added servlets for IMG pt2

client/src/css/userPage.css

@@ -39,3 +39,9 @@
 .message-body {
   margin: 5px;
 }
+
+.message-body img {
+  display: block;
+  margin-top: 25px;
+  max-width: 75%;
+}

server/src/main/java/com/google/codeu/servlets/BlobstoreUploadUrlServlet .java

@@ -0,0 +1,12 @@
+@WebServlet("/blobstore-upload-url")
+public class BlobstoreUploadUrlServlet extends HttpServlet {
+
+    @Override
+    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
+        BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
+        String uploadUrl = blobstoreService.createUploadUrl("/my-form-handler");
+
+        response.setContentType("text/html");
+        response.getOutputStream().println(uploadUrl);
+    }
+}

server/src/main/java/com/google/codeu/servlets/FormHandlerServlet.java

@@ -0,0 +1,59 @@
+@WebServlet("/my-form-handler")
+public class FormHandlerServlet extends HttpServlet {
+
+    @Override
+    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
+
+        // Get the message entered by the user.
+        String message = request.getParameter("message");
+
+        // Get the URL of the image that the user uploaded to Blobstore.
+        String imageUrl = getUploadedFileUrl(request, "image");
+
+        // Output some HTML that shows the data the user entered.
+        // A real codebase would probably store these in Datastore.
+        ServletOutputStream out = response.getOutputStream();
+        out.println("<p>Here's the image you uploaded:</p>");
+        out.println("<a href=\"" + imageUrl + "\">");
+        out.println("<img src=\"" + imageUrl + "\" />");
+        out.println("</a>");
+        out.println("<p>Here's the text you entered:</p>");
+        out.println(message);
+    }
+
+    /**
+     * Returns a URL that points to the uploaded file, or null if the user didn't
+     * upload a file.
+     */
+    private String getUploadedFileUrl(HttpServletRequest request, String formInputElementName) {
+        BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService();
+        Map<String, List<BlobKey>> blobs = blobstoreService.getUploads(request);
+        List<BlobKey> blobKeys = blobs.get("image");
+
+        // User submitted form without selecting a file, so we can't get a URL.
+        // (devserver)
+        if (blobKeys == null || blobKeys.isEmpty()) {
+            return null;
+        }
+
+        // Our form only contains a single file input, so get the first index.
+        BlobKey blobKey = blobKeys.get(0);
+
+        // User submitted form without selecting a file, so we can't get a URL. (live
+        // server)
+        BlobInfo blobInfo = new BlobInfoFactory().loadBlobInfo(blobKey);
+        if (blobInfo.getSize() == 0) {
+            blobstoreService.delete(blobKey);
+            return null;
+        }
+
+        // We could check the validity of the file here, e.g. to make sure it's an image
+        // file
+        // https://stackoverflow.com/q/10779564/873165
+
+        // Use ImagesService to get a URL that points to the uploaded file.
+        ImagesService imagesService = ImagesServiceFactory.getImagesService();
+        ServingUrlOptions options = ServingUrlOptions.Builder.withBlobKey(blobKey);
+        return imagesService.getServingUrl(options);
+    }
+}