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package org.apache.pdfbox.preflight.process;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import javax.imageio.ImageIO;
import javax.xml.bind.DatatypeConverter;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSDocument;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSObject;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.preflight.PreflightConstants;
import org.apache.pdfbox.preflight.PreflightContext;
import org.apache.pdfbox.preflight.ValidationResult.ValidationError;
import org.apache.pdfbox.preflight.exception.ValidationException;
import org.apache.pdfbox.preflight.metadata.PDFAIdentificationValidation;
import org.apache.pdfbox.preflight.metadata.RDFAboutAttributeConcordanceValidation;
import org.apache.pdfbox.preflight.metadata.RDFAboutAttributeConcordanceValidation.DifferentRDFAboutException;
import org.apache.pdfbox.preflight.metadata.SynchronizedMetaDataValidation;
import org.apache.pdfbox.preflight.metadata.XpacketParsingException;
import org.apache.pdfbox.preflight.utils.COSUtils;
import org.apache.xmpbox.XMPMetadata;
import org.apache.xmpbox.schema.XMPBasicSchema;
import org.apache.xmpbox.type.BadFieldValueException;
import org.apache.xmpbox.type.ThumbnailType;
import org.apache.xmpbox.xml.DomXmpParser;
import org.apache.xmpbox.xml.XmpParsingException;
import org.apache.xmpbox.xml.XmpParsingException.ErrorType;
public class MetadataValidationProcess extends AbstractProcess
{
@Override
public void validate(PreflightContext ctx) throws ValidationException
{
try
{
PDDocument document = ctx.getDocument();
InputStream is = getXpacket(document.getDocument());
DomXmpParser builder = new DomXmpParser();
XMPMetadata metadata = builder.parse(is);
is.close();
ctx.setMetadata(metadata);
// 6.7.5 no deprecated attribute in xpacket processing instruction
if (metadata.getXpacketBytes() != null)
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_XPACKET_DEPRECATED,
"bytes attribute is forbidden"));
}
if (metadata.getXpacketEncoding() != null)
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_XPACKET_DEPRECATED,
"encoding attribute is forbidden"));
}
checkThumbnails(ctx, metadata);
// Call metadata synchronization checking
addValidationErrors(ctx,
new SynchronizedMetaDataValidation().validateMetadataSynchronization(document, metadata));
// Call PDF/A Identifier checking
addValidationErrors(ctx, new PDFAIdentificationValidation().validatePDFAIdentifer(metadata));
// Call rdf:about checking
try
{
new RDFAboutAttributeConcordanceValidation().validateRDFAboutAttributes(metadata);
}
catch (DifferentRDFAboutException e)
{
addValidationError(ctx, new ValidationError(
PreflightConstants.ERROR_METADATA_RDF_ABOUT_ATTRIBUTE_INEQUAL_VALUE, e.getMessage(), e));
}
}
catch (XpacketParsingException e)
{
if (e.getError() != null)
{
addValidationError(ctx, e.getError());
}
else
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_MAIN, "Unexpected error", e));
}
}
catch (XmpParsingException e)
{
if (e.getErrorType() == ErrorType.NoValueType)
{
addValidationError(ctx,
new ValidationError(PreflightConstants.ERROR_METADATA_UNKNOWN_VALUETYPE, e.getMessage(), e));
}
else if (e.getErrorType() == ErrorType.RequiredProperty)
{
addValidationError(ctx,
new ValidationError(PreflightConstants.ERROR_METADATA_PROPERTY_MISSING, e.getMessage(), e));
}
else if (e.getErrorType() == ErrorType.InvalidPrefix)
{
addValidationError(ctx, new ValidationError(
PreflightConstants.ERROR_METADATA_ABSENT_DESCRIPTION_SCHEMA, e.getMessage(), e));
}
else if (e.getErrorType() == ErrorType.InvalidType)
{
addValidationError(ctx,
new ValidationError(PreflightConstants.ERROR_METADATA_PROPERTY_UNKNOWN, e.getMessage(), e));
}
else if (e.getErrorType() == ErrorType.XpacketBadEnd)
{
throw new ValidationException("Unable to parse font metadata due to : " + e.getMessage(), e);
}
else if (e.getErrorType() == ErrorType.NoSchema)
{
addValidationError(ctx, new ValidationError(
PreflightConstants.ERROR_METADATA_ABSENT_DESCRIPTION_SCHEMA, e.getMessage(), e));
}
else if (e.getErrorType() == ErrorType.InvalidPdfaSchema)
{
addValidationError(ctx,
new ValidationError(PreflightConstants.ERROR_METADATA_WRONG_NS_URI, e.getMessage(), e));
}
else
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT, e.getMessage(), e));
}
}
catch (IOException e)
{
throw new ValidationException("Failed while validating", e);
}
}
// check thumbnails. See Bavaria Testsuite file PDFA_Conference_2009_nc.pdf for an example.
