/*
* Copyright (C) 2008 The Android Open Source Project
*
* 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 com.android.emailcommon.internet;
import com.android.emailcommon.Logging;
import com.android.emailcommon.mail.Body;
import com.android.emailcommon.mail.BodyPart;
import com.android.emailcommon.mail.Message;
import com.android.emailcommon.mail.MessagingException;
import com.android.emailcommon.mail.Multipart;
import com.android.emailcommon.mail.Part;
import org.apache.commons.io.IOUtils;
import org.apache.james.mime4j.codec.EncoderUtil;
import org.apache.james.mime4j.decoder.DecoderUtil;
import org.apache.james.mime4j.decoder.QuotedPrintableInputStream;
import org.apache.james.mime4j.util.CharsetUtil;
import android.util.Base64;
import android.util.Base64DataException;
import android.util.Base64InputStream;
import android.util.Log;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MimeUtility {
public static final String MIME_TYPE_RFC822 = "message/rfc822";
private final static Pattern PATTERN_CR_OR_LF = Pattern.compile("\r|\n");
/**
* Replace sequences of CRLF+WSP with WSP. Tries to preserve original string
* object whenever possible.
*/
public static String unfold(String s) {
if (s == null) {
return null;
}
Matcher patternMatcher = PATTERN_CR_OR_LF.matcher(s);
if (patternMatcher.find()) {
patternMatcher.reset();
s = patternMatcher.replaceAll("");
}
return s;
}
public static String decode(String s) {
if (s == null) {
return null;
}
return DecoderUtil.decodeEncodedWords(s);
}
public static String unfoldAndDecode(String s) {
return decode(unfold(s));
}
// TODO implement proper foldAndEncode
// NOTE: When this really works, we *must* remove all calls to foldAndEncode2() to prevent
// duplication of encoding.
public static String foldAndEncode(String s) {
return s;
}
/**
* INTERIM version of foldAndEncode that will be used only by Subject: headers.
* This is safer than implementing foldAndEncode() (see above) and risking unknown damage
* to other headers.
*
* TODO: Copy this code to foldAndEncode(), get rid of this function, confirm all working OK.
*
* @param s original string to encode and fold
* @param usedCharacters number of characters already used up by header name
* @return the String ready to be transmitted
*/
public static String foldAndEncode2(String s, int usedCharacters) {
// james.mime4j.codec.EncoderUtil.java
// encode: encodeIfNecessary(text, usage, numUsedInHeaderName)
// Usage.TEXT_TOKENlooks like the right thing for subjects
// use WORD_ENTITY for address/names
String encoded = EncoderUtil.encodeIfNecessary(s, EncoderUtil.Usage.TEXT_TOKEN,
usedCharacters);
return fold(encoded, usedCharacters);
}
/**
* INTERIM: From newer version of org.apache.james (but we don't want to import
* the entire MimeUtil class).
*
* 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;
}
}
/**
* INTERIM: From newer version of org.apache.james (but we don't want to import
* the entire MimeUtil class).
*
* Search for whitespace.
*/
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;
}
/**
* Returns the named parameter of a header field. If name is null the first
* parameter is returned, or if there are no additional parameters in the
* field the entire field is returned. Otherwise the named parameter is
* searched for in a case insensitive fashion and returned. If the parameter
* cannot be found the method returns null.
*
* TODO: quite inefficient with the inner trimming & splitting.
* TODO: Also has a latent bug: uses "startsWith" to match the name, which can false-positive.
* TODO: The doc says that for a null name you get the first param, but you get the header.
* Should probably just fix the doc, but if other code assumes that behavior, fix the code.
* TODO: Need to decode %-escaped strings, as in: filename="ab%22d".
* ('+' -> ' ' conversion too? check RFC)
*
* @param header
* @param name
* @return the entire header (if name=null), the found parameter, or null
*/
public static String getHeaderParameter(String header, String name) {
if (header == null) {
return null;
}
String[] parts = unfold(header).split(";");
if (name == null) {
return parts[0].trim();
}
String lowerCaseName = name.toLowerCase();
for (String part : parts) {
if (part.trim().toLowerCase().startsWith(lowerCaseName)) {
String[] parameterParts = part.split("=", 2);
if (parameterParts.length < 2) {
return null;
}
String parameter = parameterParts[1].trim();
if (parameter.startsWith("\"") && parameter.endsWith("\"")) {
return parameter.substring(1, parameter.length() - 1);
} else {
return parameter;
}
}
}
return null;
}
public static Part findFirstPartByMimeType(Part part, String mimeType)
throws MessagingException {
if (part.getBody() instanceof Multipart) {
Multipart multipart = (Multipart)part.getBody();
for (int i = 0, count = multipart.getCount(); i < count; i++) {
BodyPart bodyPart = multipart.getBodyPart(i);
Part ret = findFirstPartByMimeType(bodyPart, mimeType);
if (ret != null) {
return ret;
}
}
}
else if (part.getMimeType().equalsIgnoreCase(mimeType)) {
return part;
}
return null;
}
public static Part findPartByContentId(Part part, String contentId) throws Exception {
if (part.getBody() instanceof Multipart) {
Multipart multipart = (Multipart)part.getBody();
for (int i = 0, count = multipart.getCount(); i < count; i++) {
BodyPart bodyPart = multipart.getBodyPart(i);
Part ret = findPartByContentId(bodyPart, contentId);
if (ret != null) {
return ret;
}
}
}
String cid = part.getContentId();
if (contentId.equals(cid)) {
return part;
}
return null;
}
/**
* Reads the Part's body and returns a String based on any charset conversion that needed
* to be done.
* @param part The part containing a body
* @return a String containing the converted text in the body, or null if there was no text
* or an error during conversion.
*/
public static String getTextFromPart(Part part) {
try {
if (part != null && part.getBody() != null) {
InputStream in = part.getBody().getInputStream();
String mimeType = part.getMimeType();
if (mimeType != null && MimeUtility.mimeTypeMatches(mimeType, "text/*")) {
/*
* Now we read the part into a buffer for further processing. Because
* the stream is now wrapped we'll remove any transfer encoding at this point.
*/
ByteArrayOutputStream out = new ByteArrayOutputStream();
IOUtils.copy(in, out);
in.close();
in = null; // we want all of our memory back, and close might not release
/*
* We've got a text part, so let's see if it needs to be processed further.
*/
String charset = getHeaderParameter(part.getContentType(), "charset");
if (charset != null) {
/*
* See if there is conversion from the MIME charset to the Java one.
*/
charset = CharsetUtil.toJavaCharset(charset);
}
/*
* No encoding, so use us-ascii, which is the standard.
*/
if (charset == null) {
charset = "ASCII";
}
/*
* Convert and return as new String
*/
String result = out.toString(charset);
out.close();
return result;
}
}
}
catch (OutOfMemoryError oom) {
/*
* If we are not able to process the body there's nothing we can do about it. Return
* null and let the upper layers handle the missing content.
*/
Log.e(Logging.LOG_TAG, "Unable to getTextFromPart " + oom.toString());
}
catch (Exception e) {
/*
* If we are not able to process the body there's nothing we can do about it. Return
* null and let the upper layers handle the missing content.
*/
Log.e(Logging.LOG_TAG, "Unable to getTextFromPart " + e.toString());
}
return null;
}
/**
* Returns true if the given mimeType matches the matchAgainst specification. The comparison
* ignores case and the matchAgainst string may include "*" for a wildcard (e.g. "image/*").
*
* @param mimeType A MIME type to check.
* @param matchAgainst A MIME type to check against. May include wildcards.
* @return true if the mimeType matches
*/
public static boolean mimeTypeMatches(String mimeType, String matchAgainst) {
Pattern p = Pattern.compile(matchAgainst.replaceAll("\\*", "\\.\\*"),
Pattern.CASE_INSENSITIVE);
return p.matcher(mimeType).matches();
}
/**
* Returns true if the given mimeType matches any of the matchAgainst specifications. The
* comparison ignores case and the matchAgainst strings may include "*" for a wildcard
* (e.g. "image/*").
*
* @param mimeType A MIME type to check.
* @param matchAgainst An array of MIME types to check against. May include wildcards.
