"""
Helpers.
"""
from collections import OrderedDict
from django_elasticsearch_dsl.registries import registry
from elasticsearch_dsl import Search
from elasticsearch_dsl.connections import connections
from elasticsearch_dsl.query import MoreLikeThis
from six import PY3
__title__ = 'django_elasticsearch_dsl_drf.helpers'
__author__ = 'Artur Barseghyan <artur.barseghyan@gmail.com>'
__copyright__ = '2016-2017 Artur Barseghyan'
__license__ = 'GPL 2.0/LGPL 2.1'
__all__ = (
'get_document_for_model',
'get_index_and_mapping_for_model',
'more_like_this',
'sort_by_list',
)
[docs]def get_document_for_model(model):
"""Get document for model given.
:param model: Model to get document index for.
:type model: Subclass of `django.db.models.Model`.
:return: Document index for the given model.
:rtype: Subclass of `django_elasticsearch_dsl.DocType`.
"""
documents = registry.get_documents()
for document in documents:
if model == document._doc_type.model:
return document
[docs]def get_index_and_mapping_for_model(model):
"""Get index and mapping for model.
:param model: Django model for which to get index and mapping for.
:type model: Subclass of `django.db.models.Model`.
:return: Index and mapping values.
:rtype: tuple.
"""
document = get_document_for_model(model)
if document is not None:
return (
document._doc_type.index,
document._doc_type.mapping.properties.name
)
[docs]def sort_by_list(unsorted_dict, sorted_keys):
"""Sort an OrderedDict by list of sorted keys.
:param unsorted_dict: Source dictionary.
:param sorted_keys: Keys to sort on.
:type unsorted_dict: collections.OrderedDict
:type sorted_keys: list
:return: Sorted dictionary.
:rtype: collections.OrderedDict
"""
__unsorted_dict_keys = [__key for __key in unsorted_dict.keys()]
__sorted_keys = (
tuple(sorted_keys) + tuple(
set(__unsorted_dict_keys) - set(sorted_keys)
)
)
if PY3:
for key in __sorted_keys:
unsorted_dict.move_to_end(key)
return unsorted_dict
else:
sorted_dict = OrderedDict(
(key, unsorted_dict[key]) for key in __sorted_keys
)
return sorted_dict
[docs]def more_like_this(obj,
fields,
max_query_terms=25,
min_term_freq=2,
min_doc_freq=5,
max_doc_freq=0):
"""More like this.
https://www.elastic.co/guide/en/elasticsearch/reference/current/
query-dsl-mlt-query.html
:param obj: Django model instance for which similar objects shall be found.
:param fields: Fields to search in.
:param max_query_terms:
:param min_term_freq:
:param min_doc_freq:
:param max_doc_freq:
:type obj: Instance of `django.db.models.Model` (sub-classed) model.
:type fields: list
:type max_query_terms: int
:type min_term_freq: int
:type min_doc_freq: int
:type max_doc_freq: int
:return: List of objects.
:rtype: elasticsearch_dsl.search.Search
Example:
>>> from django_elasticsearch_dsl_drf.helpers import more_like_this
>>> from books.models import Book
>>> book = Book.objects.first()
>>> similar_books = more_like_this(
>>> book,
>>> ['title', 'description', 'summary']
>>> )
"""
_index, _mapping = get_index_and_mapping_for_model(obj._meta.model)
if _index is None:
return None
_client = connections.get_connection()
_search = Search(using=_client, index=_index)
return _search.query(
MoreLikeThis(
fields=fields,
like={
'_id': "{}".format(obj.pk),
'_index': "{}".format(_index),
'_type': "{}".format(_mapping)
},
max_query_terms=max_query_terms,
min_term_freq=min_term_freq,
min_doc_freq=min_doc_freq,
max_doc_freq=max_doc_freq,
)
)