From 722317603da31fbf9073f416bf87cb966835c855 Mon Sep 17 00:00:00 2001
From: Jef Roosens <roosensjef@gmail.com>
Date: Thu, 28 Aug 2025 14:21:26 +0200
Subject: [PATCH] feat(server): add routes for private sign-up links

---
 CHANGELOG.md                    |  3 +-
 gpodder/src/repository/admin.rs |  5 ---
 gpodder/src/repository/mod.rs   | 11 +++++-
 otter/src/server/web/auth.rs    | 66 ++++++++++++++++++++++++++++++++-
 4 files changed, 76 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ac346d..c4ad50a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased](https://git.rustybever.be/Chewing_Bever/otter)
 
 * CLI command to add new users
-* Added public sign-up page (disabled by default)
+* Public sign-up page (disabled by default)
+* Private sign-up links
 
 ## [0.2.1](https://git.rustybever.be/Chewing_Bever/otter/src/tag/0.2.1)
 
diff --git a/gpodder/src/repository/admin.rs b/gpodder/src/repository/admin.rs
index 495d982..3c98a52 100644
--- a/gpodder/src/repository/admin.rs
+++ b/gpodder/src/repository/admin.rs
@@ -29,9 +29,4 @@ impl<'a> AdminRepository<'a> {
 
         Ok(link)
     }
-
-    /// Remove the signup link with the given ID, if it exists
-    pub fn remove_signup_link(&self, id: i64) -> Result<bool, AuthErr> {
-        self.store.remove_signup_link(id)
-    }
 }
diff --git a/gpodder/src/repository/mod.rs b/gpodder/src/repository/mod.rs
index f850a05..100f49f 100644
--- a/gpodder/src/repository/mod.rs
+++ b/gpodder/src/repository/mod.rs
@@ -8,7 +8,7 @@ use chrono::{TimeDelta, Utc};
 use rand::rngs::OsRng;
 
 use crate::{
-    models,
+    SignupLink, models,
     store::{AuthErr, GpodderStore},
 };
 
@@ -117,4 +117,13 @@ impl GpodderRepository {
 
         self.store.remove_old_sessions(min_last_seen)
     }
+
+    pub fn get_signup_link(&self, id: i64) -> Result<Option<SignupLink>, AuthErr> {
+        self.store.get_signup_link(id)
+    }
+
+    /// Remove the signup link with the given ID, if it exists
+    pub fn remove_signup_link(&self, id: i64) -> Result<bool, AuthErr> {
+        self.store.remove_signup_link(id)
+    }
 }
diff --git a/otter/src/server/web/auth.rs b/otter/src/server/web/auth.rs
index 34b84af..198d53a 100644
--- a/otter/src/server/web/auth.rs
+++ b/otter/src/server/web/auth.rs
@@ -1,7 +1,7 @@
 use axum::{
     Form, RequestExt, Router,
-    extract::{Request, State},
-    http::HeaderMap,
+    extract::{Path, Request, State},
+    http::{HeaderMap, StatusCode},
     middleware::Next,
     response::{IntoResponse, Redirect, Response},
     routing::{get, post},
@@ -35,6 +35,8 @@ pub fn router(ctx: Context) -> Router<Context> {
     // security mistakes
     if ctx.config.allow_public_signup {
         router = router.route("/signup", get(get_signup).post(post_signup))
+    } else {
+        router = router.route("/signup/{id}", get(get_signup_link).post(post_signup_link));
     }
 
     router
@@ -261,3 +263,63 @@ async fn post_signup(
         .into_response())
     }
 }
+
+async fn get_signup_link(
+    State(ctx): State<Context>,
+    Path(id): Path<i64>,
+    headers: HeaderMap,
+    jar: CookieJar,
+) -> AppResult<Response> {
+    let ctx_clone = ctx.clone();
+    let signup_link = tokio::task::spawn_blocking(move || ctx_clone.store.get_signup_link(id))
+        .await
+        .unwrap()?;
+
+    // Just redirect to / if it's an invalid sign-up link
+    if signup_link.is_none()
+        || extract_session(ctx.clone(), &jar)
+            .await
+            .ok()
+            .flatten()
+            .is_some()
+    {
+        Ok(Redirect::to("/").into_response())
+    } else {
+        Ok(View::Signup {
+            username: None,
+            username_available: true,
+            passwords_match: true,
+        }
+        .page(&headers)
+        .response(&ctx.tera)
+        .into_response())
+    }
+}
+
+async fn post_signup_link(
+    State(ctx): State<Context>,
+    Path(id): Path<i64>,
+    jar: CookieJar,
+    headers: HeaderMap,
+    user_agent: Option<TypedHeader<UserAgent>>,
+    signup: Form<SignupForm>,
+) -> AppResult<Response> {
+    let ctx_clone = ctx.clone();
+
+    if tokio::task::spawn_blocking(move || ctx_clone.store.get_signup_link(id))
+        .await
+        .unwrap()?
+        .is_some()
+    {
+        let response = post_signup(State(ctx.clone()), jar, headers, user_agent, signup).await?;
+
+        // Signup flow was successful, so remove the signup link
+        tokio::task::spawn_blocking(move || ctx.store.remove_signup_link(id))
+            .await
+            .unwrap()?;
+
+        Ok(response)
+    } else {
+        Ok(StatusCode::NOT_FOUND.into_response())
+    }
+}