/*---------------------------------------------------------------------------*\
$Id: 2cb90d317083e277d466de421b660d5e3b225c88 $
---------------------------------------------------------------------------
This software is released under a BSD-style license:
Copyright (c) 2004-2007 Brian M. Clapper. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. The end-user documentation included with the redistribution, if any,
must include the following acknowlegement:
"This product includes software developed by Brian M. Clapper
(bmc@clapper.org, http://www.clapper.org/bmc/). That software is
copyright (c) 2004-2007 Brian M. Clapper."
Alternately, this acknowlegement may appear in the software itself,
if wherever such third-party acknowlegements normally appear.
3. Neither the names "clapper.org", "clapper.org Java Utility Library",
nor any of the names of the project contributors may be used to
endorse or promote products derived from this software without prior
written permission. For written permission, please contact
bmc@clapper.org.
4. Products derived from this software may not be called "clapper.org
Java Utility Library", nor may "clapper.org" appear in their names
without prior written permission of Brian M. Clapper.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
NO EVENT SHALL BRIAN M. CLAPPER BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\*---------------------------------------------------------------------------*/
package org.clapper.util.misc;
import org.clapper.util.io.FileUtil;
import org.clapper.util.logging.Logger;
import org.clapper.util.text.TextUtil;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;
import java.net.URLConnection;
import java.net.FileNameMap;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
/**
* The <tt>MIMETypeUtil</tt> class provides some general purpose MIME type
* utilities not found in the JDK. Among other methods, this class provides the
* {@link #fileExtensionForMIMEType fileExtensionForMIMEType()}
* method, which converts a MIME type to a file extension. That method uses
* a traditional <tt>mime.types</tt> files, similar to the file shipped
* with with web servers such as Apache. It looks for a suitable file in
* the following locations:
*
* <ol>
* <li> First, it looks for the file <tt>.mime.types</tt> in the user's
* home directory.
* <li> Next, it looks for <tt>mime.types</tt> (no leading ".") in all the
* directories in the CLASSPATH
* <li> Last, it loads a default set of mappings shipped with this library
* </ol>
*
* <p>It loads all the matching files it finds; the first mapping found for
* a given MIME type is the one that is used. The files are only loaded once
* within a given running Java VM.</p>
*
* <p>The syntax of the file follows the classic <tt>mime.types</tt>
* syntax:</p>
*
* <pre>
* # The format is <mime type> <space separated file extensions>
* # Comments begin with a '#'
*
* text/plain txt text TXT
* text/html html htm HTML HTM
* ...
* </pre>
*
* <p>When mapping a MIME type to an extension,
* {@link #fileExtensionForMIMEType fileExtensionForMIMEType()}
* uses the first extension it finds in the <tt>mime.types</tt> file.
* MIME types that cannot be found in the file are mapped to extension
* ".dat".</p>
*
* @version <tt>$Revision$</tt>
*
* @author Copyright © 2004-2007 Brian M. Clapper
*/
public class MIMETypeUtil
{
/*----------------------------------------------------------------------*\
Public Constants
\*----------------------------------------------------------------------*/
/**
* Default MIME type, when a MIME type cannot be determined from a file's
* extension.
*
* @see #MIMETypeForFile
* @see #MIMETypeForFileName
*/
public static final String DEFAULT_MIME_TYPE = "application/octet-stream";
/*----------------------------------------------------------------------*\
Private Constants
\*----------------------------------------------------------------------*/
/**
* Resource bundle containing MIME type mappings
*/
private static final String MIME_MAPPINGS_BUNDLE =
"org.clapper.util.misc.MIMETypes";
/*----------------------------------------------------------------------*\
Instance Data
\*----------------------------------------------------------------------*/
/**
* Table for converting MIME type strings to file extensions. The table
* is initialized the first time fileExtensionForMIMEType() is
* called.
*/
private static Map<String, String> mimeTypeToExtensionMap = null;
/**
* Reverse lookup table, by extension.
*/
private static Map<String, String> extensionToMIMETypeMap = null;
/**
* For issuing log messages
*/
private static final Logger log = new Logger (MIMETypeUtil.class);
/*----------------------------------------------------------------------*\
Constructor
\*----------------------------------------------------------------------*/
private MIMETypeUtil()
{
// Can't be instantiated
}
/*----------------------------------------------------------------------*\
Public Methods
\*----------------------------------------------------------------------*/
/**
* Get an appropriate extension for a MIME type.
