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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337
//! Redirect Handling
//!
//! By default, a `Client` will automatically handle HTTP redirects, having a
//! maximum redirect chain of 10 hops. To customize this behavior, a
//! `redirect::Policy` can be used with a `ClientBuilder`.
use std::error::Error as StdError;
use std::fmt;
use crate::header::{HeaderMap, AUTHORIZATION, COOKIE, PROXY_AUTHORIZATION, WWW_AUTHENTICATE};
use hyper::StatusCode;
use crate::Url;
/// A type that controls the policy on how to handle the following of redirects.
///
/// The default value will catch redirect loops, and has a maximum of 10
/// redirects it will follow in a chain before returning an error.
///
/// - `limited` can be used have the same as the default behavior, but adjust
/// the allowed maximum redirect hops in a chain.
/// - `none` can be used to disable all redirect behavior.
/// - `custom` can be used to create a customized policy.
pub struct Policy {
inner: PolicyKind,
}
/// A type that holds information on the next request and previous requests
/// in redirect chain.
#[derive(Debug)]
pub struct Attempt<'a> {
status: StatusCode,
next: &'a Url,
previous: &'a [Url],
}
/// An action to perform when a redirect status code is found.
#[derive(Debug)]
pub struct Action {
inner: ActionKind,
}
impl Policy {
/// Create a `Policy` with a maximum number of redirects.
///
/// An `Error` will be returned if the max is reached.
pub fn limited(max: usize) -> Self {
Self {
inner: PolicyKind::Limit(max),
}
}
/// Create a `Policy` that does not follow any redirect.
pub fn none() -> Self {
Self {
inner: PolicyKind::None,
}
}
/// Create a custom `Policy` using the passed function.
///
/// # Note
///
/// The default `Policy` handles a maximum loop
/// chain, but the custom variant does not do that for you automatically.
/// The custom policy should have some way of handling those.
///
/// Information on the next request and previous requests can be found
/// on the [`Attempt`] argument passed to the closure.
///
/// Actions can be conveniently created from methods on the
/// [`Attempt`].
///
/// # Example
///
/// ```rust
/// # use reqwest::{Error, redirect};
/// #
/// # fn run() -> Result<(), Error> {
/// let custom = redirect::Policy::custom(|attempt| {
/// if attempt.previous().len() > 5 {
/// attempt.error("too many redirects")
/// } else if attempt.url().host_str() == Some("example.domain") {
/// // prevent redirects to 'example.domain'
/// attempt.stop()
/// } else {
/// attempt.follow()
/// }
/// });
/// let client = reqwest::Client::builder()
/// .redirect(custom)
/// .build()?;
/// # Ok(())
/// # }
/// ```
///
/// [`Attempt`]: struct.Attempt.html
pub fn custom<T>(policy: T) -> Self
where
T: Fn(Attempt) -> Action + Send + Sync + 'static,
{
Self {
inner: PolicyKind::Custom(Box::new(policy)),
}
}
/// Apply this policy to a given [`Attempt`] to produce a [`Action`].
///
/// # Note
///
/// This method can be used together with `Policy::custom()`
/// to construct one `Policy` that wraps another.
///
/// # Example
///
/// ```rust
/// # use reqwest::{Error, redirect};
/// #
/// # fn run() -> Result<(), Error> {
/// let custom = redirect::Policy::custom(|attempt| {
/// eprintln!("{}, Location: {:?}", attempt.status(), attempt.url());
/// redirect::Policy::default().redirect(attempt)
/// });
/// # Ok(())
/// # }
/// ```
pub fn redirect(&self, attempt: Attempt) -> Action {
match self.inner {
PolicyKind::Custom(ref custom) => custom(attempt),
PolicyKind::Limit(max) => {
if attempt.previous.len() >= max {
attempt.error(TooManyRedirects)
} else {
attempt.follow()
}
}
PolicyKind::None => attempt.stop(),
}
}
pub(crate) fn check(&self, status: StatusCode, next: &Url, previous: &[Url]) -> ActionKind {
self.redirect(Attempt {
status,
next,
previous,
})
.inner
}
pub(crate) fn is_default(&self) -> bool {
matches!(self.inner, PolicyKind::Limit(10))
}
}
impl Default for Policy {
fn default() -> Policy {
// Keep `is_default` in sync
Policy::limited(10)
}
}
impl<'a> Attempt<'a> {
/// Get the type of redirect.
pub fn status(&self) -> StatusCode {
self.status
}
/// Get the next URL to redirect to.
pub fn url(&self) -> &Url {
self.next
}
/// Get the list of previous URLs that have already been requested in this chain.
pub fn previous(&self) -> &[Url] {
self.previous
}
/// Returns an action meaning reqwest should follow the next URL.
pub fn follow(self) -> Action {
Action {
inner: ActionKind::Follow,
}
}
/// Returns an action meaning reqwest should not follow the next URL.
