Burnex

Installation

def deps do
 [
 {:burnex, "~> 3.1.0"}
 ]
end

Usage

iex> Burnex.is_burner?("my-email@gmail.com")
false
iex> Burnex.is_burner?("my-email@yopmail.fr")
true
iex> Burnex.is_burner? "invalid.format.yopmail.fr"
false
iex> Burnex.is_burner? "\"this is a valid address! crazy right ?\"@yopmail.fr"
true
iex> Burnex.providers |> MapSet.member?("yopmail.fr")
true

With an Ecto changeset

def changeset(model, params) do
 model
 |> cast(params, @required_fields ++ @optional_fields)
 |> validate_required([:email])
 |> validate_email()
end
@email_regex ~r/\A([\w+\-].?)+@[a-z\d\-]+(\.[a-z]+)*\.[a-z]+\z/i
defp validate_email(%{changes: %{email: email}} = changeset) do
 case Regex.match?(@email_regex, email) do
 true ->
 case Burnex.is_burner?(email) do
 true -> add_error(changeset, :email, "forbidden_provider")
 false -> changeset
 end
 false -> add_error(changeset, :email, "invalid_format")
 end
end
defp validate_email(changeset), do: changeset

MX record DNS resolution

iex> Burnex.check_domain_mx_record("gmail.com")
:ok
iex> Burnex.check_domain_mx_record("gmail.dklfsd")
{:error, "Cannot find MX records"}

 # Use a regex capture to get the "domain" part of an email
 @email_regex ~r/^\S+@(\S+\.\S+)$/
 # hard-code some trusted domains to avoid checking their MX record every time
 @good_email_domains [
 "gmail.com",
 "fastmail.com"
 ]
 defp email_domain(email), do: Regex.run(@email_regex, String.downcase(email))
 defp is_not_burner?(email, domain) do
 with {:is_burner, false} <- {:is_burner, Burnex.is_burner?(email)},
 {:check_mx_record, :ok} <- {:check_mx_record, Burnex.check_domain_mx_record(domain)} do
 true
 else
 {:is_burner, true} ->
 {false, "forbidden email"}
 {:check_mx_record, {:error, error_message}} when is_binary(error_message) ->
 {false, error_message}
 {:check_mx_record, :error} ->
 {false, "forbidden provider"}
 end
 end
 @spec is_valid?(String.t()) :: true | {false, String.t()}
 def is_valid?(email) do
 case email_domain(email) do
 [_ | [domain]] when domain in @good_email_domains ->
 true
 [_ | [domain]] ->
 is_not_burner?(email, domain)
 _ ->
 {false, "Email in bad format"}
 end
 end

License