Support hosting service on non-root path prefix (#160)

fixes #159.


The path prefix is inferred by the following order:

1. The environment `RSS_FUNNEL_PATH_PREFIX` (Example value: `"app/"`),
or if unspecified
2. The path of environment `RSS_FUNNEL_APP_BASE`, or if unspecified
3. `"/"`.

src/cli.rs

@@ -7,6 +7,7 @@ use url::Url;
 
 use crate::{
   server::{self, EndpointConfig, ServerConfig},
+  util::relative_path,
   ConfigError, Result,
 };
 
@@ -167,7 +168,8 @@ async fn health_check(health_check_config: HealthCheckConfig) -> Result<()> {
     server = format!("http://{server}");
   }
 
-  let url = Url::parse(&server)?.join("/_health")?;
+  let path = relative_path("_health");
+  let url = Url::parse(&server)?.join(&path)?;
   match reqwest::get(url.clone()).await {
     Ok(res) if res.status().is_success() => {
       eprintln!("{server} is healthy");

src/filter/image_proxy.rs

@@ -8,7 +8,7 @@ use url::Url;
 use super::{FeedFilter, FeedFilterConfig, FilterContext};
 use crate::{feed::Feed, ConfigError, Error, Result};
 
-const IMAGE_PROXY_ROUTE: &str = "/_image";
+const IMAGE_PROXY_ROUTE: &str = "_image";
 
 #[derive(
   JsonSchema, Serialize, Deserialize, Clone, Debug, PartialEq, Eq, Hash,

src/filter/merge.rs

@@ -16,6 +16,7 @@ use super::{FeedFilter, FeedFilterConfig, FilterContext};
   JsonSchema, Serialize, Deserialize, Clone, Debug, PartialEq, Eq, Hash,
 )]
 #[serde(untagged)]
+#[allow(clippy::large_enum_variant)]
 pub enum MergeConfig {
   /// Simple merge with default client and no filters
   Simple(MergeSimpleConfig),

src/server.rs

@@ -9,13 +9,21 @@ mod web;
 
 use std::{path::Path, sync::Arc};
 
-use axum::{routing::get, Extension, Router};
+use axum::{
+  response::{IntoResponse, Redirect},
+  routing::get,
+  Extension, Router,
+};
 use clap::Parser;
 use http::StatusCode;
 use tower_http::compression::CompressionLayer;
 use tracing::{info, warn};
 
-use crate::Result;
+use crate::{
+  util::{self, relative_path},
+  Result,
+};
+
 pub use endpoint::{EndpointConfig, EndpointParam};
 
 use self::{feed_service::FeedService, watcher::Watcher};
@@ -62,7 +70,10 @@ impl ServerConfig {
 
   pub async fn run_without_config(self) -> Result<()> {
     let feed_service = FeedService::new_otf().await?;
-    info!("serving on-the-fly endpoint on /otf");
+    let rel_path = relative_path("otf");
+    info!(
+      "No config detected. Serving automatic on-the-fly endpoint on {rel_path}"
+    );
     self.serve(feed_service).await
   }
 
@@ -108,27 +119,23 @@ impl ServerConfig {
     self.serve(feed_service).await
   }
 
-  pub async fn serve(self, feed_service: FeedService) -> Result<()> {
-    info!("listening on {}", &self.bind);
-    let listener = tokio::net::TcpListener::bind(&*self.bind).await?;
-
-    let mut app = Router::new();
+  pub fn router(&self, feed_service: FeedService) -> Router {
+    let mut routes = Router::new();
 
     #[cfg(feature = "inspector-ui")]
     if self.inspector_ui {
-      app = app
+      routes = routes
         .nest("/", inspector::router())
         .nest("/_/", web::router())
-        .route(
-          "/",
-          get(|| async { axum::response::Redirect::temporary("/_/") }),
-        );
+        .route("/", get(redirect_to_home));
     } else {
-      app = app.route("/", get(|| async { "rss-funnel is up and running!" }));
+      routes =
+        routes.route("/", get(|| async { "rss-funnel is up and running!" }));
     }
 
     if !cfg!(feature = "inspector-ui") {
-      app = app.route("/", get(|| async { "rss-funnel is up and running!" }));
+      routes =
+        routes.route("/", get(|| async { "rss-funnel is up and running!" }));
     }
 
     let feed_service_router = Router::new()
@@ -138,17 +145,39 @@ impl ServerConfig {
       }))
       .layer(CompressionLayer::new().gzip(true));
 
-    app = app
+    routes = routes
       // deprecated, will be removed on 0.2
       .route("/health", get(|| async { "ok" }))
       .route("/_health", get(|| async { "ok" }))
       .merge(image_proxy::router())
       .merge(feed_service_router)
       .layer(Extension(feed_service));
 
