/*
* 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.ocr;
import static java.nio.charset.StandardCharsets.UTF_8;
import javax.imageio.ImageIO;
import javax.xml.parsers.SAXParser;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.apache.commons.exec.CommandLine;
import org.apache.commons.exec.DefaultExecutor;
import org.apache.commons.exec.PumpStreamHandler;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.tika.exception.TikaException;
import org.apache.tika.io.TemporaryResources;
import org.apache.tika.io.TikaInputStream;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.mime.MediaTypeRegistry;
import org.apache.tika.parser.AbstractParser;
import org.apache.tika.parser.CompositeParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.apache.tika.parser.external.ExternalParser;
import org.apache.tika.parser.image.ImageParser;
import org.apache.tika.parser.image.TiffParser;
import org.apache.tika.parser.jpeg.JpegParser;
import org.apache.tika.sax.OfflineContentHandler;
import org.apache.tika.sax.XHTMLContentHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
/**
* TesseractOCRParser powered by tesseract-ocr engine. To enable this parser,
* create a {@link TesseractOCRConfig} object and pass it through a
* ParseContext. Tesseract-ocr must be installed and on system path or the path
* to its root folder must be provided:
* <p>
* TesseractOCRConfig config = new TesseractOCRConfig();<br>
* //Needed if tesseract is not on system path<br>
* config.setTesseractPath(tesseractFolder);<br>
* parseContext.set(TesseractOCRConfig.class, config);<br>
* </p>
*
*
*/
public class TesseractOCRParser extends AbstractParser {
private static final Logger LOG = LoggerFactory.getLogger(TesseractOCRParser.class);
private static final long serialVersionUID = -8167538283213097265L;
private static final TesseractOCRConfig DEFAULT_CONFIG = new TesseractOCRConfig();
private static final Set<MediaType> SUPPORTED_TYPES = Collections.unmodifiableSet(
new HashSet<>(Arrays.asList(new MediaType[]{
MediaType.image("png"), MediaType.image("jpeg"), MediaType.image("tiff"),
MediaType.image("bmp"), MediaType.image("gif"), MediaType.image("jp2"),
MediaType.image("jpx"), MediaType.image("x-portable-pixmap")
})));
private static Map<String,Boolean> TESSERACT_PRESENT = new HashMap<>();
private static volatile boolean HAS_ALERTED = false;
@Override
public Set<MediaType> getSupportedTypes(ParseContext context) {
// If Tesseract is installed, offer our supported image types
TesseractOCRConfig config = context.get(TesseractOCRConfig.class, DEFAULT_CONFIG);
if (hasTesseract(config)) {
if (! HAS_ALERTED) {
LOG.info("Tesseract OCR is installed and will be automatically applied to image files.\n"+
"This may dramatically slow down content extraction (TIKA-2359).\n"+
"As of Tika 1.15 (and prior versions), Tesseract is automatically called.\n"+
"In future versions of Tika, users may need to turn the TesseractOCRParser on via TikaConfig."
);
HAS_ALERTED = true;
}
return SUPPORTED_TYPES;
}
// Otherwise don't advertise anything, so the other image parsers
// can be selected instead
return Collections.emptySet();
}
private void setEnv(TesseractOCRConfig config, ProcessBuilder pb) {
String tessdataPrefix = "TESSDATA_PREFIX";
Map<String, String> env = pb.environment();
if (!config.getTessdataPath().isEmpty()) {
env.put(tessdataPrefix, config.getTessdataPath());
}
else if(!config.getTesseractPath().isEmpty()) {
env.put(tessdataPrefix, config.getTesseractPath());
}
}
public boolean hasTesseract(TesseractOCRConfig config) {
// Fetch where the config says to find Tesseract
String tesseract = config.getTesseractPath() + getTesseractProg();
// Have we already checked for a copy of Tesseract there?
if (TESSERACT_PRESENT.containsKey(tesseract)) {
return TESSERACT_PRESENT.get(tesseract);
}
// Try running Tesseract from there, and see if it exists + works
String[] checkCmd = { tesseract };
boolean hasTesseract = ExternalParser.check(checkCmd);
TESSERACT_PRESENT.put(tesseract, hasTesseract);
return hasTesseract;
}
private boolean hasImageMagick(TesseractOCRConfig config) {
// Fetch where the config says to find ImageMagick Program
String ImageMagick = config.getImageMagickPath() + getImageMagickProg();
// Have we already checked for a copy of ImageMagick Program there?
