panikweb/search.py

   1 import haystack.backends.solr_backend
   2 from haystack.query import SearchQuerySet
   3 from haystack.constants import ID, DJANGO_CT, DJANGO_ID
   4 from haystack.utils import get_identifier
   5
   6
   7 from django.conf import settings
   8
   9
  10 class MoreLikeThisSearchQuerySet(SearchQuerySet):
  11     def more_like_this(self, model_instance, **kwargs):
  12         clone = self._clone()
  13         clone.query.more_like_this(model_instance, **kwargs)
  14         return clone
  15
  16
  17 class CustomSolrSearchQuery(haystack.backends.solr_backend.SolrSearchQuery):
  18     def more_like_this(self, model_instance, **kwargs):
  19         self._more_like_this = True
  20         self._mlt_instance = model_instance
  21
  22     def run_mlt(self, **kwargs):
  23         """Builds and executes the query. Returns a list of search results."""
  24         if self._more_like_this is False or self._mlt_instance is None:
  25             raise MoreLikeThisError("No instance was provided to determine 'More Like This' results.")
  26
  27         additional_query_string = self.build_query()
  28         search_kwargs = {
  29             'start_offset': self.start_offset,
  30             'result_class': self.result_class,
  31             'models': self.models,
  32             'mlt.fl': 'tags',
  33         }
  34
  35         if self.end_offset is not None:
  36             search_kwargs['end_offset'] = self.end_offset - self.start_offset
  37
  38         results = self.backend.more_like_this(self._mlt_instance, additional_query_string, **search_kwargs)
  39         self._results = results.get('results', [])
  40         self._hit_count = results.get('hits', 0)
  41
  42
  43 class CustomSolrSearchBackend(haystack.backends.solr_backend.SolrSearchBackend):
  44     def more_like_this(self, model_instance, additional_query_string=None,
  45                        start_offset=0, end_offset=None, models=None,
  46                        limit_to_registered_models=None, result_class=None, **kwargs):
  47         from haystack import connections
  48
  49         # Deferred models will have a different class ("RealClass_Deferred_fieldname")
  50         # which won't be in our registry:
  51         model_klass = model_instance._meta.concrete_model
  52
  53         index = connections[self.connection_alias].get_unified_index().get_index(model_klass)
  54         field_name = index.get_content_field()
  55         params = {
  56             'fl': '*,score',
  57             'mlt.fl': 'text,title',
  58             'mlt.qf': 'text^0.3 tags^2.0 title^1.0',
  59         }
  60
  61         if start_offset is not None:
  62             params['start'] = start_offset
  63
  64         if end_offset is not None:
  65             params['rows'] = end_offset
  66
  67         narrow_queries = set()
  68
  69         if limit_to_registered_models is None:
  70             limit_to_registered_models = getattr(settings, 'HAYSTACK_LIMIT_TO_REGISTERED_MODELS', True)
  71
  72         if models and len(models):
  73             model_choices = sorted(['%s.%s' % (model._meta.app_label, model._meta.module_name) for model in models])
  74         elif limit_to_registered_models:
  75             # Using narrow queries, limit the results to only models handled
  76             # with the current routers.
  77             model_choices = self.build_models_list()
  78         else:
  79             model_choices = []
  80
  81         if len(model_choices) > 0:
  82             if narrow_queries is None:
  83                 narrow_queries = set()
  84
  85             narrow_queries.add('%s:(%s)' % (DJANGO_CT, ' OR '.join(model_choices)))
  86
  87         if additional_query_string:
  88             narrow_queries.add(additional_query_string)
  89
  90         if narrow_queries:
  91             params['fq'] = list(narrow_queries)
  92
  93         query = "%s:%s" % (ID, get_identifier(model_instance))
  94
  95         try:
  96             raw_results = self.conn.more_like_this(query, field_name, **params)
  97         except (IOError, SolrError) as e:
  98             if not self.silently_fail:
  99                 raise
 100
 101             self.log.error("Failed to fetch More Like This from Solr for document '%s': %s", query, e)
 102             raw_results = EmptyResults()
 103
 104         return self._process_results(raw_results, result_class=result_class)
 105
 106
 107 haystack.backends.solr_backend.SolrEngine.query = CustomSolrSearchQuery
 108 haystack.backends.solr_backend.SolrEngine.backend = CustomSolrSearchBackend
 109
 110 from haystack.views import search_view_factory, FacetedSearchView
 111 from haystack.forms import FacetedSearchForm
 112
 113
 114 class SearchView(FacetedSearchView):
 115     def extra_context(self):
 116         context = super(SearchView, self).extra_context()
 117         context['sectionName'] = 'Search'
 118         context['selected_categories'] = [
 119                 x.split(':', 1)[1] for x in self.request.GET.getlist('selected_facets')
 120                 if x.startswith('categories_exact')]
 121         context['selected_tags'] = [
 122                 x.split(':', 1)[1] for x in self.request.GET.getlist('selected_facets')
 123                 if x.startswith('tags_exact')]
 124         return context
 125
 126 sqs = SearchQuerySet().facet('categories').facet('tags')
 127
 128 view = search_view_factory(SearchView,
 129         form_class=FacetedSearchForm,
 130         searchqueryset=sqs)