Java tutorial
package org.apache.tika.parser.pdf18; /* * 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. */ import javax.xml.stream.XMLStreamException; import java.io.BufferedInputStream; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.Writer; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.HashMap; import java.util.HashSet; import java.util.List; import java.util.ListIterator; import java.util.Locale; import java.util.Map; import java.util.Set; import java.util.TreeMap; import org.apache.commons.io.IOExceptionWithCause; import org.apache.commons.io.IOUtils; import org.apache.pdfbox.cos.COSBase; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDDocumentCatalog; import org.apache.pdfbox.pdmodel.PDDocumentNameDictionary; import org.apache.pdfbox.pdmodel.PDEmbeddedFilesNameTreeNode; import org.apache.pdfbox.pdmodel.PDPage; import org.apache.pdfbox.pdmodel.PDResources; import org.apache.pdfbox.pdmodel.common.COSObjectable; import org.apache.pdfbox.pdmodel.common.PDNameTreeNode; import org.apache.pdfbox.pdmodel.common.filespecification.PDComplexFileSpecification; import org.apache.pdfbox.pdmodel.common.filespecification.PDEmbeddedFile; import org.apache.pdfbox.pdmodel.graphics.xobject.PDCcitt; import org.apache.pdfbox.pdmodel.graphics.xobject.PDJpeg; import org.apache.pdfbox.pdmodel.graphics.xobject.PDPixelMap; import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObject; import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectForm; import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectImage; import org.apache.pdfbox.pdmodel.interactive.action.type.PDAction; import org.apache.pdfbox.pdmodel.interactive.action.type.PDActionURI; import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation; import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationFileAttachment; import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationLink; import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationMarkup; import org.apache.pdfbox.pdmodel.interactive.digitalsignature.PDSignature; import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDDocumentOutline; import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineItem; import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineNode; import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm; import org.apache.pdfbox.pdmodel.interactive.form.PDField; import org.apache.pdfbox.pdmodel.interactive.form.PDSignatureField; import org.apache.pdfbox.pdmodel.interactive.form.PDXFA; import org.apache.pdfbox.util.PDFTextStripper; import org.apache.pdfbox.util.TextPosition; import org.apache.tika.exception.TikaException; import org.apache.tika.extractor.EmbeddedDocumentExtractor; import org.apache.tika.extractor.ParsingEmbeddedDocumentExtractor; import org.apache.tika.io.TikaInputStream; import org.apache.tika.metadata.Metadata; import org.apache.tika.metadata.TikaCoreProperties; import org.apache.tika.parser.ParseContext; import org.apache.tika.sax.EmbeddedContentHandler; import org.apache.tika.sax.XHTMLContentHandler; import org.xml.sax.ContentHandler; import org.xml.sax.SAXException; import org.xml.sax.helpers.AttributesImpl; /** * Utility class that overrides the {@link PDFTextStripper} functionality * to produce a semi-structured XHTML SAX events instead of a plain text * stream. */ class PDF2XHTML extends PDFTextStripper { /** * Maximum recursive depth during AcroForm processing. * Prevents theoretical AcroForm recursion bomb. */ private final static int MAX_ACROFORM_RECURSIONS = 10; /** * Format used for signature dates * TODO Make this thread-safe */ private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.ROOT); private final ContentHandler originalHandler; private final ParseContext context; private final XHTMLContentHandler handler; private final PDFParserConfig config; private final Metadata metadata; /** * This keeps track of the pdf object ids for inline * images that have been processed. * If {@link PDFParserConfig#getExtractUniqueInlineImagesOnly() * is true, this will be checked before extracting an embedded image. * The integer keeps track of the inlineImageCounter for that image. * This integer is used to identify images in the markup. * <p> * This is used across the document. To avoid infinite recursion * TIKA-1742, we're limiting