1use hyper_util::client::legacy::connect::dns::Name as HyperName;
2use tower_service::Service;
3
4use std::collections::HashMap;
5use std::future::Future;
6use std::net::SocketAddr;
7use std::pin::Pin;
8use std::str::FromStr;
9use std::sync::Arc;
10use std::task::{Context, Poll};
11
12use crate::error::BoxError;
13
14/// Alias for an `Iterator` trait object over `SocketAddr`.
15pub type Addrs = Box<dyn Iterator<Item = SocketAddr> + Send>;
16
17/// Alias for the `Future` type returned by a DNS resolver.
18pub type Resolving = Pin<Box<dyn Future<Output = Result<Addrs, BoxError>> + Send>>;
19
20/// Trait for customizing DNS resolution in reqwest.
21pub trait Resolve: Send + Sync {
22 /// Performs DNS resolution on a `Name`.
23 /// The return type is a future containing an iterator of `SocketAddr`.
24 ///
25 /// It differs from `tower_service::Service<Name>` in several ways:
26 /// * It is assumed that `resolve` will always be ready to poll.
27 /// * It does not need a mutable reference to `self`.
28 /// * Since trait objects cannot make use of associated types, it requires
29 /// wrapping the returned `Future` and its contained `Iterator` with `Box`.
30 ///
31 /// Explicitly specified port in the URL will override any port in the resolved `SocketAddr`s.
32 /// Otherwise, port `0` will be replaced by the conventional port for the given scheme (e.g. 80 for http).
33 fn resolve(&self, name: Name) -> Resolving;
34}
35
36/// A name that must be resolved to addresses.
37#[derive(Debug)]
38pub struct Name(pub(super) HyperName);
39
40impl Name {
41 /// View the name as a string.
42 pub fn as_str(&self) -> &str {
43 self.0.as_str()
44 }
45}
46
47impl FromStr for Name {
48 type Err = sealed::InvalidNameError;
49
50 fn from_str(host: &str) -> Result<Self, Self::Err> {
51 HyperName::from_str(host)
52 .map(Name)
53 .map_err(|_| sealed::InvalidNameError { _ext: () })
54 }
55}
56
57#[derive(Clone)]
58pub(crate) struct DynResolver {
59 resolver: Arc<dyn Resolve>,
60}
61
62impl DynResolver {
63 pub(crate) fn new(resolver: Arc<dyn Resolve>) -> Self {
64 Self { resolver }
65 }
66}
67
68impl Service<HyperName> for DynResolver {
69 type Response = Addrs;
70 type Error = BoxError;
71 type Future = Resolving;
72
73 fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
74 Poll::Ready(Ok(()))
75 }
76
77 fn call(&mut self, name: HyperName) -> Self::Future {
78 self.resolver.resolve(Name(name))
79 }
80}
81
82pub(crate) struct DnsResolverWithOverrides {
83 dns_resolver: Arc<dyn Resolve>,
84 overrides: Arc<HashMap<String, Vec<SocketAddr>>>,
85}
86
87impl DnsResolverWithOverrides {
88 pub(crate) fn new(
89 dns_resolver: Arc<dyn Resolve>,
90 overrides: HashMap<String, Vec<SocketAddr>>,
91 ) -> Self {
92 DnsResolverWithOverrides {
93 dns_resolver,
94 overrides: Arc::new(data:overrides),
95 }
96 }
97}
98
99impl Resolve for DnsResolverWithOverrides {
100 fn resolve(&self, name: Name) -> Resolving {
101 match self.overrides.get(name.as_str()) {
102 Some(dest: &Vec) => {
103 let addrs: Addrs = Box::new(dest.clone().into_iter());
104 Box::pin(std::future::ready(Ok(addrs)))
105 }
106 None => self.dns_resolver.resolve(name),
107 }
108 }
109}
110
111mod sealed {
112 use std::fmt;
113
114 #[derive(Debug)]
115 pub struct InvalidNameError {
116 pub(super) _ext: (),
117 }
118
119 impl fmt::Display for InvalidNameError {
120 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
121 f.write_str(data:"invalid DNS name")
122 }
123 }
124
125 impl std::error::Error for InvalidNameError {}
126}
127