Add youdotcom retriever (#11304)

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/retrievers/you.py

@@ -0,0 +1,46 @@
+from typing import Any, Dict, List
+
+from langchain.callbacks.manager import CallbackManagerForRetrieverRun
+from langchain.pydantic_v1 import root_validator
+from langchain.schema import BaseRetriever, Document
+from langchain.utils import get_from_dict_or_env
+
+
+class YouRetriever(BaseRetriever):
+    """`You` retriever that uses You.com's search API.
+
+    To connect to the You.com api requires an API key which
+    you can get by emailing api@you.com.
+    You can check out our docs at https://documentation.you.com.
+
+    You need to set the environment variable `YDC_API_KEY` for retriever to operate.
+    """
+
+    ydc_api_key: str
+
+    @root_validator(pre=True)
+    def validate_client(
+        cls,
+        values: Dict[str, Any],
+    ) -> Dict[str, Any]:
+        values["ydc_api_key"] = get_from_dict_or_env(
+            values, "ydc_api_key", "YDC_API_KEY"
+        )
+        return values
+
+    def _get_relevant_documents(
+        self, query: str, *, run_manager: CallbackManagerForRetrieverRun
+    ) -> List[Document]:
+        import requests
+
+        headers = {"X-API-Key": self.ydc_api_key}
+        results = requests.get(
+            f"https://api.ydc-index.io/search?query={query}",
+            headers=headers,
+        ).json()
+
+        docs = []
+        for hit in results["hits"]:
+            for snippet in hit["snippets"]:
+                docs.append(Document(page_content=snippet))
+        return docs

libs/langchain/tests/integration_tests/retrievers/test_you.py

@@ -0,0 +1,16 @@
+import os
+
+from langchain.retrievers.you import YouRetriever
+
+
+class TestYouRetriever:
+    @classmethod
+    def setup_class(cls) -> None:
+        if not os.getenv("YDC_API_KEY"):
+            raise ValueError("YDC_API_KEY environment variable is not set")
+
+    def test_get_relevant_documents(self) -> None:
+        retriever = YouRetriever()
+        actual = retriever.get_relevant_documents("test")
+
+        assert len(actual) > 0

libs/langchain/tests/unit_tests/retrievers/test_you.py

@@ -0,0 +1,26 @@
+import json
+import os
+from unittest import mock
+
+from requests import Response
+
+from langchain.retrievers.you import YouRetriever
+from langchain.schema import Document
+
+
+class TestYouRetriever:
+    def test_get_relevant_documents(self) -> None:
+        os.environ["YDC_API_KEY"] = "MOCK KEY!"
+        retriever = YouRetriever()
+
+        with mock.patch("requests.get") as mock_get:
+            fixture = {"hits": [{"snippets": ["yo"]}, {"snippets": ["bird up"]}]}
+            response = Response()
+            response._content = bytes(json.dumps(fixture).encode("utf-8"))
+            mock_get.return_value = response
+
+            actual = retriever.get_relevant_documents("test")
+            assert actual == [
+                Document(page_content="yo"),
+                Document(page_content="bird up"),
+            ]