feat: manage static assets properly in Unix and Windows

crates/server/src/handlers/assets.rs

@@ -4,7 +4,45 @@
 use crate::AppData;
 use actix_files::NamedFile;
 use actix_web::{web::Data, HttpRequest};
-use std::io::{Error, ErrorKind};
+use std::{
+    io::{Error, ErrorKind},
+    path::{Component, Path, PathBuf},
+};
+
+/// Clean up invalid components in the paths and returns it. For a file
+/// in the public folder, only "normal" components are valid.
+fn clean_up_path(uri: &str) -> PathBuf {
+    // First split the URI as it always uses the /.
+    let path = PathBuf::from_iter(uri.split('/'));
+
+    let valid_components: Vec<Component<'_>> = path
+        .components()
+        // Keep only normal components
+        .filter(|c| matches!(c, Component::Normal(_)))
+        .collect();
+
+    // Build a new PathBuf based only on valid components
+    PathBuf::from_iter(valid_components)
+}
+
+/// Build the file path to retrieve and check if it exists. To build, it takes the project
+/// root and the parsed path. You can set it the index_folder flag to manage the
+/// parsed_path as a folder an look for an index.html inside it.
+fn retrieve_asset_path(root_path: &Path, file_path: &Path, index_folder: bool) -> Option<PathBuf> {
+    let public_folder = root_path.join("public");
+    let asset_path = if index_folder {
+        public_folder.join(file_path).join("index.html")
+    } else {
+        public_folder.join(file_path)
+    };
+
+    // Checks the output path is a child of public folder
+    if asset_path.starts_with(public_folder) && asset_path.exists() && asset_path.is_file() {
+        Some(asset_path)
+    } else {
+        None
+    }
+}
 
 /// Find a static HTML file in the `public` folder. This function is used
 /// when there's no direct file to be served. It will look for certain patterns
@@ -18,20 +56,234 @@ pub async fn handle_assets(req: &HttpRequest) -> Result<NamedFile, Error> {
         .root_path;
     let uri_path = req.path();
 
-    // File path. This is required for the wasm_handler as dynamic routes may capture static files
-    let file_path = root_path.join(format!("public{uri_path}"));
-    // A.k.a pretty urls. We may access /about and this matches to /about/index.html
-    let index_folder_path = root_path.join(format!("public{uri_path}/index.html"));
-    // Same as before, but the file is located at ./about.html
-    let html_ext_path = root_path.join(format!("public{uri_path}.html"));
+    // Double-check the given path path does not contain any unexpected value.
+    // It was previously sanitized, but this is a double check.
+    let parsed_path = clean_up_path(uri_path);
 
