axum-syntax-responses

What problem does it solve?

It prevents Axum handler return-value mistakes that either fail compilation or silently produce incorrect HTTP responses, especially around IntoResponse / IntoResponseParts tuple rules, status/header/body ordering, redirect status codes, cookie jar behavior, and the Axum 0.8 body type.

Core Features & Use Cases

• IntoResponse return typing: Ensures your handler returns a type that actually implements IntoResponse (e.g., Json, Html, Redirect, StatusCode, Response), avoiding Handler trait bound failures.
• Tuple composition correctness: Guarantees correct use of (StatusCode, parts..., body) and enforces that the body is the final tuple element while earlier elements are IntoResponseParts.
• Status, headers, and cookies right: Correctly combines status and headers (including AppendHeaders for multiple Set-Cookie), picks correct Redirect constructors (303/307/308 only), and ensures the modified CookieJar is returned.
• Axum 0.8 body requirement: Uses axum::body::Body instead of hyper::Body when manually building a Response.
• Common scenarios: Returning JSON/HTML/raw bytes, setting response headers, redirecting after POST/PUT, mapping fallible results to responses with Result, and applying cookie-based session/auth patterns.

Quick Start

Use axum-syntax-responses when your Axum handler must return a proper status/headers/body (or cookies/redirects) or when compilation fails with an IntoResponse/Handler trait-bound error.