src/java/org/apache/commons/fileupload/FileUploadBase.java

/*
 * Copyright 2001-2005 The Apache Software Foundation
 *
 * 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.apache.commons.fileupload;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.servlet.ServletRequestContext;

/**
 * <p>High level API for processing file uploads.</p>
 *
 * <p>This class handles multiple files per single HTML widget, sent using
 * <code>multipart/mixed</code> encoding type, as specified by
 * <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>.  Use {@link
 * #parseRequest(HttpServletRequest)} to acquire a list of {@link
 * org.apache.commons.fileupload.FileItem}s associated with a given HTML
 * widget.</p>
 *
 * <p>How the data for individual parts is stored is determined by the factory
 * used to create them; a given part may be in memory, on disk, or somewhere
 * else.</p>
 *
 * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a>
 * @author <a href="mailto:dlr@collab.net">Daniel Rall</a>
 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
 * @author <a href="mailto:jmcnally@collab.net">John McNally</a>
 * @author <a href="mailto:martinc@apache.org">Martin Cooper</a>
 * @author Sean C. Sullivan
 *
 * @version $Id$
 */
public abstract class FileUploadBase {

    // ---------------------------------------------------------- Class methods


    /**
     * <p>Utility method that determines whether the request contains multipart
     * content.</p>
     *
     * <p><strong>NOTE:</strong>This method will be moved to the
     * <code>ServletFileUpload</code> class after the FileUpload 1.1 release.
     * Unfortunately, since this method is static, it is not possible to
     * provide its replacement until this method is removed.</p>
     *
     * @param ctx The request context to be evaluated. Must be non-null.
     *
     * @return <code>true</code> if the request is multipart;
     *         <code>false</code> otherwise.
     */
    public static final boolean isMultipartContent(RequestContext ctx) {
        String contentType = ctx.getContentType();
        if (contentType == null) {
            return false;
        }
        if (contentType.toLowerCase().startsWith(MULTIPART)) {
            return true;
        }
        return false;
    }


    /**
     * Utility method that determines whether the request contains multipart
     * content.
     *
     * @param req The servlet request to be evaluated. Must be non-null.
     *
     * @return <code>true</code> if the request is multipart;
     *         <code>false</code> otherwise.
     *
     * @deprecated Use the method on <code>ServletFileUpload</code> instead.
     */
    public static final boolean isMultipartContent(HttpServletRequest req) {
        if (!"post".equals(req.getMethod().toLowerCase())) {
            return false;
        }
        String contentType = req.getContentType();
        if (contentType == null) {
            return false;
        }
        if (contentType.toLowerCase().startsWith(MULTIPART)) {
            return true;
        }
        return false;
    }


    // ----------------------------------------------------- Manifest constants


    /**
     * HTTP content type header name.
     */
    public static final String CONTENT_TYPE = "Content-type";


    /**
     * HTTP content disposition header name.
     */
    public static final String CONTENT_DISPOSITION = "Content-disposition";


    /**
     * Content-disposition value for form data.
     */
    public static final String FORM_DATA = "form-data";


    /**
     * Content-disposition value for file attachment.
     */
    public static final String ATTACHMENT = "attachment";


    /**
     * Part of HTTP content type header.
     */
    public static final String MULTIPART = "multipart/";


    /**
     * HTTP content type header for multipart forms.
     */
    public static final String MULTIPART_FORM_DATA = "multipart/form-data";


    /**
     * HTTP content type header for multiple uploads.
     */
    public static final String MULTIPART_MIXED = "multipart/mixed";


    /**
     * The maximum length of a single header line that will be parsed
     * (1024 bytes).
     */
    public static final int MAX_HEADER_SIZE = 1024;


    // ----------------------------------------------------------- Data members


    /**
     * The maximum size permitted for an uploaded file. A value of -1 indicates
     * no maximum.
     */
    private long sizeMax = -1;


    /**
     * The content encoding to use when reading part headers.
     */
    private String headerEncoding;


    // ----------------------------------------------------- Property accessors


    /**
     * Returns the factory class used when creating file items.
     *
     * @return The factory class for new file items.
     */
    public abstract FileItemFactory getFileItemFactory();


    /**
     * Sets the factory class to use when creating file items.
     *
     * @param factory The factory class for new file items.
     */
    public abstract void setFileItemFactory(FileItemFactory factory);


    /**
     * Returns the maximum allowed upload size.
     *
     * @return The maximum allowed size, in bytes.
     *
     * @see #setSizeMax(long)
     *
     */
    public long getSizeMax() {
        return sizeMax;
    }


