CreateBlog.go

func (s *BlogServiceServer) CreateBlog(ctx context.Context, req *blogpb.CreateBlogReq) (*blogpb.CreateBlogRes, error) {
	// Essentially doing req.Blog to access the struct with a nil check
	blog := req.GetBlog()
	// Now we have to convert this into a BlogItem type to convert into BSON
	data := BlogItem{
		// ID:    Empty, so it gets omitted and MongoDB generates a unique Object ID upon insertion.
		AuthorID: blog.GetAuthorId(),
		Title:    blog.GetTitle(),
		Content:  blog.GetContent(),
	}

	// Insert the data into the database, result contains the newly generated Object ID for the new document
	result, err := blogdb.InsertOne(mongoCtx, data)
	// check for potential errors
	if err != nil {
		// return internal gRPC error to be handled later
		return nil, status.Errorf(
			codes.Internal,
			fmt.Sprintf("Internal error: %v", err),
		)
	}
  // add the id to blog, first cast the "generic type" (go doesn't have real generics yet) to an Object ID.
	oid := result.InsertedID.(primitive.ObjectID)
  // Convert the object id to it's string counterpart
	blog.Id = oid.Hex()
	// return the blog in a CreateBlogRes type
	return &blogpb.CreateBlogRes{Blog: blog}, nil
}