Displaying BLOBs

Question

Recently i've been working on a rather modest application, which lists contacts. When a detail-link was clicked, a popup would come up with more details and an image of that contact.
The table this was based on contained a column photo_reference, which held a path to a folder under /i/. With this setup, it was easy to get the images working for each contact.
The popup i showed was a bunch of htmlcode i put in the region footer, and hid. When the detail was clicked, i retrieved data via an application process, and show a modal dialog.
Now the scope has changed: users need to be able to upload their own images. So, i went to work and made it so the images get uploaded into wwv_flow_files, and then i move them to a new contact_image table. So far so good. But now i want to display these pictures, and here i'm kind of stuck.
* I could include a column in my IR, and put a blob format mask on it with image. I've got this working, but annoyingly. My image table has as primary key the field 'ID'. My contacts table also has 'ID' as PK.
The format mask: IMAGE:APXT_CONTACTS_IMG:SMALL_PHOTO:ID::::::inline:.
Here the PK field (ID) works with the PK of my base table (contacts). My link between tables is apxt_contacts.contact_image_id->apxt_contacts_img.id . The way i could make it work is to rename my id field in the image table to contact_image_id. (why couldnt it just take the column it's based on as the value :( ). I could then hide the column, and take the image with javascript to show in my popup. Also, this way preloads all images for the amount of selected rows.
* get_blob_file_src also seems no use to me because of the limited use of the parameters (page items required etc).
* I'd much rather be able to get the image blob via ajax to then display in my popup, but i have no clue as to how to do this. I've made a stored procedure which gets the file to download and call this from an application process (ajax callback), and with firebug i can see the post/response, but i wouldn't know how to get this displayed as an image.
begin
SELECT mime_type, lengthb(small_photo), filename, small_photo
INTO v_mime, v_length, v_filename, v_lob
FROM apxt_contacts_img
WHERE id = p_contact_image_id;
OWA_UTIL.mime_header (NVL (v_mime, 'application/octet'), FALSE);
HTP.p ('Content-length: ' || v_length);
OWA_UTIL.http_header_close;
wpg_docload.download_file (v_lob);
end;
This way i'd only have to load the pictures of links clicked.
I'd rather not have to grant execute to public and call the stored procedure via the link, but if this is my only route, id rather go solve it the first way.
Instead of my existing code, should i make this work through creating another page, and juggle page items and their values around to try and get the same layout going, and then get that page through ajax? This would also mean extra work, im trying to minimize impact (=work) on the existing app.
tl;dr: is it possible to retrieve an image blob from a table not in the report query, preferably through ajax?
This is Apex 4.02 on an 11g db
Thanks,
Tom (handle pending :) )

Answer 1

Our clients are a mixture of everything from Win98 to XP, including some Macs. There's no single place on every client I can be guranteed to have write access to. Many of our Windows users don't have write access to most of their C: drive, for exqample. Our Windows users have a standard F: drive on the network, but our Mac users don't.
So I would have to ask them via a file requestor where to save the file to for viewing. And since WEB.SHOW_DOCUMENT needs a URL anyway, it seemed it would be more "transparent" to the user to move the BLOB file invisibly to the Apache server and launch it from there.
My guess is there's an Oracle BLOB utility out there that writes a BLOB back to a disk file. I'm just new to the whole BLOB process and am hoping someone could get me pointed in the right direction.
Dave