Django admin的一些有用定制

Model实例,myapp/models.py：

from django.db import models

class Blog(models.Model):

    name = models.CharField(max_length=100)

    tagline = models.TextField()

    # On Python 3: def __str__(self):

    def __unicode__(self):

        return self.name

class Author(models.Model):

    name = models.CharField(max_length=50)

    email = models.EmailField()

    # On Python 3: def __str__(self):

    def __unicode__(self):

        return self.name

class Entry(models.Model):

    blog = models.ForeignKey(Blog)

    headline = models.CharField(max_length=255)

    body_text = models.TextField()

    pub_date = models.DateField()

    mod_date = models.DateField()

    authors = models.ManyToManyField(Author)

    n_comments = models.IntegerField()

    n_pingbacks = models.IntegerField()

    rating = models.IntegerField()

    # On Python 3: def __str__(self):

    def __unicode__(self):

        return self.headline

类级别权限

默认情况下，superuser可以访问admin界面的所有Model，但有时候只想让一些用户只能访问一些特定的Model。

可以定制自己的User对象的has_perm()方法：

class MyUser(AbstractBaseUser):

    ...

    def has_perm(self, perm, obj=None):

        if self.is_superuser:

            return True

        elif self.can_edit:

            if perm=='myapp.add_entry':

                return True

            else:

                return False

        else:

            return False

这样superuser具有全部权限。普通user的can_edit属性为True时，就具有了创建Entry实例的权限，其余用户无权限。

也可以定制ModelAdmin的has_add_permission(),has_change_permission(),has_delete_permission()方法：

    def has_add_permission(self, request):

        """

        Returns True if the given request has permission to add an object.

        Can be overridden by the user in subclasses.

        """

        opts = self.opts

        codename = get_permission_codename('add', opts)

        if request.user.can_edit:

            return True

        else:

            return request.user.has_perm("%s.%s" % (opts.app_label, codename))

字段级别的权限

不同权限的可以编辑不同的内容，可以通过get_readonly_fileds()来添加字段只读权限。

class EntryAdmin(admin.ModelAdmin):

    list_display=(...)

    search_fields=(...)

    def get_readonly_fields(self,request,obj=None):

        if not request.user.is_superuser and not request.user.can_edit:

            return [f.name for f in self.model._meta.fields]

        return self.readonly_fields

重写Model的save行为

可以直接重写model的save()方法：

from django.db import models

class Blog(models.Model):

    name = models.CharField(max_length=100)

    tagline = models.TextField()

    def save(self, *args, **kwargs):

        do_something()

        super(Blog, self).save(*args, **kwargs) # Call the "real" save() method.

        do_something_else()

阻止save()：

from django.db import models

class Blog(models.Model):

    name = models.CharField(max_length=100)

    tagline = models.TextField()

    def save(self, *args, **kwargs):

        if self.name == "Yoko Ono's blog":

            return # Yoko shall never have her own blog!

        else:

            super(Blog, self).save(*args, **kwargs) # Call the "real" save() method.

也可以重写ModelAdmin的save_model()方法，根据不同的用户定制不同的save行为：

from django.contrib import admin

class ArticleAdmin(admin.ModelAdmin):

    def save_model(self, request, obj, form, change):

        obj.user = request.user

        obj.save()

其中obj是修改后的对象，当新建一个对象时 change = False, 当修改一个对象时 change = True，可以获得修改前的对象：

from django.contrib import admin

class ArticleAdmin(admin.ModelAdmin):

    def save_model(self, request, obj, form, change):

        if change:

            obj_old = self.model.objects.get(pk=obj.pk)

        else:

            obj_old = None

        obj.user = request.user

        obj.save()

不同的用户显示不同的数据行，重写列表页面返回的查询集

ModelAdmin提供了一个钩子程序 —— 它有一个名为queryset() 的方法，该方法可以确定任何列表页面返回的默认查询集。

class MyModelAdmin(admin.ModelAdmin):

    def get_queryset(self, request):

        qs = super(MyModelAdmin, self).get_queryset(request)

        if request.user.is_superuser:

            return qs

        return qs.filter(author=request.user)

