Registration step to set a display name

crates/handlers/src/lib.rs

@@ -383,6 +383,11 @@ where
             get(self::views::register::steps::verify_email::get)
                 .post(self::views::register::steps::verify_email::post),
         )
+        .route(
+            mas_router::RegisterDisplayName::route(),
+            get(self::views::register::steps::display_name::get)
+                .post(self::views::register::steps::display_name::post),
+        )
         .route(
             mas_router::RegisterFinish::route(),
             get(self::views::register::steps::finish::get),

crates/handlers/src/views/register/steps/display_name.rs

@@ -0,0 +1,182 @@
+// Copyright 2025 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only
+// Please see LICENSE in the repository root for full details.
+
+use anyhow::Context as _;
+use axum::{
+    extract::{Path, State},
+    response::{Html, IntoResponse, Response},
+    Form,
+};
+use mas_axum_utils::{
+    cookies::CookieJar,
+    csrf::{CsrfExt as _, ProtectedForm},
+    FancyError,
+};
+use mas_router::{PostAuthAction, UrlBuilder};
+use mas_storage::{BoxClock, BoxRepository, BoxRng};
+use mas_templates::{
+    FieldError, RegisterStepsDisplayNameContext, RegisterStepsDisplayNameFormField,
+    TemplateContext as _, Templates, ToFormState,
+};
+use serde::{Deserialize, Serialize};
+use ulid::Ulid;
+
+use crate::{views::shared::OptionalPostAuthAction, PreferredLanguage};
+
+#[derive(Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+enum FormAction {
+    #[default]
+    Set,
+    Skip,
+}
+
+#[derive(Deserialize, Serialize)]
+pub(crate) struct DisplayNameForm {
+    #[serde(skip_serializing, default)]
+    action: FormAction,
+    #[serde(default)]
+    display_name: String,
+}
+
+impl ToFormState for DisplayNameForm {
+    type Field = mas_templates::RegisterStepsDisplayNameFormField;
+}
+
+#[tracing::instrument(
+    name = "handlers.views.register.steps.display_name.get",
+    fields(user_registration.id = %id),
+    skip_all,
+    err,
+)]
+pub(crate) async fn get(
+    mut rng: BoxRng,
+    clock: BoxClock,
+    PreferredLanguage(locale): PreferredLanguage,
+    State(templates): State<Templates>,
+    State(url_builder): State<UrlBuilder>,
+    mut repo: BoxRepository,
+    Path(id): Path<Ulid>,
+    cookie_jar: CookieJar,
+) -> Result<Response, FancyError> {
+    let (csrf_token, cookie_jar) = cookie_jar.csrf_token(&clock, &mut rng);
+
+    let registration = repo
+        .user_registration()
+        .lookup(id)
+        .await?
+        .context("Could not find user registration")?;
+
+    // If the registration is completed, we can go to the registration destination
+    // XXX: this might not be the right thing to do? Maybe an error page would be
+    // better?
+    if registration.completed_at.is_some() {
+        let post_auth_action: Option<PostAuthAction> = registration
+            .post_auth_action
+            .map(serde_json::from_value)
+            .transpose()?;
+
+        return Ok((
+            cookie_jar,
+            OptionalPostAuthAction::from(post_auth_action)
+                .go_next(&url_builder)
+                .into_response(),
+        )
+            .into_response());
+    }
+
+    let ctx = RegisterStepsDisplayNameContext::new()
+        .with_csrf(csrf_token.form_value())
+        .with_language(locale);
+
+    let content = templates.render_register_steps_display_name(&ctx)?;
+
+    Ok((cookie_jar, Html(content)).into_response())
+}
+
+#[tracing::instrument(
+    name = "handlers.views.register.steps.display_name.post",
+    fields(user_registration.id = %id),
+    skip_all,
+    err,
+)]
+pub(crate) async fn post(
+    mut rng: BoxRng,
+    clock: BoxClock,
+    PreferredLanguage(locale): PreferredLanguage,
+    State(templates): State<Templates>,
+    State(url_builder): State<UrlBuilder>,
+    mut repo: BoxRepository,
+    Path(id): Path<Ulid>,
+    cookie_jar: CookieJar,
+    Form(form): Form<ProtectedForm<DisplayNameForm>>,
+) -> Result<Response, FancyError> {
+    let registration = repo
+        .user_registration()
+        .lookup(id)
+        .await?
+        .context("Could not find user registration")?;
+
+    // If the registration is completed, we can go to the registration destination
+    // XXX: this might not be the right thing to do? Maybe an error page would be
+    // better?
+    if registration.completed_at.is_some() {
+        let post_auth_action: Option<PostAuthAction> = registration
+            .post_auth_action
+            .map(serde_json::from_value)
+            .transpose()?;
+
+        return Ok((
+            cookie_jar,
+            OptionalPostAuthAction::from(post_auth_action)
+                .go_next(&url_builder)
+                .into_response(),
+        )
+            .into_response());
+    }
+
+    let form = cookie_jar.verify_form(&clock, form)?;
+
+    let (csrf_token, cookie_jar) = cookie_jar.csrf_token(&clock, &mut rng);
+
+    let display_name = match form.action {
+        FormAction::Set => {
+            let display_name = form.display_name.trim();
+
+            if display_name.is_empty() || display_name.len() > 255 {
+                let ctx = RegisterStepsDisplayNameContext::new()
+                    .with_form_state(form.to_form_state().with_error_on_field(
+                        RegisterStepsDisplayNameFormField::DisplayName,
+                        FieldError::Invalid,
+                    ))
+                    .with_csrf(csrf_token.form_value())
+                    .with_language(locale);
+
+                return Ok((
+                    cookie_jar,
+                    Html(templates.render_register_steps_display_name(&ctx)?),
+                )
+                    .into_response());
+            }
+
+            display_name.to_owned()
+        }
+        FormAction::Skip => {
+            // If the user chose to skip, we do the same as Synapse and use the localpart as
+            // default display name
+            registration.username.clone()
+        }
+    };
+
+    let registration = repo
+        .user_registration()
+        .set_display_name(registration, display_name)
+        .await?;
+
+    repo.save().await?;
+
+    let destination = mas_router::RegisterFinish::new(registration.id);
+    return Ok((cookie_jar, url_builder.redirect(&destination)).into_response());
+}

