Mega Code Archive
A utility class, which provides some MIME related application logic
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/****************************************************************
* 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. *
****************************************************************/
import java.text.DateFormat;
import java.text.FieldPosition;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.Random;
import java.util.TimeZone;
/**
* A utility class, which provides some MIME related application logic.
*/
public final class MimeUtil {
/**
* The <code>quoted-printable</code> encoding.
*/
public static final String ENC_QUOTED_PRINTABLE = "quoted-printable";
/**
* The <code>binary</code> encoding.
*/
public static final String ENC_BINARY = "binary";
/**
* The <code>base64</code> encoding.
*/
public static final String ENC_BASE64 = "base64";
/**
* The <code>8bit</code> encoding.
*/
public static final String ENC_8BIT = "8bit";
/**
* The <code>7bit</code> encoding.
*/
public static final String ENC_7BIT = "7bit";
/** <code>MIME-Version</code> header name (lowercase) */
public static final String MIME_HEADER_MIME_VERSION = "mime-version";
/** <code>Content-ID</code> header name (lowercase) */
public static final String MIME_HEADER_CONTENT_ID = "content-id";
/** <code>Content-Description</code> header name (lowercase) */
public static final String MIME_HEADER_CONTENT_DESCRIPTION = "content-description";
/**
* <code>Content-Disposition</code> header name (lowercase).
* See <a href='http://www.faqs.org/rfcs/rfc2183.html'>RFC2183</a>.
*/
public static final String MIME_HEADER_CONTENT_DISPOSITION = "content-disposition";
/**
* <code>Content-Disposition</code> filename parameter (lowercase).
* See <a href='http://www.faqs.org/rfcs/rfc2183.html'>RFC2183</a>.
*/
public static final String PARAM_FILENAME = "filename";
/**
* <code>Content-Disposition</code> modification-date parameter (lowercase).
* See <a href='http://www.faqs.org/rfcs/rfc2183.html'>RFC2183</a>.
*/
public static final String PARAM_MODIFICATION_DATE = "modification-date";
/**
* <code>Content-Disposition</code> creation-date parameter (lowercase).
* See <a href='http://www.faqs.org/rfcs/rfc2183.html'>RFC2183</a>.
*/
public static final String PARAM_CREATION_DATE = "creation-date";
/**
* <code>Content-Disposition</code> read-date parameter (lowercase).
* See <a href='http://www.faqs.org/rfcs/rfc2183.html'>RFC2183</a>.
*/
public static final String PARAM_READ_DATE = "read-date";
/**
* <code>Content-Disposition</code> size parameter (lowercase).
* See <a href='http://www.faqs.org/rfcs/rfc2183.html'>RFC2183</a>.
*/
public static final String PARAM_SIZE = "size";
/**
* <code>Content-Langauge</code> header (lower case).
* See <a href='http://www.faqs.org/rfcs/rfc4646.html'>RFC4646</a>.
*/
public static final String MIME_HEADER_LANGAUGE = "content-language";
/**
* <code>Content-Location</code> header (lower case).
* See <a href='http://www.faqs.org/rfcs/rfc2557.html'>RFC2557</a>.
*/
public static final String MIME_HEADER_LOCATION = "content-location";
/**
* <code>Content-MD5</code> header (lower case).
* See <a href='http://www.faqs.org/rfcs/rfc1864.html'>RFC1864</a>.
*/
public static final String MIME_HEADER_MD5 = "content-md5";
// used to create unique ids
private static final Random random = new Random();
// used to create unique ids
private static int counter = 0;
private MimeUtil() {
// this is an utility class to be used statically.
// this constructor protect from instantiation.
}
/**
* Returns, whether the given two MIME types are identical.
*/
public static boolean isSameMimeType(String pType1, String pType2) {
return pType1 != null && pType2 != null && pType1.equalsIgnoreCase(pType2);
}
/**
* Returns true, if the given MIME type is that of a message.
*/
public static boolean isMessage(String pMimeType) {
return pMimeType != null && pMimeType.equalsIgnoreCase("message/rfc822");
}
/**
* Return true, if the given MIME type indicates a multipart entity.
*/
public static boolean isMultipart(String pMimeType) {
return pMimeType != null && pMimeType.toLowerCase().startsWith("multipart/");
}
/**
* Returns, whether the given transfer-encoding is "base64".
*/
public static boolean isBase64Encoding(String pTransferEncoding) {
return ENC_BASE64.equalsIgnoreCase(pTransferEncoding);
}
/**
* Returns, whether the given transfer-encoding is "quoted-printable".
