django-immutablemodel 0.3.4

历史和学分

很大程度上基于rob madole在https://bitbucket.org/robmadole/django-immutablefield和 希尔瓦的叉子在https://bitbucket.org/skandal/django-immutablefield。 Rob's的灵感来自于一个谷歌搜索，它没有提供可重复使用的解决方案 django模型中不可变的字段。

从hg/bitbucket转到git/github，因为它们对我来说更亲密无间（tim）

安装

下列之一：

通过OLE“待机：

easy_install django-immutablemodel

管道：

pip install django-immutablemodel

直接从github安装：

pip install git+https://github.com/red56/django-immutablemodel

它做什么

允许您将django模型声明为不可变的。

它可以替代django自己的Model。这意味着你 可以ImmutableModel。

from django.db import models

from immutablemodel.models import ImmutableModel

CruiseShip(ImmutableModel):
    name = models.CharField(max_length=50)

    class Meta:
        mutable_fields = [] # you can actually leave this out...

现在你可以尽力尝试，但是一旦你保存了它就不会改变（在合理的范围内， 当然这是python，只要我们努力，我们几乎可以做任何事情）

>>> queen_anne = CruiseShip.objects.create(name='Queen Anne')
<CruiseShip 'Queen Anne'>
>>> queen_anne.name = 'King George'
>>> queen_anne.name
'Queen Anne'

你可以让它抱怨

将元节更改为包含immutable_quiet = False，它将引发 ValueError如果试图更改此值

class Meta:
    mutable_fields = [] # you can actually leave this out...
    immutable_quiet = False

只要您尝试设置字段，就会引发错误，而不是在save()为 打电话。

>>> queen_anne = CruiseShip.objects.create(name='Queen Anne')
<CruiseShip 'Queen Anne'>
>>> queen_anne.name = 'King George'
ValueError: name is immutable and cannot be changed

如果需要，可以通过添加 IMMUTABLE_QUIET=False到您的设置.py

您可以使某些字段可变

在“可变字段”中列出您实际需要可变的字段

CruiseShip(ImmutableModel):
    name = models.CharField(max_length=50)
            passengers = models.PositiveIntegerField()

    class Meta:
         mutable_fields = ['passengers']

请注意，ImmutableModel忽略了以下划线开头的字段-这允许Immutable\u lock\u字段是@property （即，由于https://github.com/Bouke为此提供了修补程序，它们是自动可变的–请参见https://github.com/red56/django-immutablemodel/pull/1）

参考

meta

Specify options (in addition to the normal django model’s Meta options) that control how immutable fields are handled when subclassing the ^{tt3}$ class

^{tt9}$

Tell ^{tt3}$ which fields should be allowed to change. This value must be a tuple or a list and contain the names of the fields as strings.:

class Meta:
    mutable_fields = ['some_transient_data']

Specify multiple fields:

class ImmutableMeta:
    mutable_fields = ['some_transient_data', 'name', 'foreign_key']

immutable_fields

Tell ^{tt3}$ which fields should not be allowed to change. NB: you can’t specify mutable_fields AND immutable_fields. This value must be a tuple or a list and contain the names of the fields as strings.:

class Meta:
    immutable_fields = ['my_special_id']

Specify multiple fields:

class ImmutableMeta:
    immutable_fields = ['my_special_id', 'name', 'foreign_key']

immutable_quiet

If an attempt is made to change an immutable field, should we quietly prevent it.

Set this value to ^{tt14}$ to raise a ^{tt5}$ when an immutable field is changed.:

class ImmutableMeta:
    immutable_quiet = False

immutable_lock_field

This determines when to enforce immutability. By default it is equal to immutable_model.models.PK_FIELD. This means that when the PK_FIELD is full (typically when saved) the model is immutable, but before it is saved it is mutable. Alternatively you can specify a field by name, or you can set it to None, which means that you can’t change immutable fields once they are set (even before saving).

class ImmutableMeta:

immutable_lock_field = [‘is_locked’]

settings.py

^{tt17}$

Set this to ^{tt14}$ to make all immutable_fields raise an Exception when attempting to be changed.

0.1

发布日期：2010年4月28日

• Rob Madole以Django ImmutableField的身份首次发布

0.2

• 由Helder Silva（Skandal）在Bitbucket上编写的版本，在字段外添加符号。（未正式发布）

0.3

• 由tim diggins（red56）编写的版本，称之为django immutablemodel，并在默认情况下保存后使其成为不变性

0.3.1条 -

用抽象模型< /LI>固定问题

0.3.2条 -

• 允许在meta中完全继承不变性选项

0.3.3条 -

• 缺省锁字段中不可变的（不可删除的）模型的保存问题，保存后不能删除（因为Django删除收集器需要改变ID字段）

0.3.4条 -

• 使以“始终可变”开头的字段（不可变模型忽略此字段）