tballison commented on code in PR #2769: URL: https://github.com/apache/tika/pull/2769#discussion_r3096349397
########## tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-ocr-encode-module/src/main/java/org/apache/tika/parser/ocrencode/EncodeOCRParser.java: ########## @@ -0,0 +1,374 @@ +/* + * 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.ocrencode; + +import static java.nio.charset.StandardCharsets.UTF_8; +import static org.apache.tika.sax.XHTMLContentHandler.XHTML; + +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.io.Reader; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashSet; +import java.util.Set; +import java.util.concurrent.atomic.AtomicInteger; + +import org.apache.commons.codec.binary.Base64InputStream; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import org.xml.sax.ContentHandler; +import org.xml.sax.SAXException; +import org.xml.sax.helpers.AttributesImpl; + +import org.apache.tika.config.ConfigDeserializer; +import org.apache.tika.config.Initializable; +import org.apache.tika.config.JsonConfig; +import org.apache.tika.config.TikaComponent; +import org.apache.tika.exception.TikaConfigException; +import org.apache.tika.exception.TikaException; +import org.apache.tika.extractor.ParentContentHandler; +import org.apache.tika.io.TemporaryResources; +import org.apache.tika.io.TikaInputStream; +import org.apache.tika.metadata.Metadata; +import org.apache.tika.metadata.TikaCoreProperties; +import org.apache.tika.mime.MediaType; +import org.apache.tika.parser.AbstractExternalProcessParser; +import org.apache.tika.parser.ParseContext; +import org.apache.tika.sax.BodyContentHandler; +import org.apache.tika.sax.EmbeddedContentHandler; +import org.apache.tika.sax.TeeContentHandler; +import org.apache.tika.sax.XHTMLContentHandler; + +/** + * Parser that base64-encodes image content instead of performing OCR + * text extraction. This is useful when you need to preserve the original + * image data in the parsed output for downstream processing by an + * external service. + * <p> + * To configure this parser, pass an {@link EncodeOCRConfig} object + * through the ParseContext, or configure it via tika-config.xml/json. + */ +@TikaComponent(spi = false) +public class EncodeOCRParser + extends AbstractExternalProcessParser + implements Initializable { + + private static final String OCR = "ocr-"; + private static final Logger LOG = LoggerFactory.getLogger( + EncodeOCRParser.class); + private static final Object[] LOCK = new Object[0]; + private static final long serialVersionUID = -8167538283213097266L; + private static final Set<MediaType> SUPPORTED_TYPES = + Collections.unmodifiableSet(new HashSet<>(Arrays.asList( + MediaType.image(OCR + "png"), + MediaType.image(OCR + "jpeg"), + MediaType.image(OCR + "tiff"), + MediaType.image(OCR + "bmp"), + MediaType.image(OCR + "gif"), + // these are not currently covered by other parsers + MediaType.image("jp2"), + MediaType.image("jpx"), + MediaType.image("x-portable-pixmap"), + // add the ocr- versions as well + MediaType.image(OCR + "jp2"), + MediaType.image(OCR + "jpx"), + MediaType.image(OCR + "x-portable-pixmap") + ))); + private static volatile boolean hasWarned = false; + + private EncodeOCRConfig defaultConfig = new EncodeOCRConfig(); + + public EncodeOCRParser() { + } + + public EncodeOCRParser(EncodeOCRConfig config) { + this.defaultConfig = config; + } + + /** + * Constructor for JSON configuration. + * Requires Jackson on the classpath. + * + * @param jsonConfig JSON configuration + */ + public EncodeOCRParser(JsonConfig jsonConfig) { + this(ConfigDeserializer.buildConfig( + jsonConfig, EncodeOCRConfig.class)); + } + + @Override + public void initialize() throws TikaConfigException { + //no-op + } + + public void checkInitialization() throws TikaConfigException { + //no-op + } + + @Override + public Set<MediaType> getSupportedTypes(ParseContext context) { + EncodeOCRConfig userConfig = context.get(EncodeOCRConfig.class); + EncodeOCRConfig config = defaultConfig; + if (userConfig != null) { + try { + config = defaultConfig.cloneAndUpdate(userConfig); + } catch (TikaException e) { + LOG.warn("Failed to merge config, using default", e); + } + } + if (config.isSkipOcr()) { + return Collections.emptySet(); + } + return SUPPORTED_TYPES; + } + + @Override + public void parse( + TikaInputStream tis, + ContentHandler handler, + Metadata metadata, + ParseContext parseContext + ) throws IOException, SAXException, TikaException { + normalizeOCRMimeMetadata(metadata); + + ParseContext workingContext = + parseContext != null ? parseContext : new ParseContext(); + + EncodeOCRConfig userConfig = workingContext.get( + EncodeOCRConfig.class); + EncodeOCRConfig config = defaultConfig; + if (userConfig != null) { + config = defaultConfig.cloneAndUpdate(userConfig); + } + + if (config != null && config.isSkipOcr()) { + return; + } + + try (TemporaryResources tmp = new TemporaryResources()) { + TikaInputStream tikaStream = TikaInputStream.get( + tis, tmp, metadata); + + ContentHandler