*/
public static boolean isQuotedPrintableEncoded(String pTransferEncoding) {
return ENC_QUOTED_PRINTABLE.equalsIgnoreCase(pTransferEncoding);
}
/**
* <p>Parses a complex field value into a map of key/value pairs. You may
* use this, for example, to parse a definition like
* <pre>
* text/plain; charset=UTF-8; boundary=foobar
* </pre>
* The above example would return a map with the keys "", "charset",
* and "boundary", and the values "text/plain", "UTF-8", and "foobar".
* </p><p>
* Header value will be unfolded and excess white space trimmed.
* </p>
* @param pValue The field value to parse.
* @return The result map; use the key "" to retrieve the first value.
*/
@SuppressWarnings("fallthrough")
public static Map<String, String> getHeaderParams(String pValue) {
pValue = pValue.trim();
pValue = unfold(pValue);
Map<String, String> result = new HashMap<String, String>();
// split main value and parameters
String main;
String rest;
if (pValue.indexOf(";") == -1) {
main = pValue;
rest = null;
} else {
main = pValue.substring(0, pValue.indexOf(";"));
rest = pValue.substring(main.length() + 1);
}
result.put("", main);
if (rest != null) {
char[] chars = rest.toCharArray();
StringBuilder paramName = new StringBuilder(64);
StringBuilder paramValue = new StringBuilder(64);
final byte READY_FOR_NAME = 0;
final byte IN_NAME = 1;
final byte READY_FOR_VALUE = 2;
final byte IN_VALUE = 3;
final byte IN_QUOTED_VALUE = 4;
final byte VALUE_DONE = 5;
final byte ERROR = 99;
byte state = READY_FOR_NAME;
boolean escaped = false;
for (char c : chars) {
switch (state) {
case ERROR:
if (c == ';')
state = READY_FOR_NAME;
break;
case READY_FOR_NAME:
if (c == '=') {
state = ERROR;
break;
}
paramName.setLength(0);
paramValue.setLength(0);
state = IN_NAME;
// fall-through
case IN_NAME:
if (c == '=') {
if (paramName.length() == 0)
state = ERROR;
else
state = READY_FOR_VALUE;
break;
}
// not '='... just add to name
paramName.append(c);
break;
case READY_FOR_VALUE:
boolean fallThrough = false;
switch (c) {
case ' ':
case '\t':
break; // ignore spaces, especially before '"'
case '"':
state = IN_QUOTED_VALUE;
break;
default:
state = IN_VALUE;
fallThrough = true;
break;
}
if (!fallThrough)
break;
// fall-through
case IN_VALUE:
fallThrough = false;
switch (c) {
case ';':
case ' ':
case '\t':
result.put(
paramName.toString().trim().toLowerCase(),
paramValue.toString().trim());
state = VALUE_DONE;
fallThrough = true;
break;
default:
paramValue.append(c);
break;
}
if (!fallThrough)
break;
case VALUE_DONE:
switch (c) {
case ';':
state = READY_FOR_NAME;
break;
case ' ':
case '\t':
break;
default:
state = ERROR;
break;
}
break;
case IN_QUOTED_VALUE:
switch (c) {
case '"':
if (!escaped) {
// don't trim quoted strings; the spaces could be intentional.
result.put(
paramName.toString().trim().toLowerCase(),
paramValue.toString());
state = VALUE_DONE;
} else {
escaped = false;
paramValue.append(c);
}
break;
case '\\':
if (escaped) {
paramValue.append('\\');
}
escaped = !escaped;
break;
default:
if (escaped) {
paramValue.append('\\');
}
escaped = false;
paramValue.append(c);
break;
}
break;
}
}
// done looping. check if anything is left over.
if (state == IN_VALUE) {
result.put(
paramName.toString().trim().toLowerCase(),
paramValue.toString().trim());
}
}
return result;
}
/**
* Creates a new unique message boundary string that can be used as boundary
* parameter for the Content-Type header field of a message.
*
* @return a new unique message boundary string.
*/
public static String createUniqueBoundary() {
StringBuilder sb = new StringBuilder();
sb.append("-=Part.");
sb.append(Integer.toHexString(nextCounterValue()));
sb.append('.');
sb.append(Long.toHexString(random.nextLong()));
sb.append('.');
sb.append(Long.toHexString(System.currentTimeMillis()));
sb.append('.');
sb.append(Long.toHexString(random.nextLong()));
sb.append("=-");
return sb.toString();
}
/**
* Creates a new unique message identifier that can be used in message
* header field such as Message-ID or In-Reply-To. If the given host name is
* not <code>null</code> it will be used as suffix for the message ID
* (following an at sign).
