背景介绍

在Django的官网上有专门介绍如何处理文件上传的文档，其中说到了如何利用model来处理文件上传的场景。但是，在Django中最快速的开发方式是利用class-based views来进行开发。所以，我自己整理了一下如何利用class-based views来处理文件上传的场景，特此记录。

model

既然是数据驱动的web，自然先要有model。

from django.db import models
from django.contrib.auth.models import User
from django.conf import settings
import os

_roles_path = os.path.join(_base_path, \'roles\')


def var_dir(instance, filename):
    return os.path.join(_roles_path, instance.name, \'vars\', filename)


def task_dir(instance, filename):
    return os.path.join(_roles_path, instance.name, \'tasks\', filename)


class Roles(models.Model):
    id = models.AutoField(primary_key=True)
    name = models.CharField(max_length=50)
    creator = models.ForeignKey(User)
    createDatetime = models.DateTimeField(auto_now_add=True)
    directory = models.FilePathField(path=_roles_path, match=\'*.yml\', recursive=True, max_length=200)
    tasks = models.FileField(upload_to=task_dir, blank=False)
    vars = models.FileField(upload_to=var_dir)

    def __unicode__(self):
        return u\'%s\' % self.name

上面用到了动态的upload_to，对应每个FileField都提供不同的上传路径。因为upload_to可以接受一个callable的对象，所以我尝试过把lambda赋值给upload_to，但是在测试中发现，给upload_to赋值为lambda表达式是会报错的ValueError: Cannot serialize function: lambda。应该可以尝试利用闭包的方式来给upload_to赋值，以解决多种动态路径的需求。

经过后续的测试发现，闭包也是不支持的

def _roles_subdir(roles_path, subdir):
    def wrapper(instance, filename):
        return os.path.join(roles_path, instance.name, subdir, filename)
    return wrapper

Please note that due to Python 2 limitations, you cannot serialize unbound method functions (e.g. a method declared
and used in the same class body). Please move the function into the main module body to use migrations.
For more information, see
https://docs.djangoproject.com/en/1.7/topics/migrations/#serializing-values

view

本例中使用Django提供的CreateView。在实际的使用中，可以针对于自己的应用场景选择CreateView、UpdateView。

from django.views.generic.edit import FormView, CreateView
from django.views.decorators.csrf import csrf_exempt
from django.core.urlresolvers import reverse_lazy

class UploadRolesFormView(CreateView):
    template_name = \'app/upload_roles.html\'
    model = Roles
    fields = [\'name\', \'tasks\', \'vars\']
    success_url = reverse_lazy(\'app:index\')

    #临时去掉CSRF保护，千万别学我！
    @csrf_exempt
    def dispatch(self, request, *args, **kwargs):
        return super(UploadRolesFormView, self).dispatch(request, *args, **kwargs)

    #override
    def form_valid(self, form):
        #在form中加入user对象存入model
        form.instance.creator = self.request.user
        return super(UploadRolesFormView, self).form_valid(form)

template

url

在app的urls.py中加入一条对应的url规则：

url(r\'^upload/$\', views.UploadRolesFormView.as_view(), name=\'rolesUpload\'),

这样，就可以利用Django最方便的class-based views开处理文件上传的场景了。