rustango 0.38.0

Django-shaped batteries-included web framework for Rust: ORM + migrations + auto-admin + multi-tenancy + audit log + auth (sessions, JWT, OAuth2/OIDC, HMAC) + APIs (ViewSet, OpenAPI auto-derive, JSON:API) + jobs (in-mem + Postgres) + email + media (S3 / R2 / B2 / MinIO + presigned uploads + collections + tags) + production middleware (CSRF, CSP, rate-limiting, compression, idempotency, etc.).
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314

//! Real-IP extraction middleware for apps behind a trusted reverse proxy.
//!
//! `axum::extract::ConnectInfo<SocketAddr>` always reports the
//! immediate peer — useless when your app sits behind nginx /
//! Cloudflare / ELB. This middleware parses one of the common
//! forwarded-for headers and stuffs the resolved client IP into the
//! request extensions as a [`RealIp`] value.
//!
//! ## Quick start
//!
//! ```ignore
//! use rustango::real_ip::{RealIpLayer, RealIpRouterExt, RealIp};
//! use axum::Extension;
//!
//! // Trust the immediate proxy; read the leftmost (= original client)
//! // entry in X-Forwarded-For.
//! let app = axum::Router::new()
//!     .route("/", axum::routing::get(home))
//!     .real_ip(RealIpLayer::default());
//!
//! async fn home(Extension(ip): Extension<RealIp>) -> String {
//!     format!("hi, {}", ip.0)
//! }
//! ```
//!
//! ## Important security note
//!
//! **Never trust forwarded-for headers from the open internet** — any
//! client can set them. Apply this layer ONLY when a proxy you
//! control terminates inbound requests and rewrites these headers,
//! and configure that proxy to scrub them on the way in.

use std::net::IpAddr;
use std::sync::Arc;

use axum::body::Body;
use axum::extract::{ConnectInfo, Request};
use axum::middleware::Next;
use axum::Router;

/// Resolved client IP. Stored in `request.extensions` by
/// [`RealIpLayer`]; pull it out via `axum::Extension<RealIp>` in your
/// handler.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct RealIp(pub IpAddr);

#[derive(Clone, Debug)]
pub enum HeaderStrategy {
    /// Standard `Forwarded: for=<ip>` (RFC 7239). Picks the leftmost
    /// `for=` parameter.
    ForwardedRfc7239,
    /// `X-Forwarded-For: client, proxy1, proxy2`. Picks the leftmost
    /// IP (= original client). Almost universally what reverse proxies
    /// emit.
    XForwardedFor,
    /// `X-Real-IP: <ip>`. Single value; some proxies (nginx) set this
    /// rather than X-Forwarded-For.
    XRealIp,
    /// Cloudflare's `CF-Connecting-IP`.
    CfConnectingIp,
    /// Try each strategy in order; first hit wins. Default.
    Auto,
}

#[derive(Clone, Debug)]
pub struct RealIpLayer {
    pub strategy: HeaderStrategy,
}

impl Default for RealIpLayer {
    fn default() -> Self {
        Self {
            strategy: HeaderStrategy::Auto,
        }
    }
}

impl RealIpLayer {
    #[must_use]
    pub fn new(strategy: HeaderStrategy) -> Self {
        Self { strategy }
    }
}

pub trait RealIpRouterExt {
    #[must_use]
    fn real_ip(self, layer: RealIpLayer) -> Self;
}

impl<S: Clone + Send + Sync + 'static> RealIpRouterExt for Router<S> {
    fn real_ip(self, layer: RealIpLayer) -> Self {
        let cfg = Arc::new(layer);
        self.layer(axum::middleware::from_fn(
            move |mut req: Request<Body>, next: Next| {
                let cfg = cfg.clone();
                async move {
                    if let Some(ip) = extract(&req, &cfg.strategy) {
                        req.extensions_mut().insert(RealIp(ip));
                    }
                    next.run(req).await
                }
            },
        ))
    }
}

