com.google.zxing.web.DecodeServlet.java Source code

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Here is the source code for com.google.zxing.web.DecodeServlet.java

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/*
 * Copyright 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * 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 com.google.zxing.web;

import com.google.common.collect.Lists;
import com.google.common.io.Resources;
import com.google.common.net.HttpHeaders;
import com.google.common.net.MediaType;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.DecodeHintType;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.Reader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.ImageReader;
import com.google.zxing.common.GlobalHistogramBinarizer;
import com.google.zxing.common.HybridBinarizer;

import com.google.zxing.multi.GenericMultipleBarcodeReader;
import com.google.zxing.multi.MultipleBarcodeReader;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.FileCleanerCleanup;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileCleaningTracker;

import java.awt.color.CMMException;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.EnumMap;
import java.util.EnumSet;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.imageio.ImageIO;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * {@link HttpServlet} which decodes images containing barcodes. Given a URL, it will
 * retrieve the image and decode it. It can also process image files uploaded via POST.
 *
 * @author Sean Owen
 */
public final class DecodeServlet extends HttpServlet {

    private static final Logger log = Logger.getLogger(DecodeServlet.class.getName());

    // No real reason to let people upload more than a 10MB image
    private static final long MAX_IMAGE_SIZE = 10_000_000L;
    // No real reason to deal with more than maybe 10 megapixels
    private static final int MAX_PIXELS = 10_000_000;
    private static final byte[] REMAINDER_BUFFER = new byte[32768];
    private static final Map<DecodeHintType, Object> HINTS;
    private static final Map<DecodeHintType, Object> HINTS_PURE;

    static {
        HINTS = new EnumMap<>(DecodeHintType.class);
        HINTS.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
        HINTS.put(DecodeHintType.POSSIBLE_FORMATS, EnumSet.allOf(BarcodeFormat.class));
        HINTS_PURE = new EnumMap<>(HINTS);
        HINTS_PURE.put(DecodeHintType.PURE_BARCODE, Boolean.TRUE);
    }

    private DiskFileItemFactory diskFileItemFactory;
    private Iterable<String> blockedURLSubstrings;

    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        Logger logger = Logger.getLogger("com.google.zxing");
        ServletContext context = servletConfig.getServletContext();
        logger.addHandler(new ServletContextLogHandler(context));
        File repository = (File) context.getAttribute("javax.servlet.context.tempdir");
        FileCleaningTracker fileCleaningTracker = FileCleanerCleanup.getFileCleaningTracker(context);
        diskFileItemFactory = new DiskFileItemFactory(1 << 16, repository);
        diskFileItemFactory.setFileCleaningTracker(fileCleaningTracker);

        URL blockURL = context.getClassLoader().getResource("/private/uri-block-substrings.txt");
        if (blockURL == null) {
            blockedURLSubstrings = Collections.emptyList();
        } else {
            try {
                blockedURLSubstrings = Resources.readLines(blockURL, StandardCharsets.UTF_8);
            } catch (IOException ioe) {
                throw new ServletException(ioe);
            }
            log.info("Blocking URIs containing: " + blockedURLSubstrings);
        }
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        String imageURIString = request.getParameter("u");
        if (imageURIString == null || imageURIString.isEmpty()) {
            log.info("URI was empty");
            response.sendRedirect("badurl.jspx");
            return;
        }

        imageURIString = imageURIString.trim();
        for (CharSequence substring : blockedURLSubstrings) {
            if (imageURIString.contains(substring)) {
                log.info("Disallowed URI " + imageURIString);
                response.sendRedirect("badurl.jspx");
                return;
            }
        }

        URI imageURI;
        try {
            imageURI = new URI(imageURIString);
            // Assume http: if not specified
            if (imageURI.getScheme() == null) {
                imageURI = new URI("http://" + imageURIString);
            }
        } catch (URISyntaxException urise) {
            log.info("URI " + imageURIString + " was not valid: " + urise);
            response.sendRedirect("badurl.jspx");
            return;
        }