    /**
     * Sets the maximum allowed upload size. If negative, there is no maximum.
     *
     * @param sizeMax The maximum allowed size, in bytes, or -1 for no maximum.
     *
     * @see #getSizeMax()
     *
     */
    public void setSizeMax(long sizeMax) {
        this.sizeMax = sizeMax;
    }


    /**
     * Retrieves the character encoding used when reading the headers of an
     * individual part. When not specified, or <code>null</code>, the request
     * encoding is used. If that is also not specified, or <code>null</code>,
     * the platform default encoding is used.
     *
     * @return The encoding used to read part headers.
     */
    public String getHeaderEncoding() {
        return headerEncoding;
    }


    /**
     * Specifies the character encoding to be used when reading the headers of
     * individual part. When not specified, or <code>null</code>, the request
     * encoding is used. If that is also not specified, or <code>null</code>,
     * the platform default encoding is used.
     *
     * @param encoding The encoding used to read part headers.
     */
    public void setHeaderEncoding(String encoding) {
        headerEncoding = encoding;
    }


    // --------------------------------------------------------- Public methods


    /**
     * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
     * compliant <code>multipart/form-data</code> stream.
     *
     * @param req The servlet request to be parsed.
     *
     * @return A list of <code>FileItem</code> instances parsed from the
     *         request, in the order that they were transmitted.
     *
     * @throws FileUploadException if there are problems reading/parsing
     *                             the request or storing files.
     *
     * @deprecated Use the method in <code>ServletFileUpload</code> instead.
     */
    public List /* FileItem */ parseRequest(HttpServletRequest req)
            throws FileUploadException {
        return parseRequest(new ServletRequestContext(req));
    }

    /**
     * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
     * compliant <code>multipart/form-data</code> stream.
     *
     * @param ctx The context for the request to be parsed.
     *
     * @return An iterator to instances of <code>FileItemStream</code>
     *         parsed from the request, in the order that they were
     *         transmitted.
     *
     * @throws FileUploadException if there are problems reading/parsing
     *                             the request or storing files.
     */
    public FileItemIterator getItemIterator(RequestContext ctx)
            throws FileUploadException {
        return new FileItemIteratorImpl(ctx);
    }

    /**
     * Processes an <a href="http://www.ietf.org/rfc/rfc1867.txt">RFC 1867</a>
     * compliant <code>multipart/form-data</code> stream.
     *
     * @param ctx The context for the request to be parsed.
     *
     * @return A list of <code>FileItem</code> instances parsed from the
     *         request, in the order that they were transmitted.
     *
     * @throws FileUploadException if there are problems reading/parsing
     *                             the request or storing files.
     */
    public List /* FileItem */ parseRequest(RequestContext ctx)
            throws FileUploadException {
        FileItemIterator iter = getItemIterator(ctx);
        List items = new ArrayList();
        FileItemFactory fac = getFileItemFactory();
        final byte[] buffer = new byte[8192];
        while (iter.hasNext()) {
            FileItemStream item = iter.next();
            FileItem fileItem = fac.createItem(item.getFieldName(),
                    item.getContentType(), item.isFormField(),
                    item.getName());
            try {
                StreamUtil.copy(item.openStream(), fileItem.getOutputStream(),
                            true, buffer);
            } catch (FileUploadIOException e) {
                throw (FileUploadException) e.getCause();
            } catch (IOException e) {
                throw new IOFileUploadException(
                    "Processing of " + MULTIPART_FORM_DATA
                        + " request failed. " + e.getMessage(), e);
            }
            items.add(fileItem);
        }
        return items;
    }


    // ------------------------------------------------------ Protected methods


    /**
     * Retrieves the boundary from the <code>Content-type</code> header.
     *
     * @param contentType The value of the content type header from which to
     *                    extract the boundary value.
     *
     * @return The boundary, as a byte array.
     */
    protected byte[] getBoundary(String contentType) {
        ParameterParser parser = new ParameterParser();
        parser.setLowerCaseNames(true);
        // Parameter parser can handle null input
        Map params = parser.parse(contentType, ';');
        String boundaryStr = (String) params.get("boundary");

        if (boundaryStr == null) {
            return null;
        }
        byte[] boundary;
        try {
            boundary = boundaryStr.getBytes("ISO-8859-1");
        } catch (UnsupportedEncodingException e) {
            boundary = boundaryStr.getBytes();
        }
        return boundary;
    }