* @return true if the mimeType matches any of the matchAgainst strings
*/
public static boolean mimeTypeMatches(String mimeType, String[] matchAgainst) {
for (String matchType : matchAgainst) {
if (mimeTypeMatches(mimeType, matchType)) {
return true;
}
}
return false;
}
/**
* Given an input stream and a transfer encoding, return a wrapped input stream for that
* encoding (or the original if none is required)
* @param in the input stream
* @param contentTransferEncoding the content transfer encoding
* @return a properly wrapped stream
*/
public static InputStream getInputStreamForContentTransferEncoding(InputStream in,
String contentTransferEncoding) {
if (contentTransferEncoding != null) {
contentTransferEncoding =
MimeUtility.getHeaderParameter(contentTransferEncoding, null);
if ("quoted-printable".equalsIgnoreCase(contentTransferEncoding)) {
in = new QuotedPrintableInputStream(in);
}
else if ("base64".equalsIgnoreCase(contentTransferEncoding)) {
in = new Base64InputStream(in, Base64.DEFAULT);
}
}
return in;
}
/**
* Removes any content transfer encoding from the stream and returns a Body.
*/
public static Body decodeBody(InputStream in, String contentTransferEncoding)
throws IOException {
/*
* We'll remove any transfer encoding by wrapping the stream.
*/
in = getInputStreamForContentTransferEncoding(in, contentTransferEncoding);
BinaryTempFileBody tempBody = new BinaryTempFileBody();
OutputStream out = tempBody.getOutputStream();
try {
IOUtils.copy(in, out);
} catch (Base64DataException bde) {
// TODO Need to fix this somehow
//String warning = "\n\n" + Email.getMessageDecodeErrorString();
//out.write(warning.getBytes());
} finally {
out.close();
}
return tempBody;
}
/**
* Recursively scan a Part (usually a Message) and sort out which of its children will be
* "viewable" and which will be attachments.
*
* @param part The part to be broken down
* @param viewables This arraylist will be populated with all parts that appear to be
* the "message" (e.g. text/plain & text/html)
* @param attachments This arraylist will be populated with all parts that appear to be
* attachments (including inlines)
* @throws MessagingException
*/
public static void collectParts(Part part, ArrayList<Part> viewables,
ArrayList<Part> attachments) throws MessagingException {
String disposition = part.getDisposition();
String dispositionType = null;
String dispositionFilename = null;
if (disposition != null) {
dispositionType = MimeUtility.getHeaderParameter(disposition, null);
dispositionFilename = MimeUtility.getHeaderParameter(disposition, "filename");
}
// An attachment filename can be defined in either the Content-Disposition header
// or the Content-Type header. Content-Disposition is preferred, so we only try
// the Content-Type header as a last resort.
if (dispositionFilename == null) {
String contentType = part.getContentType();
dispositionFilename = MimeUtility.getHeaderParameter(contentType, "name");
}
boolean attachmentDisposition = "attachment".equalsIgnoreCase(dispositionType);
// If a disposition is not specified, default to "inline"
boolean inlineDisposition = dispositionType == null
|| "inline".equalsIgnoreCase(dispositionType);
// A guess that this part is intended to be an attachment
boolean attachment = attachmentDisposition
|| (dispositionFilename != null && !inlineDisposition);
// A guess that this part is intended to be an inline.
boolean inline = inlineDisposition && (dispositionFilename != null);
// One or the other
boolean attachmentOrInline = attachment || inline;
if (part.getBody() instanceof Multipart) {
// If the part is Multipart but not alternative it's either mixed or
// something we don't know about, which means we treat it as mixed
// per the spec. We just process its pieces recursively.
Multipart mp = (Multipart)part.getBody();
for (int i = 0; i < mp.getCount(); i++) {
collectParts(mp.getBodyPart(i), viewables, attachments);
}
} else if (part.getBody() instanceof Message) {
// If the part is an embedded message we just continue to process
// it, pulling any viewables or attachments into the running list.
Message message = (Message)part.getBody();
collectParts(message, viewables, attachments);
} else if ((!attachmentOrInline) && ("text/html".equalsIgnoreCase(part.getMimeType()))) {
// If the part is HTML and we got this far, it's a viewable part of a mixed
viewables.add(part);
} else if ((!attachmentOrInline) && ("text/plain".equalsIgnoreCase(part.getMimeType()))) {
// If the part is text and we got this far, it's a viewable part of a mixed
viewables.add(part);
} else if (attachmentOrInline) {
// Finally, if it's an attachment or an inline we will include it as an attachment.
attachments.add(part);
}
}
}