private void checkThumbnails(PreflightContext ctx, XMPMetadata metadata)
{
XMPBasicSchema xmp = metadata.getXMPBasicSchema();
if (xmp == null)
{
return;
}
List<ThumbnailType> tbProp;
try
{
tbProp = xmp.getThumbnailsProperty();
}
catch (BadFieldValueException e)
{
// should not happen here because it would have happened in XmpParser already
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT, e.getMessage(), e));
return;
}
if (tbProp == null)
{
return;
}
for (ThumbnailType tb : tbProp)
{
checkThumbnail(tb, ctx);
}
}
private void checkThumbnail(ThumbnailType tb, PreflightContext ctx)
{
byte[] binImage;
try
{
binImage = DatatypeConverter.parseBase64Binary(tb.getImage());
}
catch (IllegalArgumentException e)
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"xapGImg:image is not correct base64 encoding"));
return;
}
if (!hasJpegMagicNumber(binImage))
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"xapGImg:image decoded base64 content is not in JPEG format"));
return;
}
BufferedImage bim;
try
{
bim = ImageIO.read(new ByteArrayInputStream(binImage));
}
catch (IOException e)
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT, e.getMessage(), e));
return;
}
if (!"JPEG".equals(tb.getFormat()))
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"xapGImg:format must be 'JPEG'"));
}
if (bim.getHeight() != tb.getHeight())
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"xapGImg:height does not match the actual base64-encoded thumbnail image data"));
}
if (bim.getWidth() != tb.getWidth())
{
addValidationError(ctx, new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"xapGImg:witdh does not match the actual base64-encoded thumbnail image data"));
}
}
private boolean hasJpegMagicNumber(byte[] binImage)
{
if (binImage.length < 4)
{
return false;
}
return (binImage[0] == (byte) 0xFF
&& binImage[1] == (byte) 0xD8
&& binImage[binImage.length - 2] == (byte) 0xFF
&& binImage[binImage.length - 1] == (byte) 0xD9);
}
/**
* Return the xpacket from the dictionary's stream
*/
private static InputStream getXpacket(COSDocument cdocument) throws IOException, XpacketParsingException
{
COSObject catalog = cdocument.getCatalog();
COSBase cb = catalog.getDictionaryObject(COSName.METADATA);
if (cb == null)
{
// missing Metadata Key in catalog
ValidationError error = new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"Missing Metadata Key in catalog");
throw new XpacketParsingException("Failed while retrieving xpacket", error);
}
// no filter key
COSDictionary metadataDictionnary = COSUtils.getAsDictionary(cb, cdocument);
if (metadataDictionnary.getItem(COSName.FILTER) != null)
{
// should not be defined
ValidationError error = new ValidationError(PreflightConstants.ERROR_SYNTAX_STREAM_INVALID_FILTER,
"Filter specified in metadata dictionnary");
throw new XpacketParsingException("Failed while retrieving xpacket", error);
}
if (!(metadataDictionnary instanceof COSStream))
{
// missing Metadata Key in catalog
ValidationError error = new ValidationError(PreflightConstants.ERROR_METADATA_FORMAT,
"Metadata is not a stream");
throw new XpacketParsingException("Failed while retrieving xpacket", error);
}
COSStream stream = (COSStream) metadataDictionnary;
return stream.createInputStream();
}
/**
* Check if metadata dictionary has no stream filter
*
* @param doc the document to check.
* @return the list of validation errors.
*/
protected List<ValidationError> checkStreamFilterUsage(PDDocument doc)
{
List<ValidationError> ve = new ArrayList<>();
List<?> filters = doc.getDocumentCatalog().getMetadata().getFilters();
if (filters != null && !filters.isEmpty())
{
ve.add(new ValidationError(PreflightConstants.ERROR_METADATA_MAIN,
"Using stream filter on metadata dictionary is forbidden"));
}
return ve;
}
}