我通常在视图和模型之间实现一个服务层。这就像你的项目的API，给你一个良好的直升机视图正在发生什么。我从我的一个同事那里继承了这个实践，他在Java项目(JSF)中经常使用这种分层技术，例如:

models.py

class Book:
   author = models.ForeignKey(User)
   title = models.CharField(max_length=125)

   class Meta:
       app_label = "library"

services.py

from library.models import Book

def get_books(limit=None, **filters):
    """ simple service function for retrieving books can be widely extended """
    return Book.objects.filter(**filters)[:limit]  # list[:None] will return the entire list

views.py

from library.services import get_books

class BookListView(ListView):
    """ simple view, e.g. implement a _build and _apply filters function """
    queryset = get_books()

请注意，我通常将模型、视图和服务放在模块级别 根据项目的大小，可以进一步分开

我不得不同意你的看法。django中有很多可能性，但最好的起点是回顾django的设计理念。

Calling an API from a model property would not be ideal, it seems like it would make more sense to do something like this in the view and possibly create a service layer to keep things dry. If the call to the API is non-blocking and the call is an expensive one, sending the request to a service worker (a worker that consumes from a queue) might make sense. As per Django's design philosophy models encapsulate every aspect of an "object". So all business logic related to that object should live there:

包括所有相关的领域逻辑 模型应该封装“对象”的每个方面，遵循Martin Fowler的活动记录设计模式。

The side effects you describe are apparent, the logic here could be better broken down into Querysets and managers. Here is an example: models.py import datetime from djongo import models from django.db.models.query import QuerySet from django.contrib import admin from django.db import transaction class MyUser(models.Model): present_name = models.TextField(null=False, blank=True) status = models.TextField(null=False, blank=True) last_active = models.DateTimeField(auto_now=True, editable=False) # As mentioned you could put this in a template tag to pull it # from cache there. Depending on how it is used, it could be # retrieved from within the admin view or from a custom view # if that is the only place you will use it. #def get_present_name(self): # # property became non-deterministic in terms of database # # data is taken from another service by api # return remote_api.request_user_name(self.uid) or 'Anonymous' # Moved to admin as an action # def activate(self): # # method now has a side effect (send message to user) # self.status = 'activated' # self.save() # # send email via email service # #send_mail('Your account is activated!', '…', [self.email]) class Meta: ordering = ['-id'] # Needed for DRF pagination def __unicode__(self): return '{}'.format(self.pk) class MyUserRegistrationQuerySet(QuerySet): def for_inactive_users(self): new_date = datetime.datetime.now() - datetime.timedelta(days=3*365) # 3 Years ago return self.filter(last_active__lte=new_date.year) def by_user_id(self, user_ids): return self.filter(id__in=user_ids) class MyUserRegistrationManager(models.Manager): def get_query_set(self): return MyUserRegistrationQuerySet(self.model, using=self._db) def with_no_activity(self): return self.get_query_set().for_inactive_users() admin.py # Then in model admin class MyUserRegistrationAdmin(admin.ModelAdmin): actions = ( 'send_welcome_emails', ) def send_activate_emails(self, request, queryset): rows_affected = 0 for obj in queryset: with transaction.commit_on_success(): # send_email('welcome_email', request, obj) # send email via email service obj.status = 'activated' obj.save() rows_affected += 1 self.message_user(request, 'sent %d' % rows_affected) admin.site.register(MyUser, MyUserRegistrationAdmin)

首先，不要重复你自己。

然后，请注意不要过度设计，有时只是浪费时间，让人失去对重要事情的关注。时不时复习一下python的禅意。

看一看活跃的项目

more people = more need to organize properly the django repository they have a straightforward structure. the pip repository they have a straigtforward directory structure. the fabric repository is also a good one to look at. you can place all your models under yourapp/models/logicalgroup.py e.g User, Group and related models can go under yourapp/models/users.py e.g Poll, Question, Answer ... could go under yourapp/models/polls.py load what you need in __all__ inside of yourapp/models/__init__.py

更多关于MVC

model is your data this includes your actual data this also includes your session / cookie / cache / fs / index data user interacts with controller to manipulate the model this could be an API, or a view that saves/updates your data this can be tuned with request.GET / request.POST ...etc think paging or filtering too. the data updates the view the templates take the data and format it accordingly APIs even w/o templates are part of the view; e.g. tastypie or piston this should also account for the middleware.