crates/handlers/src/views/register/steps/finish.rs

@@ -102,6 +102,14 @@ pub(crate) async fn get(
         )));
     }
 
+    // Check that the display name is set
+    if registration.display_name.is_none() {
+        return Ok((
+            cookie_jar,
+            url_builder.redirect(&mas_router::RegisterDisplayName::new(registration.id)),
+        ));
+    }
+
     // Everuthing is good, let's complete the registration
     let registration = repo
         .user_registration()

crates/handlers/src/views/register/steps/mod.rs

@@ -3,5 +3,6 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 // Please see LICENSE in the repository root for full details.
 
+pub(crate) mod display_name;
 pub(crate) mod finish;
 pub(crate) mod verify_email;

crates/router/src/endpoints.rs

@@ -444,6 +444,30 @@ impl From<Option<PostAuthAction>> for PasswordRegister {
     }
 }
 
+/// `GET|POST /register/steps/:id/display-name`
+#[derive(Debug, Clone)]
+pub struct RegisterDisplayName {
+    id: Ulid,
+}
+
+impl RegisterDisplayName {
+    #[must_use]
+    pub fn new(id: Ulid) -> Self {
+        Self { id }
+    }
+}
+
+impl Route for RegisterDisplayName {
+    type Query = ();
+    fn route() -> &'static str {
+        "/register/steps/:id/display-name"
+    }
+
+    fn path(&self) -> std::borrow::Cow<'static, str> {
+        format!("/register/steps/{}/display-name", self.id).into()
+    }
+}
+
 /// `GET|POST /register/steps/:id/verify-email`
 #[derive(Debug, Clone)]
 pub struct RegisterVerifyEmail {

crates/templates/src/context.rs

@@ -1000,6 +1000,57 @@ impl TemplateContext for RegisterStepsVerifyEmailContext {
     }
 }
 
