Add setting ldap.usernameField

This determines which ldap field is used as the username on
HackMD. By default, the "id" is used as username, too. The id
is taken from the fields `uidNumber`, `uid` or
`sAMAccountName`. To give the user more flexibility, they can
now choose the field used for the username instead.

README.md

@@ -170,6 +170,7 @@ There are some configs you need to change in the files below
 | HMD_LDAP_SEARCHBASE | `o=users,dc=example,dc=com` | LDAP directory to begin search from |
 | HMD_LDAP_SEARCHFILTER | `(uid={{username}})` | LDAP filter to search with |
 | HMD_LDAP_SEARCHATTRIBUTES | no example | LDAP attributes to search with |
+| HMD_LDAP_USERNAMEFIELD | `uid` | The LDAP field which is used as the username on HackMD |
 | HMD_LDAP_TLS_CA | `server-cert.pem, root.pem` | Root CA for LDAP TLS in PEM format (use comma to separate) |
 | HMD_LDAP_PROVIDERNAME | `My institution` | Optional name to be displayed at login form indicating the LDAP provider |
 | HMD_SAML_IDPSSOURL | `https://idp.example.com/sso` | authentication endpoint of IdP. for details, see [guide](docs/guides/auth.md#saml-onelogin). |

config.json.example

@@ -71,6 +71,7 @@
             "searchBase": "change this",
             "searchFilter": "change this",
             "searchAttributes": "change this",
+            "usernameField": "change this e.g. uid"
             "tlsOptions": {
                 "changeme": "See https://nodejs.org/api/tls.html#tls_tls_connect_options_callback"
             }

lib/config/default.js

@@ -96,6 +96,7 @@ module.exports = {
     searchBase: undefined,
     searchFilter: undefined,
     searchAttributes: undefined,
+    usernameField: undefined,
     tlsca: undefined
   },
   saml: {

lib/config/environment.js

@@ -71,6 +71,7 @@ module.exports = {
     searchBase: process.env.HMD_LDAP_SEARCHBASE,
     searchFilter: process.env.HMD_LDAP_SEARCHFILTER,
     searchAttributes: process.env.HMD_LDAP_SEARCHATTRIBUTES,
+    usernameField: process.env.HMD_LDAP_USERNAMEFIELD,
     tlsca: process.env.HMD_LDAP_TLS_CA
   },
   saml: {

lib/web/auth/ldap/index.js

@@ -24,9 +24,15 @@ passport.use(new LDAPStrategy({
   }
 }, function (user, done) {
   var uuid = user.uidNumber || user.uid || user.sAMAccountName
+  var username = uuid
+
+  if (config.ldap.usernameField && user[config.ldap.usernameField]) {
+    username = user[config.ldap.usernameField]
+  }
+
   var profile = {
     id: 'LDAP-' + uuid,
-    username: uuid,
+    username: username,
     displayName: user.displayName,
     emails: user.mail ? [user.mail] : [],
     avatarUrl: null,