2 files changed, 34 insertions, 0 deletions
diff --git a/app/assets/javascripts/pages/sessions/new/index.js b/app/assets/javascripts/pages/sessions/new/index.js
index 07f32210d93..d54bff88f70 100644
--- a/app/assets/javascripts/pages/sessions/new/index.js
+++ b/app/assets/javascripts/pages/sessions/new/index.js
@@ -2,6 +2,7 @@ import $ from 'jquery';
 import UsernameValidator from './username_validator';
 import SigninTabsMemoizer from './signin_tabs_memoizer';
 import OAuthRememberMe from './oauth_remember_me';
+import preserveUrlFragment from './preserve_url_fragment';
 
 document.addEventListener('DOMContentLoaded', () => {
   new UsernameValidator(); // eslint-disable-line no-new
@@ -10,4 +11,8 @@ document.addEventListener('DOMContentLoaded', () => {
   new OAuthRememberMe({
     container: $('.omniauth-container'),
   }).bindEvents();
+
+  // Save the URL fragment from the current window location. This will be present if the user was
+  // redirected to sign-in after attempting to access a protected URL that included a fragment.
+  preserveUrlFragment(window.location.hash);
 });
diff --git a/app/assets/javascripts/pages/sessions/new/preserve_url_fragment.js b/app/assets/javascripts/pages/sessions/new/preserve_url_fragment.js
new file mode 100644
index 00000000000..82ac59224df
--- /dev/null
+++ b/app/assets/javascripts/pages/sessions/new/preserve_url_fragment.js
@@ -0,0 +1,29 @@
+import { setUrlFragment, setUrlParam } from '../../../lib/utils/common_utils';
+
+/**
+ * Ensure the given URL fragment is preserved by appending it to sign-in/sign-up form actions and
+ * OAuth/SAML login links.
+ *
+ * @param fragment {string} - url fragment to be preserved
+ */
+export default function preserveUrlFragment(fragment) {
+  if (fragment && fragment !== '') {
+    const normalFragment = fragment.replace(/^#/, '');
+
+    // Append the fragment to all sign-in/sign-up form actions so it is preserved when the user is
+    // eventually redirected back to the originally requested URL.
+    const forms = document.querySelectorAll('#signin-container form');
+    Array.prototype.forEach.call(forms, (form) => {
+      const actionWithFragment = setUrlFragment(form.getAttribute('action'), `#${normalFragment}`);
+      form.setAttribute('action', actionWithFragment);
+    });
+
+    // Append a redirect_fragment query param to all oauth provider links. The redirect_fragment
+    // query param will be available in the omniauth callback upon successful authentication
+    const anchors = document.querySelectorAll('#signin-container a.oauth-login');
+    Array.prototype.forEach.call(anchors, (anchor) => {
+      const newHref = setUrlParam(anchor.getAttribute('href'), 'redirect_fragment', normalFragment);
+      anchor.setAttribute('href', newHref);
+    });
+  }
+}