implement endpoint to list files in a directory

casket-backend/src/errors.rs

@@ -1,6 +1,17 @@
+use axum::http::StatusCode;
+use problem_details::ProblemDetails;
+use std::fmt::Debug;
+use tracing::error;
+
 pub const ERROR_DETAILS_PATH_TRAVERSAL: &str = "You must not traverse!";
 pub const ERROR_DETAILS_INTERNAL_ERROR: &str =
     "Internal Error! Check the logs of the backend service for details.";
 pub const ERROR_DETAILS_ABSOLUTE_PATH_NOT_ALLOWED: &str = "Absolute paths are not allowed.";
 pub const ERROR_DETAILS_NO_NAME_PROVIDED_MULTIPART_FIELD: &str =
     "No name provided for multipart form field";
+
+pub fn to_internal_error(error: impl Debug) -> ProblemDetails {
+    error!("{:?}", error);
+    ProblemDetails::from_status_code(StatusCode::INTERNAL_SERVER_ERROR)
+        .with_detail(ERROR_DETAILS_INTERNAL_ERROR)
+}

casket-backend/src/extractor_helper.rs

@@ -0,0 +1,24 @@
+use axum::extract::FromRequestParts;
+use axum::http::request::Parts;
+use axum::http::StatusCode;
+use problem_details::ProblemDetails;
+use std::fmt::Debug;
+
+pub struct WithProblemDetails<T>(pub T);
+
+impl<T, S> FromRequestParts<S> for WithProblemDetails<T>
+where
+    T: FromRequestParts<S>,
+    T::Rejection: Debug,
+    S: Sync,
+{
+    type Rejection = ProblemDetails;
+
+    async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
+        match T::from_request_parts(parts, state).await {
+            Ok(inner) => Ok(Self(inner)),
+            Err(rejection) => Err(ProblemDetails::from_status_code(StatusCode::BAD_REQUEST)
+                .with_detail(format!("{rejection:?}"))),
+        }
+    }
+}

casket-backend/src/files/list.rs

@@ -0,0 +1,107 @@
+use crate::errors::to_internal_error;
+use crate::extractor_helper::WithProblemDetails;
+use crate::files::build_system_path;
+use crate::{errors, AppState};
+use axum::extract::{Query, State};
+use axum::http::StatusCode;
+use axum::{debug_handler, Json};
+use problem_details::ProblemDetails;
+use serde::{Deserialize, Serialize};
+use std::io::Error;
+use std::path::PathBuf;
+use tokio::fs::{read_dir, DirEntry};
+use tracing::{debug, error};
+
+#[debug_handler]
+pub async fn query_file_tree(
+    State(state): State<AppState>,
+    axum::extract::Path(user_id): axum::extract::Path<String>,
+    WithProblemDetails(Query(query)): WithProblemDetails<Query<FileQuery>>,
+) -> Result<Json<PathElements>, ProblemDetails> {
+    let path = build_system_path(&state.config.files.directory, &user_id, &query.path)?;
+    debug!("Loading path: {:?}", path);
+    Ok(PathElements::new(load_directory(path, query.nesting).await?).into())
+}
+
+async fn load_directory(path: PathBuf, nesting: u32) -> Result<Vec<PathElement>, ProblemDetails> {
+    match read_dir(path).await {
+        Err(error) => Err(map_io_error(error)),
+        Ok(mut value) => {
+            let mut result = vec![];
+            while let Some(next) = value.next_entry().await.map_err(map_io_error)? {
+                result.push(PathElement::from(next, nesting).await?);
+            }
+            Ok(result)
+        }
+    }
+}
+
+fn map_io_error(error: Error) -> ProblemDetails {
+    match error.kind() {
+        std::io::ErrorKind::NotFound => ProblemDetails::from_status_code(StatusCode::NOT_FOUND),
+        _ => to_internal_error(error),
+    }
+}
+
+#[derive(Deserialize)]
+pub struct FileQuery {
+    path: PathBuf,
+    #[serde(default = "u32::min_value")]
+    nesting: u32,
+}
+
+#[derive(Serialize)]
+pub struct PathElements {
+    files: Vec<PathElement>,
+}
+
+impl PathElements {
+    pub fn new(files: Vec<PathElement>) -> Self {
+        Self { files }
+    }
+}
+
+#[derive(Serialize)]
+pub struct PathElement {
+    name: String,
+    is_dir: bool,
+    children: Option<Vec<PathElement>>,
+}
+
+impl PathElement {
+    async fn from(value: DirEntry, nesting: u32) -> Result<Self, ProblemDetails> {
+        let metadata = value.metadata().await.unwrap();
+        debug!("File type: {:?}", value.file_type().await.unwrap());
+        let is_dir = metadata.is_dir();
+        if is_dir || metadata.is_file() {
+            Ok(PathElement {
+                name: value.file_name().into_string().unwrap(),
+                is_dir,
+                children: load_children(value.path(), nesting, is_dir).await?,
+            })
+        } else {
+            error!(
+                "File <{:?}> is neither a directory nor a file. ",
+                value.file_name()
+            );
+            Err(
+                ProblemDetails::from_status_code(StatusCode::INTERNAL_SERVER_ERROR)
+                    .with_detail(errors::ERROR_DETAILS_INTERNAL_ERROR),
+            )
+        }
+    }
+}
+
+async fn load_children(
+    path: PathBuf,
+    nesting: u32,
+    is_dir: bool,
+) -> Result<Option<Vec<PathElement>>, ProblemDetails> {
+    if nesting == 0 {
+        Ok(None)
+    } else if !is_dir {
+        Ok(Some(vec![]))
+    } else {
+        Ok(Some(Box::pin(load_directory(path, nesting - 1)).await?))
+    }
+}

