Generalise SwaggerUI plug config supplementing for Phoenix app

README.md

@@ -338,6 +338,8 @@ scope "/api" do
 end
 ```
 
+Additionally, you can set plug option values as a tuple. In this tuple, the first element should be either `:endpoint_url` or `:endpoint_path` and the second element should be the specific path. This tuple will be converted to the respective URL or path of the Endpoint. This feature is particularly useful in cases where your Phoenix app's Endpoint URL is configured with a non-empty path. It allows you to obtain the full path to the local spec or, as an example, to retrieve the URL for the `oauth2RedirectUrl` parameter, which can then be passed to the [Swagger UI configuration](https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/).
+
 ## Importing an existing schema file
 
 > :warning: This functionality currently converts Strings into Atoms, which makes it potentially [vulnerable to DoS attacks](https://til.hashrocket.com/posts/gkwwfy9xvw-converting-strings-to-atoms-safely). We recommend that you load Open API Schemas from _known files_ during application startup and _not dynamically from external sources at runtime_.

lib/open_api_spex/plug/swagger_ui.ex

@@ -193,14 +193,23 @@ defmodule OpenApiSpex.Plug.SwaggerUI do
   end
 
   if Code.ensure_loaded?(Phoenix.Controller) do
-    defp supplement_config(%{oauth2_redirect_url: {:endpoint_url, path}} = config, conn) do
+    defp supplement_config(config, conn) do
       endpoint_module = Phoenix.Controller.endpoint_module(conn)
-      url = Path.join(endpoint_module.url(), path)
-      Map.put(config, :oauth2_redirect_url, url)
-    end
-  end
 
-  defp supplement_config(config, _conn) do
-    config
+      Map.new(config, fn
+        {k, {:endpoint_url, path}} ->
+          {k, Path.join(endpoint_module.url(), endpoint_module.path(path))}
+
+        {k, {:endpoint_path, path}} ->
+          {k, endpoint_module.path(path)}
+
+        k_v ->
+          k_v
+      end)
+    end
+  else
+    defp supplement_config(config, _conn) do
+      config
+    end
   end
 end

test/plug/swagger_ui_test.exs

@@ -2,15 +2,53 @@ defmodule OpenApiSpec.Plug.SwaggerUITest do
   use ExUnit.Case
 
   alias OpenApiSpex.Plug.SwaggerUI
-
-  @opts SwaggerUI.init(path: "/ui")
+  alias OpenApiSpexTest.Endpoint
 
   test "renders csrf token" do
+    start_supervised!(Endpoint)
+
+    config = SwaggerUI.init(path: "/ui")
+
     token = Plug.CSRFProtection.get_csrf_token()
 
-    conn = Plug.Test.conn(:get, "/ui")
-    conn = SwaggerUI.call(conn, @opts)
-    assert conn.resp_body =~ ~r[pathname.+?/ui]
+    conn =
+      Plug.Test.conn(:get, "/ui")
+      |> Plug.Conn.put_private(:phoenix_endpoint, Endpoint)
+
+    conn = SwaggerUI.call(conn, config)
+    assert conn.resp_body =~ ~r[pathname.+?"/ui"]
     assert String.contains?(conn.resp_body, token)
   end
+
+  test "generate actual path dependent to endpoint" do
+    Application.put_env(:open_api_spex_test, Endpoint, url: [path: "/some-prefix"])
+
+    start_supervised!(Endpoint)
+
+    config = SwaggerUI.init(path: {:endpoint_path, "/ui"})
+
+    conn =
+      Plug.Test.conn(:get, "/ui")
+      |> Plug.Conn.put_private(:phoenix_endpoint, Endpoint)
+
+    conn = SwaggerUI.call(conn, config)
+    assert conn.resp_body =~ ~r[pathname.+?"/some-prefix/ui"]
+  end
+
+  test "generate actual url dependent to endpoint" do
+    Application.put_env(:open_api_spex_test, Endpoint,
+      url: [scheme: "https", host: "some-host.com", port: 1234, path: "/some-prefix"]
+    )
+
+    start_supervised!(Endpoint)
+
+    config = SwaggerUI.init(path: {:endpoint_url, "/ui"})
+
+    conn =
+      Plug.Test.conn(:get, "/ui")
+      |> Plug.Conn.put_private(:phoenix_endpoint, Endpoint)
+
+    conn = SwaggerUI.call(conn, config)
+    assert conn.resp_body =~ ~r[pathname.+?"https://some-host.com:1234/some-prefix/ui"]
+  end
 end

test/server_test.exs

@@ -27,6 +27,6 @@ defmodule OpenApiSpex.ServerTest do
       ]
     )
 
-    Endpoint.start_link()
+    start_supervised!(Endpoint)
   end
 end