python - upload_to dynamically generated url to callable -

i've seen lot of post problem without understanding how solve it.

i have model:

class project(timestampedmodel):     name = models.textfield(max_length=100, default='no name')     logo = models.imagefield() 

i'd have image saved media root following template:

<name>/logo/<filename> 

at first glance, do:

logo = models.imagefield(upload_to="{}/logo/".format(name))

but raises error: attributeerror: 'textfield' object has no attribute 'model'

using callable fine, partially though:

def upload_to_project(self, filename):     url = ("%s/%s") % (self.name, filename)     return url 

and using:

logo = models.imagefield(upload_to=upload_to_project) 

at least have: <name>/<filename>

but how pass argument in case? i'd reuse function upload in other subfolders, not logo as:

<name>/logo/<filename> <name>/history/<filename> <name>/whatever/<filename> 

any idea on do?

it looks (re-reading post it's not 100% clear) want partial application. news, it's part of python's stdlib:

import os functools import partial  def generic_upload_to(instance, filename, folder):     return os.path.join(instance.name, folder, filename)   class project(timestampedmodel):     name = models.textfield(max_length=100, default='no name')     logo = models.imagefield(         upload_to=partial(generic_upload_to, folder="logo")         ) 

note implementation assumes instance has name attribute... if instance attribute want use first part has configurable can rewrite upload_to as:

def generic_upload_to(instance, filename, folder, attrname):     return os.path.join(getattr(instance, attrname), folder, filename) 

then use as

class project(timestampedmodel):     name = models.textfield(max_length=100, default='no name')     logo = models.imagefield(         upload_to=partial(generic_upload_to, attrname="name", folder="logo")         ) 

and if have more 1 filefield or imagefield in model , don't want repeat attrname part:

class something(timestampedmodel):     my_upload_to = partial(generic_upload_to, attrname="label")      label = models.charfield(max_length=100, default='no label')     logo = models.imagefield(         upload_to=partial(my_upload_to, folder="logo")         )     attachment = models.filefield(         upload_to=partial(my_upload_to, folder="attachment")         )