Use a different path for static files

Author: jsha

src/docbuilder/rustwide_builder.rs

@@ -11,6 +11,7 @@ use crate::storage::{rustdoc_archive_path, source_archive_path};
 use crate::utils::{
     copy_dir_all, parse_rustc_version, queue_builder, set_config, CargoMetadata, ConfigName,
 };
+use crate::RUSTDOC_STATIC_STORAGE_PREFIX;
 use crate::{db::blacklist::is_blacklisted, utils::MetadataPackage};
 use crate::{Config, Context, Index, Metrics, Storage};
 use anyhow::{anyhow, bail, Error};
@@ -225,7 +226,8 @@ impl RustwideBuilder {
                         .prefix("essential-files")
                         .tempdir()?;
                     copy_dir_all(source, &dest)?;
-                    add_path_into_database(&self.storage, "", &dest)?;
+
+                    add_path_into_database(&self.storage, RUSTDOC_STATIC_STORAGE_PREFIX, &dest)?;
 
                     set_config(
                         &mut conn,
@@ -710,7 +712,7 @@ impl RustwideBuilder {
 
         #[rustfmt::skip]
         const UNCONDITIONAL_ARGS: &[&str] = &[
-            "--static-root-path", "/",
+            "--static-root-path", "/-/rustdoc.static/",
             "--cap-lints", "warn",
             "--disable-per-crate-search",
             "--extern-html-root-takes-precedence",

src/lib.rs

@@ -55,3 +55,6 @@ pub const BUILD_VERSION: &str = concat!(
     " ",
     include_str!(concat!(env!("OUT_DIR"), "/git_version"))
 );
+
+/// Where rustdoc's static files are stored in S3.
+pub const RUSTDOC_STATIC_STORAGE_PREFIX: &str = "/rustdoc-static/";

src/web/mod.rs

@@ -138,8 +138,10 @@ impl MainHandler {
         let inject_extensions = InjectExtensions::new(context, template_data)?;
 
         let routes = routes::build_routes();
-        let shared_resources =
-            Self::chain(inject_extensions.clone(), rustdoc::SharedResourceHandler);
+        let shared_resources = Self::chain(
+            inject_extensions.clone(),
+            rustdoc::LegacySharedResourceHandler,
+        );
         let router_chain = Self::chain(inject_extensions.clone(), routes.iron_router());
 
         Ok(MainHandler {
@@ -174,13 +176,13 @@ impl Handler for MainHandler {
         // removes the shared static files from individual builds to save space, the "../mainXXX.js"
         // path doesn't really exist in storage for any particular build. The appropriate main file
         // *does* exist in the storage root, which is where the shared static files are put for each
-        // new rustdoc version. So here we give SharedResourceHandler a chance to handle all URLs
-        // before they go to the router. SharedResourceHandler looks at the last component of the
+        // new rustdoc version. So here we give LegacySharedResourceHandler a chance to handle all URLs
+        // before they go to the router. LegacySharedResourceHandler looks at the last component of the
         // request path ("main-20181217-1.33.0-nightly-adbfec229.js") and tries to fetch it from
         // the storage root (if it's JS, CSS, etc). If the file doesn't exist, we fall through to
         // the normal router, which may wind up serving an invocation-specific file from the crate
         // itself. For instance, a request for "/crate/foo/search-index-XYZ.js" will get a 404 from
-        // the SharedResourceHandler because "search-index-XYZ.js" doesn't exist in the storage root
+        // the LegacySharedResourceHandler because "search-index-XYZ.js" doesn't exist in the storage root
         // (it's not a shared static file), but it will get a 200 from rustdoc_html_server_handler
         // because it exists in a specific crate.
         //
@@ -192,8 +194,8 @@ impl Handler for MainHandler {
         // https://docs.rs/this.path.does.not.exist/main-20181217-1.33.0-nightly-adbfec229.js
         //
         // If those 2018 crates get rebuilt, we won't have this problem anymore, and
-        // SharedResourceHandler can receive dispatch from the router, as other handlers do. That
-        // will also allow SharedResourceHandler to look up full paths in storage rather than just
+        // LegacySharedResourceHandler can receive dispatch from the router, as other handlers do. That
+        // will also allow LegacySharedResourceHandler to look up full paths in storage rather than just
         // the last component of the requested path.
         //
         // Also note: this approach means that a request for a given JS/CSS may serve from two