    /**
     * Retrieves the file name from the <code>Content-disposition</code>
     * header.
     *
     * @param headers A <code>Map</code> containing the HTTP request headers.
     *
     * @return The file name for the current <code>encapsulation</code>.
     */
    protected String getFileName(Map /* String, String */ headers) {
        String fileName = null;
        String cd = getHeader(headers, CONTENT_DISPOSITION);
        if (cd != null) {
            String cdl = cd.toLowerCase();
            if (cdl.startsWith(FORM_DATA) || cdl.startsWith(ATTACHMENT)) {
                ParameterParser parser = new ParameterParser();
                parser.setLowerCaseNames(true);
                // Parameter parser can handle null input
                Map params = parser.parse(cd, ';');
                if (params.containsKey("filename")) {
                    fileName = (String) params.get("filename");
                    if (fileName != null) {
                        fileName = fileName.trim();
                    } else {
                        // Even if there is no value, the parameter is present,
                        // so we return an empty file name rather than no file
                        // name.
                        fileName = "";
                    }
                }
            }
        }
        return fileName;
    }


    /**
     * Retrieves the field name from the <code>Content-disposition</code>
     * header.
     *
     * @param headers A <code>Map</code> containing the HTTP request headers.
     *
     * @return The field name for the current <code>encapsulation</code>.
     */
    protected String getFieldName(Map /* String, String */ headers) {
        String fieldName = null;
        String cd = getHeader(headers, CONTENT_DISPOSITION);
        if (cd != null && cd.toLowerCase().startsWith(FORM_DATA)) {

            ParameterParser parser = new ParameterParser();
            parser.setLowerCaseNames(true);
            // Parameter parser can handle null input
            Map params = parser.parse(cd, ';');
            fieldName = (String) params.get("name");
            if (fieldName != null) {
                fieldName = fieldName.trim();
            }
        }
        return fieldName;
    }


    /**
     * <p> Parses the <code>header-part</code> and returns as key/value
     * pairs.
     *
     * <p> If there are multiple headers of the same names, the name
     * will map to a comma-separated list containing the values.
     *
     * @param headerPart The <code>header-part</code> of the current
     *                   <code>encapsulation</code>.
     *
     * @return A <code>Map</code> containing the parsed HTTP request headers.
     */
    protected Map /* String, String */ parseHeaders(String headerPart) {
        Map headers = new HashMap();
        char[] buffer = new char[MAX_HEADER_SIZE];
        boolean done = false;
        int j = 0;
        int i;
        String header, headerName, headerValue;
        try {
            while (!done) {
                i = 0;
                // Copy a single line of characters into the buffer,
                // omitting trailing CRLF.
                while (i < 2
                        || buffer[i - 2] != '\r' || buffer[i - 1] != '\n') {
                    buffer[i++] = headerPart.charAt(j++);
                }
                header = new String(buffer, 0, i - 2);
                if (header.equals("")) {
                    done = true;
                } else {
                    if (header.indexOf(':') == -1) {
                        // This header line is malformed, skip it.
                        continue;
                    }
                    headerName = header.substring(0, header.indexOf(':'))
                        .trim().toLowerCase();
                    headerValue =
                        header.substring(header.indexOf(':') + 1).trim();
                    if (getHeader(headers, headerName) != null) {
                        // More that one heder of that name exists,
                        // append to the list.
                        headers.put(headerName,
                                    getHeader(headers, headerName) + ','
                                        + headerValue);
                    } else {
                        headers.put(headerName, headerValue);
                    }
                }
            }
        } catch (IndexOutOfBoundsException e) {
            // Headers were malformed. continue with all that was
            // parsed.
        }
        return headers;
    }


    /**
     * Returns the header with the specified name from the supplied map. The
     * header lookup is case-insensitive.
     *
     * @param headers A <code>Map</code> containing the HTTP request headers.
     * @param name    The name of the header to return.
     *
     * @return The value of specified header, or a comma-separated list if
     *         there were multiple headers of that name.
     */
    protected final String getHeader(Map /* String, String */ headers,
                                     String name) {
        return (String) headers.get(name.toLowerCase());
    }

    /**
     * The iterator, which is returned by
     * {@link FileUploadBase#getItemIterator(RequestContext)}.
     */
    private class FileItemIteratorImpl implements FileItemIterator {
        private class FileItemStreamImpl implements FileItemStream {
            private final String contentType, fieldName, name;
            private final boolean formField;
            private final MultipartStream.ItemInputStream stream;
            private boolean opened;

