django - 如何根据 ManyToManyField 在 Wagtail 中过滤搜索结果？

Question

我有一个 Wagtail 站点，它定义了一个 Event 模型。这些事件有多个事件发起者，它们通过 EventSponsor 模型上的 ManyToManyField 关联:

class Event(index.Indexed, ClusterableModel):

    title       = models.CharField(max_length=255)
    start_date  = models.DateTimeField()
    end_date    = models.DateTimeField(null=True, blank=True)
    description = RichTextField(blank=True)

    search_fields = [
        index.SearchField('title', partial_match=True, boost=2.0),
        index.SearchField('description'),
        index.RelatedFields('sponsors', [
            index.SearchField('name', partial_match=True)
        ]),

        index.FilterField('end_date'),
        index.FilterField('sponsors'),
    ]

class EventSponsor(index.Indexed, models.Model):

    sponsor_id = models.IntegerField()
    name = models.CharField(max_length=255)
    url = models.URLField(blank=True)

    events = models.ManyToManyField(Event, related_name='sponsors')

    search_fields = [
        index.SearchField('name', partial_match=True),
    ]

除此之外，我的 Wagtail 服务器上的不同站点还根据特定于该站点的一组选定的事件赞助商将事件包含在其日历中。

因此，为每个站点构建日历列表​​查询集如下所示:

def get_events_for_current_site(request, listing):
    try:
        event_sponsor_settings = EventSponsorSettings.objects.get(site=request.site)
    except EventSponsorSettings.DoesNotExist:
        # If there's no EventSponsorSettings for this Site, return an empty QuerySet. This shouldn't really ever happen.
        return Event.objects.none()

    # Return the selected Events in decending order of start date.
    query = Event.objects.filter(sponsors__in=event_sponsor_settings.selected_event_sponsors)
    if listing == 'upcoming_events':
        return query.order_by('start_date').filter(end_date__gte=timezone.now())
    else:
        return query.order_by('-start_date').filter(end_date__lt=timezone.now())

event_sponsor_settings.selected_event_sponsors 是 EventSponsor 对象的列表。这个查询集对于列表页面来说效果很好。

我需要每个站点上的搜索功能(使用 Elasticsearch 后端)以仅包含当前站点日历上显示的事件。所以我希望我的基本查询集与日历页面使用的查询集相同(或者至少进行相同的过滤)。所以我的事件搜索代码基本上调用:

backend.search(search_query, get_events_for_current_site())

但是，我遇到了两个问题:

1) 如果我在 Event.search_fields 中使用 index.FilterField('sponsors')，则在运行 manage.py update_index< 时会收到此错误:

Traceback (most recent call last):
  File "./manage.py", line 33, in <module>
    execute_from_command_line(argv)
  File "/multitenant-ve/lib/python2.7/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/multitenant-ve/lib/python2.7/site-packages/django/core/management/__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/multitenant-ve/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/multitenant-ve/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/management/commands/update_index.py", line 120, in handle
    self.update_backend(backend_name, schema_only=options.get('schema_only', False))
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/management/commands/update_index.py", line 77, in update_backend
    index.add_model(model)
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/elasticsearch.py", line 536, in add_model
    index=self.name, doc_type=mapping.get_document_type(), body=mapping.get_mapping()
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/elasticsearch.py", line 137, in get_mapping
    self.get_field_mapping(field) for field in self.model.get_search_fields()
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/elasticsearch.py", line 137, in <genexpr>
    self.get_field_mapping(field) for field in self.model.get_search_fields()
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/elasticsearch.py", line 119, in get_field_mapping
    return self.get_field_column_name(field), mapping
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/elasticsearch.py", line 72, in get_field_column_name
    return field.get_attname(self.model) + '_filter'
  File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/index.py", line 178, in get_attname
    return field.attname
AttributeError: 'ManyToManyRel' object has no attribute 'attname'

2) 如果我取出 index.FilterField('sponsors')，manage.py update_index 可以工作，但在搜索时出现错误:

Cannot filter search results with field "eventsponsor_id". Please add index.FilterField('eventsponsor_id') to Event.search_fields.

