MnistFetcher.java

/*-
 *
 *  * Copyright 2015 Skymind,Inc.
 *  *
 *  *    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 org.deeplearning4j.base;

import lombok.Data;
import lombok.NoArgsConstructor;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.codec.digest.DigestUtils;

import org.deeplearning4j.util.ArchiveUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;

@Data
@NoArgsConstructor
public class MnistFetcher {
    protected static final Logger log = LoggerFactory.getLogger(MnistFetcher.class);

    protected File BASE_DIR = new File(System.getProperty("user.home"));
    protected static final String LOCAL_DIR_NAME = "MNIST";
    protected File FILE_DIR = new File(BASE_DIR, LOCAL_DIR_NAME);

    private File fileDir;
    private static final String trainingFilesURL = "http://benchmark.deeplearn.online/mnist/train-images-idx3-ubyte.gz";
    private static final String trainingFilesMD5 = "f68b3c2dcbeaaa9fbdd348bbdeb94873";
    private static final String trainingFilesFilename = "train-images-idx3-ubyte.gz";
    public static final String trainingFilesFilename_unzipped = "train-images-idx3-ubyte";
    private static final String trainingFileLabelsURL =
                    "http://benchmark.deeplearn.online/mnist/train-labels-idx1-ubyte.gz";
    private static final String trainingFileLabelsMD5 = "d53e105ee54ea40749a09fcbcd1e9432";
    private static final String trainingFileLabelsFilename = "train-labels-idx1-ubyte.gz";
    public static final String trainingFileLabelsFilename_unzipped = "train-labels-idx1-ubyte";

    //Test data:
    private static final String testFilesURL = "http://benchmark.deeplearn.online/mnist/t10k-images-idx3-ubyte.gz";
    private static final String testFilesMD5 = "9fb629c4189551a2d022fa330f9573f3";
    private static final String testFilesFilename = "t10k-images-idx3-ubyte.gz";
    public static final String testFilesFilename_unzipped = "t10k-images-idx3-ubyte";
    private static final String testFileLabelsURL = "http://benchmark.deeplearn.online/mnist/t10k-labels-idx1-ubyte.gz";
    private static final String testFileLabelsMD5 = "ec29112dd5afa0611ce80d1b7f02629c";
    private static final String testFileLabelsFilename = "t10k-labels-idx1-ubyte.gz";
    public static final String testFileLabelsFilename_unzipped = "t10k-labels-idx1-ubyte";


    public File downloadAndUntar() throws IOException {
        if (fileDir != null) {
            return fileDir;
        }

        File baseDir = FILE_DIR;
        if (!(baseDir.isDirectory() || baseDir.mkdir())) {
            throw new IOException("Could not mkdir " + baseDir);
        }

        log.info("Downloading mnist...");
        // getFromOrigin training records
        File tarFile = new File(baseDir, trainingFilesFilename);
        File testFileLabels = new File(baseDir, testFilesFilename);

        tryDownloadingAFewTimes(new URL(trainingFilesURL), tarFile, trainingFilesMD5);
        tryDownloadingAFewTimes(new URL(testFilesURL), testFileLabels, testFilesMD5);

        ArchiveUtils.unzipFileTo(tarFile.getAbsolutePath(), baseDir.getAbsolutePath());
        ArchiveUtils.unzipFileTo(testFileLabels.getAbsolutePath(), baseDir.getAbsolutePath());

        // getFromOrigin training records
        File labels = new File(baseDir, trainingFileLabelsFilename);
        File labelsTest = new File(baseDir, testFileLabelsFilename);

        tryDownloadingAFewTimes(new URL(trainingFileLabelsURL), labels, trainingFileLabelsMD5);
        tryDownloadingAFewTimes(new URL(testFileLabelsURL), labelsTest, testFileLabelsMD5);

        ArchiveUtils.unzipFileTo(labels.getAbsolutePath(), baseDir.getAbsolutePath());
        ArchiveUtils.unzipFileTo(labelsTest.getAbsolutePath(), baseDir.getAbsolutePath());

        fileDir = baseDir;
        return fileDir;
    }

    private void tryDownloadingAFewTimes(URL url, File f, String targetMD5) throws IOException {
        tryDownloadingAFewTimes(0, url, f, targetMD5);
    }

    private void tryDownloadingAFewTimes(int attempt, URL url, File f, String targetMD5) throws IOException {
        int maxTries = 3;
        boolean isCorrectFile = f.isFile();
        if (attempt < maxTries && !isCorrectFile) {
            FileUtils.copyURLToFile(url, f);
            if (!checkMD5OfFile(targetMD5, f))
                tryDownloadingAFewTimes(attempt + 1, url, f, targetMD5);
        } else if (isCorrectFile) {
            // do nothing, file downloaded
        } else {
            throw new IOException("Could not download " + url.getPath() + "\n properly despite trying " + maxTries
                            + " times, check your connection. File info:" + "\nTarget MD5: " + targetMD5
                            + "\nHash matches: " + checkMD5OfFile(targetMD5, f) + "\nIs valid file: " + f.isFile());
        }
    }

    private boolean checkMD5OfFile(String targetMD5, File file) throws IOException {
        InputStream in = FileUtils.openInputStream(file);
        String trueMd5 = DigestUtils.md5Hex(in);
        IOUtils.closeQuietly(in);
        return (targetMD5.equals(trueMd5));
    }

    public static void gunzipFile(File baseDir, File gzFile) throws IOException {
        log.info("gunzip'ing File: " + gzFile.toString());
        Process p = Runtime.getRuntime().exec(String.format("gunzip %s", gzFile.getAbsolutePath()));
        BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));
        log.info("Here is the standard error of the command (if any):\n");
        String s;
        while ((s = stdError.readLine()) != null) {
            log.info(s);
        }
        stdError.close();
    }


}