利用中间件/模板标签

如果您需要为每个请求做一些工作，中间件是一种方法。 例如，添加时间戳 例如，更新页面点击率的指标 例如，填充缓存 如果你的代码片段总是在格式化对象时重复出现，那么templatetags是很好的选择。 例如，active TAB / url面包屑

利用模型管理器

创建用户可以进入用户管理器(models.Manager)。 实例的血淋淋的细节应该放在models.Model上。 queryset的详细信息可以放到models.Manager中。 你可能想一次创建一个User，所以你可能认为它应该存在于模型本身，但在创建对象时，你可能没有所有的细节:

例子:

class UserManager(models.Manager):
   def create_user(self, username, ...):
      # plain create
   def create_superuser(self, username, ...):
      # may set is_superuser field.
   def activate(self, username):
      # may use save() and send_mail()
   def activate_in_bulk(self, queryset):
      # may use queryset.update() instead of save()
      # may use send_mass_mail() instead of send_mail()

尽可能使用表单

如果您有映射到模型的表单，那么可以省去大量的样板代码。ModelForm文档非常好。如果您有很多自定义(或者有时为了更高级的用途避免循环导入错误)，那么将表单代码与模型代码分离是很好的。

尽可能使用管理命令

例如yourapp /管理/命令/ createsuperuser.py 例如yourapp /管理/命令/ activateinbulk.py

如果您有业务逻辑，您可以将其分离出来

Django.contrib.auth使用后端，就像db有后端一样…等等。 为您的业务逻辑添加一个设置(例如AUTHENTICATION_BACKENDS) 你可以使用django.contrib.auth.backends.RemoteUserBackend 你可以使用yourapp.backend .remote_api. remoteuserbackend 你可以使用yourapp.backend .memcache . remoteuserbackend 将困难的业务逻辑委托给后端 确保在输入/输出上设置正确的期望。 更改业务逻辑就像更改设置一样简单:)

后端例子:

class User(db.Models):
    def get_present_name(self): 
        # property became not deterministic in terms of database
        # data is taken from another service by api
        return remote_api.request_user_name(self.uid) or 'Anonymous' 

可能成为:

class User(db.Models):
   def get_present_name(self):
      for backend in get_backends():
         try:
            return backend.get_present_name(self)
         except: # make pylint happy.
            pass
      return None

关于设计模式的更多信息

关于设计模式已经有了一个很好的问题 一个关于实用设计模式的很好的视频 Django的后端明显使用了委托设计模式。

关于接口边界的更多信息

Is the code you want to use really part of the models? -> yourapp.models Is the code part of business logic? -> yourapp.vendor Is the code part of generic tools / libs? -> yourapp.libs Is the code part of business logic libs? -> yourapp.libs.vendor or yourapp.vendor.libs Here is a good one: can you test your code independently? yes, good :) no, you may have an interface problem when there is clear separation, unittest should be a breeze with the use of mocking Is the separation logical? yes, good :) no, you may have trouble testing those logical concepts separately. Do you think you will need to refactor when you get 10x more code? yes, no good, no bueno, refactor could be a lot of work no, that's just awesome!

简而言之，你本可以

yourapp/core/backends.py yourapp/core/models/__init__.py yourapp/core/models/users.py yourapp/core/models/questions.py yourapp/core/backends.py yourapp/core/forms.py yourapp/core/handlers.py yourapp/core/management/commands/__init__.py yourapp/core/management/commands/closepolls.py yourapp/core/management/commands/removeduplicates.py yourapp/core/middleware.py yourapp/core/signals.py yourapp/core/templatetags/__init__.py yourapp/core/templatetags/polls_extras.py yourapp/core/views/__init__.py yourapp/core/views/users.py yourapp/core/views/questions.py yourapp/core/signals.py yourapp/lib/utils.py yourapp/lib/textanalysis.py yourapp/lib/ratings.py yourapp/vendor/backends.py yourapp/vendor/morebusinesslogic.py yourapp/vendor/handlers.py yourapp/vendor/middleware.py yourapp/vendor/signals.py yourapp/tests/test_polls.py yourapp/tests/test_questions.py yourapp/tests/test_duplicates.py yourapp/tests/test_ratings.py

或者其他对你有帮助的东西;找到你需要的接口和界限会对你有帮助。

Django使用了一种稍微修改过的MVC。在Django中没有“控制器”的概念。最接近的代理是一个“视图”，它容易引起MVC转换的混淆，因为在MVC中，视图更像是Django的“模板”。

In Django, a "model" is not merely a database abstraction. In some respects, it shares duty with the Django's "view" as the controller of MVC. It holds the entirety of behavior associated with an instance. If that instance needs to interact with an external API as part of it's behavior, then that's still model code. In fact, models aren't required to interact with the database at all, so you could conceivable have models that entirely exist as an interactive layer to an external API. It's a much more free concept of a "model".

