Why

很多東西光看文檔搞不明白，遂找相關(guān)源碼讀之。

Model

在被較復(fù)雜數(shù)據(jù)關(guān)系搞暈后天揖，我這LowLow的設(shè)計(jì)代碼能力根本不夠用了童叠。
那么從django的用戶脂信、組佣渴、權(quán)限系統(tǒng)開(kāi)始吧。

編碼設(shè)計(jì)

我自己的代碼設(shè)計(jì)就是坨屎。

編碼規(guī)范

我自己的代碼就是坨屎数焊。

Djanog 1.9.6 >> Lib/site-packages/django/contrib/auth/models.py

• 權(quán)限：

class Permission(models.Model):
    """
    The permissions system provides a way to assign permissions to specific
    users and groups of users.

    The permission system is used by the Django admin site, but may also be
    useful in your own code. The Django admin site uses permissions as follows:

        - The "add" permission limits the user's ability to view the "add" form
          and add an object.
        - The "change" permission limits a user's ability to view the change
          list, view the "change" form and change an object.
        - The "delete" permission limits the ability to delete an object.

    Permissions are set globally per type of object, not per specific object
    instance. It is possible to say "Mary may change news stories," but it's
    not currently possible to say "Mary may change news stories, but only the
    ones she created herself" or "Mary may only change news stories that have a
    certain status or publication date."

    Three basic permissions -- add, change and delete -- are automatically
    created for each Django model.
    """
    name = models.CharField(_('name'), max_length=255)
    content_type = models.ForeignKey(
        ContentType,
        models.CASCADE,
        verbose_name=_('content type'),
    )
    codename = models.CharField(_('codename'), max_length=100)
    objects = PermissionManager()
    class Meta:
        verbose_name = _('permission')
        verbose_name_plural = _('permissions')
        unique_together = (('content_type', 'codename'),)
        ordering = ('content_type__app_label', 'content_type__model',
                    'codename')

• 組管理：

class GroupManager(models.Manager):
    """
    The manager for the auth's Group model.
    """
    use_in_migrations = True

    def get_by_natural_key(self, name):
        return self.get(name=name)

• 組：

class Group(models.Model):
    """
    Groups are a generic way of categorizing users to apply permissions, or
    some other label, to those users. A user can belong to any number of
    groups.

    A user in a group automatically has all the permissions granted to that
    group. For example, if the group Site editors has the permission
    can_edit_home_page, any user in that group will have that permission.

    Beyond permissions, groups are a convenient way to categorize users to
    apply some label, or extended functionality, to them. For example, you
    could create a group 'Special users', and you could write code that would
    do special things to those users -- such as giving them access to a
    members-only portion of your site, or sending them members-only email
    messages.
    """
    name = models.CharField(_('name'), max_length=80, unique=True)
    permissions = models.ManyToManyField(
        Permission,
        verbose_name=_('permissions'),
        blank=True,
    )

    objects = GroupManager()

    class Meta:
        verbose_name = _('group')
        verbose_name_plural = _('groups')

• 用戶管理：

class UserManager(BaseUserManager):
    use_in_migrations = True

    def _create_user(self, username, email, password, **extra_fields):
        """
        Creates and saves a User with the given username, email and password.
        """
        if not username:
            raise ValueError('The given username must be set')
        email = self.normalize_email(email)
        user = self.model(username=username, email=email, **extra_fields)
        user.set_password(password)
        user.save(using=self._db)
        return user

    def create_user(self, username, email=None, password=None, **extra_fields):
        extra_fields.setdefault('is_staff', False)
        extra_fields.setdefault('is_superuser', False)
        return self._create_user(username, email, password, **extra_fields)

    def create_superuser(self, username, email, password, **extra_fields):
        extra_fields.setdefault('is_staff', True)
        extra_fields.setdefault('is_superuser', True)

        if extra_fields.get('is_staff') is not True:
            raise ValueError('Superuser must have is_staff=True.')
        if extra_fields.get('is_superuser') is not True:
            raise ValueError('Superuser must have is_superuser=True.')

        return self._create_user(username, email, password, **extra_fields)

• 組與權(quán)限關(guān)聯(lián)：

class PermissionsMixin(models.Model):
    """
    A mixin class that adds the fields and methods necessary to support
    Django's Group and Permission model using the ModelBackend.
    """
    is_superuser = models.BooleanField(
        _('superuser status'),
        default=False,
        help_text=_(
            'Designates that this user has all permissions without '
            'explicitly assigning them.'
        ),
    )
    groups = models.ManyToManyField(
        Group,
        verbose_name=_('groups'),
        blank=True,
        help_text=_(
            'The groups this user belongs to. A user will get all permissions '
            'granted to each of their groups.'
        ),
        related_name="user_set",
        related_query_name="user",
    )
    user_permissions = models.ManyToManyField(
        Permission,
        verbose_name=_('user permissions'),
        blank=True,
        help_text=_('Specific permissions for this user.'),
        related_name="user_set",
        related_query_name="user",
    )

    class Meta:
        abstract = True

• 抽象用戶：

class AbstractUser(AbstractBaseUser, PermissionsMixin):
    """
    An abstract base class implementing a fully featured User model with
    admin-compliant permissions.

    Username and password are required. Other fields are optional.
    """
    username = models.CharField(
        _('username'),
        max_length=30,
        unique=True,
        help_text=_('Required. 30 characters or fewer. Letters, digits and @/./+/-/_ only.'),
        validators=[
            validators.RegexValidator(
                r'^[\w.@+-]+$',
                _('Enter a valid username. This value may contain only '
                  'letters, numbers ' 'and @/./+/-/_ characters.')
            ),
        ],
        error_messages={
            'unique': _("A user with that username already exists."),
        },
    )
    first_name = models.CharField(_('first name'), max_length=30, blank=True)
    last_name = models.CharField(_('last name'), max_length=30, blank=True)
    email = models.EmailField(_('email address'), blank=True)
    is_staff = models.BooleanField(
        _('staff status'),
        default=False,
        help_text=_('Designates whether the user can log into this admin site.'),
    )
    is_active = models.BooleanField(
        _('active'),
        default=True,
        help_text=_(
            'Designates whether this user should be treated as active. '
            'Unselect this instead of deleting accounts.'
        ),
    )
    date_joined = models.DateTimeField(_('date joined'), default=timezone.now)

    objects = UserManager()

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = ['email']

    class Meta:
        verbose_name = _('user')
        verbose_name_plural = _('users')
        abstract = True

• 用戶（Why永淌？）：

class User(AbstractUser):
    """
    Users within the Django authentication system are represented by this
    model.

    Username, password and email are required. Other fields are optional.
    """
    class Meta(AbstractUser.Meta):
        swappable = 'AUTH_USER_MODEL'