fn extract(req: &Request<Body>, strategy: &HeaderStrategy) -> Option<IpAddr> {
    let h = req.headers();
    match strategy {
        HeaderStrategy::ForwardedRfc7239 => {
            parse_forwarded_rfc7239(h.get("forwarded").and_then(|v| v.to_str().ok())?)
        }
        HeaderStrategy::XForwardedFor => {
            parse_x_forwarded_for(h.get("x-forwarded-for").and_then(|v| v.to_str().ok())?)
        }
        HeaderStrategy::XRealIp => h
            .get("x-real-ip")
            .and_then(|v| v.to_str().ok())
            .and_then(|s| s.trim().parse().ok()),
        HeaderStrategy::CfConnectingIp => h
            .get("cf-connecting-ip")
            .and_then(|v| v.to_str().ok())
            .and_then(|s| s.trim().parse().ok()),
        HeaderStrategy::Auto => extract(req, &HeaderStrategy::CfConnectingIp)
            .or_else(|| extract(req, &HeaderStrategy::ForwardedRfc7239))
            .or_else(|| extract(req, &HeaderStrategy::XForwardedFor))
            .or_else(|| extract(req, &HeaderStrategy::XRealIp))
            .or_else(|| {
                req.extensions()
                    .get::<ConnectInfo<std::net::SocketAddr>>()
                    .map(|ci| ci.ip())
            }),
    }
}

/// Parse the leftmost `for=<ip>` token from an RFC 7239 `Forwarded`
/// header. Strips IPv6 brackets and `:port` suffixes. Returns `None`
/// on any malformed value.
fn parse_forwarded_rfc7239(s: &str) -> Option<IpAddr> {
    // Comma-separated forwarded elements; pick the first one.
    let first = s.split(',').next()?.trim();
    // Each element is semicolon-separated key=value pairs.
    for kv in first.split(';') {
        let kv = kv.trim();
        let (k, v) = kv.split_once('=')?;
        if k.eq_ignore_ascii_case("for") {
            // Strip surrounding quotes if any.
            let v = v.trim().trim_matches('"');
            return parse_ip_with_optional_port(v);
        }
    }
    None
}

fn parse_x_forwarded_for(s: &str) -> Option<IpAddr> {
    // Leftmost = original client. Proxies APPEND, never prepend.
    let first = s.split(',').next()?.trim();
    parse_ip_with_optional_port(first)
}

/// Parse an IP that may be wrapped in brackets (`[::1]`) or carry a
/// `:port` suffix. The brackets-without-port case is also handled.
fn parse_ip_with_optional_port(s: &str) -> Option<IpAddr> {
    let s = s.trim();
    // [v6]:port
    if let Some(rest) = s.strip_prefix('[') {
        let close = rest.find(']')?;
        return rest[..close].parse().ok();
    }
    // bare v4:port — at most one colon; bare v6 has multiple.
    if s.matches(':').count() == 1 {
        if let Some((ip, _port)) = s.rsplit_once(':') {
            return ip.parse().ok();
        }
    }
    s.parse().ok()
}

#[cfg(test)]
mod tests {
    use super::*;
    use axum::http::Request;

    fn req_with_header(name: &'static str, value: &str) -> Request<Body> {
        Request::builder()
            .header(name, value)
            .body(Body::empty())
            .unwrap()
    }

    #[test]
    fn x_forwarded_for_picks_leftmost() {
        let r = req_with_header("x-forwarded-for", "1.2.3.4, 10.0.0.1, 172.16.0.5");
        let ip = extract(&r, &HeaderStrategy::XForwardedFor).unwrap();
        assert_eq!(ip.to_string(), "1.2.3.4");
    }

    #[test]
    fn x_forwarded_for_strips_ipv4_port() {
        let r = req_with_header("x-forwarded-for", "203.0.113.7:51234, 10.0.0.1");
        let ip = extract(&r, &HeaderStrategy::XForwardedFor).unwrap();
        assert_eq!(ip.to_string(), "203.0.113.7");
    }

    #[test]
    fn x_forwarded_for_handles_ipv6_brackets() {
        let r = req_with_header("x-forwarded-for", "[2001:db8::1]:443, 10.0.0.1");
        let ip = extract(&r, &HeaderStrategy::XForwardedFor).unwrap();
        assert_eq!(ip.to_string(), "2001:db8::1");
    }

