customize template when linking account

Author: odelcroi

crates/handlers/src/upstream_oauth2/link.rs

@@ -487,7 +487,7 @@ pub(crate) async fn get(
                                 .with_code("User exists")
                                 .with_description(format!(
                                     r"Upstream account provider returned {localpart:?} as username,
-                                    which is not linked to that upstream account"
+                                    which is not linked to that upstream account. Homeserver does not allow linking existing account"
                                 ))
                                 .with_language(&locale);
 
@@ -509,7 +509,13 @@ pub(crate) async fn get(
                             })
                             .await?;
 
-                        if res.valid() {
+                        if provider.allow_existing_users && maybe_existing_user.is_some(){
+                            // use existing user if allowed
+                            ctx
+                                .with_existing_user(maybe_existing_user.unwrap())
+                                .with_localpart(localpart, true)
+                        }
+                        else if res.valid() {
                             // The username passes the policy check, add it to the context
                             ctx.with_localpart(
                                 localpart,

crates/templates/src/context.rs

@@ -1366,6 +1366,7 @@ pub struct UpstreamRegister {
     imported_email: Option<String>,
     force_email: bool,
     form_state: FormState<UpstreamRegisterFormField>,
+    existing_user: Option<User>,
 }
 
 impl UpstreamRegister {
@@ -1386,6 +1387,7 @@ impl UpstreamRegister {
             imported_email: None,
             force_email: false,
             form_state: FormState::default(),
+            existing_user: None,
         }
     }
 
@@ -1447,6 +1449,15 @@ impl UpstreamRegister {
     pub fn with_form_state(self, form_state: FormState<UpstreamRegisterFormField>) -> Self {
         Self { form_state, ..self }
     }
+
+    /// Set the imported email
+    #[must_use]
+    pub fn with_existing_user(self, user: User) -> Self {
+        Self {
+            existing_user: Some(user),
+            ..self
+        }
+    }
 }
 
 impl TemplateContext for UpstreamRegister {

templates/pages/upstream_oauth2/do_register.html

@@ -11,7 +11,24 @@
 {% from "components/idp_brand.html" import logo %}
 
 {% block content %}
-  {% if force_localpart %}
+  {% if existing_user %}
+    <header class="page-heading">
+      <div class="icon">
+        {{ icon.download() }}
+      </div>
+
+      <div class="header">
+        <h1 class="title">
+          {# todo translate #} 
+          Link your existing account
+        </h1>
+        <p class="text">
+          {# todo translate #} 
+          We have detected you have an existing account, confirm you want to use this account
+        </p>
+      </div>
+    </header>
+  {% elif force_localpart %}
     <header class="page-heading">
       <div class="icon">
         {{ icon.download() }}
@@ -188,8 +205,11 @@ <h3 class="provider">
       {% endcall %}
     {% endif %}
 
-
-    {{ button.button(text=_("action.create_account")) }}
+    {% if existing_user %}
+      {{ button.button(text=_("mas.upstream_oauth2.register.link_existing")) }}
+    {% else %}
+      {{ button.button(text=_("action.create_account")) }}
+    {% endif %}
   </form>
 
   {# Leave this for now as we don't have that fully designed yet