https://tomcat.apache.org/: Tomcat Connectors and HTTP parser 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.tomcat.util.http.fileupload.disk;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.tomcat.util.http.fileupload.DeferredFileOutputStream;
import org.apache.tomcat.util.http.fileupload.FileItem;
import org.apache.tomcat.util.http.fileupload.FileItemHeaders;
import org.apache.tomcat.util.http.fileupload.FileUploadException;
import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.apache.tomcat.util.http.fileupload.ParameterParser;
import org.apache.tomcat.util.http.fileupload.util.Streams;


 The default implementation of the FileItem interface. 
 After retrieving an instance of this class from a FileUpload instance (see FileUploadBase.parseRequest(RequestContext)), you may either request all contents of file at once using get() or request an InputStream with getInputStream() and process the file without attempting to load it into memory, which may come handy with large files. 
Temporary files, which are created for file items, should be
deleted later on.


Since:FileUpload 1.1
/**
 * <p> The default implementation of the
 * {@link org.apache.tomcat.util.http.fileupload.FileItem FileItem} interface.
 *
 * <p> After retrieving an instance of this class from a {@link
 * org.apache.tomcat.util.http.fileupload.FileUpload FileUpload} instance (see
 * {@link org.apache.tomcat.util.http.fileupload.FileUpload
 * #parseRequest(org.apache.tomcat.util.http.fileupload.RequestContext)}), you
 * may either request all contents of file at once using {@link #get()} or
 * request an {@link java.io.InputStream InputStream} with
 * {@link #getInputStream()} and process the file without attempting to load
 * it into memory, which may come handy with large files.
 *
 * <p>Temporary files, which are created for file items, should be
 * deleted later on.</p>
 *
 * @since FileUpload 1.1
 */
public class DiskFileItem
    implements FileItem {

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

    
Default content charset to be used when no explicit charset
parameter is provided by the sender. Media subtypes of the
"text" type are defined to have a default charset value of
"ISO-8859-1" when received via HTTP.

/**
     * Default content charset to be used when no explicit charset
     * parameter is provided by the sender. Media subtypes of the
     * "text" type are defined to have a default charset value of
     * "ISO-8859-1" when received via HTTP.
     */
    public static final String DEFAULT_CHARSET = "ISO-8859-1";

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

    
UID used in unique file name generation.

/**
     * UID used in unique file name generation.
     */
    private static final String UID =
            UUID.randomUUID().toString().replace('-', '_');

    
Counter used in unique identifier generation.

/**
     * Counter used in unique identifier generation.
     */
    private static final AtomicInteger COUNTER = new AtomicInteger(0);

    
The name of the form field as provided by the browser.

/**
     * The name of the form field as provided by the browser.
     */
    private String fieldName;

    
The content type passed by the browser, or null if not defined. 
/**
     * The content type passed by the browser, or {@code null} if
     * not defined.
     */
    private final String contentType;

    
Whether or not this item is a simple form field.

/**
     * Whether or not this item is a simple form field.
     */
    private boolean isFormField;

    
The original file name in the user's file system.

/**
     * The original file name in the user's file system.
     */
    private final String fileName;

    
The size of the item, in bytes. This is used to cache the size when a
file item is moved from its original location.

/**
     * The size of the item, in bytes. This is used to cache the size when a
     * file item is moved from its original location.
     */
    private long size = -1;


    
The threshold above which uploads will be stored on disk.

/**
     * The threshold above which uploads will be stored on disk.
     */
    private final int sizeThreshold;

    
The directory in which uploaded files will be stored, if stored on disk.

/**
     * The directory in which uploaded files will be stored, if stored on disk.
     */
    private final File repository;

    
Cached contents of the file.

/**
     * Cached contents of the file.
     */
    private byte[] cachedContent;

    
Output stream for this item.

/**
     * Output stream for this item.
     */
    private transient DeferredFileOutputStream dfos;

    
The temporary file to use.

/**
     * The temporary file to use.
     */
    private transient File tempFile;

    
The file items headers.

/**
     * The file items headers.
     */
    private FileItemHeaders headers;

    
Default content charset to be used when no explicit charset
parameter is provided by the sender.