if (TESSERACT_PRESENT.containsKey(ImageMagick)) {
return TESSERACT_PRESENT.get(ImageMagick);
}
// Try running ImageMagick program from there, and see if it exists + works
String[] checkCmd = { ImageMagick };
boolean hasImageMagick = ExternalParser.check(checkCmd);
TESSERACT_PRESENT.put(ImageMagick, hasImageMagick);
return hasImageMagick;
}
private static boolean hasPython() {
// check if python is installed and if the rotation program path has been specified correctly
boolean hasPython = false;
try {
Process proc = Runtime.getRuntime().exec("python -h");
BufferedReader stdInput = new BufferedReader(new InputStreamReader(proc.getInputStream(), "UTF-8"));
if(stdInput.read() != -1) {
hasPython = true;
}
} catch (IOException e) {
}
return hasPython;
}
public void parse(Image image, ContentHandler handler, Metadata metadata, ParseContext context) throws IOException,
SAXException, TikaException {
TemporaryResources tmp = new TemporaryResources();
FileOutputStream fos = null;
TikaInputStream tis = null;
try {
int w = image.getWidth(null);
int h = image.getHeight(null);
BufferedImage bImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
File file = tmp.createTemporaryFile();
fos = new FileOutputStream(file);
ImageIO.write(bImage, "png", fos);
tis = TikaInputStream.get(file);
parse(tis, handler, metadata, context);
} finally {
tmp.dispose();
if (tis != null)
tis.close();
if (fos != null)
fos.close();
}
}
@Override
public void parse(InputStream stream, ContentHandler handler, Metadata metadata, ParseContext parseContext)
throws IOException, SAXException, TikaException {
TesseractOCRConfig config = parseContext.get(TesseractOCRConfig.class, DEFAULT_CONFIG);
// If Tesseract is not on the path with the current config, do not try to run OCR
// getSupportedTypes shouldn't have listed us as handling it, so this should only
// occur if someone directly calls this parser, not via DefaultParser or similar
if (! hasTesseract(config))
return;
TemporaryResources tmp = new TemporaryResources();
try {
TikaInputStream tikaStream = TikaInputStream.get(stream, tmp);
//trigger the spooling to a tmp file if the stream wasn't
//already a TikaInputStream that contained a file
tikaStream.getPath();
//this is the text output file name specified on the tesseract
//commandline. The actual output file name will have a suffix added.
File tmpOCROutputFile = tmp.createTemporaryFile();
// Temporary workaround for TIKA-1445 - until we can specify
// composite parsers with strategies (eg Composite, Try In Turn),
// always send the image onwards to the regular parser to have
// the metadata for them extracted as well
_TMP_IMAGE_METADATA_PARSER.parse(tikaStream, new DefaultHandler(), metadata, parseContext);
XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
xhtml.startDocument();
parse(tikaStream, tmpOCROutputFile, parseContext, xhtml, config);
xhtml.endDocument();
} finally {
tmp.dispose();
}
}
/**
* Use this to parse content without starting a new document.
* This appends SAX events to xhtml without re-adding the metadata, body start, etc.
*
* @param stream inputstream
* @param xhtml handler
* @param config TesseractOCRConfig to use for this parse
* @throws IOException
* @throws SAXException
* @throws TikaException
*
* @deprecated use {@link #parseInline(InputStream, XHTMLContentHandler, ParseContext, TesseractOCRConfig)}
*/
public void parseInline(InputStream stream, XHTMLContentHandler xhtml, TesseractOCRConfig config)
throws IOException, SAXException, TikaException {
parseInline(stream, xhtml, new ParseContext(), config);
}
/**
* Use this to parse content without starting a new document.
* This appends SAX events to xhtml without re-adding the metadata, body start, etc.
*
* @param stream inputstream
* @param xhtml handler
* @param config TesseractOCRConfig to use for this parse
* @throws IOException
* @throws SAXException
* @throws TikaException
*
*/
public void parseInline(InputStream stream, XHTMLContentHandler xhtml, ParseContext parseContext,
TesseractOCRConfig config)
throws IOException, SAXException, TikaException {
// If Tesseract is not on the path with the current config, do not try to run OCR
// getSupportedTypes shouldn't have listed us as handling it, so this should only
// occur if someone directly calls this parser, not via DefaultParser or similar
if (! hasTesseract(config))
return;
TemporaryResources tmp = new TemporaryResources();
try {
TikaInputStream tikaStream = TikaInputStream.get(stream, tmp);
File tmpImgFile = tmp.createTemporaryFile();
parse(tikaStream, tmpImgFile, parseContext, xhtml, config);
} finally {
tmp.dispose();
}
}
/**
* This method is used to process the image to an OCR-friendly format.
