How to insert and load TFileStream with TmongoWire - delphi

Question

I use Delphi and TmongoWire. I would like to insert TFileStream (picture, pdf) with TmongoWire on a MongoDb server. My work is based on this demo file: Delphi MongoDB driver
d:=BSON([
'id',mongoObjectID,
'name',ItemForm.txtName.Text,
'address',ItemForm.txtAddress.Text,
'phone',ItemForm.txtPhone.Text,
'picture', TFileStream.Create('C:\temp\mongotest.jpeg', fmOpenRead or fmShareDenyWrite)
]);
FMongoWire.Insert(mwx1Collection,d);
//LoadItems;
LoadItem(ListView1.Items.Add,d);
UpdateCount;}
Inserting a stream file does not work, can somebody see why ?
The program does not compile : Error --> BSON can not be called with these arguments
There is no problem to insert a simple text field (code below) :
d:=BSON([
'id',mongoObjectID,
'name',ItemForm.txtName.Text,
'address',ItemForm.txtAddress.Text,
'phone',ItemForm.txtPhone.Text
]);
Thanks

Answer 1

Please refer to this tutorial: http://owlyci.com/docs/articles/WorkingWithGridFS
In GridFS files are referenced by names (or _id in rare cases), so you should save streams to GridFS with some filenames (aaa.jpg, 81276482634823.dat or any other), and then store this filenames to your collection
d:=BSON([
'id',mongoObjectID,
'name',ItemForm.txtName.Text,
'address',ItemForm.txtAddress.Text,
'phone',ItemForm.txtPhone.Text,
'picture', 'aaa.jpg'
]);

Answer 2

MongoDB has it's own sub-system specifically to store (large) files: GridFS
see more here: http://docs.mongodb.org/manual/core/gridfs/
and for a TMongoStream object that uses this: https://github.com/stijnsanders/TMongoWire/blob/master/mongoStream.pas
(For the sake of completeness: Delphi doesn't know by itself how to convert a TFileStream to a Variant, which causes the error.)