ReadBlog.go

func (s *BlogServiceServer) ReadBlog(ctx context.Context, req *blogpb.ReadBlogReq) (*blogpb.ReadBlogRes, error) {
	// convert string id (from proto) to mongoDB ObjectId
	oid, err := primitive.ObjectIDFromHex(req.GetId())
	if err != nil {
		return nil, status.Errorf(codes.InvalidArgument, fmt.Sprintf("Could not convert to ObjectId: %v", err))
	}
	result := blogdb.FindOne(ctx, bson.M{"_id": oid})
	// Create an empty BlogItem to write our decode result to
	data := BlogItem{}
	// decode and write to data
	if err := result.Decode(&data); err != nil {
		return nil, status.Errorf(codes.NotFound, fmt.Sprintf("Could not find blog with Object Id %s: %v", req.GetId(), err))
	}
	// Cast to ReadBlogRes type
	response := &blogpb.ReadBlogRes{
		Blog: &blogpb.Blog{
			Id:       oid.Hex(),
			AuthorId: data.AuthorID,
			Title:    data.Title,
			Content:  data.Content,
		},
	}
	return response, nil
}