changes and improvements to rewrite PR

core/lib/src/fs/mod.rs

@@ -5,6 +5,8 @@ mod named_file;
 mod temp_file;
 mod file_name;
 
+pub mod rewrite;
+
 pub use server::*;
 pub use named_file::*;
 pub use temp_file::*;

core/lib/src/fs/rewrite.rs

@@ -0,0 +1,329 @@
+use std::borrow::Cow;
+use std::path::Path;
+
+use crate::{Request, Response};
+use crate::http::{HeaderMap, ContentType};
+use crate::http::ext::IntoOwned;
+use crate::response::{self, Redirect, Responder};
+
+/// Trait used to implement [`FileServer`] customization.
+///
+/// Conceptually, a [`FileServer`] is a sequence of `Rewriter`s, which transform
+/// a path from a request to a final response. [`FileServer`] add a set of default
+/// `Rewriter`s, which filter out dotfiles, apply a root path, normalize directories,
+/// and use `index.html`.
+///
+/// After running the chain of `Rewriter`s,
+/// [`FileServer`] uses the final [`Option<Rewrite>`](Rewrite)
+/// to respond to the request. If the response is `None`, a path that doesn't
+/// exist or a directory path, [`FileServer`] will respond with a
+/// [`Status::NotFound`](crate::http::Status::NotFound). Otherwise the [`FileServer`]
+/// will respond with a redirect or the contents of the file specified.
+///
+/// [`FileServer`] provides several helper methods to add `Rewriter`s:
+/// - [`FileServer::rewrite()`]
+/// - [`FileServer::filter()`]
+/// - [`FileServer::map()`]
+pub trait Rewriter: Send + Sync + 'static {
+    /// Alter the [`Rewrite`] as needed.
+    fn rewrite<'r>(&self, file: Option<Rewrite<'r>>, req: &'r Request<'_>) -> Option<Rewrite<'r>>;
+}
+
+/// A Response from a [`FileServer`]
+#[derive(Debug, Clone)]
+#[non_exhaustive]
+pub enum Rewrite<'r> {
+    /// Return the contents of the specified file.
+    File(File<'r>),
+    /// Returns a Redirect.
+    Redirect(Redirect),
+}
+
+/// A File response from a [`FileServer`]
+#[derive(Debug, Clone)]
+pub struct File<'r> {
+    /// The path to the file that [`FileServer`] will respond with.
+    pub path: Cow<'r, Path>,
+    /// A list of headers to be added to the generated response.
+    pub headers: HeaderMap<'r>,
+}
+
+impl<'r> Rewrite<'r> {
+    pub fn file(&self) -> Option<&File<'r>> {
+        match self {
+            Rewrite::File(f) => Some(f),
+            _ => None,
+        }
+    }
+
+    pub fn redirect(&self) -> Option<&Redirect> {
+        match self {
+            Rewrite::Redirect(r) => Some(r),
+            _ => None,
+        }
+    }
+}
+
+impl<'r> From<File<'r>> for Rewrite<'r> {
+    fn from(value: File<'r>) -> Self {
+        Self::File(value)
+    }
+}
+
+impl<'r> From<Redirect> for Rewrite<'r> {
+    fn from(value: Redirect) -> Self {
+        Self::Redirect(value)
+    }
+}
+
+impl<'r> File<'r> {
+    pub fn new(path: impl Into<Cow<'r, Path>>) -> Self {
+        Self { path: path.into(), headers: HeaderMap::new() }
+    }
+
+    pub(crate) async fn open(self) -> std::io::Result<NamedFile<'r>> {
+        let file = tokio::fs::File::open(&self.path).await?;
+        let metadata = file.metadata().await?;
+        if metadata.is_dir() {
+            return Err(std::io::Error::new(std::io::ErrorKind::Other, "is a directory"));
+        }
+
+        Ok(NamedFile {
+            file,
+            len: metadata.len(),
+            path: self.path,
+            headers: self.headers,
+        })
+    }
+
+    /// Replace the path of this `File`.
+    pub fn map_path<F, P>(self, f: F) -> Self
+        where F: FnOnce(Cow<'r, Path>) -> P,
+              P: Into<Cow<'r, Path>>,
