how can i get the filename of an uploaded file for indexing?

[Solange Silva Ajuria]

hello,
your collaboration please.
I'm using solr 8.11

I need to configure the requestHandler (/update/extract) to add a field that 
stores the name of the uploaded file, but I can't find how to do it.

in mager-schema.xml, I define a field :
<field name="name" type="string" multiValued="false" indexed="true" 
stored="true" />

FieldType string is defined.

But I don't know how to capture the filename and store it in "name"


<requestHandler name="/update/extract"
  startup="lazy"
  class="solr.extraction.ExtractingRequestHandler" >
  <lst name="defaults">
    <str name="lowernames">true</str>
    <str name="uprefix">ignored_</str>
  <str name="fmap.content">content</str>
  <str name="fmap.stream_name">name</str>
<str name="processor">uuid,remove-blank,field-name-mutating</str>
  </lst>
</requestHandler>

results:

... "name":"file"....


I need something like:

..."name" : "my_file_name.pdf"...

Your help please

Thanks
Solange