the export to one image per page. */ private Map<String, Integer> processedInlineImages = new HashMap<>(); private int inlineImageCounter = 0; private PDF2XHTML(ContentHandler handler, ParseContext context, Metadata metadata, PDFParserConfig config) throws IOException { // super(ResourceLoader.loadProperties(config.getTextStripperPropsLocation(), true)); //source of config (derives from context or PDFParser?) is //already determined in PDFParser. No need to check context here. this.config = config; this.originalHandler = handler; this.context = context; this.handler = new XHTMLContentHandler(handler, metadata); this.metadata = metadata; } /** * Converts the given PDF document (and related metadata) to a stream * of XHTML SAX events sent to the given content handler. * * @param document PDF document * @param handler SAX content handler * @param metadata PDF metadata * @throws SAXException if the content handler fails to process SAX events * @throws TikaException if the PDF document can not be processed */ public static void process(PDDocument document, ContentHandler handler, ParseContext context, Metadata metadata, PDFParserConfig config) throws SAXException, TikaException { try { // Extract text using a dummy Writer as we override the // key methods to output to the given content // handler. PDF2XHTML pdf2XHTML = new PDF2XHTML(handler, context, metadata, config); config.configure(pdf2XHTML); pdf2XHTML.writeText(document, new Writer() { @Override public void write(char[] cbuf, int off, int len) { } @Override public void flush() { } @Override public void close() { } }); } catch (IOException e) { if (e.getCause() instanceof SAXException) { throw (SAXException) e.getCause(); } else { throw new TikaException("Unable to extract PDF content", e); } } } void extractBookmarkText() throws SAXException { PDDocumentOutline outline = document.getDocumentCatalog().getDocumentOutline(); if (outline != null) { extractBookmarkText(outline); } } void extractBookmarkText(PDOutlineNode bookmark) throws SAXException { PDOutlineItem current = bookmark.getFirstChild(); if (current != null) { handler.startElement("ul"); while (current != null) { handler.startElement("li"); handler.characters(current.getTitle()); handler.endElement("li"); // Recurse: extractBookmarkText(current); current = current.getNextSibling(); } handler.endElement("ul"); } } @Override protected void startDocument(PDDocument pdf) throws IOException { try { handler.startDocument(); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to start a document", e); } } @Override protected void endDocument(PDDocument pdf) throws IOException { try { // Extract text for any bookmarks: extractBookmarkText(); extractEmbeddedDocuments(pdf, originalHandler); //extract acroform data at end of doc if (config.getExtractAcroFormContent() == true) { extractAcroForm(pdf, handler); } handler.endDocument(); } catch (TikaException e) { throw new IOExceptionWithCause("Unable to end a document", e); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to end a document", e); } } @Override protected void startPage(PDPage page) throws IOException { try { handler.startElement("div", "class", "page"); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to start a page", e); } writeParagraphStart(); } @Override protected void endPage(PDPage page) throws IOException { try { writeParagraphEnd(); extractImages(page.getResources(), new HashSet<COSBase>()); EmbeddedDocumentExtractor extractor = getEmbeddedDocumentExtractor(); for (PDAnnotation annotation : page.getAnnotations()) { if (annotation instanceof PDAnnotationFileAttachment) { PDAnnotationFileAttachment fann = (PDAnnotationFileAttachment) annotation; PDComplexFileSpecification fileSpec = (PDComplexFileSpecification) fann.getFile(); try { extractMultiOSPDEmbeddedFiles("", fileSpec, extractor); } catch (SAXException e) { throw new IOExceptionWithCause("file embedded in annotation sax exception", e); } catch (TikaException e) { throw new IOExceptionWithCause("file embedded in annotation tika exception", e); } } // TODO: remove once PDFBOX-1143 is fixed: if (config.getExtractAnnotationText()) { if (annotation instanceof PDAnnotationLink) { PDAnnotationLink annotationlink = (PDAnnotationLink) annotation; if (annotationlink.getAction() != null) { PDAction action = annotationlink.getAction(); if (action instanceof PDActionURI) { PDActionURI uri = (PDActionURI) action; String link = uri.getURI(); if (link != null) { handler.startElement("div", "class", "annotation"); handler.startElement("a", "href", link); handler.endElement("a"); handler.endElement("div"); } } } } if (annotation instanceof PDAnnotationMarkup) { PDAnnotationMarkup annotationMarkup = (PDAnnotationMarkup) annotation; String title = annotationMarkup.getTitlePopup(); String subject = annotationMarkup.getSubject(); String contents = annotationMarkup.getContents(); // TODO: maybe also annotationMarkup.getRichContents()? if (title != null || subject != null || contents != null) { handler.startElement("div", "class", "annotation"); if (title != null) { handler.startElement("div", "class", "annotationTitle"); handler.characters(title); handler.endElement("div"); } if (subject != null) { handler.startElement("div", "class", "annotationSubject"); handler.characters(subject); handler.endElement("div"); } if (contents != null) { handler.startElement("div", "class", "annotationContents"); handler.characters(contents); handler.endElement("div"); } handler.endElement("div"); } } } } handler.endElement("div"); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to end a page", e); } page.clear(); } private void extractImages(PDResources resources, Set<COSBase> seenThisPage) throws SAXException { if (resources == null || config.getExtractInlineImages() == false) { return; } Map<String, PDXObject> xObjects = resources.getXObjects(); if (xObjects == null) { return; } for (Map.Entry<String, PDXObject> entry : xObjects.entrySet()) { PDXObject object = entry.getValue(); if (object == null) { continue; } COSBase cosObject = object.getCOSObject(); if (seenThisPage.contains(cosObject)) { //avoid infinite recursion TIKA-1742 continue; } seenThisPage.add(cosObject); if (object instanceof PDXObjectForm) { extractImages(((PDXObjectForm) object).getResources(), seenThisPage); } else if (object instanceof PDXObjectImage) { PDXObjectImage image = (PDXObjectImage) object; Metadata metadata = new Metadata(); String extension = ""; if (image instanceof PDJpeg) { metadata.set(Metadata.CONTENT_TYPE, "image/jpeg"); extension = ".jpg"; } else if (image instanceof PDCcitt) { metadata.set(Metadata.CONTENT_TYPE, "image/tiff"); extension = ".tif"; } else if (image instanceof PDPixelMap) { metadata.set(Metadata.CONTENT_TYPE, "image/png"); extension = ".png"; } Integer imageNumber = processedInlineImages.get(entry.getKey()); if (imageNumber == null) { imageNumber = inlineImageCounter++; } String fileName = "image" + imageNumber + extension; metadata.set(Metadata.RESOURCE_NAME_KEY, fileName); // Output the img tag AttributesImpl attr = new AttributesImpl(); attr.addAttribute("", "src", "src", "CDATA", "embedded:" + fileName); attr.addAttribute("", "alt", "alt", "CDATA", fileName); handler.startElement("img", attr); handler.endElement("img"); //Do we only want to process unique COSObject ids? //If so, have we already processed this one? if (config.getExtractUniqueInlineImagesOnly() == true) { String cosObjectId = entry.getKey(); if (processedInlineImages.containsKey(cosObjectId)) { continue; } processedInlineImages.put(cosObjectId, imageNumber); } metadata.set(TikaCoreProperties.EMBEDDED_RESOURCE_TYPE, TikaCoreProperties.EmbeddedResourceType.INLINE.toString()); EmbeddedDocumentExtractor extractor = getEmbeddedDocumentExtractor(); if (extractor.shouldParseEmbedded(metadata)) { ByteArrayOutputStream buffer = new ByteArrayOutputStream(); try { image.write2OutputStream(buffer); image.clear(); extractor.parseEmbedded(new ByteArrayInputStream(buffer.toByteArray()), new EmbeddedContentHandler(handler), metadata, false); } catch (IOException e) { // could not extract this image, so just skip it... } } } } resources.clear(); } protected EmbeddedDocumentExtractor getEmbeddedDocumentExtractor() { EmbeddedDocumentExtractor extractor = context.get(EmbeddedDocumentExtractor.class); if (extractor == null) { extractor = new ParsingEmbeddedDocumentExtractor(context); } return extractor; } @Override protected void writeParagraphStart() throws IOException { super.writeParagraphStart(); try { handler.startElement("p"); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to start a paragraph", e); } } @Override