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
|
use crate::{Body, SizeHint};
use bytes::Buf;
use http::HeaderMap;
use pin_project_lite::pin_project;
use std::error::Error;
use std::fmt;
use std::pin::Pin;
use std::task::{Context, Poll};
pin_project! {
/// A length limited body.
///
/// This body will return an error if more than the configured number
/// of bytes are returned on polling the wrapped body.
#[derive(Clone, Copy, Debug)]
pub struct Limited<B> {
remaining: usize,
#[pin]
inner: B,
}
}
impl<B> Limited<B> {
/// Create a new `Limited`.
pub fn new(inner: B, limit: usize) -> Self {
Self {
remaining: limit,
inner,
}
}
}
impl<B> Body for Limited<B>
where
B: Body,
B::Error: Into<Box<dyn Error + Send + Sync>>,
{
type Data = B::Data;
type Error = Box<dyn Error + Send + Sync>;
fn poll_data(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
let this = self.project();
let res = match this.inner.poll_data(cx) {
Poll::Pending => return Poll::Pending,
Poll::Ready(None) => None,
Poll::Ready(Some(Ok(data))) => {
if data.remaining() > *this.remaining {
*this.remaining = 0;
Some(Err(LengthLimitError.into()))
} else {
*this.remaining -= data.remaining();
Some(Ok(data))
}
}
Poll::Ready(Some(Err(err))) => Some(Err(err.into())),
};
Poll::Ready(res)
}
fn poll_trailers(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
let this = self.project();
let res = match this.inner.poll_trailers(cx) {
Poll::Pending => return Poll::Pending,
Poll::Ready(Ok(data)) => Ok(data),
Poll::Ready(Err(err)) => Err(err.into()),
};
Poll::Ready(res)
}
fn is_end_stream(&self) -> bool {
self.inner.is_end_stream()
}
fn size_hint(&self) -> SizeHint {
use std::convert::TryFrom;
match u64::try_from(self.remaining) {
Ok(n) => {
let mut hint = self.inner.size_hint();
if hint.lower() >= n {
hint.set_exact(n)
} else if let Some(max) = hint.upper() {
hint.set_upper(n.min(max))
} else {
hint.set_upper(n)
}
hint
}
Err(_) => self.inner.size_hint(),
}
}
}
/// An error returned when body length exceeds the configured limit.
#[derive(Debug)]
#[non_exhaustive]
pub struct LengthLimitError;
impl fmt::Display for LengthLimitError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str("length limit exceeded")
}
}
impl Error for LengthLimitError {}
#[cfg(test)]
mod tests {
use super::*;
use crate::Full;
use bytes::Bytes;
use std::convert::Infallible;
#[tokio::test]
async fn read_for_body_under_limit_returns_data() {
const DATA: &[u8] = b"testing";
let inner = Full::new(Bytes::from(DATA));
let body = &mut Limited::new(inner, 8);
let mut hint = SizeHint::new();
hint.set_upper(7);
assert_eq!(body.size_hint().upper(), hint.upper());
let data = body.data().await.unwrap().unwrap();
assert_eq!(data, DATA);
hint.set_upper(0);
assert_eq!(body.size_hint().upper(), hint.upper());
assert!(matches!(body.data().await, None));
}
#[tokio::test]
async fn read_for_body_over_limit_returns_error() {
const DATA: &[u8] = b"testing a string that is too long";
let inner = Full::new(Bytes::from(DATA));
let body = &mut Limited::new(inner, 8);
let mut hint = SizeHint::new();
hint.set_upper(8);
assert_eq!(body.size_hint().upper(), hint.upper());
let error = body.data().await.unwrap().unwrap_err();
assert!(matches!(error.downcast_ref(), Some(LengthLimitError)));
}
struct Chunky(&'static [&'static [u8]]);
impl Body for Chunky {
type Data = &'static [u8];
type Error = Infallible;