* @param streamingObject input image to be processed
* @param config TesseractOCRconfig class to get ImageMagick properties
* @throws IOException if an input error occurred
* @throws TikaException if an exception timed out
*/
private void processImage(File streamingObject, TesseractOCRConfig config) throws IOException, TikaException {
// fetch rotation script from resources
InputStream in = getClass().getResourceAsStream("rotation.py");
TemporaryResources tmp = new TemporaryResources();
File rotationScript = tmp.createTemporaryFile();
Files.copy(in, rotationScript.toPath(), StandardCopyOption.REPLACE_EXISTING);
String cmd = "python " + rotationScript.getAbsolutePath() + " -f " + streamingObject.getAbsolutePath();
String angle = "0";
DefaultExecutor executor = new DefaultExecutor();
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
PumpStreamHandler streamHandler = new PumpStreamHandler(outputStream);
executor.setStreamHandler(streamHandler);
// determine the angle of rotation required to make the text horizontal
CommandLine cmdLine = CommandLine.parse(cmd);
if(hasPython()) {
try {
executor.execute(cmdLine);
angle = outputStream.toString("UTF-8").trim();
} catch(Exception e) {
}
}
// process the image - parameter values can be set in TesseractOCRConfig.properties
String line = "convert -density " + config.getDensity() + " -depth " + config.getDepth() +
" -colorspace " + config.getColorspace() + " -filter " + config.getFilter() +
" -resize " + config.getResize() + "% -rotate "+ angle + " " + streamingObject.getAbsolutePath() +
" " + streamingObject.getAbsolutePath();
cmdLine = CommandLine.parse(line);
try {
executor.execute(cmdLine);
} catch(Exception e) {
}
tmp.close();
}
private void parse(TikaInputStream tikaInputStream, File tmpOCROutputFile, ParseContext parseContext,
XHTMLContentHandler xhtml, TesseractOCRConfig config)
throws IOException, SAXException, TikaException {
File tmpTxtOutput = null;
try {
File input = tikaInputStream.getFile();
long size = tikaInputStream.getLength();
if (size >= config.getMinFileSizeToOcr() && size <= config.getMaxFileSizeToOcr()) {
// Process image if ImageMagick Tool is present
if(config.isEnableImageProcessing() == 1 && hasImageMagick(config)) {
// copy the contents of the original input file into a temporary file
// which will be preprocessed for OCR
TemporaryResources tmp = new TemporaryResources();
try {
File tmpFile = tmp.createTemporaryFile();
FileUtils.copyFile(input, tmpFile);
processImage(tmpFile, config);
doOCR(tmpFile, tmpOCROutputFile, config);
} finally {
if (tmp != null) {
tmp.dispose();
}
}
} else {
doOCR(input, tmpOCROutputFile, config);
}
// Tesseract appends the output type (.txt or .hocr) to output file name
tmpTxtOutput = new File(tmpOCROutputFile.getAbsolutePath() + "." +
config.getOutputType().toString().toLowerCase(Locale.US));
if (tmpTxtOutput.exists()) {
try (InputStream is = new FileInputStream(tmpTxtOutput)) {
if (config.getOutputType().equals(TesseractOCRConfig.OUTPUT_TYPE.HOCR)) {
extractHOCROutput(is, parseContext, xhtml);
} else {
extractOutput(is, xhtml);
}
}
}
}
} finally {
if (tmpTxtOutput != null) {
tmpTxtOutput.delete();
}
}
}
// TIKA-1445 workaround parser
private static Parser _TMP_IMAGE_METADATA_PARSER = new CompositeImageParser();
private static class CompositeImageParser extends CompositeParser {
private static final long serialVersionUID = -2398203346206381382L;
private static List<Parser> imageParsers = Arrays.asList(new Parser[]{
new ImageParser(), new JpegParser(), new TiffParser()
});
CompositeImageParser() {
super(new MediaTypeRegistry(), imageParsers);
}
}
/**
* Run external tesseract-ocr process.
