openerp-connector-community team mailing list archive

[Sebastien Beau <sebastien.beau@xxxxxxxxxxxx>]

Hi all,

If like me you want to store image and binary in you file system instead of
the database this mail can interest you.

Since version 6 we make some improvement in the product image module in
order to be able to store image in the file system (
http://bazaar.launchpad.net/~product-core-editors/openerp-product-attributes/7.0/files/head:/product_images/
)
But I am not satisfy by the work done (I did it) because this
implementation only support the image of product. More over we use the
product default code in the path for storing the image and this make
mandatory the default code on product which do not fit with every customer.

After thinking twice, I think the best solution is to introduce new type of
field that will manage the storage for us. Indeed if we implement this with
a field, we can use it everythere (product, category, user, company....)

Here is my proposal:
Adding 3 new fields:
- BinaryField
- ImageField
- ImageResizeField


An exemple of how using it will be this :


    _columns = {
        'binary_test': fields.BinaryField('Test Binary'),
        'image_test': fields.ImageField('Test Image'),
        'image_test_resize': fields.ImageResizeField(
            related_field='image_test',
            string='Test Image small',
            height=64,
            width=64,
            ),
    }

Adding this kind of field will also create this field (on fly):

- binary_test_info_id
- image_test_info_id
- image_test_resize_info_id

Why adding this field?
The aim is simple, I want to read the metadata of my image (path, size,
extension...)
For exemple, if you build an external application maybe you want to get the
path of the image.
In this case you just have to do "product.image_test_info_id.store_fname"
and you get the path.
Acceding to the image with you external application using the images served
by nginx (or apache) is really easy.

I know that "Explicit is better than implicit." but I think It will be a
paint to add this field manually. I don't see any other solution that make
easy (and compatible with the existing API) to access to the image content
or to the image metadata (using the context is not a good idea because you
may access to the content of a field and the information of an other field
at the same time)


I start a POC here :
https://code.launchpad.net/~akretion-team/server-env-tools/server-env-tools

How this work

First the object "binary.binary"
=================================

It's just a table that store the metadata of my binary field (image, pdf,
video...) and store the path of the binary.

I try to reuse the function to create/write/delete of the "ir.attachment"
class, because is kind of the same feature.


Then the new fields :
========================

BinaryField
--------------

BinaryField is a function field with a "fnct" and a "fnct_inv" already
defined. Basically when I add a pdf in this kind of field, the "fnc_inv"
will create (or update) the "binary.binary" and store the id of the
"binary.binary" in the field "my_field_info_id"


ImageField
---------------
ImageField inherit of BinaryField. The only difference is that ImageField
can have resized Image linked so this class will trigger a refresh of
resized image


ImageResizeField
-----------------
ImageResizeField inherit of ImageField. The best way to explain it is to
give an exemple. Let's say that we have added the fields "image_test" and
"image_test_resize" (like on the top of my email)

First setting a image in "image_test"
-------------------------------------
If you set a image into the field "image_test" then the "image_test_resize"
will be refresh.
The ImageResizefield like the BinaryField create a "xxx_info_id" field.
So in this case the resized image is stored in a "binary.binary" and the id
of this binary is stored in "image_test_resize_info_id"


First setting a image in "image_test_resize"
---------------------------------------------------
Giving the posibility to set the image from the resize field is necessary
(OpenERP already do that on product image).
So if you set an image in this king of field, the image will be store in
the ImageField related, this mean in the "image_test" and then the cache of
the ImageResizeField will be refresh.


If you need more details, ask me. I will push some change/fix in the branch
so be carefull when you update the code when you test it. (creating a new
db after pulling the code maybe the best idea)


If you are ok with that I will propose a new version of product_image based
on it.

If you have better naming idea, share it !

Thanks for your feedback.