+    routes
+  }
+
+  pub async fn serve(self, feed_service: FeedService) -> Result<()> {
+    info!("listening on {}", &self.bind);
+    let listener = tokio::net::TcpListener::bind(&*self.bind).await?;
+
+    let mut app = Router::new();
+
+    let prefix = util::relative_path("");
+    if prefix == "/" {
+      app = self.router(feed_service);
+    } else {
+      info!("Path prefix set to {prefix}");
+      app = app.nest(&prefix, self.router(feed_service))
+    };
+
     info!("starting server");
     let server = axum::serve(listener, app);
 
     Ok(server.await?)
   }
 }
+
+async fn redirect_to_home() -> impl IntoResponse {
+  let home_path = relative_path("_/");
+  Redirect::temporary(&home_path)
+}

src/server/auth.rs

@@ -6,6 +6,8 @@ use axum::{
 use axum_extra::extract::CookieJar;
 use http::request::Parts;
 
+use crate::util::relative_path;
+
 use super::feed_service::FeedService;
 
 pub struct Auth;
@@ -42,7 +44,8 @@ impl<S: Send + Sync> FromRequestParts<S> for Auth {
 }
 
 fn login() -> Response {
-  Redirect::to("/_inspector/login.html?login_required=1").into_response()
+  let login_path = relative_path("_inspector/login.html?login_required=1");
+  Redirect::to(&login_path).into_response()
 }
 
 #[derive(serde::Deserialize)]
@@ -59,17 +62,18 @@ pub async fn handle_login(
   match feed_service.login(&params.username, &params.password).await {
     Some(session_id) => {
       let cookie_jar = cookie_jar.add(("session_id", session_id));
-      (cookie_jar, Redirect::to("/_inspector/index.html")).into_response()
+      let home_path = relative_path("_inspector/index.html");
+      (cookie_jar, Redirect::to(&home_path)).into_response()
+    }
+    _ => {
+      let login_path = relative_path("_inspector/login.html?bad_auth=1");
+      Redirect::to(&login_path).into_response()
     }
-    _ => Redirect::to("/_inspector/login.html?bad_auth=1").into_response(),
   }
 }
 
 pub async fn handle_logout(cookie_jar: CookieJar) -> Response {
   let cookie_jar = cookie_jar.remove("session_id");
-  (
-    cookie_jar,
-    Redirect::to("/_inspector/login.html?logged_out=1"),
-  )
-    .into_response()
+  let logout_path = relative_path("_inspector/login.html?logged_out=1");
+  (cookie_jar, Redirect::to(&logout_path)).into_response()
 }

src/server/endpoint.rs

@@ -188,7 +188,7 @@ impl EndpointParam {
   }
 
   fn get_base(req: &Parts) -> Option<Url> {
-    if let Some(url) = Self::base_from_env().as_ref() {
+    if let Some(url) = crate::util::app_base_from_env().as_ref() {
       return Some(url.clone());
     }
 
@@ -222,20 +222,6 @@ impl EndpointParam {
     let base = base.parse().ok()?;
     Some(base)
   }
-
-  fn base_from_env() -> &'static Option<Url> {
-    use std::env;
-    use std::sync::OnceLock;
-
-    static APP_BASE_URL: OnceLock<Option<Url>> = OnceLock::new();
-    APP_BASE_URL.get_or_init(|| {
-      let var = env::var("RSS_FUNNEL_APP_BASE").ok();
-      var.map(|v| {
-        v.parse()
-          .expect("Invalid base url specified in RSS_FUNNEL_APP_BASE")
-      })
-    })
-  }
 }
 
 impl Service<Request> for EndpointService {

src/server/feed_service.rs

@@ -15,6 +15,7 @@ use crate::{cli::RootConfig, ConfigError};
 
 use super::{endpoint::EndpointService, EndpointConfig};
 
+// can be cheaply cloned.
 #[derive(Clone)]
 pub struct FeedService {
   inner: Arc<RwLock<Inner>>,

src/server/image_proxy.rs

@@ -12,12 +12,15 @@ use tower_http::cors::CorsLayer;
 use tracing::{info, warn};
 use url::Url;
 
+use crate::util::relative_path;
+
 lazy_static::lazy_static! {
   static ref SIGN_KEY: Box<[u8]> = init_sign_key();
 }
 
 pub fn router() -> Router {
-  info!("handling image proxy: /_image");
+  let image_proxy_path = relative_path("_image");
+  info!("handling image proxy: {image_proxy_path}");
 
   use tower_http::cors::AllowOrigin;
   let cors = CorsLayer::new()

src/server/web.rs

@@ -13,6 +13,8 @@ use http::StatusCode;
 use login::Auth;
 use maud::{html, Markup};
 
+use crate::util::relative_path;
+
 use super::{feed_service::FeedService, EndpointParam};
 
