/**
* 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.mahout.utils.email;
import org.apache.mahout.common.iterator.FileLineIterable;
import org.apache.mahout.utils.io.ChunkedWriter;
import org.apache.mahout.utils.io.ChunkedWrapper;
import org.apache.mahout.utils.io.IOWriterWrapper;
import org.apache.mahout.utils.io.WrappedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Writer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MailProcessor {
private static final Pattern MESSAGE_START =
Pattern.compile("^From \\S+@\\S.*\\d{4}$", Pattern.CASE_INSENSITIVE);
private static final Pattern MESSAGE_ID_PREFIX =
Pattern.compile("^message-id: <(.*)>$", Pattern.CASE_INSENSITIVE);
// regular expressions used to parse individual messages
public static final Pattern SUBJECT_PREFIX =
Pattern.compile("^subject: (.*)$", Pattern.CASE_INSENSITIVE);
public static final Pattern FROM_PREFIX =
Pattern.compile("^from: (\\S.*)$", Pattern.CASE_INSENSITIVE);//we need to have at least one character
public static final Pattern REFS_PREFIX =
Pattern.compile("^references: (.*)$", Pattern.CASE_INSENSITIVE);
public static final Pattern TO_PREFIX =
Pattern.compile("^to: (.*)$", Pattern.CASE_INSENSITIVE);
private final String prefix;
private final MailOptions options;
private final WrappedWriter writer;
public MailProcessor(MailOptions options, String prefix, Writer writer) {
this.writer = new IOWriterWrapper(writer);
this.options = options;
this.prefix = prefix;
}
public MailProcessor(MailOptions options, String prefix, ChunkedWriter writer) {
this.writer = new ChunkedWrapper(writer);
this.options = options;
this.prefix = prefix;
}
public long parseMboxLineByLine(File mboxFile) throws IOException {
long messageCount = 0;
try {
StringBuilder contents = new StringBuilder();
// tmps used during mail message parsing
StringBuilder body = new StringBuilder();
Matcher messageIdMatcher = MESSAGE_ID_PREFIX.matcher("");
Matcher messageBoundaryMatcher = MESSAGE_START.matcher("");
String[] patternResults = new String[options.getPatternsToMatch().length];
Matcher[] matchers = new Matcher[options.getPatternsToMatch().length];
for (int i = 0; i < matchers.length; i++) {
matchers[i] = options.getPatternsToMatch()[i].matcher("");
}
String messageId = null;
boolean inBody = false;
Pattern quotedTextPattern = options.getQuotedTextPattern();
for (String nextLine : new FileLineIterable(mboxFile, options.getCharset(), false)) {
if (options.isStripQuotedText() && quotedTextPattern.matcher(nextLine).find()){
continue;
}
for (int i = 0; i < matchers.length; i++) {
Matcher matcher = matchers[i];
matcher.reset(nextLine);
if (matcher.matches()) {
patternResults[i] = matcher.group(1);
}
}
// only start appending body content after we've seen a message ID
if (messageId != null) {
// first, see if we hit the end of the message
messageBoundaryMatcher.reset(nextLine);
if (messageBoundaryMatcher.matches()) {
// done parsing this message ... write it out
String key = generateKey(mboxFile, prefix, messageId);
//if this ordering changes, then also change FromEmailToDictionaryMapper
writeContent(options.getSeparator(), contents, body, patternResults);
writer.write(key, contents.toString());
contents.setLength(0); // reset the buffer
body.setLength(0);
messageId = null;
inBody = false;
} else {
if (inBody && options.isIncludeBody()) {
if (!nextLine.isEmpty()) {
body.append(nextLine).append(options.getBodySeparator());
}
} else {
// first empty line we see after reading the message Id
// indicates that we are in the body ...
inBody = nextLine.isEmpty();
}
}
} else {
if (nextLine.length() > 14) {
messageIdMatcher.reset(nextLine);
if (messageIdMatcher.matches()) {
messageId = messageIdMatcher.group(1);
++messageCount;
}
}
}
}
// write the last message in the file if available
if (messageId != null) {
String key = generateKey(mboxFile, prefix, messageId);
writeContent(options.getSeparator(), contents, body, patternResults);
writer.write(key, contents.toString());
contents.setLength(0); // reset the buffer
}
} catch (FileNotFoundException e) {
// Skip file.
}
// TODO: report exceptions and continue;
return messageCount;
}
protected static String generateKey(File mboxFile, String prefix, String messageId) {
return prefix + File.separator + mboxFile.getName() + File.separator + messageId;
}
public String getPrefix() {
return prefix;
}
public MailOptions getOptions() {
return options;
}
private static void writeContent(String separator, StringBuilder contents, CharSequence body, String[] matches) {
for (String match : matches) {
if (match != null) {
contents.append(match).append(separator);
} else {
contents.append("").append(separator);
}
}
contents.append('\n').append(body);
}
}