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利用model中的save方法，变相的实现递归循环，所有子分类都能在其中更新，感觉挺巧妙，之前的实现方式确实太烂了。 order的方法竟然支持1:23:2 这种方式的排序，轻松解决以前靠order_id排序的弊端。精简了代码。
其中一断代码： 利用reverse 方法反推url，与无限级的order 还能用在自动生成类别链接上，便捷灵活。
| 1 2 3 4 5 6 7 | def htmlpath ( self ): paths = [ ] for p in self. path. split ( ':' ): c = ArticleCategory. objects. get (id__exact =p ) url = reverse ( 'cms.article.list' , kwargs = { 'cid':c. id } ) paths. append ( '<a href="%s" target="_blank">%s</a>' % (url , c. name ) ) return " > ". join (paths ) |
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | from django. db. models. signals import pre_save class ArticleCategory (models. Model ): name = models. CharField (max_length = 50 ) parent = models. ForeignKey ( 'self' , null = True , blank = True , related_name = 'children' ) path = models. CharField (max_length = 255 , null = True , blank = True ) def __unicode__ ( self ): if self. id == self. path: return self. name else: return self. node def _node ( self ): indent_num = len ( self. path. split ( ':' ) ) - 1 indent = '....' * indent_num node = u '%s%s' % (indent , self. name ) return node node = property (_node ) class Meta: ordering = [ 'path' ] #设置在model中的用途是，是在所有节点保存时递归的循环下去，更新所有的节点的路径 def save ( self , * args , ** kwargs ): super (ArticleCategory , self ). save (*args , ** kwargs ) if self. parent: self. path = '%s:%s' % ( self. parent. path , self. id ) else: self. path = self. id childrens = self. children. all ( ) if len (childrens ) > 0: for children in childrens: children. path = '%s:%s' % ( self. path , children. id ) children. save ( ) super (ArticleCategory , self ). save (*args , ** kwargs ) #信号触发，更新 def inital_articlecategory_path (sender , instance , **kwargs ): if instance. id: if instance. parent: instance. path = '%s:%s' % (instance. parent. path , instance. id ) else: instance. path = instance. id pre_save. connect (inital_articlecategory_path , sender =ArticleCategory ) |
admin.py
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | class ArticleCategoryAdmin (admin. ModelAdmin ): list_display = [ 'treenode' , 'patha' , 'id' , ] ordering = [ 'path' ] def patha ( self , obj ): if obj. parent: return u '%s > %s' % (obj. parent , obj. name ) return obj. name patha. short_description = 'path' patha. allow_tags = True def treenode ( self , obj ): indent_num = len (obj. path. split ( ':' ) ) - 1 p = '<div style="text-indent:%spx;">%s</div>' % (indent_num* 25 , obj. name ) return p treenode. short_description = 'tree path' treenode. allow_tags = True admin. site. register (ArticleCategory , ArticleCategoryAdmin ) |
分析代码后，发现该方法可以不使用signals 来实现，在path变换后 再次运行 super(ArticleCategory,self).save(*args, ** kwargs) ，这样在children中才能在新的循环save中更新path时变更正确，否则path保存时会异常。
这个是不使用signals的代码，依靠model的save的实现。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | class ArticleCategory (models. Model ): name = models. CharField (max_length = 50 ) parent = models. ForeignKey ( 'self' , null = True , blank = True , related_name = 'children' ) path = models. CharField (max_length = 255 , null = True , blank = True ) def __unicode__ ( self ): if self. id == self. path: return self. name else: return self. node def _node ( self ): indent_num = len ( self. path. split ( ':' ) ) - 1 indent = '....' * indent_num node = u '%s%s' % (indent , self. name ) return node node = property (_node ) class Meta: ordering = [ 'path' ] #设置在model中的用途是，是在所有节点保存时递归的循环下去，更新所有的节点的路径 def save ( self , * args , ** kwargs ): #先保存数据,如果是新添加的数据，放在第一行是用来获得id，因为id是path的重要组成 super (ArticleCategory , self ). save (*args , ** kwargs ) if self. parent: self. path = '%s:%s' % ( self. parent. path , self. id ) else: self. path = self. id #更新完当前节点path后，要进行一次保存，否则在编辑类别时，子分类循环保存父类path不是最新的 super (ArticleCategory , self ). save (*args , ** kwargs ) childrens = self. children. all ( ) if len (childrens ) > 0: for children in childrens: children. path = '%s:%s' % ( self. path , children. id ) children. save ( ) |
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