*
* @param mimeType the String MIME type
*
* @return the appropriate file name extension, or a default extension
* if not found. The extension will not have the leading "."
* character.
*/
public static String fileExtensionForMIMEType (String mimeType)
{
loadMappings();
String ext = (String) mimeTypeToExtensionMap.get (mimeType);
if (ext == null)
ext = "dat";
return ext;
}
/**
* Get the MIME type for a filename extension.
*
* @param extension the extension, without the "."
*
* @return the MIME type, or a default MIME type if there's no mapping
* for the extension
*
* @see #MIMETypeForFileExtension(String,String)
* @see #MIMETypeForFile(File)
* @see #MIMETypeForFile(File,String)
* @see #MIMETypeForFileName(String)
* @see #MIMETypeForFileName(String,String)
*/
public static String MIMETypeForFileExtension (String extension) // NOPMD
{
return MIMETypeForFileExtension (extension, DEFAULT_MIME_TYPE);
}
/**
* Get the MIME type for a filename extension.
*
* @param extension the extension, without the "."
* @param defaultMIMEType the default MIME type to use if one cannot
* be determined from the extension, or null to
* use {@link #DEFAULT_MIME_TYPE}
*
* @return the MIME type, or the default MIME type
*
* @see #MIMETypeForFileExtension(String)
* @see #MIMETypeForFile(File)
* @see #MIMETypeForFile(File,String)
* @see #MIMETypeForFileName(String)
* @see #MIMETypeForFileName(String,String)
*/
public static String MIMETypeForFileExtension (String extension, // NOPMD
String defaultMIMEType)
{
return MIMETypeForFileName ("test." + extension, defaultMIMEType);
}
/**
* Get the MIME type for a file. This method is simply a convenient
* front-end for <tt>java.net.FileNameMap.getContentTypeFor()</tt>,
* but it applies a consistent default when <tt>getContentTypeFor()</tt>
* returns null (which can happen).
*
* @param file the file
*
* @return the MIME type to use
*
* @see #MIMETypeForFile(File,String)
* @see #MIMETypeForFileName(String)
* @see #MIMETypeForFileExtension(String)
* @see #MIMETypeForFileExtension(String,String)
* @see #DEFAULT_MIME_TYPE
*/
public static String MIMETypeForFile (File file) // NOPMD
{
return MIMETypeForFileName (file.getName(), DEFAULT_MIME_TYPE);
}
/**
* Get the MIME type for a file. This method is simply a convenient
* front-end for <tt>java.net.FileNameMap.getContentTypeFor()</tt>,
* but it applies the supplied default when <tt>getContentTypeFor()</tt>
* returns null (which can happen).
*
* @param file the file
* @param defaultMIMEType the default MIME type to use if one cannot
* be determined from the file's name, or null to
* use {@link #DEFAULT_MIME_TYPE}
*
* @return the MIME type to use
*
* @see #MIMETypeForFile(File)
* @see #MIMETypeForFileName(String,String)
* @see #MIMETypeForFileExtension(String)
* @see #MIMETypeForFileExtension(String,String)
* @see #DEFAULT_MIME_TYPE
*/
public static String MIMETypeForFile (File file, // NOPMD
String defaultMIMEType)
{
return MIMETypeForFileName (file.getName(), defaultMIMEType);
}
/**
* Get the MIME type for a name file. This method is simply a convenient
* front-end for <tt>java.net.FileNameMap.getContentTypeFor()</tt>,
* but it applies a consistent default when <tt>getContentTypeFor()</tt>
* returns null (which can happen).
*
* @param fileName the file name
*
* @return the MIME type to use
*
* @see #MIMETypeForFile(File)
* @see #MIMETypeForFileName(String,String)
* @see #DEFAULT_MIME_TYPE
*/
public static String MIMETypeForFileName (String fileName) // NOPMD
{
return MIMETypeForFileName (fileName, DEFAULT_MIME_TYPE);
}
/**
* Get the MIME type for a file name. This method is simply a convenient
* front-end for <tt>java.net.FileNameMap.getContentTypeFor()</tt>,
* but it applies the supplied default when <tt>getContentTypeFor()</tt>
* returns null (which can happen).