            FileItemStreamImpl(String pName, String pFieldName,
                    String pContentType, boolean pFormField) {
                name = pName;
                fieldName = pFieldName;
                contentType = pContentType;
                formField = pFormField;
                stream = multi.newInputStream();
            }

            public String getContentType() {
                return contentType;
            }

            public String getFieldName() {
                return fieldName;
            }

            public String getName() {
                return name;
            }

            public boolean isFormField() {
                return formField;
            }

            public InputStream openStream() throws IOException {
                if (opened) {
                    throw new IllegalStateException("The stream was already opened.");
                }
                if (stream.isClosed()) {
                    throw new FileItemStream.ItemSkippedException();
                }
                return stream;
            }

            void close() throws IOException {
                stream.close();
            }
        }

        private final MultipartStream multi;
        private final byte[] boundary;
        private FileItemStreamImpl currentItem;
        private String currentFieldName;
        private boolean skipPreamble;
        private boolean itemValid;
        private boolean eof;

        FileItemIteratorImpl(RequestContext ctx) throws FileUploadException {
            if (ctx == null) {
                throw new NullPointerException("ctx parameter");
            }

            String contentType = ctx.getContentType();
            if ((null == contentType)
                || (!contentType.toLowerCase().startsWith(MULTIPART))) {
                throw new InvalidContentTypeException(
                    "the request doesn't contain a "
                    + MULTIPART_FORM_DATA
                    + " or "
                    + MULTIPART_MIXED
                    + " stream, content type header is "
                    + contentType);
            }

            try {
                InputStream input = ctx.getInputStream();

                if (sizeMax >= 0) {
                    int requestSize = ctx.getContentLength();
                    if (requestSize == -1) {
                        input = new LimitedInputStream(input, sizeMax);
                    } else {
                        if (sizeMax >= 0 && requestSize > sizeMax) {
                            throw new SizeLimitExceededException(
                                    "the request was rejected because its size (" + requestSize
                                    + ") exceeds the configured maximum (" + sizeMax + ")",
                                    requestSize, sizeMax);
                        }
                    }
                }

                String charEncoding = headerEncoding;
                if (charEncoding == null) {
                    charEncoding = ctx.getCharacterEncoding();
                }

                boundary = getBoundary(contentType);
                if (boundary == null) {
                    throw new FileUploadException(
                            "the request was rejected because "
                            + "no multipart boundary was found");
                }

                multi = new MultipartStream(input, boundary);
                multi.setHeaderEncoding(charEncoding);

                skipPreamble = true;
                findNextItem();
            } catch (FileUploadIOException e) {
                throw (FileUploadException) e.getCause();
            } catch (IOException e) {
                throw new FileUploadException(
                    "Processing of " + MULTIPART_FORM_DATA
                        + " request failed. " + e.getMessage());
            }
        }

        private boolean findNextItem() throws IOException {
            if (eof) {
                return false;
            }
            if (currentItem != null) {
                currentItem.close();
                currentItem = null;
            }
            for (;;) {
                boolean nextPart;
                if (skipPreamble) {
                    nextPart = multi.skipPreamble();
                } else {
                    nextPart = multi.readBoundary();
                }
                if (!nextPart) {
                    if (currentFieldName == null) {
                        // Outer multipart terminated -> No more data
                        eof = true;
                        return false;
                    }
                    // Inner multipart terminated -> Return to parsing the outer
                    multi.setBoundary(boundary);
                    currentFieldName = null;
                    continue;
                }
                Map headers = parseHeaders(multi.readHeaders());
                if (currentFieldName == null) {
                    // We're parsing the outer multipart
                    String fieldName = getFieldName(headers);
                    if (fieldName != null) {
                        String subContentType = getHeader(headers, CONTENT_TYPE);
                        if (subContentType != null  &&
                            subContentType.toLowerCase().startsWith(MULTIPART_MIXED)) {
                            currentFieldName = fieldName;
                            // Multiple files associated with this field name
                            byte[] subBoundary = getBoundary(subContentType);
                            multi.setBoundary(subBoundary);
                            skipPreamble = true;
                            continue;
                        } else {
                            String fileName = getFileName(headers);
                            currentItem = new FileItemStreamImpl(fileName,
                                    fieldName, getHeader(headers, CONTENT_TYPE),
                                    fileName == null);
                            itemValid = true;
                            return true;
                        }
                    }
                } else {
                    String fileName = getFileName(headers);
                    if (fileName != null) {
                        currentItem = new FileItemStreamImpl(fileName,
                                currentFieldName, getHeader(headers, CONTENT_TYPE),
                                false);
                        itemValid = true;
                        return true;
                    }
                }
                multi.discardBodyData();
            }
        }

