reqwest/dns/
resolve.rs

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    #[cfg(feature = "socks")]
68    pub(crate) fn gai() -> Self {
69        Self::new(Arc::new(super::gai::GaiResolver::new()))
70    }
71
72    /// Resolve an HTTP host and port, not just a domain name.
73    ///
74    /// This does the same thing that hyper-util's HttpConnector does, before
75    /// calling out to its underlying DNS resolver.
76    #[cfg(feature = "socks")]
77    pub(crate) async fn http_resolve(
78        &self,
79        target: &http::Uri,
80    ) -> Result<impl Iterator<Item = std::net::SocketAddr>, BoxError> {
81        let host = target.host().ok_or("missing host")?;
82        let port = target
83            .port_u16()
84            .unwrap_or_else(|| match target.scheme_str() {
85                Some("https") => 443,
86                Some("socks4") | Some("socks4h") | Some("socks5") | Some("socks5h") => 1080,
87                _ => 80,
88            });
89
90        let explicit_port = target.port().is_some();
91
92        let addrs = self.resolver.resolve(host.parse()?).await?;
93
94        Ok(addrs.map(move |mut addr| {
95            if explicit_port || addr.port() == 0 {
96                addr.set_port(port);
97            }
98            addr
99        }))
100    }
101}
102
103impl Service<HyperName> for DynResolver {
104    type Response = Addrs;
105    type Error = BoxError;
106    type Future = Resolving;
107
108    fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
109        Poll::Ready(Ok(()))
110    }
111
112    fn call(&mut self, name: HyperName) -> Self::Future {
113        self.resolver.resolve(Name(name))
114    }
115}
116
117pub(crate) struct DnsResolverWithOverrides {
118    dns_resolver: Arc<dyn Resolve>,
119    overrides: Arc<HashMap<String, Vec<SocketAddr>>>,
120}
121
122impl DnsResolverWithOverrides {
123    pub(crate) fn new(
124        dns_resolver: Arc<dyn Resolve>,
125        overrides: HashMap<String, Vec<SocketAddr>>,
126    ) -> Self {
127        DnsResolverWithOverrides {
128            dns_resolver,
129            overrides: Arc::new(overrides),
130        }
131    }
132}
133
134impl Resolve for DnsResolverWithOverrides {
135    fn resolve(&self, name: Name) -> Resolving {
136        match self.overrides.get(name.as_str()) {
137            Some(dest) => {
138                let addrs: Addrs = Box::new(dest.clone().into_iter());
139                Box::pin(std::future::ready(Ok(addrs)))
140            }
141            None => self.dns_resolver.resolve(name),
142        }
143    }
144}
145
146mod sealed {
147    use std::fmt;
148
149    #[derive(Debug)]
150    pub struct InvalidNameError {
151        pub(super) _ext: (),
152    }
153
154    impl fmt::Display for InvalidNameError {
155        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
156            f.write_str("invalid DNS name")
157        }
158    }
159
160    impl std::error::Error for InvalidNameError {}
161}
reqwest/dns/resolve.rs

reqwest/dns/
resolve.rs
