Fix login/signup redirection

HTMX needs special treatment for redirects on submit.

src/handlers/login.rs

@@ -1,4 +1,4 @@
-use axum::response::{IntoResponse, Redirect, Response};
+use axum::response::{IntoResponse, Response};
 use axum::{extract::State, Form};
 use maud::html;
 use serde::Deserialize;
@@ -7,6 +7,7 @@ use sqlx::PgPool;
 
 use crate::auth::verify_password;
 use crate::error::{Error, Result};
+use crate::htmx::HXRedirect;
 use crate::partials::login_form::{login_form, LoginFormProps};
 use crate::{
     models::user::{AuthContext, User},
@@ -65,5 +66,5 @@ pub async fn post(
     auth.login(&user)
         .await
         .map_err(|_| Error::InternalServerError)?;
-    Ok(Redirect::to("/").into_response())
+    Ok(HXRedirect::to("/").into_response())
 }

src/handlers/signup.rs

@@ -1,4 +1,4 @@
-use axum::response::{IntoResponse, Redirect, Response};
+use axum::response::{IntoResponse, Response};
 use axum::{extract::State, Form};
 use maud::html;
 use serde::Deserialize;
@@ -6,6 +6,7 @@ use serde_with::{serde_as, NoneAsEmptyString};
 use sqlx::PgPool;
 
 use crate::error::{Error, Result};
+use crate::htmx::HXRedirect;
 use crate::models::user::{AuthContext, CreateUser, User};
 use crate::partials::layout::Layout;
 use crate::partials::signup_form::{signup_form, SignupFormProps};
@@ -107,5 +108,5 @@ pub async fn post(
     auth.login(&user)
         .await
         .map_err(|_| Error::InternalServerError)?;
-    Ok(Redirect::to("/").into_response())
+    Ok(HXRedirect::to("/").into_response())
 }

src/htmx.rs

@@ -0,0 +1,32 @@
+use axum::response::{IntoResponse, Response};
+use http::header::{HeaderName, HeaderValue};
+use http::StatusCode;
+
+#[allow(clippy::declare_interior_mutable_const)]
+const HX_LOCATION: HeaderName = HeaderName::from_static("hx-location");
+
+/// Sets the HX-Location header so that HTMX redirects to the given URI. Unlike 
+/// axum::response::Redirect this does not return a 300-level status code (instead, a 200 status 
+/// code) so that HTMX can see the HX-Location header before the browser handles the redirect.
+#[derive(Debug, Clone)]
+pub struct HXRedirect {
+    location: HeaderValue,
+}
+
+impl HXRedirect {
+    pub fn to(uri: &str) -> Self {
+        Self {
+            location: HeaderValue::try_from(uri).expect("URI isn't a valid header value"),
+        }
+    }
+}
+
+impl IntoResponse for HXRedirect {
+    fn into_response(self) -> Response {
+        (
+            StatusCode::OK,
+            [(HX_LOCATION, self.location)],
+        )
+            .into_response()
+    }
+}

src/lib.rs

@@ -6,6 +6,7 @@ pub mod domain_locks;
 pub mod error;
 pub mod handlers;
 pub mod headers;
+pub mod htmx;
 pub mod log;
 pub mod models;
 pub mod partials;