-    if file_path.exists() {
+    if let Some(file_path) = retrieve_asset_path(root_path, &parsed_path, false) {
+        // File path. This is required for the wasm_handler as dynamic routes may capture static files
         NamedFile::open_async(file_path).await
-    } else if uri_path.ends_with('/') && index_folder_path.exists() {
+    } else if let Some(index_folder_path) = retrieve_asset_path(root_path, &parsed_path, true) {
+        // A.k.a pretty urls. We may access /about and this matches to /about/index.html
         NamedFile::open_async(index_folder_path).await
-    } else if !uri_path.ends_with('/') && html_ext_path.exists() {
-        NamedFile::open_async(html_ext_path).await
     } else {
         Err(Error::new(ErrorKind::NotFound, "The file is not present"))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_clean_up_path() {
+        let tests = if cfg!(target_os = "windows") {
+            Vec::from([
+                ("/", PathBuf::new()),
+                ("/index.js", PathBuf::from("index.js")),
+                ("/my-folder/index.js", PathBuf::from("my-folder\\index.js")),
+                // These scenarios are unlikely as actix already filters the
+                // URI, but let's test them too
+                ("/../index.js", PathBuf::from("index.js")),
+                ("/../../index.js", PathBuf::from("index.js")),
+            ])
+        } else {
+            Vec::from([
+                ("/", PathBuf::new()),
+                ("/index.js", PathBuf::from("index.js")),
+                ("////index.js", PathBuf::from("index.js")),
+                ("/my-folder/index.js", PathBuf::from("my-folder/index.js")),
+                // These scenarios are unlikely as actix already filters the
+                // URI, but let's test them too
+                ("/../index.js", PathBuf::from("index.js")),
+                ("/../../index.js", PathBuf::from("index.js")),
+            ])
+        };
+
+        for (uri, path) in tests {
+            assert_eq!(clean_up_path(uri), path);
+        }
+    }
+
+    #[test]
+    fn relative_asset_path_retrieval() {
+        let (project_root, tests) = if cfg!(target_os = "windows") {
+            let project_root = Path::new("..\\..\\tests\\data");
+            let tests = Vec::from([
+                // Existing files
+                (
+                    Path::new("index.html"),
+                    Some(PathBuf::from("..\\..\\tests\\data\\public\\index.html")),
+                ),
+                (
+                    Path::new("main.css"),
+                    Some(PathBuf::from("..\\..\\tests\\data\\public\\main.css")),
+                ),
+                // Missing files
+                (Path::new(""), None),
+                (Path::new("unknown"), None),
+                (Path::new("about"), None),
+            ]);
+
+            (project_root, tests)
+        } else {
+            let project_root = Path::new("../../tests/data");
+            let tests = Vec::from([
+                // Existing files
+                (
+                    Path::new("index.html"),
+                    Some(PathBuf::from("../../tests/data/public/index.html")),
+                ),
+                (
+                    Path::new("main.css"),
+                    Some(PathBuf::from("../../tests/data/public/main.css")),
+                ),
+                // Missing files
+                (Path::new(""), None),
+                (Path::new("unknown"), None),
+                (Path::new("about"), None),
+            ]);
+
+            (project_root, tests)
+        };
+
+        for (file, asset_path) in tests {
+            assert_eq!(retrieve_asset_path(project_root, file, false), asset_path);
+        }
+    }
+
+    #[test]
+    fn absolute_asset_path_retrieval() {
+        let (project_root, tests) = if cfg!(target_os = "windows") {
+            let project_root = Path::new("..\\..\\tests\\data").canonicalize().unwrap();
+            let tests = Vec::from([
+                // Existing files
+                (
+                    Path::new("index.html"),
+                    Some(project_root.join("public\\index.html")),
+                ),
+                (
+                    Path::new("main.css"),
+                    Some(project_root.join("public\\main.css")),
+                ),
+                // Missing files
+                (Path::new(""), None),
+                (Path::new("unknown"), None),
+                (Path::new("about"), None),
+            ]);
+
+            (project_root, tests)
+        } else {
+            let project_root = Path::new("../../tests/data").canonicalize().unwrap();
+
+            let tests = Vec::from([
+                // Existing files
+                (
+                    Path::new("index.html"),
+                    Some(project_root.join("public/index.html")),
+                ),
+                (
+                    Path::new("main.css"),
+                    Some(project_root.join("public/main.css")),
+                ),
+                // Missing files
+                (Path::new(""), None),
+                (Path::new("unknown"), None),
+                (Path::new("about"), None),
+            ]);
+
+            (project_root, tests)
+        };
+
+        for (file, asset_path) in tests {
+            assert_eq!(retrieve_asset_path(&project_root, file, false), asset_path);
+        }
+    }
+
+    #[test]
+    fn relative_asset_index_path_retrieval() {
+        let (project_root, tests) = if cfg!(target_os = "windows") {
+            let project_root = Path::new("..\\..\\tests\\data");
+            let tests = Vec::from([
+                // Existing index files
+                (
+                    Path::new("about"),
+                    Some(PathBuf::from(
+                        "..\\..\\tests\\data\\public\\about\\index.html",
+                    )),
+                ),
+                (
+                    Path::new(""),
+                    Some(PathBuf::from("..\\..\\tests\\data\\public\\index.html")),
+                ),
+                // Missing index files
+                (Path::new("main.css"), None),
+                (Path::new("unknown"), None),
+            ]);
+
+            (project_root, tests)
+        } else {
+            let project_root = Path::new("../../tests/data");
+            let tests = Vec::from([
+                // Existing index files
+                (
+                    Path::new("about"),
+                    Some(PathBuf::from("../../tests/data/public/about/index.html")),
+                ),
+                (
+                    Path::new(""),
+                    Some(PathBuf::from("../../tests/data/public/index.html")),
+                ),
+                // Missing index files
+                (Path::new("main.css"), None),
+                (Path::new("unknown"), None),
+            ]);
+
+            (project_root, tests)
+        };
+
+        for (file, asset_path) in tests {
+            assert_eq!(retrieve_asset_path(project_root, file, true), asset_path);
+        }
+    }
+
+    #[test]
+    fn absolute_asset_index_path_retrieval() {
+        let (project_root, tests) = if cfg!(target_os = "windows") {
+            let project_root = Path::new("..\\..\\tests\\data").canonicalize().unwrap();
+            let tests = Vec::from([
+                // Existing idnex files
+                (
+                    Path::new("about"),
+                    Some(project_root.join("public\\about\\index.html")),
+                ),
+                (Path::new(""), Some(project_root.join("public\\index.html"))),
+                // Missing index files
+                (Path::new("main.css"), None),
+                (Path::new("unknown"), None),
+            ]);
+
+            (project_root, tests)
+        } else {
+            let project_root = Path::new("../../tests/data").canonicalize().unwrap();
+
+            let tests = Vec::from([
+                // Existing index files
+                (
+                    Path::new("about"),
+                    Some(project_root.join("public/about/index.html")),
+                ),
+                (Path::new(""), Some(project_root.join("public/index.html"))),
+                // Missing index files
+                (Path::new("main.css"), None),
+                (Path::new("unknown"), None),
+            ]);
+
+            (project_root, tests)
+        };
+
+        for (file, asset_path) in tests {
+            assert_eq!(retrieve_asset_path(&project_root, file, true), asset_path);
+        }
+    }
+}

examples/js-json/public/robots.txt

@@ -0,0 +1,2 @@
+User-agent: *
+Disallow: /

examples/js-params/public/main.css

@@ -1,3 +1,4 @@
+/* This is just a comment for testing purposes */
 body {
     max-width: 1000px;
 }
@@ -25,4 +26,4 @@ pre>code {
 
 p {
     margin-top: 2rem;
-}
+}