On Oct 28, 10:05 pm, "Marty Alchin" <[EMAIL PROTECTED]> wrote:
> On Tue, Oct 28, 2008 at 10:31 PM, varikin <[EMAIL PROTECTED]> wrote:
> > try:
> > object.photo._require_file()
> > except ValueError:
> > #handle exception
>
> Wow, I never expected anybody to do something like that. :(
>
> > But I just don't know what this does or is suppose to. The way I read
> > it, if self is None, raise ValueError() which calls self.field.name
> > which would be invalid since self is None. Also, since calling this
> > method is done through a FieldFile object (or ImageFieldFile in this
> > case), it can't be None.
>
> Well, it can't be None, but it doesn't necessarily have a valid value.
> "if not self" doesn't actually check to see if it's None, but rather
> checks to see if the filename is blank. This can happen if you have a
> FileField that hasn't yet gotten a file attached to it, such a field
> with blank=True that never got a file in the admin or a new model
> instance created in a view that hasn't attached a file.
>
> The leading underscore means that it's meant to be a private method.
> It's there as a way to make Django's internal code simpler, so we
> didn't have to keep copying that ValueError message in a bunch of
> methods that all require a filename before they can proceed. That code
> you see is somebody checking to see if the field has a file attached
> to it or not. That's not really the best way to go about it though;
> this would be better:
>
> if not self:
> # handle "exception"
>
> -Gul
I never knew you could do that and it really threw me. Thanks for the
explanation. At least now that I understand it, I can change it to "if
not self" since I have to update the file handling in this app.
Thanks,
John
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