WP: selection to json && json to selection - write pro areas become blank

Hi,

I export a selection of records with « regular » fields plus a Write pro one.
<code 4D>
$T_JSON:=Selection to JSON([BIBLIOTHEQUE_CONTRAT])
</code 4D>
When records are imported the WP becomes totaly blank
<code 4D>
$T_JSON:=Document to text($T_Path;“UTF-8”;Document unchanged)
JSON TO SELECTION([BIBLIOTHEQUE_CONTRAT];$T_JSON)
</code 4D>

all imported fields are OK but write pro one

To be a bit clearer:
The object field is well reimported (?) but when displayed it is blank

I might be wrong, but my understanding is that JSON can not contain BLOBs.

a Write Pro object is a special class that contains binary data, which means you can not stringify it.

(well you can, but the method prototype is over-ridden to return just the basic document info in JSON)

I followed your endless advises so I switched to a new option:

EXPORT DATA("") with 4D Application format

The result is the same: WP documents are lost