distraction.party/lib/pleroma/web/plugs/o_auth_scopes_plug.ex

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# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Plugs.OAuthScopesPlug do
import Plug.Conn
import Pleroma.Web.Gettext
alias Pleroma.Config
use Pleroma.Web, :plug
def init(%{scopes: _} = options), do: options
@impl true
def perform(%Plug.Conn{assigns: assigns} = conn, %{scopes: scopes} = options) do
op = options[:op] || :|
token = assigns[:token]
scopes = transform_scopes(scopes, options)
matched_scopes = (token && filter_descendants(scopes, token.scopes)) || []
cond do
token && op == :| && Enum.any?(matched_scopes) ->
conn
token && op == :& && matched_scopes == scopes ->
conn
options[:fallback] == :proceed_unauthenticated ->
drop_auth_info(conn)
true ->
missing_scopes = scopes -- matched_scopes
permissions = Enum.join(missing_scopes, " #{op} ")
error_message =
dgettext("errors", "Insufficient permissions: %{permissions}.", permissions: permissions)
conn
|> put_resp_content_type("application/json")
|> send_resp(:forbidden, Jason.encode!(%{error: error_message}))
|> halt()
end
end
@doc "Drops authentication info from connection"
def drop_auth_info(conn) do
# To simplify debugging, setting a private variable on `conn` if auth info is dropped
conn
|> put_private(:authentication_ignored, true)
|> assign(:user, nil)
|> assign(:token, nil)
end
@doc "Keeps those of `scopes` which are descendants of `supported_scopes`"
def filter_descendants(scopes, supported_scopes) do
Enum.filter(
scopes,
fn scope ->
Enum.find(
supported_scopes,
&(scope == &1 || String.starts_with?(scope, &1 <> ":"))
)
end
)
end
@doc "Transforms scopes by applying supported options (e.g. :admin)"
def transform_scopes(scopes, options) do
if options[:admin] do
Config.oauth_admin_scopes(scopes)
else
scopes
end
end
end