src/web/routes.rs

@@ -31,6 +31,11 @@ pub(super) fn build_routes() -> Routes {
 
     routes.static_resource("/-/static/:single", super::statics::static_handler);
     routes.static_resource("/-/static/*", super::statics::static_handler);
+    routes.internal_page(
+        "/-/rustdoc.static/:single",
+        super::rustdoc::static_asset_handler,
+    );
+    routes.internal_page("/-/rustdoc.static/*", super::rustdoc::static_asset_handler);
     routes.internal_page("/-/storage-change-detection.html", {
         #[derive(Debug, serde::Serialize)]
         struct StorageChangeDetection {}
@@ -377,4 +382,41 @@ mod tests {
             Ok(())
         });
     }
+
+    #[test]
+    fn serve_rustdoc_content_not_found() {
+        wrapper(|env| {
+            let response = env.frontend().get("/-/rustdoc-static/style.css").send()?;
+            assert_eq!(response.status(), StatusCode::NOT_FOUND);
+            assert_cache_control(&response, CachePolicy::NoCaching, &env.config());
+            Ok(())
+        })
+    }
+
+    #[test]
+    fn serve_rustdoc_content() {
+        wrapper(|env| {
+            let web = env.frontend();
+            env.storage().store_one("style.css", *b"content")?;
+            env.storage()
+                .store_one("will_not/be_found.css", *b"something")?;
+
+            let response = web.get("/-/rustdoc-static/style.css").send()?;
+            assert_cache_control(
+                &response,
+                CachePolicy::ForeverInCdnAndBrowser,
+                &env.config(),
+            );
+            assert!(response.status().is_success());
+            assert_eq!(response.text()?, "content");
+
+            assert_eq!(
+                web.get("/-/rustdoc-static/will_not/be_found.css")
+                    .send()?
+                    .status(),
+                StatusCode::NOT_FOUND
+            );
+            Ok(())
+        })
+    }
 }

src/web/rustdoc.rs

@@ -3,14 +3,14 @@
 use crate::{
     db::Pool,
     repositories::RepositoryStatsUpdater,
-    storage::rustdoc_archive_path,
+    storage::{rustdoc_archive_path, PathNotFoundError},
     utils,
     web::{
         cache::CachePolicy, crate_details::CrateDetails, csp::Csp, error::Nope, file::File,
         match_version, metrics::RenderingTimesRecorder, parse_url_with_params, redirect_base,
         report_error, MatchSemver, MetaData,
     },
-    Config, Metrics, Storage,
+    Config, Metrics, Storage, RUSTDOC_STATIC_STORAGE_PREFIX,
 };
 use anyhow::{anyhow, Context};
 use iron::{
@@ -766,14 +766,51 @@ pub fn download_handler(req: &mut Request) -> IronResult<Response> {
     )))
 }
 
+/// Serves shared resources used by rustdoc-generated documentation.
+///
+/// This serves files from S3, and is pointed to by the `--static-root-path` flag to rustdoc.
+pub fn static_asset_handler(req: &mut Request) -> IronResult<Response> {
+    let storage = extension!(req, Storage);
+    let config = extension!(req, Config);
+
+    let filename = req.url.path()[2..].join("/");
+    let storage_path = format!("{}{}", RUSTDOC_STATIC_STORAGE_PREFIX, filename);
+
+    // Prevent accessing static files outside the root. This could happen if the path
+    // contains `/` or `..`. The check doesn't outright prevent those strings to be present
+    // to allow accessing files in subdirectories.
+    let canonical_path =
+        std::fs::canonicalize(&storage_path).map_err(|_| Nope::ResourceNotFound)?;
+    let canonical_root =
+        std::fs::canonicalize(&storage_path).map_err(|_| Nope::ResourceNotFound)?;
+
+    if !canonical_path.starts_with(canonical_root) {
+        return Err(Nope::ResourceNotFound.into());
+    }
+
+    match File::from_path(storage, &storage_path, config) {
+        Ok(file) => Ok(file.serve()),
+        Err(err) if err.downcast_ref::<PathNotFoundError>().is_some() => {
+            Err(Nope::ResourceNotFound.into())
+        }
+        Err(err) => {
+            utils::report_error(&err);
+            Err(Nope::InternalServerError.into())
+        }
+    }
+}
+
 /// Serves shared web resources used by rustdoc-generated documentation.
 ///
 /// This includes common `css` and `js` files that only change when the compiler is updated, but are
 /// otherwise the same for all crates documented with that compiler. Those have a custom handler to
 /// deduplicate them and save space.
-pub struct SharedResourceHandler;
+///
+/// This handler considers only the last component of the request path, and looks for a matching file
+/// in the Storage root.
+pub struct LegacySharedResourceHandler;
 
-impl Handler for SharedResourceHandler {
+impl Handler for LegacySharedResourceHandler {
     fn handle(&self, req: &mut Request) -> IronResult<Response> {
         let path = req.url.path();
         let filename = path.last().unwrap(); // unwrap is fine: vector is non-empty
@@ -796,6 +833,29 @@ impl Handler for SharedResourceHandler {
     }
 }
 
+/// Serves shared web resources used by rustdoc-generated documentation.
+///
+/// Rustdoc has certain JS, CSS, font and image files that are required for all
+/// documentation it generates, and these don't change often. We make one copy
+/// of these per rustdoc release and serve them from a common location.
+///
+/// This handler considers the whole path, and looks for a file at that path in
+/// the Storage.
+pub struct SharedResourceHandler;
+
+impl Handler for SharedResourceHandler {
+    fn handle(&self, req: &mut Request) -> IronResult<Response> {
+        let storage = extension!(req, Storage);
+        let config = extension!(req, Config);
+
+        let storage_path = format!("/{}", req.url.path().join("/"));
+        match File::from_path(storage, &storage_path, config) {
+            Ok(file) => Ok(file.serve()),
+            Err(_) => Err(Nope::ResourceNotFound.into()),
+        }
+    }
+}
+
 #[cfg(test)]
 mod test {
     use crate::{test::*, web::cache::CachePolicy, Config};