Add custom DNS resolver for *.localhost (#280)

src-tauri/src/dns.rs

@@ -0,0 +1,54 @@
+use hyper_util::client::legacy::connect::dns::{
+    GaiResolver as HyperGaiResolver, Name as HyperName,
+};
+use reqwest::dns::{Addrs, Name, Resolve, Resolving};
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
+use std::str::FromStr;
+use std::sync::Arc;
+use tower_service::Service;
+
+#[derive(Clone)]
+pub(crate) struct LocalhostResolver {
+    fallback: HyperGaiResolver,
+}
+
+impl LocalhostResolver {
+    pub fn new() -> Arc<Self> {
+        let resolver = HyperGaiResolver::new();
+        Arc::new(Self { fallback: resolver })
+    }
+}
+
+impl Resolve for LocalhostResolver {
+    fn resolve(&self, name: Name) -> Resolving {
+        let host = name.as_str().to_lowercase();
+
+        let is_localhost = host.ends_with(".localhost");
+        if is_localhost {
+            // Port 0 is fine; reqwest replaces it with the URL's explicit
+            // port or the scheme’s default (80/443, etc.).
+            // (See docs note below.)
+            let addrs: Vec<SocketAddr> = vec![
+                SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0),
+                SocketAddr::new(IpAddr::V6(Ipv6Addr::LOCALHOST), 0),
+            ];
+
+            return Box::pin(async move {
+                Ok::<Addrs, Box<dyn std::error::Error + Send + Sync>>(Box::new(addrs.into_iter()))
+            });
+        }
+
+        let mut fallback = self.fallback.clone();
+        let name_str = name.as_str().to_string();
+        Box::pin(async move {
+            match HyperName::from_str(&name_str) {
+                Ok(n) => fallback
+                    .call(n)
+                    .await
+                    .map(|addrs| Box::new(addrs) as Addrs)
+                    .map_err(|err| Box::new(err) as Box<dyn std::error::Error + Send + Sync>),
+                Err(e) => Err(Box::new(e) as Box<dyn std::error::Error + Send + Sync>),
+            }
+        })
+    }
+}

src-tauri/src/http_request.rs

@@ -33,6 +33,7 @@ use yaak_plugins::events::{
 use yaak_plugins::manager::PluginManager;
 use yaak_plugins::template_callback::PluginTemplateCallback;
 use yaak_templates::{RenderErrorBehavior, RenderOptions};
+use crate::dns::LocalhostResolver;
 
 pub async fn send_http_request<R: Runtime>(
     window: &WebviewWindow<R>,
@@ -110,6 +111,7 @@ pub async fn send_http_request<R: Runtime>(
         .gzip(true)
         .brotli(true)
         .deflate(true)
+        .dns_resolver(LocalhostResolver::new())
         .referer(false)
         .tls_info(true);
 

src-tauri/src/lib.rs

@@ -60,6 +60,7 @@ mod updates;
 mod uri_scheme;
 mod window;
 mod window_menu;
+mod dns;
 
 #[derive(serde::Serialize)]
 #[serde(default, rename_all = "camelCase")]