        // Shortcut for data URI
        if ("data".equals(imageURI.getScheme())) {
            try {
                BufferedImage image = ImageReader.readDataURIImage(imageURI);
                processImage(image, request, response);
            } catch (IOException ioe) {
                log.info(ioe.toString());
                response.sendRedirect("badurl.jspx");
            }
            return;
        }

        URL imageURL;
        try {
            imageURL = imageURI.toURL();
        } catch (MalformedURLException ignored) {
            log.info("URI was not valid: " + imageURIString);
            response.sendRedirect("badurl.jspx");
            return;
        }

        String protocol = imageURL.getProtocol();
        if (!"http".equalsIgnoreCase(protocol) && !"https".equalsIgnoreCase(protocol)) {
            log.info("URI was not valid: " + imageURIString);
            response.sendRedirect("badurl.jspx");
            return;
        }

        HttpURLConnection connection;
        try {
            connection = (HttpURLConnection) imageURL.openConnection();
        } catch (IllegalArgumentException ignored) {
            log.info("URI could not be opened: " + imageURL);
            response.sendRedirect("badurl.jspx");
            return;
        }

        connection.setAllowUserInteraction(false);
        connection.setReadTimeout(5000);
        connection.setConnectTimeout(5000);
        connection.setRequestProperty(HttpHeaders.USER_AGENT, "zxing.org");
        connection.setRequestProperty(HttpHeaders.CONNECTION, "close");

        try {
            connection.connect();
        } catch (IOException ioe) {
            // Encompasses lots of stuff, including
            //  java.net.SocketException, java.net.UnknownHostException,
            //  javax.net.ssl.SSLPeerUnverifiedException,
            //  org.apache.http.NoHttpResponseException,
            //  org.apache.http.client.ClientProtocolException,
            log.info(ioe.toString());
            response.sendRedirect("badurl.jspx");
            return;
        }

        try (InputStream is = connection.getInputStream()) {
            try {
                if (connection.getResponseCode() != HttpServletResponse.SC_OK) {
                    log.info("Unsuccessful return code: " + connection.getResponseCode());
                    response.sendRedirect("badurl.jspx");
                    return;
                }
                if (connection.getHeaderFieldInt(HttpHeaders.CONTENT_LENGTH, 0) > MAX_IMAGE_SIZE) {
                    log.info("Too large");
                    response.sendRedirect("badimage.jspx");
                    return;
                }

                log.info("Decoding " + imageURL);
                processStream(is, request, response);
            } finally {
                consumeRemainder(is);
            }
        } catch (IOException ioe) {
            log.info(ioe.toString());
            response.sendRedirect("badurl.jspx");
        } finally {
            connection.disconnect();
        }

    }

    private static void consumeRemainder(InputStream is) {
        try {
            int available;
            while ((available = is.available()) > 0) {
                is.read(REMAINDER_BUFFER, 0, available); // don't care about value, or collision
            }
        } catch (IOException | IndexOutOfBoundsException ioe) {
            // sun.net.www.http.ChunkedInputStream.read is throwing IndexOutOfBoundsException
            // continue
        }
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        if (!ServletFileUpload.isMultipartContent(request)) {
            log.info("File upload was not multipart");
            response.sendRedirect("badimage.jspx");
            return;
        }

        ServletFileUpload upload = new ServletFileUpload(diskFileItemFactory);
        upload.setFileSizeMax(MAX_IMAGE_SIZE);

        // Parse the request
        try {
            for (FileItem item : upload.parseRequest(request)) {
                if (!item.isFormField()) {
                    if (item.getSize() <= MAX_IMAGE_SIZE) {
                        log.info("Decoding uploaded file");
                        try (InputStream is = item.getInputStream()) {
                            processStream(is, request, response);
                        }
                    } else {
                        log.info("Too large");
                        response.sendRedirect("badimage.jspx");
                    }
                    break;
                }
            }
        } catch (FileUploadException fue) {
            log.info(fue.toString());
            response.sendRedirect("badimage.jspx");
        }

