add "exists" function into Document class

elasticsearch_dsl/document.py

@@ -205,6 +205,22 @@ def get(cls, id, using=None, index=None, **kwargs):
             return None
         return cls.from_es(doc)
 
+    @classmethod
+    def exists(cls, id, using=None, index=None, **kwargs):
+        """
+        check if exists a single document from elasticsearch using its ``id``.
+
+        :arg id: ``id`` of the document to check if exists
+        :arg index: elasticsearch index to use, if the ``Document`` is
+            associated with an index this can be omitted.
+        :arg using: connection alias to use, defaults to ``'default'``
+
+        Any additional keyword arguments will be passed to
+        ``Elasticsearch.exists`` unchanged.
+        """
+        es = cls._get_connection(using)
+        return es.exists(index=cls._default_index(index), id=id, **kwargs)
+
     @classmethod
     def mget(
         cls, docs, using=None, index=None, raise_on_error=True, missing="none", **kwargs

tests/test_integration/test_document.py

@@ -333,6 +333,14 @@ def test_get(data_client):
     assert datetime(2014, 3, 3) == elasticsearch_repo.created_at
 
 
+def test_exists_return_true(data_client):
+    assert Repository.exists("elasticsearch-dsl-py")
+
+
+def test_exists_false(data_client):
+    assert not Repository.exists("elasticsearch-dsl-php")
+
+
 def test_get_with_tz_date(data_client):
     first_commit = Commit.get(
         id="3ca6e1e73a071a705b4babd2f581c91a2a3e5037", routing="elasticsearch-dsl-py"