chore: import upstream snapshot with attribution

apps/webapp/app/routes/auth.github.ts

@@ -0,0 +1,37 @@
+import { type ActionFunction, type LoaderFunction, redirect, createCookie } from "@remix-run/node";
+import { authenticator } from "~/services/auth.server";
+import { env } from "~/env.server";
+import { sanitizeRedirectPath } from "~/utils";
+
+export let loader: LoaderFunction = () => redirect("/login");
+
+export let action: ActionFunction = async ({ request }) => {
+  const url = new URL(request.url);
+  const redirectTo = url.searchParams.get("redirectTo");
+  const safeRedirect = sanitizeRedirectPath(redirectTo, "/");
+
+  try {
+    // call authenticate as usual, in successRedirect use returnTo or a fallback
+    return await authenticator.authenticate("github", request, {
+      successRedirect: safeRedirect,
+      failureRedirect: "/login",
+    });
+  } catch (error) {
+    // here we catch anything authenticator.authenticate throw, this will
+    // include redirects
+    // if the error is a Response and is a redirect
+    if (error instanceof Response) {
+      // we need to append a Set-Cookie header with a cookie storing the
+      // returnTo value (store the sanitized path)
+      error.headers.append("Set-Cookie", await redirectCookie.serialize(safeRedirect));
+    }
+    throw error;
+  }
+};
+
+export const redirectCookie = createCookie("redirect-to", {
+  maxAge: 60 * 60, // 1 hour
+  httpOnly: true,
+  sameSite: "lax",
+  secure: env.NODE_ENV === "production",
+});