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
//! HTML error pages: one layer that dresses every 4xx/5xx of an app.
//!
//! ```ignore
//! use rustango::errors::{ErrorPagesLayer, ErrorPagesRouterExt as _, PageError};
//!
//! async fn edit() -> Result<String, PageError> {
//! Err(PageError::forbidden("Ask an admin for the editor role."))
//! }
//!
//! let app = Router::new()
//! .route("/edit", get(edit))
//! .fallback(rustango::errors::not_found)
//! .error_pages(ErrorPagesLayer::new().templates(tera.clone()));
//! ```
//!
//! Who asked decides the body:
//!
//! - a browser navigating (`Accept: text/html`) gets a full page;
//! - htmx (`HX-Request`) gets a fragment, with `HX-Retarget` / `HX-Reswap`;
//! - any other client gets the body unchanged, or the [`Message`] as plain
//! text when the body is empty.
//!
//! JSON bodies pass through unless they carry a [`Message`] and a browser
//! asked. `HEAD`, non-text bodies and responses marked [`KeepBody`] always
//! pass through. A 5xx shows generic text unless `RUSTANGO_DISCLOSE_ERRORS`
//! is set, the same policy as every other 5xx body.
//!
//! Templates come from the Tera you pass; the first that exists wins:
//! `errors/{code}.html`, `errors/{4|5}xx.html`, `errors/default.html`, then
//! the built-in page. htmx fragments use `errors/partial.html`, then the
//! built-in one. Context: `code`, `title`, `message`, `path`, `user`
//! (`{username, is_superuser}` or null, with `tenancy`), `username`,
//! `is_superuser`, `csrf_token`, `csrf_input`, `csp_nonce` and the
//! `brand_*` keys. A template that fails to render falls back to the
//! built-in page.
use axum::response::{IntoResponse, IntoResponseParts, Response, ResponseParts};
/// A message for the user on an error response, for the error page to
/// show. On a 5xx it is shown only when error disclosure is on.
///
/// ```ignore
/// (StatusCode::FORBIDDEN, rustango::errors::Message::new("Ask Bob for access."))
/// ```
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Message(pub String);
impl Message {
#[must_use]
pub fn new(message: impl Into<String>) -> Self {
Self(message.into())
}
}
impl IntoResponseParts for Message {
type Error = std::convert::Infallible;
fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
res.extensions_mut().insert(self);
Ok(res)
}
}
/// An empty body carrying the message: `(StatusCode::GONE, Message::new("…"))`.
impl IntoResponse for Message {
fn into_response(self) -> Response {
let mut res = ().into_response();
res.extensions_mut().insert(self);
res
}
}
/// Marks a response whose error body the handler made on purpose; the
/// error-pages layer leaves it as it is.
#[derive(Debug, Clone, Copy, Default)]
pub struct KeepBody;
impl IntoResponseParts for KeepBody {
type Error = std::convert::Infallible;
fn into_response_parts(self, mut res: ResponseParts) -> Result<ResponseParts, Self::Error> {
res.extensions_mut().insert(self);
Ok(res)
}
}
/// Marks every HTML 4xx/5xx of a framework router as [`KeepBody`]: such a
/// page (a form re-shown with its error) is rendered on purpose.
#[cfg(feature = "admin")]
pub(crate) fn own_pages<S: Clone + Send + Sync + 'static>(
router: axum::Router<S>,
) -> axum::Router<S> {
router.layer(axum::middleware::map_response(
|mut res: Response| async move {
keep_own_page(&mut res);
res
},
))
}
/// [`KeepBody`] on `res` when it is an HTML error page.
#[cfg(any(feature = "admin", feature = "template_views"))]
pub(crate) fn keep_own_page(res: &mut Response) {
let status = res.status();
let html = res
.headers()
.get(axum::http::header::CONTENT_TYPE)
.and_then(|v| v.to_str().ok())
.is_some_and(|ct| {
ct.trim_start()
.to_ascii_lowercase()
.starts_with("text/html")
});
if html && (status.is_client_error() || status.is_server_error()) {
res.extensions_mut().insert(KeepBody);
}
}
/// A handler error for the error page: a 4xx carries its message, a
/// 5xx logs its cause and keeps it out of the body (unless disclosed).
#[derive(Debug)]
pub struct PageError {
status: axum::http::StatusCode,
message: String,
}
impl PageError {
/// `status` with a user-facing `message`. A 5xx goes through
/// [`Self::server`], so its text is logged and withheld.
#[must_use]
pub fn new(status: axum::http::StatusCode, message: impl Into<String>) -> Self {
let message = message.into();
if status.is_server_error() {
let mut e = Self::server(message);
e.status = status;
return e;
}
Self { status, message }
}
/// A logged `500`; the body is the opaque server-error text.
#[must_use]
pub fn server(cause: impl std::fmt::Display) -> Self {
Self {
status: axum::http::StatusCode::INTERNAL_SERVER_ERROR,
message: crate::error::server_error_body("errors::PageError", &cause),
}
}
/// `404` with a message.
#[must_use]
pub fn not_found(message: impl Into<String>) -> Self {
Self::new(axum::http::StatusCode::NOT_FOUND, message)
}
/// `403` with a message.
#[must_use]
pub fn forbidden(message: impl Into<String>) -> Self {
Self::new(axum::http::StatusCode::FORBIDDEN, message)
}
/// The status this error renders with.
#[must_use]
pub fn status(&self) -> axum::http::StatusCode {
self.status
}
}
impl std::fmt::Display for PageError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_str(&self.message)
}
}
impl IntoResponse for PageError {
/// The message as a plain-text body, and as [`Message`] for the page.
fn into_response(self) -> Response {
let body = self.message.clone();
(self.status, Message(self.message), body).into_response()
}
}
/// Unknown paths, as a 404 for the layer to dress:
/// `.fallback(rustango::errors::not_found)`.
pub async fn not_found() -> axum::http::StatusCode {
axum::http::StatusCode::NOT_FOUND
}
/// Title, and the message when there is no better one, for a status.
#[must_use]
pub fn error_words(status: axum::http::StatusCode) -> (&'static str, &'static str) {
match status.as_u16() {
401 => (
"Please sign in",
"Your session has ended. Sign in again to continue.",
),
403 => (
"Not allowed",
"You don't have permission for this. Ask an admin for a role that includes it.",
),
404 => (
"Not found",
"This page doesn't exist, or it was moved or deleted.",
),
405 => (
"Not supported",
"This address doesn't accept that kind of request.",
),
408 | 504 => (
"Took too long",
"The request timed out. Try again in a moment.",
),
413 => (
"Too large",
"That upload is bigger than the server accepts.",
),
422 => (
"Can't do that",
"The request couldn't be processed. Check what you entered.",
),
429 => (
"Slow down",
"Too many requests. Wait a moment and try again.",
),
s if s >= 500 => (
"Something went wrong",
"That failed on our side. It has been logged; try again in a moment.",
),
_ => ("Request failed", "The request couldn't be completed."),
}
}
#[cfg(feature = "template_views")]
mod layer;
#[cfg(feature = "template_views")]
pub use layer::{ErrorPagesLayer, ErrorPagesRouterExt};