    #[test]
    fn x_forwarded_for_bare_ipv6() {
        let r = req_with_header("x-forwarded-for", "2001:db8::1");
        let ip = extract(&r, &HeaderStrategy::XForwardedFor).unwrap();
        assert_eq!(ip.to_string(), "2001:db8::1");
    }

    #[test]
    fn x_real_ip_strategy() {
        let r = req_with_header("x-real-ip", "198.51.100.42");
        let ip = extract(&r, &HeaderStrategy::XRealIp).unwrap();
        assert_eq!(ip.to_string(), "198.51.100.42");
    }

    #[test]
    fn cf_connecting_ip_strategy() {
        let r = req_with_header("cf-connecting-ip", "2606:4700::1");
        let ip = extract(&r, &HeaderStrategy::CfConnectingIp).unwrap();
        assert_eq!(ip.to_string(), "2606:4700::1");
    }

    #[test]
    fn rfc7239_for_token_parses() {
        // RFC 7239 example: `for=192.0.2.43, for=198.51.100.17`
        let r = req_with_header("forwarded", "for=192.0.2.43, for=198.51.100.17");
        let ip = extract(&r, &HeaderStrategy::ForwardedRfc7239).unwrap();
        assert_eq!(ip.to_string(), "192.0.2.43");
    }

    #[test]
    fn rfc7239_with_quoted_ipv6_port() {
        let r = req_with_header("forwarded", r#"for="[2001:db8:cafe::17]:4711""#);
        let ip = extract(&r, &HeaderStrategy::ForwardedRfc7239).unwrap();
        assert_eq!(ip.to_string(), "2001:db8:cafe::17");
    }

    #[test]
    fn rfc7239_ignores_other_keys() {
        let r = req_with_header("forwarded", "by=10.0.0.1;for=203.0.113.7;proto=https");
        let ip = extract(&r, &HeaderStrategy::ForwardedRfc7239).unwrap();
        assert_eq!(ip.to_string(), "203.0.113.7");
    }

    #[test]
    fn auto_picks_cloudflare_first_when_present() {
        let r = Request::builder()
            .header("x-forwarded-for", "1.1.1.1")
            .header("cf-connecting-ip", "9.9.9.9")
            .body(Body::empty())
            .unwrap();
        let ip = extract(&r, &HeaderStrategy::Auto).unwrap();
        assert_eq!(ip.to_string(), "9.9.9.9");
    }

    #[test]
    fn auto_falls_through_to_xff_when_no_cf_or_forwarded() {
        let r = req_with_header("x-forwarded-for", "1.1.1.1");
        let ip = extract(&r, &HeaderStrategy::Auto).unwrap();
        assert_eq!(ip.to_string(), "1.1.1.1");
    }

    #[test]
    fn no_headers_returns_none_when_no_connect_info() {
        let r = Request::builder().body(Body::empty()).unwrap();
        assert!(extract(&r, &HeaderStrategy::Auto).is_none());
    }

    #[test]
    fn malformed_header_returns_none() {
        let r = req_with_header("x-real-ip", "not-an-ip");
        assert!(extract(&r, &HeaderStrategy::XRealIp).is_none());
    }

    #[tokio::test]
    async fn middleware_inserts_realip_into_extensions() {
        use axum::routing::get;
        use axum::Extension;
        use tower::ServiceExt;

        async fn handler(Extension(RealIp(ip)): Extension<RealIp>) -> String {
            ip.to_string()
        }

        let app = Router::new()
            .route("/", get(handler))
            .real_ip(RealIpLayer::default());
        let resp = app
            .oneshot(
                Request::builder()
                    .uri("/")
                    .header("x-forwarded-for", "192.0.2.1, 10.0.0.1")
                    .body(Body::empty())
                    .unwrap(),
            )
            .await
            .unwrap();
        assert_eq!(resp.status(), 200);
        let bytes = axum::body::to_bytes(resp.into_body(), 1 << 16)
            .await
            .unwrap();
        assert_eq!(std::str::from_utf8(&bytes).unwrap(), "192.0.2.1");
    }
}