/**
     * Default content charset to be used when no explicit charset
     * parameter is provided by the sender.
     */
    private String defaultCharset = DEFAULT_CHARSET;

    // ----------------------------------------------------------- Constructors

    
Constructs a new DiskFileItem instance. 
Params:
  • fieldName –     The name of the form field.
  • contentType –  The content type passed by the browser or null if not specified.
  • isFormField –   Whether or not this item is a plain form field, as
                     opposed to a file upload.
  • fileName –  The original file name in the user's file system, or null if not specified.
  • sizeThreshold – The threshold, in bytes, below which items will be
                     retained in memory and above which they will be
                     stored as a file.
  • repository –    The data repository, which is the directory in
                     which files will be created, should the item size
                     exceed the threshold.
/**
     * Constructs a new {@code DiskFileItem} instance.
     *
     * @param fieldName     The name of the form field.
     * @param contentType   The content type passed by the browser or
     *                      {@code null} if not specified.
     * @param isFormField   Whether or not this item is a plain form field, as
     *                      opposed to a file upload.
     * @param fileName      The original file name in the user's file system, or
     *                      {@code null} if not specified.
     * @param sizeThreshold The threshold, in bytes, below which items will be
     *                      retained in memory and above which they will be
     *                      stored as a file.
     * @param repository    The data repository, which is the directory in
     *                      which files will be created, should the item size
     *                      exceed the threshold.
     */
    public DiskFileItem(String fieldName,
            String contentType, boolean isFormField, String fileName,
            int sizeThreshold, File repository) {
        this.fieldName = fieldName;
        this.contentType = contentType;
        this.isFormField = isFormField;
        this.fileName = fileName;
        this.sizeThreshold = sizeThreshold;
        this.repository = repository;
    }

    // ------------------------------- Methods from javax.activation.DataSource

    
Returns an InputStream that can be used to retrieve the contents of the file. 
Throws:
Returns:An InputStream that can be used to retrieve the contents of the file.
/**
     * Returns an {@link java.io.InputStream InputStream} that can be
     * used to retrieve the contents of the file.
     *
     * @return An {@link java.io.InputStream InputStream} that can be
     *         used to retrieve the contents of the file.
     *
     * @throws IOException if an error occurs.
     */
    @Override
    public InputStream getInputStream()
        throws IOException {
        if (!isInMemory()) {
            return new FileInputStream(dfos.getFile());
        }

        if (cachedContent == null) {
            cachedContent = dfos.getData();
        }
        return new ByteArrayInputStream(cachedContent);
    }

    
Returns the content type passed by the agent or null if not defined. 
Returns:The content type passed by the agent or null if not defined.
/**
     * Returns the content type passed by the agent or {@code null} if
     * not defined.
     *
     * @return The content type passed by the agent or {@code null} if
     *         not defined.
     */
    @Override
    public String getContentType() {
        return contentType;
    }

    
Returns the content charset passed by the agent or null if not defined. 
Returns:The content charset passed by the agent or null if not defined.
/**
     * Returns the content charset passed by the agent or {@code null} if
     * not defined.
     *
     * @return The content charset passed by the agent or {@code null} if
     *         not defined.
     */
    public String getCharSet() {
        ParameterParser parser = new ParameterParser();
        parser.setLowerCaseNames(true);
        // Parameter parser can handle null input
        Map<String, String> params = parser.parse(getContentType(), ';');
        return params.get("charset");
    }

    
Returns the original file name in the client's file system.

Throws:
Returns:The original file name in the client's file system.
/**
     * Returns the original file name in the client's file system.
     *
     * @return The original file name in the client's file system.
     * @throws org.apache.tomcat.util.http.fileupload.InvalidFileNameException
     *   The file name contains a NUL character, which might be an indicator of
     *   a security attack. If you intend to use the file name anyways, catch
     *   the exception and use {@link
     *   org.apache.tomcat.util.http.fileupload.InvalidFileNameException#getName()}.
     */
    @Override
    public String getName() {
        return Streams.checkFileName(fileName);
    }

    // ------------------------------------------------------- FileItem methods

    
Provides a hint as to whether or not the file contents will be read
from memory.

Returns:true if the file contents will be read from memory; false otherwise.
/**
     * Provides a hint as to whether or not the file contents will be read
     * from memory.
     *
     * @return {@code true} if the file contents will be read
     *         from memory; {@code false} otherwise.
     */
    @Override
    public boolean isInMemory() {
        if (cachedContent != null) {
            return true;
        }
        return dfos.isInMemory();
    }

    
Returns the size of the file.

