使用Apache PDFBox在PDF中查找javascript代码
我的目标是提取和处理PDF文档可能包含的任何JavasSript代码。 通过在编辑器中打开PDF，我可以看到如下对象：
402 0 obj <> endobj 我试图使用Apache PDFBox来实现这一目标，但到目前为止没有运气。
该行返回一个空列表：
jsObj = doc.getObjectsByType(COSName.JAVA_SCRIPT);
任何人都可以给我一些方向吗？
此工具基于PDFBox中的PrintFields示例。 它将在表单中显示Javascript字段。 我去年写了一篇关于AcroForm字段之间关系有问题的人（某些字段根据其他字段的值启用/禁用）。 还有其他地方可以有Javascript。
/* * 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 pdfboxpageimageextraction; import java.io.File; import java.io.IOException; import java.util.List; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDDocumentCatalog; import org.apache.pdfbox.pdmodel.interactive.action.PDAction; import org.apache.pdfbox.pdmodel.interactive.action.PDActionJavaScript; import org.apache.pdfbox.pdmodel.interactive.action.PDFormFieldAdditionalActions; import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget; import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm; import org.apache.pdfbox.pdmodel.interactive.form.PDField; import org.apache.pdfbox.pdmodel.interactive.form.PDNonTerminalField; import org.apache.pdfbox.pdmodel.interactive.form.PDTerminalField; /** * This example will take a PDF document and print all the fields from the file. * * @author Ben Litchfield * */ public class PrintJavaScriptFields { /** * This will print all the fields from the document. * * @param pdfDocument The PDF to get the fields from. * * @throws IOException If there is an error getting the fields. */ public void printFields(PDDocument pdfDocument) throws IOException { PDDocumentCatalog docCatalog = pdfDocument.getDocumentCatalog(); PDAcroForm acroForm = docCatalog.getAcroForm(); List fields = acroForm.getFields(); //System.out.println(fields.size() + " top-level fields were found on the form"); for (PDField field : fields) { processField(field, "|--", field.getPartialName()); } } private void processField(PDField field, String sLevel, String sParent) throws IOException { String partialName = field.getPartialName(); if (field instanceof PDTerminalField) { PDTerminalField termField = (PDTerminalField) field; PDFormFieldAdditionalActions fieldActions = field.getActions(); if (fieldActions != null) { System.out.println(field.getFullyQualifiedName() + ": " + fieldActions.getClass().getSimpleName() + " js field actionS:\n" + fieldActions.getCOSObject()); printPossibleJS(fieldActions.getK()); printPossibleJS(fieldActions.getC()); printPossibleJS(fieldActions.getF()); printPossibleJS(fieldActions.getV()); } for (PDAnnotationWidget widgetAction : termField.getWidgets()) { PDAction action = widgetAction.getAction(); if (action instanceof PDActionJavaScript) { System.out.println(field.getFullyQualifiedName() + ": " + action.getClass().getSimpleName() + " js widget action:\n" + action.getCOSObject()); printPossibleJS(action); } } } if (field instanceof PDNonTerminalField) { if (!sParent.equals(field.getPartialName())) { if (partialName != null) { sParent = sParent + "." + partialName; } } //System.out.println(sLevel + sParent); for (PDField child : ((PDNonTerminalField) field).getChildren()) { processField(child, "| " + sLevel, sParent); } } else { String fieldValue = field.getValueAsString(); StringBuilder outputString = new StringBuilder(sLevel); outputString.append(sParent); if (partialName != null) { outputString.append(".").append(partialName); } outputString.append(" = ").append(fieldValue); outputString.append(", type=").append(field.getClass().getName()); //System.out.println(outputString); } } private void printPossibleJS(PDAction kAction) { if (kAction instanceof PDActionJavaScript) { PDActionJavaScript jsAction = (PDActionJavaScript) kAction; String jsString = jsAction.getAction(); if (!jsString.contains("\n")) { // avoid display problems with netbeans jsString = jsString.replaceAll("\r", "\n").replaceAll("\n\n", "\n"); } System.out.println(jsString); System.out.println(); } } /** * This will read a PDF file and print out the form elements.
* see usage() for commandline * * @param args command line arguments * * @throws IOException If there is an error importing the FDF document. */ public static void main(String[] args) throws IOException { PDDocument pdf = null; try { pdf = PDDocument.load(new File("XXXX", "YYYYY.pdf")); PrintJavaScriptFields exporter = new PrintJavaScriptFields(); exporter.printFields(pdf); } finally { if (pdf != null) { pdf.close(); } } } }
作为奖励，这里是显示所有COSString对象的代码：
public class ShowAllCOSStrings { static Set strings = new HashSet (); static void crawl(COSBase base) { if (base instanceof COSString) { strings.add((COSString)base); return; } if (base instanceof COSDictionary) { COSDictionary dict = (COSDictionary) base; for (COSName key : dict.keySet()) { crawl(dict.getDictionaryObject(key)); } return; } if (base instanceof COSArray) { COSArray ar = (COSArray) base; for (COSBase item : ar) { crawl(item); } return; } if (base instanceof COSNull || base instanceof COSObject || base instanceof COSName || base instanceof COSNumber || base instanceof COSBoolean || base == null) { return; } System.out.println("huh? " + base); } public static void main(String[] args) throws IOException { PDDocument doc = PDDocument.load(new File("XXX","YYY.pdf")); for (COSObject obj : doc.getDocument().getObjects()) { COSBase base = obj.getObject(); //System.out.println(obj + ": " + base); crawl(base); } System.out.println(strings.size() + " strings:"); for (COSString s : strings) { String str = s.getString(); if (!str.contains("\n")) { // avoid display problems with netbeans str = str.replaceAll("\r", "\n").replaceAll("\n\n", "\n"); } System.out.println(str); } doc.close(); } }
但是，Javascript也可以在流中。 请参阅PDF规范“特定于再现操作的附加条目”，JS条目：
包含JavaScript脚本的文本字符串或流，该脚本将在触发操作时执行。
您可以更改上面的代码来捕获COSStream对象; COSStream从COSDictionary扩展而来。