Preserving instance metadata in Lua script

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1

Hello,
In my setup any instance that is received is compressed to JPEG2000 using the Lua script below. The problem is this changes the metadata on the instance to something like as follows:

{
“IndexInSeries”: “585”,
“Origin”: “Lua”,
“ReceptionDate”: “20190918T204126”,
“RemoteAET”: “”,
“SopClassUid”: “1.2.840.10008.5.1.4.1.1.2”,
“TransferSyntax”: “1.2.840.10008.1.2.4.90”
}

Is it possible to retain the original metadata as I really need to get the RemoteAET info. The script I’m using is below:

function OnStoredInstance(instanceId, tags, metadata, origin)
– Do not compress twice the same file
if origin[‘RequestOrigin’] ~= ‘Lua’ then

– Retrieve the incoming DICOM instance from Orthanc
local dicom = RestApiGet(‘/instances/’ … instanceId … ‘/file’)

– Write the DICOM content to some temporary file
local uncompressed = instanceId … ‘-uncompressed.dcm’
local target = assert(io.open(uncompressed, ‘wb’))
target:write(dicom)
target:close()

– Compress to JPEG2000 using gdcm
local compressed = instanceId … ‘-compressed.dcm’
os.execute('C:\Orthanc\Tools\GDCM\bin\gdcmconv.exe -U --j2k ’ … uncompressed … ’ ’ … compressed)

–os.execute('C:\Orthanc\Tools\dcmtk\bin\dcmodify.exe --no-backup -gin ’ … compressed)
os.execute(‘C:\Orthanc\Tools\dcmtk\bin\dcmodify.exe --no-backup -m "SOPInstanceUID=’ … tags[‘SOPInstanceUID’] … '" ’ … compressed)

– Read the JPEG2000 file
local source = assert(io.open(compressed, ‘rb’))
local jpeg2k = source:read(“*all”)
source:close()

– Upload the JPEG2000 file and remove the uncompressed file
RestApiDelete(‘/instances/’ … instanceId)
RestApiPost(‘/instances’, jpeg2k)

– Remove the temporary DICOM files
os.remove(uncompressed)
os.remove(compressed)

end
end

2

Hi Rana,

This is currently not possible.
What you could do in your lua script is:

  • read the Origin & RemoteAET from the uncompressed instance and store them in local variables
  • compress and upload the new instance
  • set new metadata in the compressed instance (however, you won’t be able to overwrite the Origin and RemoteAET since they are ‘internal’ metadatas https://book.orthanc-server.com/faq/features.html#core-metadata). So, this means that you’ll have to define “MyOrigin” and “MyRemoteAET” to store this info.

Best regards,

Alain.

3

Thank you.