Configure postgres fts backend

modules/restserver/src/main/resources/reference.conf

@@ -289,6 +289,9 @@ docspell.server {
     # Currently the SOLR search platform is supported.
     enabled = false
 
+    # Which backend to use, either solr or postgresql
+    backend = "solr"
+
     # Configuration for the SOLR backend.
     solr = {
       # The URL to solr
@@ -304,6 +307,43 @@ docspell.server {
       # The default combiner for tokens. One of {AND, OR}.
       q-op = "OR"
     }
+
+    # Configuration for PostgreSQL backend
+    postgresql = {
+      # Whether to use the default database, only works if it is
+      # postgresql
+      use-default-connection = false
+
+      # The database connection.
+      jdbc {
+        url = "jdbc:postgresql://server:5432/db"
+        user = "pguser"
+        password = ""
+      }
+
+      # A mapping from a language to a postgres text search config. By
+      # default a language is mapped to a predefined config.
+      # PostgreSQL has predefined configs for some languages. This
+      # setting allows to create a custom text search config and
+      # define it here for some or all languages.
+      #
+      # Example:
+      #  { german = "my-german" }
+      #
+      # See https://www.postgresql.org/docs/14/textsearch-tables.html ff.
+      pg-config = {
+      }
+
+      # Define which query parser to use.
+      #
+      # https://www.postgresql.org/docs/14/textsearch-controls.html#TEXTSEARCH-PARSING-QUERIES
+      pg-query-parser = "websearch_to_tsquery"
+
+      # Allows to define a normalization for the ranking.
+      #
+      # https://www.postgresql.org/docs/14/textsearch-controls.html#TEXTSEARCH-RANKING
+      pg-rank-normalization = [ 4 ]
+    }
   }
 
   # Configuration for the backend.