+    {
+        Self {
+            path: f(self.path).into(),
+            headers: self.headers,
+        }
+    }
+}
+
+impl<F: Send + Sync + 'static> Rewriter for F
+    where F: for<'r> Fn(Option<Rewrite<'r>>, &Request<'_>) -> Option<Rewrite<'r>>
+{
+    fn rewrite<'r>(&self, f: Option<Rewrite<'r>>, r: &Request<'_>) -> Option<Rewrite<'r>> {
+        self(f, r)
+    }
+}
+
+impl Rewriter for Rewrite<'static> {
+    fn rewrite<'r>(&self, _: Option<Rewrite<'r>>, _: &Request<'_>) -> Option<Rewrite<'r>> {
+        Some(self.clone())
+    }
+}
+
+impl Rewriter for File<'static> {
+    fn rewrite<'r>(&self, _: Option<Rewrite<'r>>, _: &Request<'_>) -> Option<Rewrite<'r>> {
+        Some(Rewrite::File(self.clone()))
+    }
+}
+
+impl Rewriter for Redirect {
+    fn rewrite<'r>(&self, _: Option<Rewrite<'r>>, _: &Request<'_>) -> Option<Rewrite<'r>> {
+        Some(Rewrite::Redirect(self.clone()))
+    }
+}
+
+/// Helper trait to simplify standard rewrites
+#[doc(hidden)]
+pub trait FileMap: for<'r> Fn(File<'r>, &Request<'_>) -> Rewrite<'r> + Send + Sync + 'static {}
+impl<F> FileMap for F
+    where F: for<'r> Fn(File<'r>, &Request<'_>) -> Rewrite<'r> + Send + Sync + 'static {}
+
+/// Helper trait to simplify standard rewrites
+#[doc(hidden)]
+pub trait FileFilter: Fn(&File<'_>, &Request<'_>) -> bool + Send + Sync + 'static {}
+impl<F> FileFilter for F
+    where F: Fn(&File<'_>, &Request<'_>) -> bool + Send + Sync + 'static {}
+
+/// Prepends the provided path, to serve files from a directory.
+///
+/// You can use [`relative!`] to make a path relative to the crate root, rather
+/// than the runtime directory.
+///
+/// # Example
+///
+/// ```rust,no_run
+/// # use rocket::fs::{FileServer, prefix, relative};
+/// # fn make_server() -> FileServer {
+/// FileServer::empty()
+///     .map(prefix(relative!("static")))
+/// # }
+/// ```
+///
+/// # Panics
+///
+/// Panics if `path` does not exist. See [`file_root_permissive`] for a
+/// non-panicing variant.
+pub fn prefix(path: impl AsRef<Path>) -> impl FileMap {
+    let path = path.as_ref();
+    if !path.is_dir() {
+        let path = path.display();
+        error!(%path, "FileServer path is not a directory.");
+        warn!("Aborting early to prevent inevitable handler error.");
+        panic!("invalid directory: refusing to continue");
+    }
+
+    let path = path.to_path_buf();
+    move |f, _r| {
+        Rewrite::File(f.map_path(|p| path.join(p)))
+    }
+}
+
+/// Prepends the provided path, to serve a single static file.
+///
+/// # Example
+///
+/// ```rust,no_run
+/// # use rocket::fs::{FileServer, file_root};
+/// # fn make_server() -> FileServer {
+/// FileServer::empty()
+///     .map(file_root("static/index.html"))
+/// # }
+/// ```
+///
+/// # Panics
+///
+/// Panics if `path` does not exist. See [`file_root_permissive`] for a
+/// non-panicing variant.
+pub fn file_root(path: impl AsRef<Path>) -> impl Rewriter {
+    let path = path.as_ref();
+    if !path.exists() {
+        let path = path.display();
+        error!(%path, "FileServer path does not exist.");
+        warn!("Aborting early to prevent inevitable handler error.");
+        panic!("invalid file: refusing to continue");
+    }
+
+    Rewrite::File(File::new(path.to_path_buf()))
+}
+
+/// Rewrites the entire path with `path`. Does not check if `path` exists.
+///
+/// # Example
+///
+/// ```rust,no_run
+/// # use rocket::fs::{FileServer, file_root_permissive};
+/// # fn make_server() -> FileServer {
+/// FileServer::empty()
