Rails - Oct 2005 - Re: file_column, what I need, etc...

I didn''t write file_column, that belongs to Sebastian Kanthak.  I
wrote a couple of extensions to file_column for validation, and image
handling.

That said, file_column can handle whatever relations you throw at it. 
You may have to make a separate images table, consisting of the
file_column and a primary key, and link to it using standard has_many
and HABTM relationships.

file_column doesn''t give you dynamic thumbnailing, although extensions
I wrote do give you   multiple static thumbnails on_create

Kyle Maxwell

On 10/4/05, Adam Roth <adamjroth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> Hey Kyle,
>
> I''m aware that you''ve written file_column, and
I''ve seen you chime-in in a
> few threads regarding file uploads and images. I figured I would finally
> email you and inform you of the reasons I don''t use file column
and with
> that, let you know exactly how I''m managing images on my site.
Maybe we can
> then come up with a common solution.
>
> I''m building a community site in which various models can have
multiple
> pictures:
>
> profiles
> products
> blogs
>
> I am using a HABTM relationship. Ie:
>
> tables:
>    profiles   (has a ''default_picture_id'' column)
>    products (has a ''default_picture_id'' column)
>    blogs (has a ''default_picture_id'' column)
>
>    pictures
>    thumbnails (i''d rather generate thumbnails dynamically and
cache as
> necessary, but the ImageMagick tag helper wasn''t exactly what I
was looking
> for... and required more work than it was worth to make pretty URLs.)
>
>    blogs_pictures
>    products_pictures
>    profiles_pictures
>
>
> From each model edit page (profile, product)... you can then click to
''Edit
> Pictures'' to upload, set the default_picture_id for the model,
destroy,
> etc....
>
> On upload, I create N thumbnails based on the model (size data stored in
> config files).
>
> def upload
> ...
>    ## Find the correct object based on the URL, and add the picture...
>    @object = eval( @params[:object].capitalize ).find( @params[:object_id)
)
>    @object.add_pictures( @picture )
> ...
> end
>
> Can file_column handle a situation such as this? If I made it seem to
> complex, it''s really just a case of wanting to be able to add N
pictures to
> N models as easily as possible.
>
> Best
> Adam Roth
>
>

On 5-okt-2005, at 0:02, Kyle Maxwell wrote:
> I didn''t write file_column, that belongs to Sebastian Kanthak.  I
> wrote a couple of extensions to file_column for validation, and image
> handling.
>
> That said, file_column can handle whatever relations you throw at it.
> You may have to make a separate images table, consisting of the
> file_column and a primary key, and link to it using standard has_many
> and HABTM relationships.
>
> file_column doesn''t give you dynamic thumbnailing, although
extensions
> I wrote do give you   multiple static thumbnails on_create
I was thinking - isn''t it the view that should decide how big a  
thumbnail must be? I image the following scenario:

1. Image gets uploaded and saved on the server
2. A view has a helper for image_thumbnail(image_object), which
   -- will determine if the image is bigger than the thumbnail
   -- load the thumbnail of the needed size if it exists
   -- will insert an SRC call to the controller that will resize the  
image and save it in the cache if the cached variant is not available

This would allow to cache_page where resized images are used with no  
server overhead at all, but at the sime time leave
it to the designer to decide how big a thumbnail must be. It is also  
quite predictable that you might need a handful of thumbnail sizes  
for different areas of the application.


-- 
Julian "Julik" Tarkhanov