 #[derive(rust_embed::RustEmbed)]
@@ -93,9 +95,11 @@ impl<S> axum::extract::FromRequestParts<S> for AutoReload {
 
 async fn handle_home(auth: Option<Auth>) -> impl IntoResponse {
   if auth.is_some() {
-    Redirect::temporary("/_/endpoints")
+    let endpoints_path = relative_path("_/endpoints");
+    Redirect::temporary(&endpoints_path)
   } else {
-    Redirect::temporary("/_/login")
+    let login_path = relative_path("_/login");
+    Redirect::temporary(&login_path)
   }
 }
 
@@ -147,9 +151,10 @@ fn favicon() -> Markup {
 }
 
 fn sprite(icon: &str) -> Markup {
+  let sprite_path = relative_path("_/sprite.svg");
   html! {
     svg class="icon" xmlns="http://www.w3.org/2000/svg" width="20" height="20" {
-      use xlink:href=(format!("/_/sprite.svg#{icon}"));
+      use xlink:href=(format!("{sprite_path}#{icon}"));
     }
   }
 }

src/server/web/endpoint.rs

@@ -9,6 +9,7 @@ use crate::{
   filter::FilterContext,
   server::{endpoint::EndpointService, web::sprite, EndpointParam},
   source::{FromScratch, Source},
+  util::relative_path,
 };
 
 pub async fn render_endpoint_page(
@@ -51,7 +52,8 @@ pub async fn render_endpoint_page(
     body {
       header .header-bar {
         button .left-button {
-          a href="/_/" { "Back" }
+          @let home_path = relative_path("_/");
+          a href=(home_path) { "Back" }
         }
         h2 { (path) }
         button .button title="Copy Endpoint URL" onclick="copyToClipboard()" {
@@ -108,13 +110,14 @@ fn source_control_fragment(
 ) -> Markup {
   match source {
     Source::Dynamic => html! {
+      @let endpoint_path = relative_path(&format!("_/endpoint/{path}"));
       input
         .hx-included.grow
         type="text"
         name="source"
         placeholder="Source URL"
         value=[param.source().map(|url| url.as_str())]
-        hx-get=(format!("/_/endpoint/{path}"))
+        hx-get=(endpoint_path)
         hx-trigger="keyup changed delay:500ms"
         hx-push-url="true"
         hx-indicator=".loading"
@@ -174,6 +177,7 @@ fn source_template_fragment(
       @match fragment {
         Either::Left(plain) => span style="white-space: nowrap" { (plain) },
         Either::Right((name, Some(placeholder))) => {
+          @let endpoint_path = relative_path(&format!("_/endpoint/{path}"));
           @let value=queries.get(name);
           @let default_value=placeholder.default.as_ref();
           @let value=value.or(default_value);
@@ -184,7 +188,7 @@ fn source_template_fragment(
             placeholder=(name)
             pattern=[validation]
             value=[value]
-            hx-get=(format!("/_/endpoint/{path}"))
+            hx-get=(endpoint_path)
             hx-trigger="keyup changed delay:500ms"
             hx-push-url="true"
             hx-include=".hx-included"
@@ -246,9 +250,10 @@ fn render_config_fragment(
     } @else {
       div {
         header { b { "Filters:" } }
+        @let endpoint_path = relative_path(&format!("_/endpoint/{path}"));
         ul #filter-list .hx-included
           hx-vals="js:{...gatherFilterSkip()}"
-          hx-get=(format!("/_/endpoint/{path}"))
+          hx-get=(endpoint_path)
           hx-trigger="click from:.filter-name"
           hx-push-url="true"
           hx-include=".hx-included"

src/server/web/list.rs

@@ -7,6 +7,7 @@ use crate::{
   cli::RootConfig,
   server::{web::sprite, EndpointConfig},
   source::SourceConfig,
+  util::relative_path,
 };
 
 pub fn render_endpoint_list_page(
@@ -59,7 +60,10 @@ fn endpoint_list_entry_fragment(endpoint: &EndpointConfig) -> Markup {
   html! {
     li {
       p {
-        a href={"/_/endpoint/" (endpoint.path.trim_start_matches('/'))} {
+        @let normalized_path = endpoint.path.trim_start_matches('/');
+        @let endpoint_path = format!("/_/endpoint/{}", normalized_path);
+        @let endpoint_path = relative_path(&endpoint_path);
+        a href=(endpoint_path) {
           (endpoint.path)
         }
 
@@ -104,7 +108,7 @@ fn short_source_repr(source: &SourceConfig) -> Markup {
     },
     SourceConfig::Simple(url) if url.starts_with("/") => {
       let path = url_path(url.as_str());
-      let path = path.map(|p| format!("/_/{p}"));
+      let path = path.map(|p| relative_path(&format!("_/{p})")));
       html! {
         @if let Some(path) = path {
           span .tag.local {