#252 Implement ability to automatically delete temporary file after sending it to client

Author: Igor Polevoy

activeweb/src/main/java/org/javalite/activeweb/ControllerResponse.java

@@ -15,6 +15,9 @@
 */
 package org.javalite.activeweb;
 
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -64,5 +67,14 @@ final void process(){
         doProcess();
     }
 
+    protected final void  stream(InputStream in, OutputStream out) throws IOException {
+        byte[] bytes = new byte[1024];
+        int x;
+        while((x = in.read(bytes)) != -1){
+            out.write(bytes, 0, x);
+        }
+        in.close();
+    }
+
     abstract void doProcess();
 }

activeweb/src/main/java/org/javalite/activeweb/FileResponse.java

@@ -0,0 +1,44 @@
+package org.javalite.activeweb;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.FileInputStream;
+
+/**
+ * @author Igor Polevoy on 12/30/15.
+ */
+class FileResponse extends ControllerResponse {
+    Logger logger = LoggerFactory.getLogger(FileResponse.class);
+
+    private File file;
+    private boolean delete = false;
+
+    FileResponse(File file) {
+        this.file = file;
+    }
+
+    /**
+     * @param delete true to delete file after sending to client
+     */
+    FileResponse(File file, boolean delete) {
+        this(file);
+        this.delete = delete;
+    }
+
+    @Override
+    void doProcess() {
+        try {
+            stream(new FileInputStream(file), Context.getHttpResponse().getOutputStream());
+            if (delete) {
+                if (!file.delete()) {
+                    logger.warn("failed to delete file: " + file + " after processing");
+                }
+            }
+        } catch (Exception e) {
+            throw new ControllerException(e);
+        }
+    }
+
+}

activeweb/src/main/java/org/javalite/activeweb/HttpSupport.java

@@ -490,12 +490,13 @@ protected HttpBuilder respond(String text){
      * "Content-Disposition" based on a file name.
      *
      * @param file file to download.
+     * @param delete true to delete the file after processing
      * @return builder instance.
      * @throws FileNotFoundException thrown if file not found.
      */
-    protected HttpBuilder sendFile(File file) throws FileNotFoundException {
+    protected HttpBuilder sendFile(File file, boolean delete) throws FileNotFoundException {
         try{
-            StreamResponse resp = new StreamResponse(new FileInputStream(file));
+            FileResponse resp = new FileResponse(file, delete);
             Context.setControllerResponse(resp);
             HttpBuilder builder = new HttpBuilder(resp);
             builder.header("Content-Disposition", "attachment; filename=" + file.getName());
@@ -505,6 +506,19 @@ protected HttpBuilder sendFile(File file) throws FileNotFoundException {
         }
     }
 
+    /**
+     * Convenience method for downloading files. This method will force the browser to find a handler(external program)
+     *  for  this file (content type) and will provide a name of file to the browser. This method sets an HTTP header
+     * "Content-Disposition" based on a file name.
+     *
+     * @param file file to download.
+     * @return builder instance.
+     * @throws FileNotFoundException thrown if file not found.
+     */
+    protected HttpBuilder sendFile(File file) throws FileNotFoundException {
+       return sendFile(file, false);
+    }
+
 
     /**
      * Convenience method to get file content from <code>multipart/form-data</code> request. If more than one files with the same

activeweb/src/main/java/org/javalite/activeweb/StreamResponse.java

@@ -28,18 +28,11 @@ class StreamResponse extends ControllerResponse{
     StreamResponse(InputStream in){
         this.in = in;
     }
+
     @Override
     void doProcess() {
         try{
-            OutputStream out = Context.getHttpResponse().getOutputStream();
-            byte[] bytes = new byte[1024];
-
-            int x;
-            while((x = in.read(bytes)) != -1){
-                out.write(bytes, 0, x);
-            }
-            out.flush();
-            in.close();
+            stream(in, Context.getHttpResponse().getOutputStream());
         }
         catch(Exception e){
             throw new ControllerException(e);

activeweb/src/test/java/app/controllers/StreamController.java

@@ -22,6 +22,7 @@
 import static org.javalite.common.Collections.map;
 
 import java.io.*;
+import java.nio.file.Files;
 
 /**
  * @author Igor Polevoy
@@ -48,4 +49,9 @@ public void writeWithContentTypeAndHeaders() throws IOException {
     public void streamWithContentTypeAndHeaders() throws IOException {
         outputStream("text/plain", map("Content-Length", 5), 200).write("hello".getBytes());
     }
+
+    public void deleteFile() throws IOException {
+        File f = new File(param("file"));
+        sendFile(f, true);
+    }
 }

activeweb/src/test/java/org/javalite/activeweb/StreamSpec.java

@@ -16,17 +16,11 @@
 
 package org.javalite.activeweb;
 
-import org.javalite.test.jspec.JSpecSupport;
-import org.junit.Before;
 import org.junit.Test;
-import org.springframework.mock.web.MockFilterConfig;
-import org.springframework.mock.web.MockHttpServletRequest;
-import org.springframework.mock.web.MockHttpServletResponse;
 
-import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
+import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
 
 /**
@@ -87,4 +81,22 @@ public void shouldStreamWithContentTypeAndHeaders() throws ServletException, IOE
         a(response.getHeader("Content-Length")).shouldEqual("5");
         a(response.getContentType()).shouldEqual("text/plain");
     }
+
+    @Test
+    public void shouldDeleteFileAfterProcessing() throws ServletException, IOException {
+
+        //create a file:
+        File file = File.createTempFile("file123", "suffix");
+        FileOutputStream outputStream = new FileOutputStream(file);
+        outputStream.write("hello".getBytes());
+        outputStream.flush();
+        outputStream.close();
+
+        request.setServletPath("/stream/delete-file");
+        request.setMethod("GET");
+        request.setParameter("file", file.getCanonicalPath());
+        dispatcher.doFilter(request, response, filterChain);
+        a(response.getContentAsString()).shouldBeEqual("hello");
+        the(file.exists()).shouldBeFalse();
+    }
 }