fn poll_data(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
let mut this = self;
match this.0.split_first().map(|(&head, tail)| (Ok(head), tail)) {
Some((data, new_tail)) => {
this.0 = new_tail;
Poll::Ready(Some(data))
}
None => Poll::Ready(None),
}
}
fn poll_trailers(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
Poll::Ready(Ok(Some(HeaderMap::new())))
}
}
#[tokio::test]
async fn read_for_chunked_body_around_limit_returns_first_chunk_but_returns_error_on_over_limit_chunk(
) {
const DATA: &[&[u8]] = &[b"testing ", b"a string that is too long"];
let inner = Chunky(DATA);
let body = &mut Limited::new(inner, 8);
let mut hint = SizeHint::new();
hint.set_upper(8);
assert_eq!(body.size_hint().upper(), hint.upper());
let data = body.data().await.unwrap().unwrap();
assert_eq!(data, DATA[0]);
hint.set_upper(0);
assert_eq!(body.size_hint().upper(), hint.upper());
let error = body.data().await.unwrap().unwrap_err();
assert!(matches!(error.downcast_ref(), Some(LengthLimitError)));
}
#[tokio::test]
async fn read_for_chunked_body_over_limit_on_first_chunk_returns_error() {
const DATA: &[&[u8]] = &[b"testing a string", b" that is too long"];
let inner = Chunky(DATA);
let body = &mut Limited::new(inner, 8);
let mut hint = SizeHint::new();
hint.set_upper(8);
assert_eq!(body.size_hint().upper(), hint.upper());
let error = body.data().await.unwrap().unwrap_err();
assert!(matches!(error.downcast_ref(), Some(LengthLimitError)));
}
#[tokio::test]
async fn read_for_chunked_body_under_limit_is_okay() {
const DATA: &[&[u8]] = &[b"test", b"ing!"];
let inner = Chunky(DATA);
let body = &mut Limited::new(inner, 8);
let mut hint = SizeHint::new();
hint.set_upper(8);
assert_eq!(body.size_hint().upper(), hint.upper());
let data = body.data().await.unwrap().unwrap();
assert_eq!(data, DATA[0]);
hint.set_upper(4);
assert_eq!(body.size_hint().upper(), hint.upper());
let data = body.data().await.unwrap().unwrap();
assert_eq!(data, DATA[1]);
hint.set_upper(0);
assert_eq!(body.size_hint().upper(), hint.upper());
assert!(matches!(body.data().await, None));
}
#[tokio::test]
async fn read_for_trailers_propagates_inner_trailers() {
const DATA: &[&[u8]] = &[b"test", b"ing!"];
let inner = Chunky(DATA);
let body = &mut Limited::new(inner, 8);
let trailers = body.trailers().await.unwrap();
assert_eq!(trailers, Some(HeaderMap::new()))
}
#[derive(Debug)]
enum ErrorBodyError {
Data,
Trailers,
}
impl fmt::Display for ErrorBodyError {
fn fmt(&self, _f: &mut fmt::Formatter) -> fmt::Result {
Ok(())
}
}
impl Error for ErrorBodyError {}
struct ErrorBody;
impl Body for ErrorBody {
type Data = &'static [u8];
type Error = ErrorBodyError;
fn poll_data(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
Poll::Ready(Some(Err(ErrorBodyError::Data)))
}
fn poll_trailers(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
Poll::Ready(Err(ErrorBodyError::Trailers))
}
}
#[tokio::test]
async fn read_for_body_returning_error_propagates_error() {
let body = &mut Limited::new(ErrorBody, 8);
let error = body.data().await.unwrap().unwrap_err();
assert!(matches!(error.downcast_ref(), Some(ErrorBodyError::Data)));
}
#[tokio::test]
async fn trailers_for_body_returning_error_propagates_error() {
let body = &mut Limited::new(ErrorBody, 8);
let error = body.trailers().await.unwrap_err();
assert!(matches!(
error.downcast_ref(),
Some(ErrorBodyError::Trailers)
));
}
}
|
