    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.fileupload.util;
    018
    019import java.io.ByteArrayOutputStream;
    020import java.io.IOException;
    021import java.io.InputStream;
    022import java.io.OutputStream;
    023
    024import org.apache.commons.fileupload.InvalidFileNameException;
    025import org.apache.commons.io.IOUtils;
    026import org.apache.commons.io.output.NullOutputStream;
    027
    028/**
    029 * Utility class for working with streams.
    030 */
    031public final class Streams {
    032
    033    /**
    034     * Default buffer size for use in
    035     * {@link #copy(InputStream, OutputStream, boolean)}.
    036     */
    037    public static final int DEFAULT_BUFFER_SIZE = 8192;
    038
    039    /**
    040     * This convenience method allows to read a
    041     * {@link org.apache.commons.fileupload.FileItemStream}'s
    042     * content into a string. The platform's default character encoding
    043     * is used for converting bytes into characters.
    044     *
    045     * @param inputStream The input stream to read.
    046     * @see #asString(InputStream, String)
    047     * @return The streams contents, as a string.
    048     * @throws IOException An I/O error occurred.
    049     */
    050    public static String asString(final InputStream inputStream) throws IOException {
    051        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
    052        copy(inputStream, baos, true);
    053        return baos.toString();
    054    }
    055
    056    /**
    057     * This convenience method allows to read a
    058     * {@link org.apache.commons.fileupload.FileItemStream}'s
    059     * content into a string, using the given character encoding.
    060     *
    061     * @param inputStream The input stream to read.
    062     * @param encoding The character encoding, typically "UTF-8".
    063     * @see #asString(InputStream)
    064     * @return The streams contents, as a string.
    065     * @throws IOException An I/O error occurred.
    066     */
    067    public static String asString(final InputStream inputStream, final String encoding) throws IOException {
    068        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
    069        copy(inputStream, baos, true);
    070        return baos.toString(encoding);
    071    }
    072
    073    /**
    074     * Checks, whether the given file name is valid in the sense,
    075     * that it doesn't contain any NUL characters. If the file name
    076     * is valid, it will be returned without any modifications. Otherwise,
    077     * an {@link InvalidFileNameException} is raised.
    078     *
    079     * @param fileName The file name to check
    080     * @return Unmodified file name, if valid.
    081     * @throws InvalidFileNameException The file name was found to be invalid.
    082     */
    083    public static String checkFileName(final String fileName) {
    084        if (fileName != null  &&  fileName.indexOf('\u0000') != -1) {
    085            // fileName.replace("\u0000", "\\0")
    086            final StringBuilder sb = new StringBuilder();
    087            for (int i = 0;  i < fileName.length();  i++) {
    088                final char c = fileName.charAt(i);
    089                switch (c) {
    090                    case 0:
    091                        sb.append("\\0");
    092                        break;
    093                    default:
    094                        sb.append(c);
    095                        break;
    096                }
    097            }
    098            throw new InvalidFileNameException(fileName,
    099                    "Invalid file name: " + sb);
    100        }
    101        return fileName;
    102    }
    103
    104    /**
    105     * Copies the contents of the given {@link InputStream}
    106     * to the given {@link OutputStream}. Shortcut for
    107     * <pre>
    108     *   copy(pInputStream, outputStream, new byte[8192]);
    109     * </pre>
    110     *
    111     * @param inputStream The input stream, which is being read.
    112     * It is guaranteed, that {@link InputStream#close()} is called
    113     * on the stream.
    114     * @param outputStream The output stream, to which data should
    115     * be written. May be null, in which case the input streams
    116     * contents are simply discarded.
    117     * @param closeOutputStream True guarantees, that {@link OutputStream#close()}
    118     * is called on the stream. False indicates, that only
    119     * {@link OutputStream#flush()} should be called finally.
    120     *
    121     * @return Number of bytes, which have been copied.
    122     * @throws IOException An I/O error occurred.
    123     */
    124    public static long copy(final InputStream inputStream, final OutputStream outputStream,
    125                            final boolean closeOutputStream)
    126            throws IOException {
    127        return copy(inputStream, outputStream, closeOutputStream, new byte[DEFAULT_BUFFER_SIZE]);
    128    }
    129
    130    /**
    131     * Copies the contents of the given {@link InputStream}
    132     * to the given {@link OutputStream}.
    133     *
    134     * @param inputStream The input stream, which is being read.
    135     *   It is guaranteed, that {@link InputStream#close()} is called
    136     *   on the stream.
    137     * @param outputStream The output stream, to which data should
    138     *   be written. May be null, in which case the input streams
    139     *   contents are simply discarded.
    140     * @param closeOutputStream True guarantees, that {@link OutputStream#close()}
    141     *   is called on the stream. False indicates, that only
    142     *   {@link OutputStream#flush()} should be called finally.
    143     * @param buffer Temporary buffer, which is to be used for
    144     *   copying data.
    145     * @return Number of bytes, which have been copied.
    146     * @throws IOException An I/O error occurred.
    147     */
    148    public static long copy(final InputStream inputStream, final OutputStream outputStream, final boolean closeOutputStream, final byte[] buffer)
    149            throws IOException {
    150        try {
    151            return IOUtils.copyLarge(inputStream, outputStream != null ? outputStream : NullOutputStream.INSTANCE, buffer);
    152        } finally {
    153            IOUtils.closeQuietly(inputStream);
    154            if (closeOutputStream) {
    155                IOUtils.closeQuietly(outputStream);
    156            }
    157        }
    158    }
    159
    160    /**
    161     * Private constructor, to prevent instantiation.
    162     * This class has only static methods.
    163     */
    164    private Streams() {
    165        // Does nothing
    166    }
    167
    168}