add proxy option no_redirect

When serving responses with the Trunk proxy, redirects are automatically
followed by default. This can be undesirable, e.g. when serving a login page
that response with a redirect and a set-cookie header like

```
HTTP/1.1 303 See Other
location: /
set-cookie: session=...; ...;
```

This PR adds a proxy option `no_redirect` that when set will instruct the proxy
to not automatically follow redirects. The default behavior is unchanged.

site/content/configuration.md

@@ -119,6 +119,7 @@ ws = false                                # Use WebSocket for this proxy
 insecure = false                          # Disable certificate validation
 no_system_proxy = false                   # Disable system proxy
 rewrite = ""                              # Strip the given prefix off paths
+no_redirect = false                       # Disable following redirects of proxy responses
 ```
 
 ## Hooks section

src/cmd/serve.rs

@@ -90,6 +90,13 @@ pub struct ProxyArgs {
         requires = "proxy_backend"
     )]
     pub proxy_no_system_proxy: bool,
+    /// Configure the proxy to not automatically follow redirects if a backend responds with a redirect
+    #[arg(
+        long,
+        env = "TRUNK_SERVE_PROXY_NO_REDIRECT",
+        requires = "proxy_backend"
+    )]
+    pub proxy_no_redirect: bool,
 }
 
 impl Serve {
@@ -107,6 +114,7 @@ impl Serve {
                     proxy_ws,
                     proxy_insecure,
                     proxy_no_system_proxy,
+                    proxy_no_redirect,
                 },
             no_autoreload,
             no_error_reporting,
@@ -148,6 +156,7 @@ impl Serve {
                 ws: proxy_ws,
                 insecure: proxy_insecure,
                 no_system_proxy: proxy_no_system_proxy,
+                no_redirect: proxy_no_redirect,
             });
         }
 

src/config/models/mod.rs

@@ -106,6 +106,7 @@ impl ConfigModel for Configuration {
                 ws: self.serve.proxy_ws.unwrap_or_default(),
                 insecure: self.serve.proxy_insecure.unwrap_or_default(),
                 no_system_proxy: self.serve.proxy_no_system_proxy.unwrap_or_default(),
+                no_redirect: self.serve.proxy_no_redirect.unwrap_or_default(),
             })
         }
 

src/config/models/proxy.rs

@@ -28,6 +28,10 @@ pub struct Proxy {
     #[serde(alias = "no-system-proxy")]
     #[serde(default)]
     pub no_system_proxy: bool,
+    /// Automatically redirect proxy requests? `no_redirect` Defaults to
+    /// `false`, i.e. yes, follow redirects automatically.
+    #[serde(default)]
+    pub no_redirect: bool,
 }
 
 #[derive(Clone, Debug, Default, PartialEq, Eq, Deserialize, JsonSchema)]

src/config/models/serve.rs

@@ -52,6 +52,9 @@ pub struct Serve {
     /// A base path to serve the application from
     #[serde(default)]
     pub serve_base: Option<String>,
+    /// Configure the proxy to not follow redirects
+    #[serde(default)]
+    pub proxy_no_redirect: Option<bool>,
 
     /// A URL to which requests will be proxied [default: None]
     #[deprecated]
@@ -98,6 +101,7 @@ impl Default for Serve {
             proxy_ws: None,
             proxy_insecure: None,
             proxy_no_system_proxy: None,
+            proxy_no_redirect: None,
         }
     }
 }

src/config/rt/serve.rs

@@ -93,6 +93,7 @@ impl RtcServe {
             proxy_ws: _,
             proxy_insecure: _,
             proxy_no_system_proxy: _,
+            proxy_no_redirect: _,
         } = config.serve;
 
         let tls = tls_config(

src/serve/mod.rs

@@ -384,6 +384,7 @@ fn router(state: Arc<State>, cfg: Arc<RtcServe>) -> Result<Router> {
             ProxyClientOptions {
                 insecure: proxy.insecure,
                 no_system_proxy: proxy.no_system_proxy,
+                redirect: !proxy.no_redirect,
             },
         )?;
     }

src/serve/proxy.rs

@@ -5,6 +5,7 @@ use axum::http::Uri;
 use axum::Router;
 use console::Emoji;
 use http::HeaderMap;
+use reqwest::redirect::Policy;
 use reqwest::Client;
 use std::collections::hash_map::Entry;
 use std::collections::HashMap;
@@ -86,6 +87,7 @@ impl ProxyBuilder {
 pub(crate) struct ProxyClientOptions {
     pub insecure: bool,
     pub no_system_proxy: bool,
+    pub redirect: bool,
 }
 
 #[derive(Default)]
@@ -107,7 +109,13 @@ impl ProxyClients {
 
     /// Create a new client for proxying
     fn create_client(opts: ProxyClientOptions) -> anyhow::Result<Client> {
-        let mut builder = reqwest::ClientBuilder::new().http1_only();
+        let mut builder = reqwest::ClientBuilder::new()
+            .http1_only()
+            .redirect(if opts.redirect {
+                Policy::default()
+            } else {
+                Policy::none()
+            });
 
         #[cfg(any(feature = "native-tls", feature = "rustls"))]
         if opts.insecure {