In some cases, the document paths stored inside the index do not match the actual ones, so that document previews and accesses will fail. This can occur in a number of circumstances:
When using multiple indexes it is a relatively common
occurrence that some will actually reside on a remote volume, for
exemple mounted via NFS. In this case, the paths used to access
the documents on the local machine are not necessarily the same
than the ones used while indexing on the remote machine. For
example, /home/me
may have been used as
a topdirs
elements while indexing, but the
directory might be mounted
as /net/server/home/me
on the local
machine.
The case may also occur with removable disks. It is perfectly possible to configure an index to live with the documents on the removable disk, but it may happen that the disk is not mounted at the same place so that the documents paths from the index are invalid.
As a last exemple, one could imagine that a big directory has been moved, but that it is currently inconvenient to run the indexer.
More generally, the path translation facility may be useful whenever the documents paths seen by the indexer are not the same as the ones which should be used at query time.
Recoll has a facility for rewriting access paths when extracting the data from the index. The translations can be defined for the main index and for any additional query index.
In the above NFS example, Recoll could be instructed to
rewrite any file:///home/me
URL from the
index to file:///net/server/home/me
,
allowing accesses from the client.
The translations are defined in the
ptrans
configuration file, which
can be edited by hand or from the GUI external indexes
configuration dialog.