Plone dexterity RelationList的动态源

Question

我有一个Plone (4.2)表单，它被弄糊涂了。我想有一个特定领域的动态源。架构的相关部分：

from plone.directives import form
from z3c.relationfield.schema import RelationList, RelationChoice
from five import grok
from plone.formwidget.contenttree import ObjPathSourceBinder


@grok.provider(ISourceContextBinder)
def availableAttachments(context)
    return ObjPathSourceBinder()


class IEmailFormSchema(form.Schema):

    attachments = RelationList(
        title = _(u'Attachments'),
        description = _(u'Select and upload attachments.'),
        default = [],
        value_type = RelationChoice(
                    title =_(u"attachment"),
                    default = [],
                    # source = ObjPathSourceBinder() # this works
                    source = availableAttachments),  # should do the same, but doesn't

        required = False
    )

这将导致：

ValueError: Invalid clone vocabulary

我尝试了plone dexterity developer manual中描述的每一种变体。将装饰器与RelationChoice的source属性结合使用的方法(请参见上文)和一个命名词汇类，两者都具有相同的结果。

Answer 1

我应该调用ObjPathSourceBinder对象，而不是调用帮助。此代码的工作方式与预期一致：

@grok.provider(IContextSourceBinder)
def availableAttachments(context):

    path = '/'.join(context.getTmp_folder().getPhysicalPath())
    query = { "portal_type" : ("File","Image"),
              "path": {'query' :path } 
             }

    return ObjPathSourceBinder(navigation_tree_query = query).__call__(context) 

与我问题中的模式代码相结合。