akkoma/lib/pleroma/web/web.ex
2020-10-07 13:28:39 -05:00

239 lines
7.4 KiB
Elixir

# Pleroma: A lightweight social networking server
# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Web.Plug do
# Substitute for `call/2` which is defined with `use Pleroma.Web, :plug`
@callback perform(Plug.Conn.t(), Plug.opts()) :: Plug.Conn.t()
end
defmodule Pleroma.Web do
@moduledoc """
A module that keeps using definitions for controllers,
views and so on.
This can be used in your application as:
use Pleroma.Web, :controller
use Pleroma.Web, :view
The definitions below will be executed for every view,
controller, etc, so keep them short and clean, focused
on imports, uses and aliases.
Do NOT define functions inside the quoted expressions
below.
"""
alias Pleroma.Plugs.EnsureAuthenticatedPlug
alias Pleroma.Plugs.EnsurePublicOrAuthenticatedPlug
alias Pleroma.Plugs.ExpectAuthenticatedCheckPlug
alias Pleroma.Plugs.ExpectPublicOrAuthenticatedCheckPlug
alias Pleroma.Plugs.OAuthScopesPlug
alias Pleroma.Plugs.PlugHelper
def controller do
quote do
use Phoenix.Controller, namespace: Pleroma.Web
import Plug.Conn
import Pleroma.Web.Gettext
import Pleroma.Web.Router.Helpers
import Pleroma.Web.TranslationHelpers
plug(:set_put_layout)
defp set_put_layout(conn, _) do
put_layout(conn, Pleroma.Config.get(:app_layout, "app.html"))
end
# Marks plugs intentionally skipped and blocks their execution if present in plugs chain
defp skip_plug(conn, plug_modules) do
plug_modules
|> List.wrap()
|> Enum.reduce(
conn,
fn plug_module, conn ->
try do
plug_module.skip_plug(conn)
rescue
UndefinedFunctionError ->
raise "`#{plug_module}` is not skippable. Append `use Pleroma.Web, :plug` to its code."
end
end
)
end
# Executed just before actual controller action, invokes before-action hooks (callbacks)
defp action(conn, params) do
with %{halted: false} = conn <- maybe_drop_authentication_if_oauth_check_ignored(conn),
%{halted: false} = conn <- maybe_perform_public_or_authenticated_check(conn),
%{halted: false} = conn <- maybe_perform_authenticated_check(conn),
%{halted: false} = conn <- maybe_halt_on_missing_oauth_scopes_check(conn) do
super(conn, params)
end
end
# For non-authenticated API actions, drops auth info if OAuth scopes check was ignored
# (neither performed nor explicitly skipped)
defp maybe_drop_authentication_if_oauth_check_ignored(conn) do
if PlugHelper.plug_called?(conn, ExpectPublicOrAuthenticatedCheckPlug) and
not PlugHelper.plug_called_or_skipped?(conn, OAuthScopesPlug) do
OAuthScopesPlug.drop_auth_info(conn)
else
conn
end
end
# Ensures instance is public -or- user is authenticated if such check was scheduled
defp maybe_perform_public_or_authenticated_check(conn) do
if PlugHelper.plug_called?(conn, ExpectPublicOrAuthenticatedCheckPlug) do
EnsurePublicOrAuthenticatedPlug.call(conn, %{})
else
conn
end
end
# Ensures user is authenticated if such check was scheduled
# Note: runs prior to action even if it was already executed earlier in plug chain
# (since OAuthScopesPlug has option of proceeding unauthenticated)
defp maybe_perform_authenticated_check(conn) do
if PlugHelper.plug_called?(conn, ExpectAuthenticatedCheckPlug) do
EnsureAuthenticatedPlug.call(conn, %{})
else
conn
end
end
# Halts if authenticated API action neither performs nor explicitly skips OAuth scopes check
defp maybe_halt_on_missing_oauth_scopes_check(conn) do
if PlugHelper.plug_called?(conn, ExpectAuthenticatedCheckPlug) and
not PlugHelper.plug_called_or_skipped?(conn, OAuthScopesPlug) do
conn
|> render_error(
:forbidden,
"Security violation: OAuth scopes check was neither handled nor explicitly skipped."
)
|> halt()
else
conn
end
end
end
end
def view do
quote do
use Phoenix.View,
root: "lib/pleroma/web/templates",
namespace: Pleroma.Web
# Import convenience functions from controllers
import Phoenix.Controller, only: [get_csrf_token: 0, get_flash: 2, view_module: 1]
import Pleroma.Web.ErrorHelpers
import Pleroma.Web.Gettext
import Pleroma.Web.Router.Helpers
require Logger
@doc "Same as `render/3` but wrapped in a rescue block"
def safe_render(view, template, assigns \\ %{}) do
Phoenix.View.render(view, template, assigns)
rescue
error ->
Logger.error(
"#{__MODULE__} failed to render #{inspect({view, template})}\n" <>
Exception.format(:error, error, __STACKTRACE__)
)
nil
end
@doc """
Same as `render_many/4` but wrapped in rescue block.
"""
def safe_render_many(collection, view, template, assigns \\ %{}) do
Enum.map(collection, fn resource ->
as = Map.get(assigns, :as) || view.__resource__
assigns = Map.put(assigns, as, resource)
safe_render(view, template, assigns)
end)
|> Enum.filter(& &1)
end
end
end
def router do
quote do
use Phoenix.Router
# credo:disable-for-next-line Credo.Check.Consistency.MultiAliasImportRequireUse
import Plug.Conn
import Phoenix.Controller
end
end
def channel do
quote do
# credo:disable-for-next-line Credo.Check.Consistency.MultiAliasImportRequireUse
import Phoenix.Channel
import Pleroma.Web.Gettext
end
end
def plug do
quote do
@behaviour Pleroma.Web.Plug
@behaviour Plug
@doc """
Marks a plug intentionally skipped and blocks its execution if it's present in plugs chain.
"""
def skip_plug(conn) do
PlugHelper.append_to_private_list(
conn,
PlugHelper.skipped_plugs_list_id(),
__MODULE__
)
end
@impl Plug
@doc """
Before-plug hook that
* ensures the plug is not skipped
* processes `:if_func` / `:unless_func` functional pre-run conditions
* adds plug to the list of called plugs and calls `perform/2` if checks are passed
Note: multiple invocations of the same plug (with different or same options) are allowed.
"""
def call(%Plug.Conn{} = conn, options) do
if PlugHelper.plug_skipped?(conn, __MODULE__) ||
(options[:if_func] && !options[:if_func].(conn)) ||
(options[:unless_func] && options[:unless_func].(conn)) do
conn
else
conn =
PlugHelper.append_to_private_list(
conn,
PlugHelper.called_plugs_list_id(),
__MODULE__
)
apply(__MODULE__, :perform, [conn, options])
end
end
end
end
@doc """
When used, dispatch to the appropriate controller/view/etc.
"""
defmacro __using__(which) when is_atom(which) do
apply(__MODULE__, which, [])
end
def base_url do
Pleroma.Web.Endpoint.url()
end
end