Customized registration page when auth.type=HTTP

Introduction of a new auth.registerPageUrl in
gerrit.config to specify a custom registration
page when a new user logs in the first time
to Gerrit.

If not set, the standard Gerrit registration page
`/#/register/` is displayed.

Needed when SSO with a 3rd party authentication
system (e.g. GitHub) is required and the initial
migration of the user profile (e.g. SSH Keys)
would require custom user interactions.

Change-Id: Iad0941e97c0fa749027f12f17f584eb2bd6de07b

Documentation/config-gerrit.txt

@@ -294,6 +294,13 @@ Text displayed in the loginUrl link. Only used if `auth.loginUrl` is set.
 +
 If not set, the "Sign In" text is used.
 
+[[auth.registerPageUrl]]auth.registerPageUrl::
++
+URL of the registration page when a new user logs in the first time
+to Gerrit. Used only when `auth.type` is set to `HTTP`.
++
+If not set, the standard Gerrit registration page `/#/register/` is displayed.
+
 [[auth.logoutUrl]]auth.logoutUrl::
 +
 URL to redirect a browser to after the end-user has clicked on the

gerrit-httpd/src/main/java/com/google/gerrit/httpd/auth/container/HttpLoginServlet.java

@@ -22,6 +22,7 @@ import com.google.gerrit.server.account.AccountException;
 import com.google.gerrit.server.account.AccountManager;
 import com.google.gerrit.server.account.AuthRequest;
 import com.google.gerrit.server.account.AuthResult;
+import com.google.gerrit.server.config.AuthConfig;
 import com.google.gwtexpui.server.CacheHeaders;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -59,16 +60,19 @@ class HttpLoginServlet extends HttpServlet {
   private final CanonicalWebUrl urlProvider;
   private final AccountManager accountManager;
   private final HttpAuthFilter authFilter;
+  private final AuthConfig authConfig;
 
   @Inject
   HttpLoginServlet(final Provider<WebSession> webSession,
       final CanonicalWebUrl urlProvider,
       final AccountManager accountManager,
-      final HttpAuthFilter authFilter) {
+      final HttpAuthFilter authFilter,
+      final AuthConfig authConfig) {
     this.webSession = webSession;
     this.urlProvider = urlProvider;
     this.accountManager = accountManager;
     this.authFilter = authFilter;
+    this.authConfig = authConfig;
   }
 
   @Override
@@ -122,12 +126,16 @@ class HttpLoginServlet extends HttpServlet {
     }
 
     final StringBuilder rdr = new StringBuilder();
-    rdr.append(urlProvider.get(req));
-    rdr.append('#');
-    if (arsp.isNew() && !token.startsWith(PageLinks.REGISTER + "/")) {
-      rdr.append(PageLinks.REGISTER);
+    if (arsp.isNew() && authConfig.getRegisterPageUrl() != null) {
+      rdr.append(authConfig.getRegisterPageUrl());
+    } else {
+      rdr.append(urlProvider.get(req));
+      rdr.append('#');
+      if (arsp.isNew() && !token.startsWith(PageLinks.REGISTER + "/")) {
+        rdr.append(PageLinks.REGISTER);
+      }
+      rdr.append(token);
     }
-    rdr.append(token);
 
     webSession.get().login(arsp, true /* persistent cookie */);
     rsp.sendRedirect(rdr.toString());

gerrit-server/src/main/java/com/google/gerrit/server/config/AuthConfig.java

@@ -38,6 +38,7 @@ public class AuthConfig {
   private final String httpHeader;
   private final String httpDisplaynameHeader;
   private final String httpEmailHeader;
+  private final String registerPageUrl;
   private final boolean trustContainerAuth;
   private final boolean enableRunAs;
   private final boolean userNameToLowerCase;
@@ -64,6 +65,7 @@ public class AuthConfig {
     httpEmailHeader = cfg.getString("auth", null, "httpemailheader");
     loginUrl = cfg.getString("auth", null, "loginurl");
     logoutUrl = cfg.getString("auth", null, "logouturl");
+    registerPageUrl = cfg.getString("auth", null, "registerPageUrl");
     openIdSsoUrl = cfg.getString("auth", null, "openidssourl");
     openIdDomains = Arrays.asList(cfg.getStringList("auth", null, "openIdDomain"));
     trustedOpenIDs = toPatterns(cfg, "trustedOpenID");
@@ -271,4 +273,8 @@ public class AuthConfig {
     }
     return false;
   }
+
+  public String getRegisterPageUrl() {
+    return registerPageUrl;
+  }
 }