baseHandler = getContentHandler( + config.isInlineContent(), + handler, + metadata, + workingContext); + XHTMLContentHandler xhtml = new XHTMLContentHandler( + baseHandler, metadata, workingContext); + xhtml.startDocument(); + doEncode(tikaStream, xhtml, metadata, workingContext, config); + xhtml.endDocument(); + } + } + + private ContentHandler getContentHandler( + boolean isInlineContent, + ContentHandler handler, + Metadata metadata, + ParseContext parseContext) { + if (!isInlineContent) { + return handler; + } + ParentContentHandler parentContentHandler = parseContext.get( + ParentContentHandler.class); + if (parentContentHandler == null) { + return handler; + } + String embeddedType = metadata.get( + TikaCoreProperties.EMBEDDED_RESOURCE_TYPE); + if (!TikaCoreProperties.EmbeddedResourceType.INLINE.name() + .equals(embeddedType)) { + return handler; + } + return new TeeContentHandler( + new EmbeddedContentHandler( + new BodyContentHandler( + parentContentHandler.getContentHandler())), + handler); + } + + private void normalizeOCRMimeMetadata(Metadata metadata) { + String parserOverride = metadata.get( + TikaCoreProperties.CONTENT_TYPE_PARSER_OVERRIDE); + if (parserOverride != null) { + MediaType overrideType = MediaType.parse(parserOverride); + if (overrideType != null + && overrideType.getSubtype().startsWith(OCR)) { + metadata.remove(TikaCoreProperties + .CONTENT_TYPE_PARSER_OVERRIDE.getName()); + } + } + String contentType = metadata.get(Metadata.CONTENT_TYPE); + if (contentType != null) { + MediaType parsedType = MediaType.parse(contentType); + if (parsedType != null + && parsedType.getSubtype().startsWith(OCR)) { + metadata.set(Metadata.CONTENT_TYPE, + new MediaType(parsedType.getType(), + parsedType.getSubtype().substring( + OCR.length())).toString()); + } + } + } + + private void doEncode( + TikaInputStream tikaInputStream, + ContentHandler xhtml, + Metadata metadata, + ParseContext parseContext, + EncodeOCRConfig config + ) throws IOException, SAXException, TikaException { + warnOnFirstParse(); + + long size = tikaInputStream.getLength(); + if (size >= config.getMinFileSizeToOcr() + && size <= config.getMaxFileSizeToOcr()) { + if (!reserveImageSlot(parseContext, config)) { + OCRImageCounter counter = parseContext.get( + OCRImageCounter.class); + int processed = counter != null + ? counter.get() + : config.getMaxImagesToOcr(); + LOG.info("Skipping OCR encode for image because " + + "the configured limit of {} images " + + "has been reached ({} already processed)", + config.getMaxImagesToOcr(), processed); + return; + } + encodeToBase64(tikaInputStream, size, xhtml); + } else { + LOG.debug("File size {} is outside the allowed " + + "range for OCR encode: {} - {}", + size, + config.getMinFileSizeToOcr(), + config.getMaxFileSizeToOcr()); + } + } + + private boolean reserveImageSlot( + ParseContext parseContext, + EncodeOCRConfig config) { + OCRImageCounter counter = parseContext.get(OCRImageCounter.class); + if (counter == null) { + counter = new OCRImageCounter(); + parseContext.set(OCRImageCounter.class, counter); + } + return counter.tryIncrement(config.getMaxImagesToOcr()); + } + + private void encodeToBase64( + InputStream input, + long fileSize, + ContentHandler xhtml + ) throws IOException, TikaException { + long startTime = System.nanoTime(); + + try (Base64InputStream base64InputStream = + new Base64InputStream(input, true)) { + int outputSize = extractOutput(base64InputStream, xhtml); + long endTime = System.nanoTime(); + long durationMs = (endTime - startTime) / 1_000_000; + LOG.info("OCR encoding - input file size: {} bytes, " + + "output size: {} characters, " + + "time taken: {} ms", + fileSize, outputSize, durationMs); + } catch (IOException | SAXException e) { + throw new IOException("Error encoding bytes to base64", e); + } + } + + private void warnOnFirstParse() { + if (!hasWarned) { + synchronized (LOCK) { + if (!hasWarned) { + LOG.info("OCR encode is being invoked. " + + "This can add greatly to processing time."); + hasWarned = true; + } + } + } + } + + /** + * Reads the contents of the given stream and writes it to the + * given XHTML content handler. The stream is closed once fully + * processed. + * + * @param stream Stream containing the base64-encoded data + * @param xhtml XHTML content handler + * @return number of characters written + * @throws SAXException if the XHTML SAX events could not be handled + * @throws IOException if an input error occurred + */ + private int extractOutput(InputStream stream, ContentHandler xhtml) + throws SAXException, IOException { + AttributesImpl attrs = new AttributesImpl(); + attrs.addAttribute("", "class", "class", "CDATA", "ocr"); + xhtml.startElement(XHTML, "div", "div", attrs); + + String beginMarker = + "\n<<<---IMAGE-BASE64-ENCODED-BEGIN--->>>\n"; + xhtml.characters( Review Comment: div, class=? instead of writing this to the body? -- This is an automated message from the Apache Git Service. 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