Author: jukka
Date: Sat Jul 12 03:18:32 2008
New Revision: 676141
URL: http://svn.apache.org/viewvc?rev=676141&view=rev
Log:
TIKA-99: Support external parser programs
Added:
incubator/tika/trunk/src/main/java/org/apache/tika/parser/ExternalParser.java
Modified:
incubator/tika/trunk/CHANGES.txt
Modified: incubator/tika/trunk/CHANGES.txt
URL:
http://svn.apache.org/viewvc/incubator/tika/trunk/CHANGES.txt?rev=676141&r1=676140&r2=676141&view=diff
==============================================================================
--- incubator/tika/trunk/CHANGES.txt (original)
+++ incubator/tika/trunk/CHANGES.txt Sat Jul 12 03:18:32 2008
@@ -60,6 +60,8 @@
25. TIKA-146 - Upgrade to POI 3.1 (Jukka Zitting)
+26. TIKA-99 - Support external parser programs (Jukka Zitting)
+
Release 0.1-incubating - 12/27/2007
1. TIKA-5 - Port Metadata Framework from Nutch (mattmann)
Added:
incubator/tika/trunk/src/main/java/org/apache/tika/parser/ExternalParser.java
URL:
http://svn.apache.org/viewvc/incubator/tika/trunk/src/main/java/org/apache/tika/parser/ExternalParser.java?rev=676141&view=auto
==============================================================================
---
incubator/tika/trunk/src/main/java/org/apache/tika/parser/ExternalParser.java
(added)
+++
incubator/tika/trunk/src/main/java/org/apache/tika/parser/ExternalParser.java
Sat Jul 12 03:18:32 2008
@@ -0,0 +1,147 @@
+/*
+ * 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.tika.parser;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.Reader;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.commons.io.output.NullOutputStream;
+import org.apache.tika.exception.TikaException;
+import org.apache.tika.metadata.Metadata;
+import org.apache.tika.sax.XHTMLContentHandler;
+import org.xml.sax.ContentHandler;
+import org.xml.sax.SAXException;
+
+/**
+ * Parser that uses an external program (like catdoc or pdf2txt) to extract
+ * text content from a given document.
+ */
+public class ExternalParser implements Parser {
+
+ /**
+ * The external command to invoke.
+ * @see Runtime#exec(String)
+ */
+ private String command = "cat";
+
+ /**
+ * Does nothing as metadata extraction is not supported by this parser.
+ */
+ public void parse(InputStream stream, Metadata metadata) {
+ }
+
+ /**
+ * Executes the configured external command and passes the given document
+ * stream as a simple XHTML document to the given SAX content handler.
+ * No metadata is extracted.
+ */
+ public void parse(
+ final InputStream stream, ContentHandler handler, Metadata
metadata)
+ throws IOException, SAXException, TikaException {
+ XHTMLContentHandler xhtml =
+ new XHTMLContentHandler(handler, metadata);
+
+ Process process = Runtime.getRuntime().exec(command);
+ try {
+ sendInput(process, stream);
+ ignoreError(process);
+ extractOutput(process, xhtml);
+ } finally {
+ try {
+ process.waitFor();
+ } catch (InterruptedException ignore) {
+ }
+ }
+ }
+
+ /**
+ * Starts a thread that extracts the contents of the standard output
+ * stream of the given process to the given XHTML content handler.
+ * The standard output stream is closed once fully processed.
+ *
+ * @param process process
+ * @param xhtml XHTML content handler
+ * @throws SAXException if the XHTML SAX events could not be handled
+ * @throws IOException if an input error occurred
+ */
+ private void extractOutput(Process process, XHTMLContentHandler xhtml)
+ throws SAXException, IOException {
+ Reader reader = new InputStreamReader(process.getInputStream());
+ try {
+ xhtml.startDocument();
+ xhtml.startElement("p");
+ char[] buffer = new char[1024];
+ for (int n = reader.read(buffer); n != -1; n =
reader.read(buffer)) {
+ xhtml.characters(buffer, 0, n);
+ }
+ xhtml.endElement("p");
+ xhtml.endDocument();
+ } finally {
+ reader.close();
+ }
+ }
+
+ /**
+ * Starts a thread that sends the contents of the given input stream
+ * to the standard input stream of the given process. Potential
+ * exceptions are ignored, and the standard input stream is closed
+ * once fully processed. Note that the given input stream is <em>not</em>
+ * closed by this method.
+ *
+ * @param process process
+ * @param stream input stream
+ */
+ private void sendInput(final Process process, final InputStream stream) {
+ new Thread() {
+ public void run() {
+ OutputStream stdin = process.getOutputStream();
+ try {
+ IOUtils.copy(stream, stdin);
+ } catch (IOException e) {
+ } finally {
+ IOUtils.closeQuietly(stdin);
+ }
+ }
+ }.start();
+ }
+
+ /**
+ * Starts a thread that reads and discards the contents of the
+ * standard error stream of the given process. Potential exceptions
+ * are ignored, and the error stream is closed once fully processed.
+ *
+ * @param process process
+ */
+ private void ignoreError(final Process process) {
+ new Thread() {
+ public void run() {
+ InputStream error = process.getErrorStream();
+ try {
+ IOUtils.copy(error, new NullOutputStream());
+ } catch (IOException e) {
+ } finally {
+ IOUtils.closeQuietly(error);
+ }
+ }
+ }.start();
+ }
+
+}