在Django中，MVC结构正如Chris Pratt所说，与其他框架中使用的经典MVC模型不同，我认为这样做的主要原因是避免了过于严格的应用程序结构，就像在其他MVC框架(如CakePHP)中发生的那样。

在Django中，MVC是这样实现的:

视图层被分成两部分。视图应该只用于管理HTTP请求，它们被调用并响应它们。视图与应用程序的其余部分(表单、模型表单、自定义类，在简单情况下直接与模型通信)通信。 为了创建接口，我们使用模板。对于Django来说，模板是类似字符串的，它将一个上下文映射到模板中，这个上下文由应用程序传递给视图(当视图请求时)。

Model layer gives encapsulation, abstraction, validation, intelligence and makes your data object-oriented (they say someday DBMS will also). This doesn't means that you should make huge models.py files (in fact a very good advice is to split your models in different files, put them into a folder called 'models', make an '__init__.py' file into this folder where you import all your models and finally use the attribute 'app_label' of models.Model class). Model should abstract you from operating with data, it will make your application simpler. You should also, if required, create external classes, like "tools" for your models.You can also use heritage in models, setting the 'abstract' attribute of your model's Meta class to 'True'.

剩下的在哪里?小型web应用程序通常是一种数据接口，在一些小型程序中，使用视图来查询或插入数据就足够了。更常见的情况是使用form或modelform，它们实际上是“控制器”。这是一个常见问题的实际解决方案，而且是一个非常快速的解决方案。这就是网站的作用。

If Forms are not enogh for you, then you should create your own classes to do the magic, a very good example of this is admin application: you can read ModelAmin code, this actually works as a controller. There is not a standard structure, I suggest you to examine existing Django apps, it depends on each case. This is what Django developers intended, you can add xml parser class, an API connector class, add Celery for performing tasks, twisted for a reactor-based application, use only the ORM, make a web service, modify the admin application and more... It's your responsability to make good quality code, respect MVC philosophy or not, make it module based and creating your own abstraction layers. It's very flexible.

我的建议是:尽可能多地阅读代码，周围有很多django应用程序，但不要太把它们当回事。每个案例都是不同的，模式和理论会有所帮助，但并不总是如此，这是一门不精确的科学，django只是为你提供了一些好的工具，你可以用它们来减轻一些痛苦(比如管理界面、web表单验证、i18n、观察者模式实现，以及前面提到的所有这些)，但是好的设计来自有经验的设计师。

PS.:使用'User'类从auth应用程序(从标准django)，你可以创建示例用户配置文件，或至少阅读它的代码，这将对你的情况很有用。

这是一个老问题，但我还是想提出我的解决方案。它是基于这样一种接受:模型对象也需要一些额外的功能，而把它放在models.py中是很尴尬的。重业务逻辑可以根据个人喜好单独编写，但我至少喜欢模型做与自身相关的所有事情。该解决方案还支持那些喜欢将所有逻辑置于模型本身中的人。

因此，我设计了一个hack，允许我将逻辑从模型定义中分离出来，并且仍然可以从我的IDE中得到所有的提示。

优点应该是显而易见的，但下面列出了我观察到的一些优点:

DB定义仍然是那样-没有逻辑“垃圾”附加 与模型相关的逻辑都整齐地放在一个地方 所有服务(表单、REST、视图)都有一个逻辑访问点 最棒的是:当我意识到我的models.py变得太杂乱，不得不分离逻辑时，我不需要重写任何代码。分离是平滑和迭代的:我可以一次处理一个函数，也可以一次处理整个类或整个models.py。

我一直在使用Python 3.4及更高版本和Django 1.8及更高版本。

app / models.py

....
from app.logic.user import UserLogic

class User(models.Model, UserLogic):
    field1 = models.AnyField(....)
    ... field definitions ...

应用程序/逻辑/ user.py

if False:
    # This allows the IDE to know about the User model and its member fields
    from main.models import User

class UserLogic(object):
    def logic_function(self: 'User'):
        ... code with hinting working normally ...

我唯一想不明白的是如何让我的IDE(在这种情况下是PyCharm)识别UserLogic实际上是用户模型。但由于这显然是一种hack，我很乐意接受总是为self参数指定类型的小麻烦。