Fix issue where CustomConverter is ignored in table-driven feature mapping mode and provide exemplary implementations [3.5]

[stephanr]

This PR fixes the table-driven mapping of feature types, which until now ignored custom converts.

Besides documentation, an exemplary implementation to map BLOB/bytea columns as strings encoded in RFC 4648/2397 and large text columns CLOB/text as strings is included.

see #1668 for 3.6 version

Test setup

Oracle

CREATE TABLE LOB_TEST 
(
  ID NUMBER NOT NULL 
, CLOB CLOB 
, BLOB_BASE64 BLOB 
, BLOB_DATAURL BLOB 
);

CREATE SEQUENCE LOB_TEST_SEQ;

CREATE TRIGGER BI_LOB_TEST 
BEFORE INSERT ON LOB_TEST 
FOR EACH ROW 
BEGIN
  <<COLUMN_SEQUENCES>>
  BEGIN
    IF INSERTING AND :NEW.ID IS NULL THEN
      SELECT LOB_TEST_SEQ.NEXTVAL INTO :NEW.ID FROM SYS.DUAL;
    END IF;
  END COLUMN_SEQUENCES;
END;
/

PostgreSQL

CREATE TABLE public.lob_test
(
    id serial NOT NULL,
    clob text,
    blob_base64 bytea,
    blob_dataurl bytea,
    PRIMARY KEY (id)
);

Test requests

<Transaction xmlns="http://www.opengis.net/wfs" service="WFS" version="1.1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.1.0/wfs.xsd">
    <Insert>
        <LobTestOra xmlns="http://www.deegree.org/app">
            <clob>PNG</clob>
            <base64>iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAIAAAACUFjqAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAATSURBVChTY3gro4IHjUpjQTIqAIR/dZVEjQXwAAAAAElFTkSuQmCC</base64>
            <dataUrl>data:image/ignored;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAIAAAACUFjqAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAATSURBVChTY3gro4IHjUpjQTIqAIR/dZVEjQXwAAAAAElFTkSuQmCC</dataUrl>
        </LobTestOra>
    </Insert>
</Transaction>

More example requests, which are too large for the description:
example_requests.txt

References

• Fix issue where CustomConverter is ignored in table-driven feature mapping mode and provide exemplary implementations [3.6] #1668