Returns:The size of the file, in bytes.
/**
     * Returns the size of the file.
     *
     * @return The size of the file, in bytes.
     */
    @Override
    public long getSize() {
        if (size >= 0) {
            return size;
        } else if (cachedContent != null) {
            return cachedContent.length;
        } else if (dfos.isInMemory()) {
            return dfos.getData().length;
        } else {
            return dfos.getFile().length();
        }
    }

    
Returns the contents of the file as an array of bytes.  If the
contents of the file were not yet cached in memory, they will be
loaded from the disk storage and cached.

Returns:The contents of the file as an array of bytes or null if the data cannot be read
/**
     * Returns the contents of the file as an array of bytes.  If the
     * contents of the file were not yet cached in memory, they will be
     * loaded from the disk storage and cached.
     *
     * @return The contents of the file as an array of bytes
     * or {@code null} if the data cannot be read
     */
    @Override
    public byte[] get() {
        if (isInMemory()) {
            if (cachedContent == null && dfos != null) {
                cachedContent = dfos.getData();
            }
            return cachedContent;
        }

        byte[] fileData = new byte[(int) getSize()];
        InputStream fis = null;

        try {
            fis = new FileInputStream(dfos.getFile());
            IOUtils.readFully(fis, fileData);
        } catch (IOException e) {
            fileData = null;
        } finally {
            IOUtils.closeQuietly(fis);
        }

        return fileData;
    }

    
Returns the contents of the file as a String, using the specified encoding. This method uses get() to retrieve the contents of the file. 
Params:
  • charset – The charset to use.
Throws:
Returns:The contents of the file, as a string.
/**
     * Returns the contents of the file as a String, using the specified
     * encoding.  This method uses {@link #get()} to retrieve the
     * contents of the file.
     *
     * @param charset The charset to use.
     *
     * @return The contents of the file, as a string.
     *
     * @throws UnsupportedEncodingException if the requested character
     *                                      encoding is not available.
     */
    @Override
    public String getString(final String charset)
        throws UnsupportedEncodingException {
        return new String(get(), charset);
    }

    
Returns the contents of the file as a String, using the default character encoding. This method uses get() to retrieve the contents of the file. TODO Consider making this method throw UnsupportedEncodingException.

Returns:The contents of the file, as a string.
/**
     * Returns the contents of the file as a String, using the default
     * character encoding.  This method uses {@link #get()} to retrieve the
     * contents of the file.
     *
     * <b>TODO</b> Consider making this method throw UnsupportedEncodingException.
     *
     * @return The contents of the file, as a string.
     */
    @Override
    public String getString() {
        byte[] rawdata = get();
        String charset = getCharSet();
        if (charset == null) {
            charset = defaultCharset;
        }
        try {
            return new String(rawdata, charset);
        } catch (UnsupportedEncodingException e) {
            return new String(rawdata);
        }
    }

    
A convenience method to write an uploaded item to disk. The client code
is not concerned with whether or not the item is stored in memory, or on
disk in a temporary location. They just want to write the uploaded item
to a file.


This implementation first attempts to rename the uploaded item to the
specified destination file, if the item was originally written to disk.
Otherwise, the data will be copied to the specified file.


This method is only guaranteed to work once, the first time it
is invoked for a particular item. This is because, in the event that the
method renames a temporary file, that file will no longer be available
to copy or rename again at a later time.

Params:
  • file – The File into which the uploaded item should be stored.
Throws:
/**
     * A convenience method to write an uploaded item to disk. The client code
     * is not concerned with whether or not the item is stored in memory, or on
     * disk in a temporary location. They just want to write the uploaded item
     * to a file.
     * <p>
     * This implementation first attempts to rename the uploaded item to the
     * specified destination file, if the item was originally written to disk.
     * Otherwise, the data will be copied to the specified file.
     * <p>
     * This method is only guaranteed to work <em>once</em>, the first time it
     * is invoked for a particular item. This is because, in the event that the
     * method renames a temporary file, that file will no longer be available
     * to copy or rename again at a later time.
     *
     * @param file The {@code File} into which the uploaded item should
     *             be stored.
     *
     * @throws Exception if an error occurs.
     */
    @Override
    public void write(File file) throws Exception {
        if (isInMemory()) {
            FileOutputStream fout = null;
            try {
                fout = new FileOutputStream(file);
                fout.write(get());
                fout.close();
            } finally {
                IOUtils.closeQuietly(fout);
            }
        } else {
            File outputFile = getStoreLocation();
            if (outputFile != null) {
                // Save the length of the file
                size = outputFile.length();
                /*
                 * The uploaded file is being stored on disk
                 * in a temporary location so move it to the
                 * desired file.
                 */
                if (file.exists()) {
                    if (!file.delete()) {
                        throw new FileUploadException(
                                "Cannot write uploaded file to disk!");
                    }
                }
                if (!outputFile.renameTo(file)) {
                    BufferedInputStream in = null;
                    BufferedOutputStream out = null;
                    try {
                        in = new BufferedInputStream(
                            new FileInputStream(outputFile));
                        out = new BufferedOutputStream(
                                new FileOutputStream(file));
                        IOUtils.copy(in, out);
                        out.close();
                    } finally {
                        IOUtils.closeQuietly(in);
                        IOUtils.closeQuietly(out);
                    }
                }
            } else {
                /*
                 * For whatever reason we cannot write the
                 * file to disk.
                 */
                throw new FileUploadException(
                    "Cannot write uploaded file to disk!");
            }
        }
    }

