# Question about Lua Script to Edit / Add Tag OnStoredInstance, MWL Plug-in, misc.
**URL:** https://discourse.orthanc-server.org/t/question-about-lua-script-to-edit-add-tag-onstoredinstance-mwl-plug-in-misc/2422
**Category:** Google Groups archive
**Created:** [May 6, 2021, 11:25pm UTC](https://discourse.orthanc-server.org/t/question-about-lua-script-to-edit-add-tag-onstoredinstance-mwl-plug-in-misc/2422 "2021-05-06T23:25:14Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@sdscotti](https://discourse.orthanc-server.org/u/sdscotti)
#### Post date: [May 6, 2021, 11:25pm UTC](https://discourse.orthanc-server.org/t/question-about-lua-script-to-edit-add-tag-onstoredinstance-mwl-plug-in-misc/2422/1 "2021-05-06T23:25:14Z")
Question and Comment:
1. One of the acquisition devices we have does not read StudyDescription from the MWL and the operator normally has to enter that manually, although ‘tags[‘RequestAttributesSequence’][1][‘RequestedProcedureDescription’]’ is set via the MWL. I wrote a first attempt at a Lua script (below) based on an example that seems to work, but there might be a better way and it needs some error checking etc. Basically want to populate [‘0008,1030’] with [‘RequestAttributesSequence’][1][‘RequestedProcedureDescription’] if it is present in an instance when it gets sent to a from a particular AET via DICOM. Might want to add some other similar items down the road. It seems to work, but I only want to do that if:
a. [‘0008,1030’] is not already set.
b. [‘RequestAttributesSequence’][1][‘RequestedProcedureDescription’] is set.
Probably simple to check for those conditions, but I an a novice with Lua scripting, and not clear to me that this is the best way to do that. Also, wondering about performance since it has to create a modified instance, store it, and then delete than old one, rather than just making the change before it is stored the first time. Is it possible to just edit / add a tag before storing it the first time ?
1. Also, discovered an MWL plug-in on Github after connecting with the author:
[WorklistFilePurger](https://github.com/alvinak/WorklistFilePurger)
Not sure if that is indexed on the Orthanc site somewhere. Since I am using Custom Docker images, I guess I’d have to compile that when I build the Docker Container, or rewrite it in Python with some modifiations, but could be useful because I’d like to implement MPPS also. Might actually be easier to write a Python script that as suggested here: [https://groups.google.com/g/orthanc-users/c/Tec0xgD4s2c](https://groups.google.com/g/orthanc-users/c/Tec0xgD4s2c)
**Lua Script**
function OnStoredInstance(instanceId, tags, metadata, origin)
– PrintRecursive(instanceId)
– PrintRecursive(tags)
– PrintRecursive(metadata)
– PrintRecursive(origin)
– Do not modify twice the same file
if origin.RequestOrigin == ‘DicomProtocol’ and origin.RemoteAet == ‘SOME\_AET’ then
– Need a check here for [‘0008,1030’] not set and tags[‘RequestAttributesSequence’][1][‘RequestedProcedureDescription’] is set.
local replace = {}
replace[‘0008,1030’] = tags[‘RequestAttributesSequence’][1][‘RequestedProcedureDescription’]
local request = {}
request[‘Replace’] = replace
– Create the modified instance
local modified = RestApiPost(‘/instances/’ … instanceId … ‘/modify’,
DumpJson(request, true))
– Upload the modified instance to the Orthanc store
RestApiPost(‘/instances/’, modified)
– Delete the original instance
RestApiDelete(‘/instances/’ … instanceId)
end
end
end
---
### Author:  [@sdscotti](https://discourse.orthanc-server.org/u/sdscotti)
#### Post date: [May 7, 2021, 2:35am UTC](https://discourse.orthanc-server.org/t/question-about-lua-script-to-edit-add-tag-onstoredinstance-mwl-plug-in-misc/2422/2 "2021-05-07T02:35:03Z")
Did a little more testing. **This seems to work for the Instances, but not for the Study Level Study Description. Must be that Orthanc creates a Study Objects upon receipt of a new StudyInstanceUID and populates the Study Level StudyDescription at that point, so it isn’t setting that at the StudyLevel ?** This is the current version of the Lua Script. Added a function to check if a key in the table is set and not an empty string. Not sure how to handle that ? I basically want to add the StudyDescription to the Study, Series (if that applies) and to Instances.
Thanks.
function tableHasKey(table,key)
return table[key] ~= nil and table[key] ~= ‘’
end
function OnStoredInstance(instanceId, tags, metadata, origin)
– PrintRecursive(instanceId)
– PrintRecursive(tags)
– PrintRecursive(metadata)
– PrintRecursive(origin)
– Do not modify twice the same file
– if origin.RequestOrigin == ‘DicomProtocol’ and origin.RemoteAet == ‘IMACLATE2013’ or NmrEsaote
if origin[‘RequestOrigin’] ~= ‘Lua’ then
if origin.RequestOrigin == ‘DicomProtocol’ and origin.RemoteAet == ‘IMACLATE2013’ and not tableHasKey(tags,‘0008,1030’) and tableHasKey(tags,‘RequestAttributesSequence’) then
local replace = {}
replace[‘0008,1030’] = tags[‘RequestAttributesSequence’][1][‘RequestedProcedureDescription’]
local request = {}
request[‘Replace’] = replace
– Create the modified instance
local modified = RestApiPost(‘/instances/’ … instanceId … ‘/modify’,
DumpJson(request, true))
– Upload the modified instance to the Orthanc store
RestApiPost(‘/instances/’, modified)
– Delete the original instance
RestApiDelete(‘/instances/’ … instanceId)
end
end
end
---
### Author:  [@sdscotti](https://discourse.orthanc-server.org/u/sdscotti)
#### Post date: [May 8, 2021, 2:58am UTC](https://discourse.orthanc-server.org/t/question-about-lua-script-to-edit-add-tag-onstoredinstance-mwl-plug-in-misc/2422/3 "2021-05-08T02:58:54Z")
Seems to be somewhat related to this question: [Modification of DICOM tags without changing UUID](https://groups.google.com/g/orthanc-users/c/a8vy-CLNJl0/m/bsosZculAQAJ), but not completely.
---
### Author:  [@sdscotti](https://discourse.orthanc-server.org/u/sdscotti)
#### Post date: [May 12, 2021, 5:07am UTC](https://discourse.orthanc-server.org/t/question-about-lua-script-to-edit-add-tag-onstoredinstance-mwl-plug-in-misc/2422/4 "2021-05-12T05:07:50Z")
Having a conversation with myself, but found what I was looking for, although now might modify that somewhat to integrate with RIS or MWL files so that tags not handled my the Modality can be updated / added by the RIS or python plug-in for Orthanc.
function OnStoredInstance(instanceId, tags, metadata)
– Ignore the instances that result from a modification to avoid
– infinite loops
if (metadata[‘ModifiedFrom’] == nil and
metadata[‘AnonymizedFrom’] == nil) then
– The tags to be replaced
local replace = {}
replace[‘0070,0084’] = ‘Technologist/Operator’
replace[‘StudyDescription’] = ‘TEST STUDY’
– The tags to be removed
– local remove = { ‘MilitaryRank’ }
– Modify the instance, send it, then delete the modified instance
Delete(SendToModality(ModifyInstance(instanceId, replace, remove, true), ‘sample’))
– Delete the original instance
Delete(instanceId)
end
end