protected void writeParagraphEnd() throws IOException { super.writeParagraphEnd(); try { handler.endElement("p"); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to end a paragraph", e); } } @Override protected void writeString(String text) throws IOException { try { handler.characters(text); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to write a string: " + text, e); } } @Override protected void writeCharacters(TextPosition text) throws IOException { try { handler.characters(text.getCharacter()); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to write a character: " + text.getCharacter(), e); } } @Override protected void writeWordSeparator() throws IOException { try { handler.characters(getWordSeparator()); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to write a space character", e); } } @Override protected void writeLineSeparator() throws IOException { try { handler.newline(); } catch (SAXException e) { throw new IOExceptionWithCause("Unable to write a newline character", e); } } private void extractEmbeddedDocuments(PDDocument document, ContentHandler handler) throws IOException, SAXException, TikaException { PDDocumentCatalog catalog = document.getDocumentCatalog(); PDDocumentNameDictionary names = catalog.getNames(); if (names == null) { return; } PDEmbeddedFilesNameTreeNode embeddedFiles = names.getEmbeddedFiles(); if (embeddedFiles == null) { return; } Map<String, COSObjectable> embeddedFileNames = embeddedFiles.getNames(); //For now, try to get the embeddedFileNames out of embeddedFiles or its kids. //This code follows: pdfbox/examples/pdmodel/ExtractEmbeddedFiles.java //If there is a need we could add a fully recursive search to find a non-null //Map<String, COSObjectable> that contains the doc info. if (embeddedFileNames != null) { processEmbeddedDocNames(embeddedFileNames); } else { List<PDNameTreeNode> kids = embeddedFiles.getKids(); if (kids == null) { return; } for (PDNameTreeNode n : kids) { Map<String, COSObjectable> childNames = n.getNames(); if (childNames != null) { processEmbeddedDocNames(childNames); } } } } private void processEmbeddedDocNames(Map<String, COSObjectable> embeddedFileNames) throws IOException, SAXException, TikaException { if (embeddedFileNames == null || embeddedFileNames.isEmpty()) { return; } EmbeddedDocumentExtractor extractor = getEmbeddedDocumentExtractor(); for (Map.Entry<String, COSObjectable> ent : embeddedFileNames.entrySet()) { PDComplexFileSpecification spec = (PDComplexFileSpecification) ent.getValue(); extractMultiOSPDEmbeddedFiles(ent.getKey(), spec, extractor); } } private void extractMultiOSPDEmbeddedFiles(String defaultName, PDComplexFileSpecification spec, EmbeddedDocumentExtractor extractor) throws IOException, SAXException, TikaException { if (spec == null) { return; } //current strategy is to pull all, not just first non-null extractPDEmbeddedFile(defaultName, spec.getFile(), spec.getEmbeddedFile(), extractor); extractPDEmbeddedFile(defaultName, spec.getFileMac(), spec.getEmbeddedFileMac(), extractor); extractPDEmbeddedFile(defaultName, spec.getFileDos(), spec.getEmbeddedFileDos(), extractor); extractPDEmbeddedFile(defaultName, spec.getFileUnix(), spec.getEmbeddedFileUnix(), extractor); } private void extractPDEmbeddedFile(String defaultName, String fileName, PDEmbeddedFile file, EmbeddedDocumentExtractor extractor) throws SAXException, IOException, TikaException { if (file == null) { //skip silently return; } fileName = (fileName == null) ? defaultName : fileName; // TODO: other metadata? Metadata metadata = new Metadata(); metadata.set(Metadata.RESOURCE_NAME_KEY, fileName); metadata.set(Metadata.CONTENT_TYPE, file.getSubtype()); metadata.set(Metadata.CONTENT_LENGTH, Long.toString(file.getSize())); metadata.set(TikaCoreProperties.EMBEDDED_RESOURCE_TYPE, TikaCoreProperties.EmbeddedResourceType.ATTACHMENT.toString()); if (extractor.shouldParseEmbedded(metadata)) { TikaInputStream stream = null; try { stream = TikaInputStream.get(file.createInputStream()); extractor.parseEmbedded(stream, new EmbeddedContentHandler(handler), metadata, false); AttributesImpl attributes = new AttributesImpl(); attributes.addAttribute("", "class", "class", "CDATA", "embedded"); attributes.addAttribute("", "id", "id", "CDATA", fileName); handler.startElement("div", attributes); handler.endElement("div"); } finally { IOUtils.closeQuietly(stream); } } } private void extractAcroForm(PDDocument pdf, XHTMLContentHandler handler) throws IOException, SAXException { //Thank you, Ben Litchfield, for org.apache.pdfbox.examples.fdf.PrintFields //this code derives from Ben's code PDDocumentCatalog catalog = pdf.getDocumentCatalog(); if (catalog == null) return; PDAcroForm form = catalog.getAcroForm(); if (form == null) return; //if it has xfa, try that. //if it doesn't exist or there's an exception, //go with traditional AcroForm PDXFA pdxfa = form.getXFA(); if (pdxfa != null) { XFAExtractor xfaExtractor = new XFAExtractor(); try { xfaExtractor.extract(new BufferedInputStream(new ByteArrayInputStream(pdxfa.getBytes())), handler, metadata); return; } catch (XMLStreamException | IOException e) { //if there was an xml parse exception in xfa, try the AcroForm } } @SuppressWarnings("rawtypes") List fields = form.getFields(); if (fields == null) return; @SuppressWarnings("rawtypes") ListIterator itr = fields.listIterator(); if (itr == null) return; handler.startElement("div", "class", "acroform"); handler.startElement("ol"); while (itr.hasNext()) { Object obj = itr.next(); if (obj != null && obj instanceof PDField) { processAcroField((PDField) obj, handler, 0); } } handler.endElement("ol"); handler.endElement("div"); } private void processAcroField(PDField field, XHTMLContentHandler handler, final int currentRecursiveDepth) throws SAXException, IOException { if (currentRecursiveDepth >= MAX_ACROFORM_RECURSIONS) { return; } addFieldString(field, handler); List<COSObjectable> kids = field.getKids(); if (kids != null) { int r = currentRecursiveDepth + 1; handler.startElement("ol"); //TODO: can generate <ol/>. Rework to avoid that. for (COSObjectable pdfObj : kids) { if (pdfObj != null && pdfObj instanceof PDField) { PDField kid = (PDField) pdfObj; //recurse processAcroField(kid, handler, r); } } handler.endElement("ol"); } } private void addFieldString(PDField field, XHTMLContentHandler handler) throws SAXException { //Pick partial name to present in content and altName for attribute //Ignoring FullyQualifiedName for now String partName = field.getPartialName(); String altName = field.getAlternateFieldName(); StringBuilder sb = new StringBuilder(); AttributesImpl attrs = new AttributesImpl(); if (partName != null) { sb.append(partName).append(": "); } if (altName != null) { attrs.addAttribute("", "altName", "altName", "CDATA", altName); } //return early if PDSignature field if (field instanceof PDSignatureField) { handleSignature(attrs, (PDSignatureField) field, handler); return; } try { //getValue can throw an IOException if there is no value String value = field.getValue(); if (value != null && !value.equals("null")) { sb.append(value); } } catch (IOException e) { //swallow } if (attrs.getLength() > 0 || sb.length() > 0) { handler.startElement("li", attrs); handler.characters(sb.toString()); handler.endElement("li"); } } private void handleSignature(AttributesImpl parentAttributes, PDSignatureField sigField, XHTMLContentHandler handler) throws SAXException { PDSignature sig = sigField.getSignature(); if (sig == null) { return; } Map<String, String> vals = new TreeMap<String, String>(); vals.put("name", sig.getName()); vals.put("contactInfo", sig.getContactInfo()); vals.put("location", sig.getLocation()); vals.put("reason", sig.getReason()); Calendar cal = sig.getSignDate(); if (cal != null) { dateFormat.setTimeZone(cal.getTimeZone()); vals.put("date", dateFormat.format(cal.getTime())); } //see if there is any data int nonNull = 0; for (String val : vals.keySet()) { if (val != null && !val.equals("")) { nonNull++; } } //if there is, process it if (nonNull > 0) { handler.startElement("li", parentAttributes); AttributesImpl attrs = new AttributesImpl(); attrs.addAttribute("", "type", "type", "CDATA", "signaturedata"); handler.startElement("ol", attrs); for (Map.Entry<String, String> e : vals.entrySet()) { if (e.getValue() == null || e.getValue().equals("")) { continue; } attrs = new AttributesImpl(); attrs.addAttribute("", "signdata", "signdata", "CDATA", e.getKey()); handler.startElement("li", attrs); handler.characters(e.getValue()); handler.endElement("li"); } handler.endElement("ol"); handler.endElement("li"); } } }