    
Deletes the underlying storage for a file item, including deleting any associated temporary disk file. Although this storage will be deleted automatically when the FileItem instance is garbage collected, this method can be used to ensure that this is done at an earlier time, thus preserving system resources. 
/**
     * Deletes the underlying storage for a file item, including deleting any
     * associated temporary disk file. Although this storage will be deleted
     * automatically when the {@code FileItem} instance is garbage
     * collected, this method can be used to ensure that this is done at an
     * earlier time, thus preserving system resources.
     */
    @Override
    public void delete() {
        cachedContent = null;
        File outputFile = getStoreLocation();
        if (outputFile != null && !isInMemory() && outputFile.exists()) {
            outputFile.delete();
        }
    }

    
Returns the name of the field in the multipart form corresponding to
this file item.

See Also:
Returns:The name of the form field.
/**
     * Returns the name of the field in the multipart form corresponding to
     * this file item.
     *
     * @return The name of the form field.
     *
     * @see #setFieldName(java.lang.String)
     *
     */
    @Override
    public String getFieldName() {
        return fieldName;
    }

    
Sets the field name used to reference this file item.

Params:
  • fieldName – The name of the form field.
See Also:
/**
     * Sets the field name used to reference this file item.
     *
     * @param fieldName The name of the form field.
     *
     * @see #getFieldName()
     *
     */
    @Override
    public void setFieldName(String fieldName) {
        this.fieldName = fieldName;
    }

    
Determines whether or not a FileItem instance represents a simple form field. 
See Also:
Returns:true if the instance represents a simple form field; false if it represents an uploaded file.
/**
     * Determines whether or not a {@code FileItem} instance represents
     * a simple form field.
     *
     * @return {@code true} if the instance represents a simple form
     *         field; {@code false} if it represents an uploaded file.
     *
     * @see #setFormField(boolean)
     *
     */
    @Override
    public boolean isFormField() {
        return isFormField;
    }

    
Specifies whether or not a FileItem instance represents a simple form field. 
Params:
  • state – true if the instance represents a simple form field; false if it represents an uploaded file.
See Also:
/**
     * Specifies whether or not a {@code FileItem} instance represents
     * a simple form field.
     *
     * @param state {@code true} if the instance represents a simple form
     *              field; {@code false} if it represents an uploaded file.
     *
     * @see #isFormField()
     *
     */
    @Override
    public void setFormField(boolean state) {
        isFormField = state;
    }

    
Returns an OutputStream that can be used for storing the contents of the file. 
Throws:
Returns:An OutputStream that can be used for storing the contents of the file.
/**
     * Returns an {@link java.io.OutputStream OutputStream} that can
     * be used for storing the contents of the file.
     *
     * @return An {@link java.io.OutputStream OutputStream} that can be used
     *         for storing the contents of the file.
     *
     * @throws IOException if an error occurs.
     */
    @Override
    public OutputStream getOutputStream()
        throws IOException {
        if (dfos == null) {
            File outputFile = getTempFile();
            dfos = new DeferredFileOutputStream(sizeThreshold, outputFile);
        }
        return dfos;
    }

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

    
Returns the File object for the FileItem's data's temporary location on the disk. Note that for FileItems that have their data stored in memory, this method will return null. When handling large files, you can use File.renameTo(File) to move the file to new location without copying the data, if the source and destination locations reside within the same logical volume. 
Returns:The data file, or null if the data is stored in memory.
/**
     * Returns the {@link java.io.File} object for the {@code FileItem}'s
     * data's temporary location on the disk. Note that for
     * {@code FileItem}s that have their data stored in memory,
     * this method will return {@code null}. When handling large
     * files, you can use {@link java.io.File#renameTo(java.io.File)} to
     * move the file to new location without copying the data, if the
     * source and destination locations reside within the same logical
     * volume.
     *
     * @return The data file, or {@code null} if the data is stored in
     *         memory.
     */
    public File getStoreLocation() {
        if (dfos == null) {
            return null;
        }
        if (isInMemory()) {
            return null;
        }
        return dfos.getFile();
    }

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

    
Removes the file contents from the temporary storage.

/**
     * Removes the file contents from the temporary storage.
     */
    @Override
    protected void finalize() throws Throwable {
        if (dfos == null || dfos.isInMemory()) {
            return;
        }
        File outputFile = dfos.getFile();

        if (outputFile != null && outputFile.exists()) {
            outputFile.delete();
        }
        super.finalize();
    }

    
Creates and returns a File representing a uniquely named temporary file in the configured repository path. The lifetime of the file is tied to the lifetime of the FileItem instance; the file will be deleted when the instance is garbage collected. 

Note: Subclasses that override this method must ensure that they return the
same File each time.

Returns:The File to be used for temporary storage.
/**
     * Creates and returns a {@link java.io.File File} representing a uniquely
     * named temporary file in the configured repository path. The lifetime of
     * the file is tied to the lifetime of the {@code FileItem} instance;
     * the file will be deleted when the instance is garbage collected.
     * <p>
     * <b>Note: Subclasses that override this method must ensure that they return the
     * same File each time.</b>
     *
     * @return The {@link java.io.File File} to be used for temporary storage.
     */
    protected File getTempFile() {
        if (tempFile == null) {
            File tempDir = repository;
            if (tempDir == null) {
                tempDir = new File(System.getProperty("java.io.tmpdir"));
            }

            String tempFileName = String.format("upload_%s_%s.tmp", UID, getUniqueId());

            tempFile = new File(tempDir, tempFileName);
        }
        return tempFile;
    }

    // -------------------------------------------------------- Private methods

    
Returns an identifier that is unique within the class loader used to
load this class, but does not have random-like appearance.

Returns:A String with the non-random looking instance identifier.
/**
     * Returns an identifier that is unique within the class loader used to
     * load this class, but does not have random-like appearance.
     *
     * @return A String with the non-random looking instance identifier.
     */
    private static String getUniqueId() {
        final int limit = 100000000;
        int current = COUNTER.getAndIncrement();
        String id = Integer.toString(current);

        // If you manage to get more than 100 million of ids, you'll
        // start getting ids longer than 8 characters.
        if (current < limit) {
            id = ("00000000" + id).substring(id.length());
        }
        return id;
    }

    
Returns a string representation of this object.

Returns:a string representation of this object.
/**
     * Returns a string representation of this object.
     *
     * @return a string representation of this object.
     */
    @Override
    public String toString() {
        return String.format("name=%s, StoreLocation=%s, size=%s bytes, isFormField=%s, FieldName=%s",
                      getName(), getStoreLocation(), Long.valueOf(getSize()),
                      Boolean.valueOf(isFormField()), getFieldName());
    }

    
Returns the file item headers.

Returns:The file items headers.
/**
     * Returns the file item headers.
     * @return The file items headers.
     */
    @Override
    public FileItemHeaders getHeaders() {
        return headers;
    }

    
Sets the file item headers.

Params:
  • pHeaders – The file items headers.
/**
     * Sets the file item headers.
     * @param pHeaders The file items headers.
     */
    @Override
    public void setHeaders(FileItemHeaders pHeaders) {
        headers = pHeaders;
    }

    
Returns the default charset for use when no explicit charset
parameter is provided by the sender.

Returns:the default charset
/**
     * Returns the default charset for use when no explicit charset
     * parameter is provided by the sender.
     * @return the default charset
     */
    public String getDefaultCharset() {
        return defaultCharset;
    }

    
Sets the default charset for use when no explicit charset
parameter is provided by the sender.

Params:
  • charset – the default charset
/**
     * Sets the default charset for use when no explicit charset
     * parameter is provided by the sender.
     * @param charset the default charset
     */
    public void setDefaultCharset(String charset) {
        defaultCharset = charset;
    }
}