+/// Fields for the display name form
+#[derive(Serialize, Deserialize, Debug, Clone, Copy, Hash, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum RegisterStepsDisplayNameFormField {
+    /// The display name
+    DisplayName,
+}
+
+impl FormField for RegisterStepsDisplayNameFormField {
+    fn keep(&self) -> bool {
+        match self {
+            Self::DisplayName => true,
+        }
+    }
+}
+
+/// Context used by the `display_name.html` template
+#[derive(Serialize, Default)]
+pub struct RegisterStepsDisplayNameContext {
+    form: FormState<RegisterStepsDisplayNameFormField>,
+}
+
+impl RegisterStepsDisplayNameContext {
+    /// Constructs a context for the display name page
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Set the form state
+    #[must_use]
+    pub fn with_form_state(
+        mut self,
+        form_state: FormState<RegisterStepsDisplayNameFormField>,
+    ) -> Self {
+        self.form = form_state;
+        self
+    }
+}
+
+impl TemplateContext for RegisterStepsDisplayNameContext {
+    fn sample(_now: chrono::DateTime<chrono::Utc>, _rng: &mut impl Rng) -> Vec<Self>
+    where
+        Self: Sized,
+    {
+        vec![Self {
+            form: FormState::default(),
+        }]
+    }
+}
+
 /// Fields of the account recovery start form
 #[derive(Serialize, Deserialize, Debug, Clone, Copy, Hash, PartialEq, Eq)]
 #[serde(rename_all = "snake_case")]

crates/templates/src/lib.rs

@@ -41,6 +41,7 @@ pub use self::{
         PostAuthContextInner, ReauthContext, ReauthFormField, RecoveryExpiredContext,
         RecoveryFinishContext, RecoveryFinishFormField, RecoveryProgressContext,
         RecoveryStartContext, RecoveryStartFormField, RegisterContext, RegisterFormField,
+        RegisterStepsDisplayNameContext, RegisterStepsDisplayNameFormField,
         RegisterStepsVerifyEmailContext, RegisterStepsVerifyEmailFormField, SiteBranding,
         SiteConfigExt, SiteFeatures, TemplateContext, UpstreamExistingLinkContext,
         UpstreamRegister, UpstreamRegisterFormField, UpstreamSuggestLink, WithCaptcha, WithCsrf,
@@ -335,6 +336,9 @@ register_templates! {
     /// Render the email verification page
     pub fn render_register_steps_verify_email(WithLanguage<WithCsrf<RegisterStepsVerifyEmailContext>>) { "pages/register/steps/verify_email.html" }
 
+    /// Render the display name page
+    pub fn render_register_steps_display_name(WithLanguage<WithCsrf<RegisterStepsDisplayNameContext>>) { "pages/register/steps/display_name.html" }
+
     /// Render the client consent page
     pub fn render_consent(WithLanguage<WithCsrf<WithSession<ConsentContext>>>) { "pages/consent.html" }
 
@@ -428,6 +432,7 @@ impl Templates {
         check::render_register(self, now, rng)?;
         check::render_password_register(self, now, rng)?;
         check::render_register_steps_verify_email(self, now, rng)?;
+        check::render_register_steps_display_name(self, now, rng)?;
         check::render_consent(self, now, rng)?;
         check::render_policy_violation(self, now, rng)?;
         check::render_sso_login(self, now, rng)?;

templates/components/button.html

@@ -29,6 +29,7 @@
   class="",
   value="",
   disabled=False,
+  kind="primary",
   size="lg",
   autocomplete=False,
   autocorrect=False,
@@ -39,7 +40,7 @@
     type="{{ type }}"
     {% if disabled %}disabled{% endif %}
     class="cpd-button {{ class }}"
-    data-kind="primary"
+    data-kind="{{ kind }}"
     data-size="{{ size }}"
     {% if autocapitalize %}autocapitilize="{{ autocapitilize }}"{% endif %}
     {% if autocomplete %}autocomplete="{{ autocomplete }}"{% endif %}