Query Repo Using a String

Question

I am using Phoenix with Ecto to query a database for a single record by the primary key. All of the documentation/examples show the usage as in a Phoenix Controller:

def show(conn, %{"id" => id}) do
  m = Repo.get(MyModel, id)

  ...
end

However, all params in Phoenix are strings, so this throws a ** (Ecto.InvalidModel) model App.MyModel failed validation when , field id had type string but type integer was expected. I have been working around this in my controllers by doing something like:

def show(conn, %{"id" => id}) do
   m = String.to_integer(id) |> find_my_model_by_id

  ...
end

defp find_my_model_by_id(id) do
 Repo.get(MyModel, id)
end

The problem is I haven't seen anyone else doing this sort of type conversion. I'm worried I don't have Phoenix or Ecto set up correctly. Is there a Phoenix/Ecto convention I am missing that would automatically coerce my id argument for Repo.get/2 to an int?

score 0 · Accepted Answer · edited Dec 18 '14 at 12:00

0

Your code is correct. In the upcoming Ecto version we want to add automatic casting for cases like this. But for now, you need to cast it manually.

edited Dec 18 '14 at 12:00

Patrick Oscity

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answered Dec 18 '14 at 10:47

José Valim

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1

Has it been added since then? What is the advised pattern as of 2020 to do this? – Tangui Jul 28 '20 at 12:58

score 0 · Answer 2 · answered Jul 02 '18 at 07:26

tried on Ecto 2.2.0, it still doesn't automatically cast a string to integer in my query

where: u.user_id == ^user_id,

Got error:

(ArgumentError) Postgrex expected an integer in -9223372036854775808..9223372036854775807, got "33133". Please make sure the value you are passing matches the definition in your table or in your query or convert the value accordingly.

Query Repo Using a String

2 Answers2