*
* @param fileName the file name
* @param defaultMIMEType the default MIME type to use if one cannot
* be determined from the file name, or null to
* use {@link #DEFAULT_MIME_TYPE}
*
* @return the MIME type to use
*
* @see #MIMETypeForFile(File,String)
* @see #MIMETypeForFileName(String)
* @see #MIMETypeForFileExtension(String)
* @see #MIMETypeForFileExtension(String,String)
* @see #DEFAULT_MIME_TYPE
*/
public static String MIMETypeForFileName (String fileName, // NOPMD
String defaultMIMEType)
{
String mimeType = null;
FileNameMap fileNameMap = URLConnection.getFileNameMap();
// Check ours first.
loadMappings();
String extension = FileUtil.getFileNameExtension (fileName);
mimeType = (String) extensionToMIMETypeMap.get (extension);
if (mimeType == null)
{
// Check the system one.
mimeType = fileNameMap.getContentTypeFor (fileName);
}
if (mimeType != null)
{
if (mimeType.equals (DEFAULT_MIME_TYPE) &&
(defaultMIMEType != null))
{
// Substitute the caller's default, if there is one, on the
// assumption that it'll be more useful.
mimeType = defaultMIMEType;
}
}
else
{
mimeType = (defaultMIMEType == null) ? DEFAULT_MIME_TYPE
: defaultMIMEType;
}
return mimeType;
}
/**
* <p>This method parses an HTTP-style "<tt>Content-type</tt>" header into
* its constituent pieces. The HTTP specification (RFC 2616) defines
* the <tt>Content-type</tt> header as:</p>
*
* <blockquote><pre>"Content-type" ":" <media-type></pre></blockquote>
*
* <p>A <i>media-type</i> is a MIME type ("type/subtype"), with optional
* name=value pair parameters. The parameters are separated from the
* media type, and from each other, by ";" characters.</p>
*
* <p>A common example of a <tt>Content-type</tt> header is:</p>
*
* <blockquote><pre>Content-type: text/html; charset=ISO-8859-1</pre>
* </blockquote>
*
* <p>This method parses apart the MIME type and the parameters, saving
* each one separately in caller-supplied objects.</p>
*
* @param contentTypeHeader the header value (without the
* <tt>Content-type:</tt> prefix). This value
* is what's typically returned by
* <tt>URLConnection.getContentType()</tt>.
* @param mimeType a <tt>StringBuffer</tt> to receive the
* MIME type, or null if you don't care about
* the MIME type. This method clears the string
* buffer before storing anything in it.
* @param parameters a <tt>Map</tt> to receive the parameters,
* or null if you don't care about the
* parameters. The parameter names are used
* as the map's keys. This method clears the
* map before storing anything in it.
*/
public static void parseContentTypeHeader (String contentTypeHeader,
StringBuffer mimeType,
Map<String, String> parameters)
{
// ContentType header is required, and either the MIME type or the
// parameters (or both) must be set. Otherwise, we do nothing.
if ( ((mimeType != null) || (parameters != null))
&&
(! TextUtil.stringIsEmpty (contentTypeHeader)) )
{
if (mimeType == null)
mimeType = new StringBuffer();
if (parameters == null)
parameters = new HashMap<String, String>();
String[] tokens = TextUtil.split(contentTypeHeader, " ;");
mimeType.setLength(0);
mimeType.append(tokens[0]);
parameters.clear();
for (int i = 1; i < tokens.length; i++)
{
String[] nv = TextUtil.split(tokens[i], "=");
parameters.put(nv[0], (nv.length == 1) ? "" : nv[1]);
}
}
}
/*----------------------------------------------------------------------*\
Private Methods
\*----------------------------------------------------------------------*/
/**
* Load the MIME type mappings into memory.
*/
private static synchronized void loadMappings()
{
if (mimeTypeToExtensionMap != null)
return;
mimeTypeToExtensionMap = new HashMap<String, String>();
extensionToMIMETypeMap = new HashMap<String, String>();
// First, check the user's home directory.
