defmodule Plug.MethodOverride do
@moduledoc """
This plug overrides the request's `POST` method with the method defined in
the `_method` request parameter.
The `POST` method can be overridden only by these HTTP methods:
* `PUT`
* `PATCH`
* `DELETE`
This plug expects the body parameters to be already parsed and
fetched. Those can be fetched with `Plug.Parsers`.
This plug doesn't accept any options.
## Examples
Plug.MethodOverride.call(conn, [])
"""
@behaviour Plug
@allowed_methods ~w(DELETE PUT PATCH)
def init([]), do: []
def call(%Plug.Conn{method: "POST", body_params: body_params} = conn, []),
do: override_method(conn, body_params)
def call(%Plug.Conn{} = conn, []),
do: conn
defp override_method(conn, %Plug.Conn.Unfetched{}) do
# Just skip it because maybe it is a content-type that
# we could not parse as parameters (for example, text/gps)
conn
end
defp override_method(conn, body_params) do
method = (body_params["_method"] || "") |> String.upcase
cond do
method in @allowed_methods -> %{conn | method: method}
true -> conn
end
end
end