Phoenix controller and views for bulk insert

Phoenix Forum Questions / Help
, , , ,
1

Hi, I am trying to create a POST endpoint in Phoenix that will receive an array of maps %{} and I need to insert all of that data into a database as a bulk insertion.

It would be receiving something like this:

entries = [                                                                                                                                   
     %{name: "Frank", age: 23},                                                        
     %{name: "John", age: 24}                                                                                               
   ]

Parameters look like this:

%{"data" => [%{"name" => "Frank", "age" => 23}, %{"name" => "John", "age" => 24}]}

For now I only have created the Repo functions like:

def create_users(attrs) do
    User
    |> Repo.insert_all(attrs)
  end

I’ve searched the entire web and I can’t find any article that explains how the controllers and views should be.

I know this is incorrect because it doesn’t work but it’s more or less what I have right now :frowning:

def create_many(conn, %{"data" => users_params}) do
    case Users.create_users(users_params) do
      {:ok, %{errors: _, rows_affected: _}} ->
        conn
        |> json(%{result: "ok"})
        # render(conn, "bulk_creation_result.json", %{some: result})

      # {:error, _, changeset, _} ->
      #   render(conn, MyApp.ChangesetView, "error.json", changeset: changeset)
    end

As far as the views I really have no clue :frowning:

Does someone have done this yet in the past and could show me a correct example?

Thanks in advance

2

Does Entries have relationship with User model? If so, you can pass cast_assoc to your changeset pipeline to do bulk insertion.

What do you intent to do with views? Do you want to display the returned data?
When generating a json api using mix phx.gen.json it generates similar to this:

  def render("index.json", %{contacts: contacts}) do
    %{data: render_many(contacts, ContactView, "contact.json")}
  end

  def render("show.json", %{contact: contact}) do
    %{data: render_one(contact, ContactView, "contact.json")}
  end

 def render("phone_number.json", %{number: number}) do
    %{id:  number.id, phone_number: number.phone_number}
 end

 def render("contact.json", %{contact: contact}) do
    %{id: contact.id,
       name: contact.name,
       phone_numbers: render_many(contact.numbers, ContactView, "phone_number.json")
    }
end

Make sure you know the shape of the returned data so you can structure the views.

Given the results:

[
 %Contact{
   id: 'something',
   name: 'some name',
   numbers: [
      %Number{id: 'some id', phone_number: 'some phone number'},
      %Number{id: 'some id', phone_number: 'some phone number'}
   ]
 },
%Contact{
   id: 'something',
   name: 'some name',
   numbers: [
      %Number{id: 'some id', phone_number: 'some phone number'},
      %Number{id: 'some id', phone_number: 'some phone number'}
   ]
 }
]

We can return its json format response like this:

with {:ok, entries} = Users.create_users(users_params) do
        conn
        |> render("contact.json", contact: entries)
end

Be sure to put an action_fallback to your controller so it can automatically handle changeset errors.

In the example I gave, it uses ContactView, in your case change the view name to your appropriate one.

3 Likes
3

Thanks