定制过滤器list_filter

从django.contrib.admin.SimpleListFilter继承一个子类，提供title和parameter_name属性，并重写 lookups和queryset方法。

from datetime import date

from django.contrib import admin

from django.utils.translation import ugettext_lazy as _

class DecadeBornListFilter(admin.SimpleListFilter):

    # Human-readable title which will be displayed in the

    # right admin sidebar just above the filter options.

    title = _('decade born')

    # Parameter for the filter that will be used in the URL query.

    parameter_name = 'decade'

    def lookups(self, request, model_admin):

        """

        Returns a list of tuples. The first element in each

        tuple is the coded value for the option that will

        appear in the URL query. The second element is the

        human-readable name for the option that will appear

        in the right sidebar.

        """

        return (

            ('80s', _('in the eighties')),

            ('90s', _('in the nineties')),

        )

    def queryset(self, request, queryset):

        """

        Returns the filtered queryset based on the value

        provided in the query string and retrievable via

        `self.value()`.

        """

        # Compare the requested value (either '80s' or '90s')

        # to decide how to filter the queryset.

        if self.value() == '80s':

            return queryset.filter(birthday__gte=date(1980, 1, 1),

                                    birthday__lte=date(1989, 12, 31))

        if self.value() == '90s':

            return queryset.filter(birthday__gte=date(1990, 1, 1),

                                    birthday__lte=date(1999, 12, 31))

class PersonAdmin(admin.ModelAdmin):

    list_filter = (DecadeBornListFilter,)

parameter_name和title是必须的。look_up方法返回出现在列表页右侧过滤器中的选项和描述。parameter_name为附加在url后面get请求的参数名，self.value()返回该参数对应的值。

根据不同的用户定制：

class AuthDecadeBornListFilter(DecadeBornListFilter):

    def lookups(self, request, model_admin):

        if request.user.is_superuser:

            return super(AuthDecadeBornListFilter,

                self).lookups(request, model_admin)

    def queryset(self, request, queryset):

        if request.user.is_superuser:

            return super(AuthDecadeBornListFilter,

                self).queryset(request, queryset)

model_admin为ModelAdmin实例：

class AdvancedDecadeBornListFilter(DecadeBornListFilter):

    def lookups(self, request, model_admin):

        """

        Only show the lookups if there actually is

        anyone born in the corresponding decades.

        """

        qs = model_admin.get_queryset(request)

        if qs.filter(birthday__gte=date(1980, 1, 1),

                      birthday__lte=date(1989, 12, 31)).exists():

            yield ('80s', _('in the eighties'))

        if qs.filter(birthday__gte=date(1990, 1, 1),

                      birthday__lte=date(1999, 12, 31)).exists():

            yield ('90s', _('in the nineties'))

定制搜索功能

class PersonAdmin(admin.ModelAdmin):

    list_display = ('name', 'age')

    search_fields = ('name',)

    def get_search_results(self, request, queryset, search_term):

        queryset, use_distinct = super(PersonAdmin, self).get_search_results(request, queryset, search_term)

        try:

            search_term_as_int = int(search_term)

        except ValueError:

            pass

        else:

            queryset |= self.model.objects.filter(age=search_term_as_int)

        return queryset, use_distinct

queryset是查询集，search_term是搜索词。

外键字段过滤

在添加对象时显示外键选项时，太多的选项不太友好，这时候需要过滤出符合要求的对象供选择。

class MyModelAdmin(admin.ModelAdmin):

    def formfield_for_foreignkey(self, db_field, request, **kwargs):

        if db_field.name == "car":

            kwargs["queryset"] = Car.objects.filter(owner=request.user)

        return super(MyModelAdmin, self).formfield_for_foreignkey(db_field, request, **kwargs)