*
* The resulting string is enclosed in angle brackets (< and >);
*
* @param hostName host name to be included in the message ID or
* <code>null</code> if no host name should be included.
* @return a new unique message identifier.
*/
public static String createUniqueMessageId(String hostName) {
StringBuilder sb = new StringBuilder("<Mime4j.");
sb.append(Integer.toHexString(nextCounterValue()));
sb.append('.');
sb.append(Long.toHexString(random.nextLong()));
sb.append('.');
sb.append(Long.toHexString(System.currentTimeMillis()));
if (hostName != null) {
sb.append('@');
sb.append(hostName);
}
sb.append('>');
return sb.toString();
}
/**
* Formats the specified date into a RFC 822 date-time string.
*
* @param date
* date to be formatted into a string.
* @param zone
* the time zone to use or <code>null</code> to use the default
* time zone.
* @return the formatted time string.
*/
public static String formatDate(Date date, TimeZone zone) {
DateFormat df = RFC822_DATE_FORMAT.get();
if (zone == null) {
df.setTimeZone(TimeZone.getDefault());
} else {
df.setTimeZone(zone);
}
return df.format(date);
}
/**
* Splits the specified string into a multiple-line representation with
* lines no longer than 76 characters (because the line might contain
* encoded words; see <a href='http://www.faqs.org/rfcs/rfc2047.html'>RFC
* 2047</a> section 2). If the string contains non-whitespace sequences
* longer than 76 characters a line break is inserted at the whitespace
* character following the sequence resulting in a line longer than 76
* characters.
*
* @param s
* string to split.
* @param usedCharacters
* number of characters already used up. Usually the number of
* characters for header field name plus colon and one space.
* @return a multiple-line representation of the given string.
*/
public static String fold(String s, int usedCharacters) {
final int maxCharacters = 76;
final int length = s.length();
if (usedCharacters + length <= maxCharacters)
return s;
StringBuilder sb = new StringBuilder();
int lastLineBreak = -usedCharacters;
int wspIdx = indexOfWsp(s, 0);
while (true) {
if (wspIdx == length) {
sb.append(s.substring(Math.max(0, lastLineBreak)));
return sb.toString();
}
int nextWspIdx = indexOfWsp(s, wspIdx + 1);
if (nextWspIdx - lastLineBreak > maxCharacters) {
sb.append(s.substring(Math.max(0, lastLineBreak), wspIdx));
sb.append("\r\n");
lastLineBreak = wspIdx;
}
wspIdx = nextWspIdx;
}
}
/**
* Unfold a multiple-line representation into a single line.
*
* @param s
* string to unfold.
* @return unfolded string.
*/
public static String unfold(String s) {
final int length = s.length();
for (int idx = 0; idx < length; idx++) {
char c = s.charAt(idx);
if (c == '\r' || c == '\n') {
return unfold0(s, idx);
}
}
return s;
}
private static String unfold0(String s, int crlfIdx) {
final int length = s.length();
StringBuilder sb = new StringBuilder(length);
if (crlfIdx > 0) {
sb.append(s.substring(0, crlfIdx));
}
for (int idx = crlfIdx + 1; idx < length; idx++) {
char c = s.charAt(idx);
if (c != '\r' && c != '\n') {
sb.append(c);
}
}
return sb.toString();
}
private static int indexOfWsp(String s, int fromIndex) {
final int len = s.length();
for (int index = fromIndex; index < len; index++) {
char c = s.charAt(index);
if (c == ' ' || c == '\t')
return index;
}
return len;
}
private static synchronized int nextCounterValue() {
return counter++;
}
private static final ThreadLocal<DateFormat> RFC822_DATE_FORMAT = new ThreadLocal<DateFormat>() {
@Override
protected DateFormat initialValue() {
return new Rfc822DateFormat();
}
};
private static final class Rfc822DateFormat extends SimpleDateFormat {
private static final long serialVersionUID = 1L;
public Rfc822DateFormat() {
super("EEE, d MMM yyyy HH:mm:ss ", Locale.US);
}
@Override
public StringBuffer format(Date date, StringBuffer toAppendTo,
FieldPosition pos) {
StringBuffer sb = super.format(date, toAppendTo, pos);
int zoneMillis = calendar.get(GregorianCalendar.ZONE_OFFSET);
int dstMillis = calendar.get(GregorianCalendar.DST_OFFSET);
int minutes = (zoneMillis + dstMillis) / 1000 / 60;
if (minutes < 0) {
sb.append('-');
minutes = -minutes;
} else {
sb.append('+');
}
sb.append(String.format("%02d%02d", minutes / 60, minutes % 60));
return sb;
}
}
}
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