nixos/nextcloud-notify_push: fix connecting to mysql via socket (#348114)

        dbType = if cfg.dbtype == "pgsql" then "postgresql" else cfg.dbtype;

        dbUser = lib.optionalString (cfg.dbuser != null) cfg.dbuser;

        dbPass = lib.optionalString (cfg.dbpassFile != null) ":$DATABASE_PASSWORD";

        isSocket = lib.hasPrefix "/" (toString cfg.dbhost);

        dbHostHasPrefix = prefix: lib.hasPrefix prefix (toString cfg.dbhost);

        isPostgresql = dbType == "postgresql";

        isMysql = dbType == "mysql";

        isSocket = (isPostgresql && dbHostHasPrefix "/") || (isMysql && dbHostHasPrefix "localhost:/");

        dbHost = lib.optionalString (cfg.dbhost != null) (if

          isSocket then

            if dbType == "postgresql" then "?host=${cfg.dbhost}" else

            if dbType == "mysql" then "?socket=${cfg.dbhost}" else throw "unsupported dbtype"

            lib.optionalString isMysql "@localhost"

          else

            "@${cfg.dbhost}");

        dbOpts = lib.optionalString (cfg.dbhost != null && isSocket) (

          if isPostgresql then "?host=${cfg.dbhost}" else

          if isMysql then "?socket=${lib.removePrefix "localhost:" cfg.dbhost}" else throw "unsupported dbtype"

        );

        dbName = lib.optionalString (cfg.dbname != null) "/${cfg.dbname}";

        dbUrl = "${dbType}://${dbUser}${dbPass}${lib.optionalString (!isSocket) dbHost}${dbName}${lib.optionalString isSocket dbHost}";

        dbUrl = "${dbType}://${dbUser}${dbPass}${dbHost}${dbName}${dbOpts}";

      in lib.optionalString (dbPass != "") ''

        export DATABASE_PASSWORD="$(<"${cfg.dbpassFile}")"

      '' + ''