first draft for a simple hooks based custom attribute storage,
with a BytesFileSystemStorage POC implementation.
Basically:
* a dictionary contains maps from which attribute of which entity types are
mapped to which custom storage
* hooks check for one of these entity type being added/modified/deleted
* read is based on the sql generator callback mecanism (used in vcsfile for
instance)
* all storages have the same basic interface (read, add, update, delete),
and should be pluggable in a transparent way (except at migration time
when one want to change from a storage to another)
* the sample BytesFileSystemStorage:
* may store Bytes attributes content of any entity type as file on the file system
* is based on one FSPATH rql/sql function and another _fsopen only available in sql
* has a dumb file name allocation algorithm
/* -*- sql -*-
postgres specific registered procedures,
require the plpgsql language installed
*/
DROP FUNCTION IF EXISTS comma_join (anyarray) CASCADE;
CREATE FUNCTION comma_join (anyarray) RETURNS text AS $$
SELECT array_to_string($1, ', ')
$$ LANGUAGE SQL;;
DROP AGGREGATE IF EXISTS group_concat (anyelement) CASCADE;
CREATE AGGREGATE group_concat (
basetype = anyelement,
sfunc = array_append,
stype = anyarray,
finalfunc = comma_join,
initcond = '{}'
);;
DROP FUNCTION IF EXISTS limit_size (fulltext text, format text, maxsize integer);
CREATE FUNCTION limit_size (fulltext text, format text, maxsize integer) RETURNS text AS $$
DECLARE
plaintext text;
BEGIN
IF char_length(fulltext) < maxsize THEN
RETURN fulltext;
END IF;
IF format = 'text/html' OR format = 'text/xhtml' OR format = 'text/xml' THEN
plaintext := regexp_replace(fulltext, '<[\\w/][^>]+>', '', 'g');
ELSE
plaintext := fulltext;
END IF;
IF char_length(plaintext) < maxsize THEN
RETURN plaintext;
ELSE
RETURN substring(plaintext from 1 for maxsize) || '...';
END IF;
END
$$ LANGUAGE plpgsql;;
DROP FUNCTION IF EXISTS text_limit_size (fulltext text, maxsize integer);
CREATE FUNCTION text_limit_size (fulltext text, maxsize integer) RETURNS text AS $$
BEGIN
RETURN limit_size(fulltext, 'text/plain', maxsize);
END
$$ LANGUAGE plpgsql;;