.entrySet()) {
+        	response.setHeader(currentHeaderPair.getKey(), currentHeaderPair.getValue());
+        }
+        
+		PrintWriter responseWriter = response.getWriter();
+		
+		String rawFileContent = (String) values.getMap().get("fileContent");
+		responseWriter.append(rawFileContent);
+		responseWriter.close();
+			
+    }
 
     protected void doException(VitroRequest vreq, HttpServletResponse response, ResponseValues values) {
         // Log the error, and display an error message on the page.        

webapp/src/edu/cornell/mannlib/vitro/webapp/controller/freemarker/responsevalues/BaseResponseValues.java

@@ -60,6 +60,12 @@ public abstract class BaseResponseValues implements ResponseValues {
                 "This is not a redirect response.");
     }
     
+    @Override
+    public Map<String, String> getHeader() {
+        throw new UnsupportedOperationException(
+                "This is not a header response.");
+    }
+    
     @Override
     public String getForwardUrl() {
         throw new UnsupportedOperationException(

webapp/src/edu/cornell/mannlib/vitro/webapp/controller/freemarker/responsevalues/FileResponseValues.java

@@ -0,0 +1,37 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.controller.freemarker.responsevalues;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import edu.cornell.mannlib.vitro.webapp.web.ContentType;
+
+public class FileResponseValues extends BaseResponseValues {
+    
+	private String outputFileName; 
+	private String DEFAULT_HEADER_KEY = "Content-Disposition";
+	private String DEFAULT_HEADER_VALUE_PREFIX = "attachment;filename=";
+	private final Map<String, Object> map;
+	
+	
+    public FileResponseValues(ContentType contentType, String outputFileName, Map<String, Object> map) {
+        super(contentType);
+        this.outputFileName = outputFileName;
+        this.map = map;
+    }
+    
+    @Override
+    public Map<String, String> getHeader() {
+    	Map<String, String> headerKeyToValue = new HashMap<String, String>();
+    	headerKeyToValue.put(DEFAULT_HEADER_KEY, DEFAULT_HEADER_VALUE_PREFIX + outputFileName);
+    	return headerKeyToValue;
+    }
+    
+    @Override
+    public Map<String, Object> getMap() {
+        return Collections.unmodifiableMap(this.map);
+    }
+
+}

webapp/src/edu/cornell/mannlib/vitro/webapp/controller/freemarker/responsevalues/ResponseValues.java

@@ -20,6 +20,8 @@ public interface ResponseValues {
     
     public String getRedirectUrl();
 
+    public Map<String, String> getHeader();
+    
     public String getForwardUrl();
 
     public Throwable getException();