daniel schmidt created TIKA-2591:
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Summary: Some tiffs (Big Endian with fax compression) are showing
up as x-tarr
Key: TIKA-2591
URL: https://issues.apache.org/jira/browse/TIKA-2591
Project: Tika
Issue Type: Bug
Components: core
Affects Versions: 1.16
Environment: Tika, running in a java application and a unit-test
(windows and mac environments)
Reporter: daniel schmidt
Fix For: 1.18
I have found that a certain tiff that we manage is now reporting
application/x-tar in Tika where it previously reported as a tiff (image/tiff).
Observe this code in ArchiveStreamFactory, detect method.
// COMPRESS-117 - improve auto-recognition
if (signatureLength >= TAR_HEADER_SIZE) {
TarArchiveInputStream tais = null;
try {
tais = new TarArchiveInputStream(new
ByteArrayInputStream(tarHeader));
// COMPRESS-191 - verify the header checksum
if (tais.getNextTarEntry().isCheckSumOK()) {
return TAR;
}
} catch (final Exception e) { // NOPMD // NOSONAR
// can generate IllegalArgumentException as well
// as IOException
// autodetection, simply not a TAR
// ignored
} finally {
IOUtils.closeQuietly(tais);
}
What if find is that most TIFs, when they get to tais.getNextTarEntry() fail
with an exception (i.e fall into the "simply not a tar" case). However this
tiff actually does NOT fail here. This somewhat makes sense as the internal
structure of a fax compressed tifs as a tar-like structure
Note, the CompositeDetector class eventually does recognize it as a proper tiff
as it loops through its detectors in its detect method. It is detected as tiff
in the MimeTypes class, which is one of the implementations of the Detector
interface
public MediaType detect(InputStream input, Metadata metadata)
throws IOException {
MediaType type = MediaType.OCTET_STREAM;
for (Detector detector : getDetectors()) {
//short circuit via OverrideDetector
//can't rely on ordering because subsequent detector may
//change Override's to a specialization of Override's
if (detector instanceof OverrideDetector &&
metadata.get(TikaCoreProperties.CONTENT_TYPE_OVERRIDE) != null) {
return detector.detect(input, metadata);
}
MediaType detected = detector.detect(input, metadata);
if (registry.isSpecializationOf(detected, type)) {
type = detected;
}
}
return type;
However since Image/tiff isn't a specialization of application/x-tar it does
not replace the type with tiff.
My fix was to add a "<sub-class-of type="application/x-tar"/>" to the
definition for image/tiff in the tika-mimetypes.xml file
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