feat: map preferred_username claim to user record (#2569)

server/routes/auth/providers/oidc.js

@@ -2,6 +2,7 @@
 import passport from "@outlinewiki/koa-passport";
 import fetch from "fetch-with-proxy";
 import Router from "koa-router";
+import get from "lodash/get";
 import { Strategy } from "passport-oauth2";
 import accountProvisioner from "../../../commands/accountProvisioner";
 import env from "../../../env";
@@ -22,6 +23,8 @@ const OIDC_AUTH_URI = process.env.OIDC_AUTH_URI;
 const OIDC_TOKEN_URI = process.env.OIDC_TOKEN_URI;
 const OIDC_USERINFO_URI = process.env.OIDC_USERINFO_URI;
 const OIDC_SCOPES = process.env.OIDC_SCOPES || "";
+const OIDC_USERNAME_CLAIM =
+  process.env.OIDC_USERNAME_CLAIM || "preferred_username";
 const allowedDomains = getAllowedDomains();
 
 export const config = {
@@ -103,6 +106,9 @@ if (OIDC_CLIENT_ID) {
               name: profile.name,
               email: profile.email,
               avatarUrl: profile.picture,
+              // Claim name can be overriden using an env variable.
+              // Default is 'preferred_username' as per OIDC spec.
+              username: get(profile, OIDC_USERNAME_CLAIM),
             },
             authenticationProvider: {
               name: providerName,