    }

    private static void processStream(InputStream is, ServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        BufferedImage image;
        try {
            image = ImageIO.read(is);
        } catch (IOException | CMMException | IllegalArgumentException ioe) {
            log.info(ioe.toString());
            // Have seen these in some logs
            response.sendRedirect("badimage.jspx");
            return;
        }
        if (image == null) {
            response.sendRedirect("badimage.jspx");
            return;
        }
        if (image.getHeight() <= 1 || image.getWidth() <= 1 || image.getHeight() * image.getWidth() > MAX_PIXELS) {
            log.info("Dimensions out of bounds: " + image.getWidth() + 'x' + image.getHeight());
            response.sendRedirect("badimage.jspx");
            return;
        }

        processImage(image, request, response);
    }

    private static void processImage(BufferedImage image, ServletRequest request, HttpServletResponse response)
            throws IOException, ServletException {

        LuminanceSource source = new BufferedImageLuminanceSource(image);
        BinaryBitmap bitmap = new BinaryBitmap(new GlobalHistogramBinarizer(source));
        Collection<Result> results = Lists.newArrayListWithCapacity(1);

        try {

            Reader reader = new MultiFormatReader();
            ReaderException savedException = null;
            try {
                // Look for multiple barcodes
                MultipleBarcodeReader multiReader = new GenericMultipleBarcodeReader(reader);
                Result[] theResults = multiReader.decodeMultiple(bitmap, HINTS);
                if (theResults != null) {
                    results.addAll(Arrays.asList(theResults));
                }
            } catch (ReaderException re) {
                savedException = re;
            }

            if (results.isEmpty()) {
                try {
                    // Look for pure barcode
                    Result theResult = reader.decode(bitmap, HINTS_PURE);
                    if (theResult != null) {
                        results.add(theResult);
                    }
                } catch (ReaderException re) {
                    savedException = re;
                }
            }

            if (results.isEmpty()) {
                try {
                    // Look for normal barcode in photo
                    Result theResult = reader.decode(bitmap, HINTS);
                    if (theResult != null) {
                        results.add(theResult);
                    }
                } catch (ReaderException re) {
                    savedException = re;
                }
            }

            if (results.isEmpty()) {
                try {
                    // Try again with other binarizer
                    BinaryBitmap hybridBitmap = new BinaryBitmap(new HybridBinarizer(source));
                    Result theResult = reader.decode(hybridBitmap, HINTS);
                    if (theResult != null) {
                        results.add(theResult);
                    }
                } catch (ReaderException re) {
                    savedException = re;
                }
            }

            if (results.isEmpty()) {
                handleException(savedException, response);
                return;
            }

        } catch (RuntimeException re) {
            // Call out unexpected errors in the log clearly
            log.log(Level.WARNING, "Unexpected exception from library", re);
            throw new ServletException(re);
        }

        String fullParameter = request.getParameter("full");
        boolean minimalOutput = fullParameter != null && !Boolean.parseBoolean(fullParameter);
        if (minimalOutput) {
            response.setContentType(MediaType.PLAIN_TEXT_UTF_8.toString());
            response.setCharacterEncoding(StandardCharsets.UTF_8.name());
            try (Writer out = new OutputStreamWriter(response.getOutputStream(), StandardCharsets.UTF_8)) {
                for (Result result : results) {
                    out.write(result.getText());
                    out.write('\n');
                }
            }
        } else {
            request.setAttribute("results", results);
            request.getRequestDispatcher("decoderesult.jspx").forward(request, response);
        }
    }

    private static void handleException(ReaderException re, HttpServletResponse response) throws IOException {
        if (re instanceof NotFoundException) {
            log.info("Not found: " + re);
            response.sendRedirect("notfound.jspx");
        } else if (re instanceof FormatException) {
            log.info("Format problem: " + re);
            response.sendRedirect("format.jspx");
        } else if (re instanceof ChecksumException) {
            log.info("Checksum problem: " + re);
            response.sendRedirect("format.jspx");
        } else {
            log.info("Unknown problem: " + re);
            response.sendRedirect("notfound.jspx");
        }
    }

}