Oaskit.ErrorHandler behaviour (oaskit v0.17.1)

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A behaviour for validation errors handlers.

Summary

Types

reason()

Callbacks

handle_error(t, reason, arg)

Accepts the Plug.Conn struct, an error reason and the options passed to the Oaskit.Plugs.ValidateRequest plug.

Types

reason()

@type reason() ::
  Oaskit.Errors.InvalidBodyError.t()
  | Oaskit.Errors.UnsupportedMediaTypeError.t()
  | {:parameters_errors,
     [
       Oaskit.Errors.InvalidParameterError.t()
       | Oaskit.Errors.MissingParameterError.t()
     ]}

Callbacks

handle_error(t, reason, arg)

@callback handle_error(Plug.Conn.t(), reason(), arg :: term()) :: Plug.Conn.t()

Accepts the Plug.Conn struct, an error reason and the options passed to the Oaskit.Plugs.ValidateRequest plug.

This function is called when request validation fails and an error must be returned to the remote client. This means that function must send a response and halt the conn with Plug.Conn.halt/1.

Responses can be sent just as in Phoenix controllers, using Plug.Conn.send_resp/3, Phoenix.Controller.json/2, Phoenix.Controller.text/2, etc.

The Oaskit.Plugs.ValidateRequest plug returns the conn from this function as is. Halting stops the plug pipeline, so the controller action is skipped. A conn that is sent but not halted reaches the action, which then fails with Plug.Conn.AlreadySentError when it tries to send its own response.

def handle_error(conn, reason, _opts) do
  conn
  |> Plug.Conn.put_resp_content_type("application/json")
  |> Plug.Conn.send_resp(422, encode_errors(reason))
  |> Plug.Conn.halt()
end

The arg argument is the options given to Oaskit.Plugs.ValidateRequest. See this module documentation for more information.