///
/// The 30x response will be returned as the `Ok` result.
pub fn stop(self) -> Action {
Action {
inner: ActionKind::Stop,
}
}
/// Returns an action failing the redirect with an error.
///
/// The `Error` will be returned for the result of the sent request.
pub fn error<E: Into<Box<dyn StdError + Send + Sync>>>(self, error: E) -> Action {
Action {
inner: ActionKind::Error(error.into()),
}
}
}
enum PolicyKind {
Custom(Box<dyn Fn(Attempt) -> Action + Send + Sync + 'static>),
Limit(usize),
None,
}
impl fmt::Debug for Policy {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_tuple("Policy").field(&self.inner).finish()
}
}
impl fmt::Debug for PolicyKind {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
PolicyKind::Custom(..) => f.pad("Custom"),
PolicyKind::Limit(max) => f.debug_tuple("Limit").field(&max).finish(),
PolicyKind::None => f.pad("None"),
}
}
}
// pub(crate)
#[derive(Debug)]
pub(crate) enum ActionKind {
Follow,
Stop,
Error(Box<dyn StdError + Send + Sync>),
}
pub(crate) fn remove_sensitive_headers(headers: &mut HeaderMap, next: &Url, previous: &[Url]) {
if let Some(previous) = previous.last() {
let cross_host = next.host_str() != previous.host_str()
|| next.port_or_known_default() != previous.port_or_known_default();
if cross_host {
headers.remove(AUTHORIZATION);
headers.remove(COOKIE);
headers.remove("cookie2");
headers.remove(PROXY_AUTHORIZATION);
headers.remove(WWW_AUTHENTICATE);
}
}
}
#[derive(Debug)]
struct TooManyRedirects;
impl fmt::Display for TooManyRedirects {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str("too many redirects")
}
}
impl StdError for TooManyRedirects {}
#[test]
fn test_redirect_policy_limit() {
let policy = Policy::default();
let next = Url::parse("http://x.y/z").unwrap();
let mut previous = (0..9)
.map(|i| Url::parse(&format!("http://a.b/c/{i}")).unwrap())
.collect::<Vec<_>>();
match policy.check(StatusCode::FOUND, &next, &previous) {
ActionKind::Follow => (),
other => panic!("unexpected {other:?}"),
}
previous.push(Url::parse("http://a.b.d/e/33").unwrap());
match policy.check(StatusCode::FOUND, &next, &previous) {
ActionKind::Error(err) if err.is::<TooManyRedirects>() => (),
other => panic!("unexpected {other:?}"),
}
}
#[test]
fn test_redirect_policy_limit_to_0() {
let policy = Policy::limited(0);
let next = Url::parse("http://x.y/z").unwrap();
let previous = vec![Url::parse("http://a.b/c").unwrap()];
match policy.check(StatusCode::FOUND, &next, &previous) {
ActionKind::Error(err) if err.is::<TooManyRedirects>() => (),
other => panic!("unexpected {other:?}"),
}
}
#[test]
fn test_redirect_policy_custom() {
let policy = Policy::custom(|attempt| {
if attempt.url().host_str() == Some("foo") {
attempt.stop()
} else {
attempt.follow()
}
});
let next = Url::parse("http://bar/baz").unwrap();
match policy.check(StatusCode::FOUND, &next, &[]) {
ActionKind::Follow => (),
other => panic!("unexpected {other:?}"),
}
let next = Url::parse("http://foo/baz").unwrap();
match policy.check(StatusCode::FOUND, &next, &[]) {
ActionKind::Stop => (),
other => panic!("unexpected {other:?}"),
}
}
#[test]
fn test_remove_sensitive_headers() {
use hyper::header::{HeaderValue, ACCEPT, AUTHORIZATION, COOKIE};
let mut headers = HeaderMap::new();
headers.insert(ACCEPT, HeaderValue::from_static("*/*"));
headers.insert(AUTHORIZATION, HeaderValue::from_static("let me in"));
headers.insert(COOKIE, HeaderValue::from_static("foo=bar"));
let next = Url::parse("http://initial-domain.com/path").unwrap();
let mut prev = vec![Url::parse("http://initial-domain.com/new_path").unwrap()];
let mut filtered_headers = headers.clone();
remove_sensitive_headers(&mut headers, &next, &prev);
assert_eq!(headers, filtered_headers);
prev.push(Url::parse("http://new-domain.com/path").unwrap());
filtered_headers.remove(AUTHORIZATION);
filtered_headers.remove(COOKIE);
remove_sensitive_headers(&mut headers, &next, &prev);
assert_eq!(headers, filtered_headers);
}