Load specific file types from Google Drive (issue #4878) (#4926)

# Load specific file types from Google Drive (issue #4878)
Add the possibility to define what file types you want to load from
Google Drive.
 
```
 loader = GoogleDriveLoader(
    folder_id="1yucgL9WGgWZdM1TOuKkeghlPizuzMYb5",
    file_types=["document", "pdf"]
    recursive=False
)
```

Fixes ##4878

## Who can review?
Community members can review the PR once tests pass. Tag
maintainers/contributors who might be interested:
DataLoaders
- @eyurtsev

Twitter: [@UmerHAdil](https://twitter.com/@UmerHAdil) | Discord:
RicChilligerDude#7589

---------

Co-authored-by: UmerHA <40663591+UmerHA@users.noreply.github.com>

docs/modules/indexes/document_loaders/examples/google_drive.ipynb

@@ -1,6 +1,7 @@
 {
  "cells": [
   {
+   "attachments": {},
    "cell_type": "markdown",
    "id": "b0ed136e-6983-4893-ae1b-b75753af05f8",
    "metadata": {},
@@ -75,6 +76,29 @@
    "source": [
     "docs = loader.load()"
    ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "id": "2721ba8a",
+   "metadata": {},
+   "source": [
+    "When you pass a `folder_id` by default all files of type document, sheet and pdf are loaded. You can modify this behaviour by passing a `file_types` argument "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2ff83b4c",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "loader = GoogleDriveLoader(\n",
+    "    folder_id=\"1yucgL9WGgWZdM1TOuKkeghlPizuzMYb5\",\n",
+    "    file_types=[\"document\", \"sheet\"]\n",
+    "    recursive=False\n",
+    ")"
+   ]
   }
  ],
  "metadata": {

langchain/document_loaders/googledrive.py

@@ -10,7 +10,7 @@
 #   https://cloud.google.com/iam/docs/service-accounts-create
 
 from pathlib import Path
-from typing import Any, Dict, List, Optional, Union
+from typing import Any, Dict, List, Optional, Sequence, Union
 
 from pydantic import BaseModel, root_validator, validator
 
@@ -30,11 +30,10 @@ class GoogleDriveLoader(BaseLoader, BaseModel):
     document_ids: Optional[List[str]] = None
     file_ids: Optional[List[str]] = None
     recursive: bool = False
+    file_types: Optional[Sequence[str]] = None
 
     @root_validator
-    def validate_folder_id_or_document_ids(
-        cls, values: Dict[str, Any]
-    ) -> Dict[str, Any]:
+    def validate_inputs(cls, values: Dict[str, Any]) -> Dict[str, Any]:
         """Validate that either folder_id or document_ids is set, but not both."""
         if values.get("folder_id") and (
             values.get("document_ids") or values.get("file_ids")
@@ -49,6 +48,35 @@ class GoogleDriveLoader(BaseLoader, BaseModel):
             and not values.get("file_ids")
         ):
             raise ValueError("Must specify either folder_id, document_ids, or file_ids")
+
+        file_types = values.get("file_types")
+        if file_types:
+            if values.get("document_ids") or values.get("file_ids"):
+                raise ValueError(
+                    "file_types can only be given when folder_id is given,"
+                    " (not when document_ids or file_ids are given)."
+                )
+            type_mapping = {
+                "document": "application/vnd.google-apps.document",
+                "sheet": "application/vnd.google-apps.spreadsheet",
+                "pdf": "application/pdf",
+            }
+            allowed_types = list(type_mapping.keys()) + list(type_mapping.values())
+            short_names = ", ".join([f"'{x}'" for x in type_mapping.keys()])
+            full_names = ", ".join([f"'{x}'" for x in type_mapping.values()])
+            for file_type in file_types:
+                if file_type not in allowed_types:
+                    raise ValueError(
+                        f"Given file type {file_type} is not supported. "
+                        f"Supported values are: {short_names}; and "
+                        f"their full-form names: {full_names}"
+                    )
+
+            # replace short-form file types by full-form file types
+            def full_form(x: str) -> str:
+                return type_mapping[x] if x in type_mapping else x
+
+            values["file_types"] = [full_form(file_type) for file_type in file_types]
         return values
 
     @validator("credentials_path")
@@ -171,15 +199,23 @@ class GoogleDriveLoader(BaseLoader, BaseModel):
         }
         return Document(page_content=text, metadata=metadata)
 
-    def _load_documents_from_folder(self, folder_id: str) -> List[Document]:
+    def _load_documents_from_folder(
+        self, folder_id: str, *, file_types: Optional[Sequence[str]] = None
+    ) -> List[Document]:
         """Load documents from a folder."""
         from googleapiclient.discovery import build
 
         creds = self._load_credentials()
         service = build("drive", "v3", credentials=creds)
         files = self._fetch_files_recursive(service, folder_id)
+        # If file types filter is provided, we'll filter by the file type.
+        if file_types:
+            _files = [f for f in files if f["mimeType"] in file_types]  # type: ignore
+        else:
+            _files = files
+
         returns = []
-        for file in files:
+        for file in _files:
             if file["mimeType"] == "application/vnd.google-apps.document":
                 returns.append(self._load_document_from_id(file["id"]))  # type: ignore
             elif file["mimeType"] == "application/vnd.google-apps.spreadsheet":
@@ -271,7 +307,9 @@ class GoogleDriveLoader(BaseLoader, BaseModel):
     def load(self) -> List[Document]:
         """Load documents."""
         if self.folder_id:
-            return self._load_documents_from_folder(self.folder_id)
+            return self._load_documents_from_folder(
+                self.folder_id, file_types=self.file_types
+            )
         elif self.document_ids:
             return self._load_documents_from_ids()
         else: