mobilizon/lib/graphql/error.ex

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Elixir
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defmodule Mobilizon.GraphQL.Error do
@moduledoc """
Module to handle errors in GraphQL
"""
require Logger
alias __MODULE__
alias Mobilizon.Web.Gettext, as: GettextBackend
import Mobilizon.Web.Gettext, only: [dgettext: 2]
@type t :: %{code: atom(), message: String.t(), status_code: pos_integer(), field: atom()}
defstruct [:code, :message, :status_code, :field]
@type error :: {:error, any()} | {:error, any(), any(), any()} | atom()
@doc """
Normalize an error to return `t`.
"""
# Error Tuples
# ------------
# Regular errors
@spec normalize(any()) :: t() | list(t())
def normalize({:error, reason}) do
handle(reason)
end
# Ecto transaction errors
def normalize({:error, _operation, reason, _changes}) do
handle(reason)
end
# Unhandled errors
def normalize(other) do
handle(other)
end
# Handle Different Errors
# -----------------------
defp handle(code) when is_atom(code) do
{status, message} = metadata(code)
%Error{
code: code,
message: message,
status_code: status
}
end
defp handle(errors) when is_list(errors) do
Enum.map(errors, &handle/1)
end
defp handle(%Ecto.Changeset{} = changeset) do
changeset
|> Ecto.Changeset.traverse_errors(&translate_error/1)
|> Enum.map(fn {k, v} ->
%Error{
code: :validation,
message: v,
field: k,
status_code: 422
}
end)
end
defp handle(reason) when is_binary(reason) do
%Error{
code: :unknown_error,
message: reason,
status_code: 500
}
end
defp handle(%Error{} = error), do: error
# ... Handle other error types here ...
defp handle(other) do
Logger.error("Unhandled error term:\n#{inspect(other)}")
handle(:unknown)
end
# Build Error Metadata
# --------------------
defp metadata(:unknown_resource), do: {400, dgettext("errors", "Unknown Resource")}
defp metadata(:invalid_argument), do: {400, dgettext("errors", "Invalid arguments passed")}
defp metadata(:unauthenticated), do: {401, dgettext("errors", "You need to be logged in")}
defp metadata(:password_hash_missing),
do: {401, dgettext("errors", "Reset your password to login")}
defp metadata(:incorrect_password), do: {401, dgettext("errors", "Invalid credentials")}
defp metadata(:unauthorized),
do: {403, dgettext("errors", "You don't have permission to do this")}
defp metadata(:not_found), do: {404, dgettext("errors", "Resource not found")}
defp metadata(:user_not_found), do: {404, dgettext("errors", "User not found")}
defp metadata(:post_not_found), do: {404, dgettext("errors", "Post not found")}
defp metadata(:event_not_found), do: {404, dgettext("errors", "Event not found")}
defp metadata(:group_not_found), do: {404, dgettext("errors", "Group not found")}
defp metadata(:resource_not_found), do: {404, dgettext("errors", "Resource not found")}
defp metadata(:discussion_not_found), do: {404, dgettext("errors", "Discussion not found")}
defp metadata(:unknown), do: {500, dgettext("errors", "Something went wrong")}
defp metadata(code) do
Logger.warn("Unhandled error code: #{inspect(code)}")
{422, to_string(code)}
end
# Translates an error message using gettext.
defp translate_error({msg, opts}) do
# Because error messages were defined within Ecto, we must
# call the Gettext module passing our Gettext backend. We
# also use the "errors" domain as translations are placed
# in the errors.po file.
# Ecto will pass the :count keyword if the error message is
# meant to be pluralized.
# On your own code and templates, depending on whether you
# need the message to be pluralized or not, this could be
# written simply as:
#
# dngettext "errors", "1 file", "%{count} files", count
# dgettext "errors", "is invalid"
#
if count = opts[:count] do
Gettext.dngettext(GettextBackend, "errors", msg, msg, count, opts)
else
Gettext.dgettext(GettextBackend, "errors", msg, opts)
end
end
end