de.whs.poodle.controllers.ImageController.java Source code

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Here is the source code for de.whs.poodle.controllers.ImageController.java

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/*
 * Copyright 2015 Westflische Hochschule
 *
 * This file is part of Poodle.
 *
 * Poodle is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Poodle is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Poodle.  If not, see <http://www.gnu.org/licenses/>.
 */
package de.whs.poodle.controllers;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import de.whs.poodle.beans.Course;
import de.whs.poodle.beans.Instructor;
import de.whs.poodle.beans.UploadedImage;
import de.whs.poodle.beans.forms.BrowseImagesFilter;
import de.whs.poodle.repositories.CourseRepository;
import de.whs.poodle.repositories.ImageRepository;

/*
 * Controller for the image integration with CKEditor (Upload and ImageBrowser).
 * Also provides /images/{id} to download an image.
 *
 * See also http://docs.ckeditor.com/#!/guide/dev_file_browser_api regarding the CKEditor API
 */
@Controller
public class ImageController {

    @Autowired
    private ImageRepository imageRepo;

    @Autowired
    private CourseRepository courseRepo;

    protected static Logger log = LoggerFactory.getLogger(ImageController.class);

    // maximum time a client can cache an image
    private static final int IMAGE_CACHE_MAX_AGE = 365 * 24 * 60 * 60; // one year

    /*
     * The image browser called by CKEditor on click on "browse server".
     */
    @RequestMapping(value = "/instructor/browseImages", method = RequestMethod.GET)
    public String browseImages(Model model, @ModelAttribute Instructor instructor,
            @ModelAttribute BrowseImagesFilter filter) {
        List<Course> courses = courseRepo.getAllForInstructor(instructor.getId());
        List<UploadedImage> images = imageRepo.getForCourse(filter.getCourseId());
        model.addAttribute("courses", courses);
        model.addAttribute("images", images);
        model.addAttribute("filter", filter);
        return "instructor/browseImages";
    }

    /*
     * Called by CKEditor to upload an image after it has been chosen by the user. Uploads
     * the image and returns the path according to the CKEditor File API.
     */
    @RequestMapping(value = "/instructor/images/{courseId}", method = RequestMethod.POST)
    @ResponseBody // send the response directly to the client instead of rendering an HTML page
    public String uploadImage(@ModelAttribute Instructor instructor, @PathVariable int courseId,
            @RequestParam int CKEditorFuncNum, MultipartHttpServletRequest request) throws IOException {
        InputStream in = null;

        try {
            String filename = request.getFileNames().next();
            MultipartFile multipartFile = request.getFile(filename);
            String originalFilename = multipartFile.getOriginalFilename();

            String mimetype = multipartFile.getContentType();
            in = multipartFile.getInputStream();
            long length = multipartFile.getSize();

            UploadedImage image = new UploadedImage();
            image.setCourseId(courseId);
            image.setInstructor(instructor);
            image.setFilename(originalFilename);
            image.setMimeType(mimetype);

            imageRepo.uploadImage(image, in, length);

            String path = request.getContextPath() + "/images/" + image.getId();

            return generateResponse(CKEditorFuncNum, path, null);

        } catch (Exception e) {
            log.error("Error uploading image", e);
            return generateResponse(CKEditorFuncNum, null, "Fehler beim Upload");
        } finally {
            if (in != null)
                in.close();
        }
    }

    /*
     * Generates the callback for the CKEditor that it needs after a file has been uploaded.
     */
    private String generateResponse(int CKEditorFuncNum, String path, String message) {
        if (message != null) { // error
            return "<script type='text/javascript'>window.parent.CKEDITOR.tools.callFunction(" + CKEditorFuncNum
                    + ", '', '" + message + "');</script>";
        } else {
            return "<script type='text/javascript'>window.parent.CKEDITOR.tools.callFunction(" + CKEditorFuncNum
                    + ", '" + path + "');</script>";
        }
    }

    /*
     * Allows downloading an image.
     */
    @RequestMapping(value = "/images/{imageId}", method = RequestMethod.GET)
    public void getImage(@PathVariable int imageId, HttpServletResponse response) throws IOException {
        /* Allow the client to cache the image. We can assume that a particular image
         * doesn't change anymore once it is in the database. */
        response.setHeader("Cache-Control", "max-age=" + IMAGE_CACHE_MAX_AGE);
        response.setHeader("Pragma", "public"); // shouldn't be necessary, but defaults to no-cache, so override it

        imageRepo.writeImageToHttpResponse(imageId, response);
    }
}