The index data and the access method are linked by the
rclbes (recoll backend storage) Doc field. You
should set this to a short string value identifying your indexer (e.g. the filesystem
indexer uses either FS or an empty value, the Web history indexer
uses BGL, the Joplin notes indexer
uses JOPLIN).
The link is actually performed inside a backends configuration
file (stored in the configuration directory). This defines commands to execute to access
data from the specified indexer. Example, for the mbox indexing sample found in the
Recoll source (which sets rclbes="MBOX"):
[MBOX] fetch = /path/to/recoll/src/python/samples/rclmbox.py fetch makesig = /path/to/recoll/src/python/samples/rclmbox.py makesig index = /path/to/recoll/src/python/samples/rclmbox.py index
When updating the index, the recollindex will execute the value
of the the index parameter, if present (it may not be present if this
concerns an external index).
If an external indexer needs to store additional configuration parameters, e.g. path
to a specific instance of the indexed application, etc., I suggest storing them
inside recoll.conf, with a backend-specific prefix
(e.g. joplin_db, mbox_directory)
and using methods from the rclconfig module to access them.
