标签:zope circular-reference python plone schema
我遇到了一个非常类似于this SO question的问题,但是我尝试应用这些以前的答案的尝试没有通过,建议我将其作为一个新问题开始:
在下面的代码中,我定义了几个getChoices()函数,我认为这些函数会延迟循环引用,但不!请问这是怎么了?
# ns.content/ns/content/foo.py
from zope import schema
from plone.directives import form
from z3c.relationfield.schema import Relation, RelationChoice
from plone.formwidget.contenttree import ObjPathSourceBinder
class IFoo(form.Schema):
def getBarChoices():
# avoiding circular refs...
from bar import IBar
return ObjPathSourceBinder(object_provides=IBar.__identifier__)
barChoices = getBarChoices()
form.widget(bar=AutocompleteFieldWidget)
bar = Relation(source= barChoices,required=False)
# ns.content/ns/content/bar.py
from zope import schema
from plone.directives import form
from z3c.relationfield.schema import Relation, RelationChoice
from plone.formwidget.contenttree import ObjPathSourceBinder
class IBar(form.Schema):
def getFooChoices():
# avoiding circular refs...
from foo import IFoo
return ObjPathSourceBinder(object_provides=IFoo.__identifier__)
fooChoices = getFooChoices()
form.widget(foo=AutocompleteFieldWidget)
foo = Relation(source= fooChoices,required=False)
resultingError = """
File ".../buildout-cache/eggs/martian-0.11.3-py2.7.egg/martian/scan.py", line 217, in resolve
__import__(used)
File ".../zeocluster/src/ns.content/ns/content/bar.py", line 32, in <module>
class IBar(form.Schema):
File ".../zeocluster/src/ns.content/ns/content/bar.py", line 48, in IBar
fooChoices = getFooChoices()
File ".../zeocluster/src/ns.content/ns/content/bar.py", line 38, in getFooChoices
from ns.content.foo import IFoo
File ".../zeocluster/src/ns.content/ns/content/foo.py", line 33, in <module>
class IFoo(form.Schema):
File ".../zeocluster/src/ns.content/ns/content/foo.py", line 73, in IFoo
barChoices = getBarChoices()
File ".../zeocluster/src/ns.content/ns/content/foo.py", line 39, in getBarChoices
from ns.content.bar import IBar
zope.configuration.xmlconfig.ZopeXMLConfigurationError: File ".../zeocluster/parts/client1/etc/site.zcml", line 16.2-16.23
ZopeXMLConfigurationError: File ".../buildout-cache/eggs/Products.CMFPlone-4.2.0.1-py2.7.egg/Products/CMFPlone/configure.zcml", line 102.4-106.10
ZopeXMLConfigurationError: File ".../zeocluster/src/ns.content/ns/content/configure.zcml", line 18.2-18.27
ImportError: cannot import name IBar
"""
解决方法:
定义类IFoo时,您在定义时调用getBarChoices().因此,从bar导入时,将在解析foo.py并执行循环导入时执行IBar.
据我所知,您基本上有两种选择:
1)使用字符串作为object_provides的标识符.
无论如何,您已经通过使用IFoo .__ identifier__做到了这一点,但是如果将其设置为静态而非动态,则将消除循环依赖:
source = ObjPathSourceBinder(object_provides='ns.content.bar.IBar')
bar = Relation(source=source,required=False)
无需在foo.py中导入IBar.这具有明显的缺点,即现在在代码中对IBar的位置进行了硬编码,因此,每当更改IBar的名称或位置时,都需要在foo.py中更新其点分名称.
2)标记接口
另一种选择是让IFoo和IBar实现保存在第三个文件中的标记接口,例如ns / content / interfaces.py.这样,您可以按照以下方式进行操作
interfaces.py
from zope.interface import Interface
class IBarMarker(Interface):
"""Marker interface for IBar objects.
"""
class IFooMarker(Interface):
"""Marker interface for IFoo objects.
"""
foo.py
from zope.interface import directlyProvides
from plone.directives import form
from plone.formwidget.contenttree import ObjPathSourceBinder
from plone.formwidget.autocomplete import AutocompleteFieldWidget
from z3c.relationfield.schema import RelationChoice
from ns.content.interfaces import IBarMarker
from ns.content.interfaces import IFooMarker
class IFoo(form.Schema):
directlyProvides(IFooMarker)
form.widget(bar=AutocompleteFieldWidget)
bar = RelationChoice(source=ObjPathSourceBinder(
object_provides=IBarMarker.__identifier__),
required=False)
bar.py
class IBar(form.Schema):
directlyProvides(IBarMarker)
form.widget(foo=AutocompleteFieldWidget)
foo = RelationChoice(source=ObjPathSourceBinder(
object_provides=IFooMarker.__identifier__),
required=False)
标签:zope,circular-reference,python,plone,schema
来源: https://codeday.me/bug/20191013/1907261.html
本站声明:
1. iCode9 技术分享网(下文简称本站)提供的所有内容,仅供技术学习、探讨和分享;
2. 关于本站的所有留言、评论、转载及引用,纯属内容发起人的个人观点,与本站观点和立场无关;
3. 关于本站的所有言论和文字,纯属内容发起人的个人观点,与本站观点和立场无关;
4. 本站文章均是网友提供,不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属;如您发现该文章侵犯了您的权益,可联系我们第一时间进行删除;
5. 本站为非盈利性的个人网站,所有内容不会用来进行牟利,也不会利用任何形式的广告来间接获益,纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。