        public boolean hasNext() throws FileUploadException {
            if (eof) {
                return false;
            }
            if (itemValid) {
                return true;
            }
            try {
                return findNextItem();
            } catch (FileUploadIOException e) {
                throw (FileUploadException) e.getCause();
            } catch (IOException e) {
                throw new FileUploadException(
                    "Processing of " + MULTIPART_FORM_DATA
                        + " request failed. " + e.getMessage());
            }
        }

        public FileItemStream next() throws FileUploadException {
            if (eof  ||  (!itemValid && !hasNext())) {
                throw new NoSuchElementException();
            }
            itemValid = false;
            return currentItem;
        }
    }

    /**
     * An input stream, which limits its data size. This stream is
     * used, if the content length is unknown.
     */
    private static class LimitedInputStream extends FilterInputStream {
        private long sizeMax;
        private long count;

        private void checkLimit() throws IOException {
            if (count > sizeMax) {
                FileUploadException ex = new SizeLimitExceededException(
                        "the request was rejected because its size (" + count
                        + ") exceeds the configured maximum (" + sizeMax + ")",
                        count, sizeMax);
                throw new FileUploadIOException(ex);
            }
        }

        public int read() throws IOException {
            int res = super.read();
            if (res != -1) {
                count++;
                checkLimit();
            }
            return res;
        }

        public int read(byte[] b, int off, int len) throws IOException {
            int res = super.read(b, off, len);
            if (res > 0) {
                count += res;
                checkLimit();
            }
            return res;
        }

        LimitedInputStream(InputStream pIn, long pSizeMax) {
            super(pIn);
            sizeMax = pSizeMax;
        }
    }

    /**
     * This exception is thrown for hiding an inner 
     * {@link FileUploadException} in an {@link IOException}.
     */
    public static class FileUploadIOException extends IOException {
        private static final long serialVersionUID = -7047616958165584154L;
        private final FileUploadException cause;

        /**
         * Creates a <code>FileUploadIOException</code> with the
         * given cause.
         */
        public FileUploadIOException(FileUploadException pCause) {
            // We're not doing super(pCause) cause of 1.3 compatibility.
            cause = pCause;
        }

        public Throwable getCause() {
            return cause;
        }
    }

    /**
     * Thrown to indicate that the request is not a multipart request.
     */
    public static class InvalidContentTypeException
        extends FileUploadException {
        private static final long serialVersionUID = -9073026332015646668L;

        /**
         * Constructs a <code>InvalidContentTypeException</code> with no
         * detail message.
         */
        public InvalidContentTypeException() {
            super();
        }

        /**
         * Constructs an <code>InvalidContentTypeException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public InvalidContentTypeException(String message) {
            super(message);
        }
    }

    /**
     * Thrown to indicate an IOException.
     */
    public static class IOFileUploadException extends FileUploadException {
		private static final long serialVersionUID = 1749796615868477269L;
		private final IOException cause;

    	/**
    	 * Creates a new instance with the given cause.
    	 */
    	public IOFileUploadException(String pMsg, IOException pException) {
    		super(pMsg);
    		cause = pException;
    	}

    	public Throwable getCause() {
    		return cause;
    	}
    }

    /**
     * Thrown to indicate that the request size exceeds the configured maximum.
     */
    public static class SizeLimitExceededException
        extends FileUploadException {
        private static final long serialVersionUID = -2474893167098052828L;

        /**
         * The actual size of the request.
         */
        private long actual;

        /**
         * The maximum permitted size of the request.
         */
        private long permitted;

        /**
         * Constructs a <code>SizeExceededException</code> with no
         * detail message.
         */
        public SizeLimitExceededException() {
            super();
        }

        /**
         * Constructs a <code>SizeExceededException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public SizeLimitExceededException(String message) {
            super(message);
        }

        /**
         * Constructs a <code>SizeExceededException</code> with
         * the specified detail message, and actual and permitted sizes.
         *
         * @param message   The detail message.
         * @param actual    The actual request size.
         * @param permitted The maximum permitted request size.
         */
        public SizeLimitExceededException(String message, long actual,
                long permitted) {
            super(message);
            this.actual = actual;
            this.permitted = permitted;
        }

        /**
         * Retrieves the actual size of the request.
         *
         * @return The actual size of the request.
         */
        public long getActualSize() {
            return actual;
        }

        /**
         * Retrieves the permitted size of the request.
         *
         * @return The permitted size of the request.
         */
        public long getPermittedSize() {
            return permitted;
        }
    }

}