nautilus_network/transport/
error.rs

1// -------------------------------------------------------------------------------------------------
2//  Copyright (C) 2015-2026 Nautech Systems Pty Ltd. All rights reserved.
3//  https://nautechsystems.io
4//
5//  Licensed under the GNU Lesser General Public License Version 3.0 (the "License");
6//  You may not use this file except in compliance with the License.
7//  You may obtain a copy of the License at https://www.gnu.org/licenses/lgpl-3.0.en.html
8//
9//  Unless required by applicable law or agreed to in writing, software
10//  distributed under the License is distributed on an "AS IS" BASIS,
11//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12//  See the License for the specific language governing permissions and
13//  limitations under the License.
14// -------------------------------------------------------------------------------------------------
15
16//! Neutral error type for the WebSocket transport abstraction.
17
18use std::io;
19
20use thiserror::Error;
21
22use super::message::CloseFrame;
23
24/// A backend-agnostic WebSocket transport error.
25///
26/// Each backend translates its native error type into this enum via `From` impls
27/// so the higher layers operate against a single error surface.
28#[derive(Debug, Error)]
29pub enum TransportError {
30    /// Underlying I/O error from the socket.
31    #[error("I/O error: {0}")]
32    Io(#[from] io::Error),
33
34    /// HTTP upgrade handshake failed.
35    #[error("handshake failed: {0}")]
36    Handshake(String),
37
38    /// Server rejected the WebSocket HTTP upgrade.
39    #[error("WebSocket upgrade rejected with status {0}")]
40    UpgradeRejected(u16),
41
42    /// Proxy rejected the HTTP CONNECT request.
43    #[error("proxy CONNECT rejected with status {0}")]
44    ProxyConnectRejected(u16),
45
46    /// URL was invalid or unsupported.
47    #[error("invalid URL: {0}")]
48    InvalidUrl(String),
49
50    /// TLS-layer failure during connect or stream operation.
51    #[error("TLS error: {0}")]
52    Tls(String),
53
54    /// WebSocket protocol violation reported by the peer or detected locally.
55    #[error("protocol error: {0}")]
56    Protocol(String),
57
58    /// Peer sent a close frame and the connection is closing.
59    #[error("connection closed by peer")]
60    ClosedByPeer(Option<CloseFrame>),
61
62    /// Connection closed without a close frame (abnormal).
63    #[error("connection closed")]
64    ConnectionClosed,
65
66    /// Connection reset by peer.
67    #[error("connection reset")]
68    ConnectionReset,
69
70    /// Message exceeded the configured maximum size.
71    #[error("message too large")]
72    MessageTooLarge,
73
74    /// Frame exceeded the configured maximum size.
75    #[error("frame too large")]
76    FrameTooLarge,
77
78    /// UTF-8 validation failed on a text frame.
79    ///
80    /// Both shipped backends validate incoming text frames: tokio-tungstenite
81    /// during frame assembly and sockudo-ws at parse time.
82    #[error("invalid UTF-8 in text frame")]
83    InvalidUtf8,
84
85    /// Backend returned an error not covered by other variants. Carries a
86    /// short description; consumers should treat as fatal.
87    #[error("transport error: {0}")]
88    Other(String),
89}
90
91impl TransportError {
92    /// Returns `true` if the error indicates the connection is no longer usable.
93    ///
94    /// `InvalidUrl` is the only non-fatal variant: a bad URL is a caller-side
95    /// configuration mistake that does not damage an existing connection.
96    /// Everything else (including `Io` and the catch-all `Other`) implies the
97    /// underlying transport cannot be reused.
98    #[must_use]
99    pub fn is_fatal(&self) -> bool {
100        !matches!(self, Self::InvalidUrl(_))
101    }
102
103    /// Returns `true` for connection-closed style errors.
104    #[must_use]
105    pub fn is_closed(&self) -> bool {
106        matches!(
107            self,
108            Self::ConnectionClosed | Self::ConnectionReset | Self::ClosedByPeer(_)
109        )
110    }
111}
112
113#[cfg(test)]
114mod tests {
115    use rstest::rstest;
116
117    use super::*;
118
119    #[rstest]
120    fn io_error_is_fatal() {
121        let err = TransportError::Io(io::Error::other("boom"));
122        assert!(err.is_fatal());
123        assert!(!err.is_closed());
124    }
125
126    #[rstest]
127    fn other_error_is_fatal() {
128        let err = TransportError::Other("unexpected".into());
129        assert!(err.is_fatal());
130        assert!(!err.is_closed());
131    }
132
133    #[rstest]
134    fn invalid_url_is_not_fatal() {
135        let err = TransportError::InvalidUrl("ws://".into());
136        assert!(!err.is_fatal());
137        assert!(!err.is_closed());
138    }
139
140    #[rstest]
141    fn closed_variants_are_closed_and_fatal() {
142        let err = TransportError::ConnectionClosed;
143        assert!(err.is_fatal());
144        assert!(err.is_closed());
145
146        let err = TransportError::ConnectionReset;
147        assert!(err.is_fatal());
148        assert!(err.is_closed());
149
150        let err = TransportError::ClosedByPeer(Some(CloseFrame::new(1000, "bye")));
151        assert!(err.is_fatal());
152        assert!(err.is_closed());
153    }
154
155    #[rstest]
156    fn protocol_error_is_fatal() {
157        let err = TransportError::Protocol("bad opcode".into());
158        assert!(err.is_fatal());
159        assert!(!err.is_closed());
160    }
161
162    #[rstest]
163    fn capacity_and_handshake_variants_are_fatal() {
164        for err in [
165            TransportError::MessageTooLarge,
166            TransportError::FrameTooLarge,
167            TransportError::InvalidUtf8,
168            TransportError::Tls("bad".into()),
169            TransportError::Handshake("bad".into()),
170            TransportError::UpgradeRejected(429),
171            TransportError::ProxyConnectRejected(503),
172        ] {
173            assert!(err.is_fatal(), "expected fatal: {err:?}");
174            assert!(!err.is_closed(), "expected not closed: {err:?}");
175        }
176    }
177}
nautilus_network/transport/error.rs

nautilus_network/transport/
error.rs