*
* @param input
* File to be ocred
* @param output
* File to collect ocr result
* @param config
* Configuration of tesseract-ocr engine
* @throws TikaException
* if the extraction timed out
* @throws IOException
* if an input error occurred
*/
private void doOCR(File input, File output, TesseractOCRConfig config) throws IOException, TikaException {
String[] cmd = { config.getTesseractPath() + getTesseractProg(), input.getPath(), output.getPath(), "-l",
config.getLanguage(), "-psm", config.getPageSegMode(),
config.getOutputType().name().toLowerCase(Locale.US),
"-c",
(config.getPreserveInterwordSpacing())? "preserve_interword_spaces=1" : "preserve_interword_spaces=0"};
ProcessBuilder pb = new ProcessBuilder(cmd);
setEnv(config, pb);
final Process process = pb.start();
process.getOutputStream().close();
InputStream out = process.getInputStream();
InputStream err = process.getErrorStream();
logStream("OCR MSG", out, input);
logStream("OCR ERROR", err, input);
FutureTask<Integer> waitTask = new FutureTask<>(new Callable<Integer>() {
public Integer call() throws Exception {
return process.waitFor();
}
});
Thread waitThread = new Thread(waitTask);
waitThread.start();
try {
waitTask.get(config.getTimeout(), TimeUnit.SECONDS);
} catch (InterruptedException e) {
waitThread.interrupt();
process.destroy();
Thread.currentThread().interrupt();
throw new TikaException("TesseractOCRParser interrupted", e);
} catch (ExecutionException e) {
// should not be thrown
} catch (TimeoutException e) {
waitThread.interrupt();
process.destroy();
throw new TikaException("TesseractOCRParser timeout", e);
}
}
/**
* Reads the contents of the given stream and write it to the given XHTML
* content handler. The stream is closed once fully processed.
*
* @param stream
* Stream where is the result of ocr
* @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(InputStream stream, XHTMLContentHandler xhtml) throws SAXException, IOException {
xhtml.startElement("div", "class", "ocr");
try (Reader reader = new InputStreamReader(stream, UTF_8)) {
char[] buffer = new char[1024];
for (int n = reader.read(buffer); n != -1; n = reader.read(buffer)) {
if (n > 0) {
xhtml.characters(buffer, 0, n);
}
}
}
xhtml.endElement("div");
}
private void extractHOCROutput(InputStream is, ParseContext parseContext,
XHTMLContentHandler xhtml) throws TikaException, IOException, SAXException {
if (parseContext == null) {
parseContext = new ParseContext();
}
SAXParser parser = parseContext.getSAXParser();
xhtml.startElement("div", "class", "ocr");
parser.parse(is, new OfflineContentHandler(new HOCRPassThroughHandler(xhtml)));
xhtml.endElement("div");
}
/**
* Starts a thread that reads the contents of the standard output or error
* stream of the given process to not block the process. The stream is closed
* once fully processed.
*/
private void logStream(final String logType, final InputStream stream, final File file) {
new Thread() {
public void run() {
Reader reader = new InputStreamReader(stream, UTF_8);
StringBuilder out = new StringBuilder();
char[] buffer = new char[1024];
try {
for (int n = reader.read(buffer); n != -1; n = reader.read(buffer))
out.append(buffer, 0, n);
} catch (IOException e) {
} finally {
IOUtils.closeQuietly(stream);
}
LOG.debug("{}", out);
}
}.start();
}
static String getTesseractProg() {
return System.getProperty("os.name").startsWith("Windows") ? "tesseract.exe" : "tesseract";
}
static String getImageMagickProg() {
return System.getProperty("os.name").startsWith("Windows") ? "convert.exe" : "convert";
}
private static class HOCRPassThroughHandler extends DefaultHandler {
private final ContentHandler xhtml;
public static final Set<String> IGNORE = unmodifiableSet(
"html", "head", "title", "meta", "body");
public HOCRPassThroughHandler(ContentHandler xhtml) {
this.xhtml = xhtml;
}
/**
* Starts the given element. Table cells and list items are automatically
* indented by emitting a tab character as ignorable whitespace.
*/
@Override
public void startElement(
String uri, String local, String name, Attributes attributes)
throws SAXException {
if (!IGNORE.contains(name)) {
xhtml.startElement(uri, local, name, attributes);
}
}
/**
* Ends the given element. Block elements are automatically followed
* by a newline character.
*/
@Override
public void endElement(String uri, String local, String name) throws SAXException {
if (!IGNORE.contains(name)) {
xhtml.endElement(uri, local, name);
}
}
/**
* @see <a href="https://issues.apache.org/jira/browse/TIKA-210">TIKA-210</a>
*/
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
xhtml.characters(ch, start, length);
}
private static Set<String> unmodifiableSet(String... elements) {
return Collections.unmodifiableSet(
new HashSet<>(Arrays.asList(elements)));
}
}
}