String fileSep = System.getProperty ("file.separator");
StringBuffer buf = new StringBuffer();
buf.append (System.getProperty ("user.home"));
buf.append (fileSep);
buf.append (".mime.types");
loadMIMETypesFile (buf.toString());
// Now, check every directory in the classpath.
String pathSep = System.getProperty ("path.separator");
String classPath = System.getProperty ("java.class.path");
String[] pathComponents = TextUtil.split (classPath, pathSep);
int i;
for (i = 0; i < pathComponents.length; i++)
{
buf.setLength (0);
buf.append (pathComponents[i]);
buf.append (fileSep);
buf.append ("mime.types");
loadMIMETypesFile (buf.toString());
}
// Finally, load the resource bundle.
ResourceBundle bundle = ResourceBundle.getBundle(MIME_MAPPINGS_BUNDLE);
for (Enumeration e = bundle.getKeys(); e.hasMoreElements(); )
{
String type = (String) e.nextElement();
try
{
String[] extensions = TextUtil.split (bundle.getString (type));
if (mimeTypeToExtensionMap.get (type) == null)
{
log.debug ("Internal: " + type + " -> \"" + extensions[0] +
"\"");
mimeTypeToExtensionMap.put (type, extensions[0]);
}
for (i = 0; i < extensions.length; i++)
{
if (extensionToMIMETypeMap.get (extensions[i]) == null)
{
log.debug ("Internal: " + "\"" + extensions[i] +
"\" -> " + type);
extensionToMIMETypeMap.put (extensions[i], type);
}
}
}
catch (MissingResourceException ex)
{
log.error ("While reading internal bundle \"" +
MIME_MAPPINGS_BUNDLE +
"\", got unexpected error on key \"" +
type + "\"",
ex);
}
}
}
/**
* Attempt to load a MIME types file. Throws no exceptions.
*
* @param path path to the file
* @param map map to load
*/
private static void loadMIMETypesFile (String path)
{
try
{
File f = new File (path);
log.debug ("Attempting to load MIME types file \"" + path + "\"");
if (! (f.exists() && f.isFile()))
log.debug ("Regular file \"" + path + "\" does not exist.");
else
{
LineNumberReader r = new LineNumberReader (new FileReader (f));
String line;
while ((line = r.readLine()) != null)
{
line = line.trim();
if ((line.length() == 0) || (line.startsWith ("#")))
continue;
String[] fields = TextUtil.split (line);
// Skip lines without at least two tokens.
if (fields.length < 2)
continue;
// Special case: Scan the extensions, and make sure we
// have at least one valid extension. Some .mime.types
// files have entries like this:
//
// mime/type desc="xxx" exts="jnlp"
//
// We don't handle those.
List<String> extensions = new ArrayList<String>();
for (int i = 1; i < fields.length; i++)
{
if (fields[i].indexOf ('=') != -1)
continue;
if (fields[i].indexOf ('"') != -1)
continue;
// Treat as valid. Remove any leading "."
if (fields[i].startsWith ("."))
{
if (fields[i].length() == 1)
continue;
fields[i] = fields[i].substring (1);
}
extensions.add (fields[i]);
}
if (extensions.size() == 0)
continue;
// If the MIME type doesn't have a "/", skip it
String mimeType = fields[0];
String extension;
if (mimeType.indexOf ('/') == -1)
continue;
// The first field is the preferred extension. Keep any
// existing mapping for the MIME type.
if (mimeTypeToExtensionMap.get (mimeType) == null)
{
extension = (String) extensions.get (0);
log.debug ("File \"" + path + "\": " + mimeType +
" -> \"" + extension + "\"");
mimeTypeToExtensionMap.put (mimeType, extension);
}
// Map the extensions back to the MIME type
for (Iterator it = extensions.iterator(); it.hasNext(); )
{
extension = (String) it.next();
if (extensionToMIMETypeMap.get (extension) == null)
{
log.debug ("File \"" + path + "\": \"" +
extension + "\" -> " + mimeType);
extensionToMIMETypeMap.put (extension, mimeType);
}
}
}
r.close();
}
}
catch (IOException ex)
{
log.debug ("Error reading \"" + path + "\"", ex);
}
}
}