This filter is used to search or extract hashes from a Message.
Supported types of hashes are:
|target||STRING||“main”||the field of the Message that should be used for the filter (it could be main or an extra field)|
... | hash(target="description", extract="true") | ...
extract parameter is “false”, the received Message will be propagated only if at least one hash is found in it.
extract is “true” and the Message contains one or more hashes, the
main field of the propagated Message will contain only the extracted hash.
extract parameter is “true” and the message is propagated, a new extra field is created:
fulltext will contain the original