User extended attributes are named pieces of information that most modern file systems can attach to any file.
Recoll processes all extended attributes as document fields. Note that most
fields are not indexed by default, you need to activate them by defining a prefix in
the fields
configuration file.
A freedesktop standard defines a few special attributes, which are handled as such by Recoll:
- mime_type
If set, this overrides any other determination of the file MIME type.
- charset
If set, this defines the file character set (mostly useful for plain text files).
By default, other attributes are handled as Recoll fields of the same name,
after removing the "user" prefix on Linux.
The name translation can be configured more precisely, inside the
fields configuration
file.
Setting the document modification/creation date
Some documents have an internal date attribute (e.g. emails), but most get their
date from the file modification time. It is possible to set a document date different from
the file's by setting a specific extended attribute. For obscure and uninteresting
reasons, the name of the attribute is harcoded as modificationdate.
Its contents should be the ASCII representation of a decimal integer representing the Unix
time (seconds since the epoch). An example Linux command line for setting this particular
field follow. The substituted date prints the example date parameter in
Unix time format (seconds since the epoch).
setfattr -n user.modificationdate -v `date -d '2022-09-30 08:30:00' +%s` /some/file
The date substitution will then be automatic, you do not need to customise
the fields file.
