philomena/lib/philomena_web/plugs/map_parameter_plug.ex

39 lines
1 KiB
Elixir

defmodule PhilomenaWeb.MapParameterPlug do
# A bunch of crappy behaviors all interacting to create a
# symphony of failure:
#
# 1.) Router helpers do not strip nil query parameters.
# iex> Routes.gallery_path(conn, :index, gallery: nil)
# "/galleries?gallery="
#
# 2.) Pagination always sets the parameter in the route in order
# to preserve the query across multiple pages
#
# 3.) When received by the router, an empty param is treated as
# an empty string instead of nil
#
# 4.) Phoenix.HTML.Form.form_for/2 raises an error if you try to
# use it on a conn object which is a string instead of a map
# (or nil)
@spec init(Keyword.t()) :: Keyword.t()
def init(opts) do
opts
end
@spec call(Plug.Conn.t(), Keyword.t()) :: Plug.Conn.t()
def call(conn, opts) do
param = Keyword.fetch!(opts, :param)
value = conn.params[param]
cond do
is_map(value) ->
conn
true ->
params = Map.delete(conn.params, param)
Map.put(conn, :params, params)
end
end
end