所以我尝试添加 index.FilterField('eventsponsor_id')，但它在 update_index 期间给出了此警告: Event.search_fields contains field 'eventsponsor_id' but它不存在，并在搜索时导致此回溯:

Traceback:
File "/multitenant-ve/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  174.                     response = self.process_exception_by_middleware(e, request)
File "/multitenant-ve/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  172.                     response = response.render()
File "/multitenant-ve/lib/python2.7/site-packages/django/template/response.py" in render
  160.             self.content = self.rendered_content
File "/multitenant-ve/lib/python2.7/site-packages/django/template/response.py" in rendered_content
  137.         content = template.render(context, self._request)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/backends/django.py" in render
  95.             return self.template.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render
  206.                     return self._render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in _render
  197.         return self.nodelist.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/loader_tags.py" in render
  173.         return compiled_parent._render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in _render
  197.         return self.nodelist.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/loader_tags.py" in render
  173.         return compiled_parent._render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in _render
  197.         return self.nodelist.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/loader_tags.py" in render
  69.                 result = block.nodelist.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render
  992.                 bit = node.render_annotated(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  220.                     nodelist.append(node.render_annotated(context))
File "/multitenant-ve/lib/python2.7/site-packages/django/template/base.py" in render_annotated
  959.             return self.render(context)
File "/multitenant-ve/lib/python2.7/site-packages/django/template/defaulttags.py" in render
  325.             if match:
File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/base.py" in __len__
  174.         return len(self.results())
File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/base.py" in results
  137.             self._results_cache = self._do_search()
File "/multitenant-ve/src/wagtail/wagtail/wagtailsearch/backends/elasticsearch.py" in _do_search
  452.         hits = self.backend.es.search(**params)
File "/multitenant-ve/lib/python2.7/site-packages/elasticsearch/client/utils.py" in _wrapped
  69.             return func(*args, params=params, **kwargs)
File "/multitenant-ve/lib/python2.7/site-packages/elasticsearch/client/__init__.py" in search
  531.             doc_type, '_search'), params=params, body=body)
File "/multitenant-ve/lib/python2.7/site-packages/elasticsearch/transport.py" in perform_request
  273.             body = self.serializer.dumps(body)
File "/multitenant-ve/lib/python2.7/site-packages/elasticsearch/serializer.py" in dumps
  47.             raise SerializationError(data, e)

Exception Type: SerializationError at /search
Exception Value: ({u'query': {u'filtered': {u'filter': {u'and': [{u'prefix': {u'content_type': u'event'}}, {'and': [{u'terms': {u'eventsponsor_id_filter': [<EventSponsor: Division of Geological and Planetary Sciences (9003)>]}}, {u'range': {u'end_date_filter': {'gte': datetime.datetime(2017, 3, 29, 0, 42, 7, 462939, tzinfo=<UTC>)}}}]}]}, u'query': {u'multi_match': {u'query': u'geo', u'fields': [u'_all', u'_partials']}}}}}, TypeError("Unable to serialize <EventSponsor: Division of Geological and Planetary Sciences (9003)> (type: <class 'templated_cms.models.events.EventSponsor'>)",))

因此，我尝试将 get_events_for_current_site() 中的查询集更改为 Event.objects.filter(sponsors__id__in=[s.id for s in event_sponsor_settings.selected_event_sponsors])

这修复了错误...但我根本没有得到任何搜索结果。

我完全不知道如何处理这个问题。 :(

Answer 1

首先，这篇文章帮助我解决了这个问题，所以谢谢你。

FilterFields 非常适合在搜索结果上运行过滤器。在这种情况下，我们只需要根据过滤后的查询集构建搜索结果。

我的解决方法如下:

1. 收集您想要形成搜索结果的事件的 ID。

   event_ids = get_events_for_current_site().values_list('id', flat=True)
   

2. 根据这些 ID 构建新的查询集。

   filtered_events = Event.objects.filter(id__in=event_ids)
   

3. 将新查询集传递到您的搜索

   backend.search(search_query, filtered_events)
   

由于传入搜索的查询集已从 id 中过滤掉，因此您需要在 Event.search_fields 中包含 index.FilterField('id') 并更新您的索引。

请注意，我没有专门测试所报告的代码，而是我自己的变体。

此外，这篇 Wagtail 支持帖子让我对解决此问题有了一些见解:https://groups.google.com/forum/#!msg/wagtail/k2-E4h2oLtI/uPOzbuwKBgAJ

这篇文章确实有一个警告，指出使用这种方法“只要您没有 1000 个 [items]，就不应该对性能造成太严重的影响”。