+///     .map(file_root_permissive("/tmp/rocket"))
+/// # }
+/// ```
+pub fn file_root_permissive(path: impl AsRef<Path>) -> impl Rewriter {
+    let path = path.as_ref().to_path_buf();
+    Rewrite::File(File::new(path))
+}
+
+/// Filters out any path that contains a file or directory name starting with a
+/// dot. If used after `prefix`, this will also check the root path for dots, and
+/// filter them.
+///
+/// # Example
+///
+/// ```rust,no_run
+/// # use rocket::fs::{FileServer, filter_dotfiles, prefix};
+/// # fn make_server() -> FileServer {
+/// FileServer::empty()
+///     .filter(filter_dotfiles)
+///     .map(prefix("static"))
+/// # }
+/// ```
+pub fn filter_dotfiles(file: &File<'_>, _req: &Request<'_>) -> bool {
+    !file.path.iter().any(|s| s.as_encoded_bytes().starts_with(b"."))
+}
+
+/// Normalize directory accesses to always include a trailing slash.
+///
+/// # Example
+///
+/// Appends a slash to any request for a directory without a trailing slash
+/// ```rust,no_run
+/// # use rocket::fs::{FileServer, normalize_dirs, prefix};
+/// # fn make_server() -> FileServer {
+/// FileServer::empty()
+///     .map(prefix("static"))
+///     .map(normalize_dirs)
+/// # }
+/// ```
+pub fn normalize_dirs<'r>(file: File<'r>, req: &Request<'_>) -> Rewrite<'r> {
+    if !req.uri().path().ends_with('/') && file.path.is_dir() {
+        // Known good path + '/' is a good path.
+        let uri = req.uri().clone().into_owned();
+        Rewrite::Redirect(Redirect::temporary(uri.map_path(|p| format!("{p}/")).unwrap()))
+    } else {
+        Rewrite::File(file)
+    }
+}
+
+/// Unconditionally rewrite a directory to a file named `index` inside of that
+/// directory.
+///
+/// # Example
+///
+/// Rewrites all directory requests to `directory/index.html`.
+///
+/// ```rust,no_run
+/// # use rocket::fs::{FileServer, index, prefix};
+/// # fn make_server() -> FileServer {
+/// FileServer::empty()
+///     .map(prefix("static"))
+///     .map(index("index.html"))
+/// # }
+/// ```
+pub fn index(index: &'static str) -> impl FileMap {
+    move |f, _r| if f.path.is_dir() {
+        Rewrite::File(f.map_path(|p| p.join(index)))
+    } else {
+        Rewrite::File(f)
+    }
+}
+
+/// Rewrite a directory to a file named `index` inside of that directory if that
+/// file exists. Otherwise, leave the rewrite unchanged.
+pub fn try_index(index: &'static str) -> impl FileMap {
+    move |f, _r| if f.path.is_dir() {
+        let original_path = f.path.clone();
+        let index = original_path.join(index);
+        if index.is_file() {
+            Rewrite::File(f.map_path(|_| index))
+        } else {
+            Rewrite::File(f)
+        }
+    } else {
+        Rewrite::File(f)
+    }
+}
+
+pub(crate) struct NamedFile<'r> {
+    file: tokio::fs::File,
+    len: u64,
+    path: Cow<'r, Path>,
+    headers: HeaderMap<'r>,
+}
+
+// Do we want to allow the user to rewrite the Content-Type?
+impl<'r> Responder<'r, 'r> for NamedFile<'r> {
+    fn respond_to(self, _: &'r Request<'_>) -> response::Result<'r> {
+        let mut response = Response::new();
+        response.set_header_map(self.headers);
+        if !response.headers().contains("Content-Type") {
+            self.path.extension()
+                .and_then(|ext| ext.to_str())
+                .and_then(ContentType::from_extension)
+                .map(|content_type| response.set_header(content_type));
+        }
+
+        response.set_sized_body(self.len as usize, self.file);
+        Ok(response)
+    }
+}