casket-backend/src/files/mod.rs

@@ -15,7 +15,7 @@ fn build_system_path(
         Err(
             ProblemDetails::from_status_code(StatusCode::BAD_REQUEST).with_detail(
                 errors::ERROR_DETAILS_ABSOLUTE_PATH_NOT_ALLOWED.to_owned()
-                    + format!(" Provided Path: {:?}", user_path).as_str(),
+                    + format!(" Provided Path: {user_path:?}",).as_str(),
             ),
         )
     } else {

casket-backend/src/files/upload.rs

@@ -1,3 +1,4 @@
+use crate::errors::to_internal_error;
 use crate::files::build_system_path;
 use crate::{errors, AppState};
 use axum::body::Bytes;
@@ -9,13 +10,11 @@ use futures::Stream;
 use futures_util::stream::MapErr;
 use futures_util::{StreamExt, TryStreamExt};
 use problem_details::ProblemDetails;
-use std::fmt::Debug;
 use std::io;
 use std::io::Error;
-use std::path::{Component, Path, PathBuf};
+use std::path::PathBuf;
 use tokio::fs::{create_dir_all, File};
 use tokio::io::AsyncWriteExt;
-use tracing::error;
 
 #[debug_handler]
 pub async fn handle_file_uploads(
@@ -66,12 +65,6 @@ pub async fn save_file(
     Ok(())
 }
 
-fn to_internal_error(error: impl Debug) -> ProblemDetails {
-    error!("{:?}", error);
-    ProblemDetails::from_status_code(StatusCode::INTERNAL_SERVER_ERROR)
-        .with_detail(errors::ERROR_DETAILS_INTERNAL_ERROR)
-}
-
 fn map_error_to_io_error(field: Field) -> MapErr<Field, fn(MultipartError) -> Error> {
     field.map_err(|err| Error::new(io::ErrorKind::Other, err))
 }

casket-backend/src/main.rs

@@ -4,6 +4,7 @@ mod config;
 mod errors;
 mod files;
 mod routes;
+mod extractor_helper;
 
 use axum::Router;
 use std::env;
@@ -11,7 +12,7 @@ use std::process::exit;
 use std::str::FromStr;
 use tracing::{debug, error, info};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct AppState {
     config: config::Config,
 }

casket-backend/src/routes.rs

@@ -2,11 +2,13 @@ use crate::files;
 use crate::AppState;
 use axum::routing::post;
 use axum::{response::Html, routing::get, Router};
+use files::list::query_file_tree;
 
 pub fn routes() -> Router<AppState> {
-    Router::new()
-        .route("/", get(handler))
-        .route("/api/v1/user/{:user_id}/files", post(files::upload::handle_file_uploads))
+    Router::new().route("/", get(handler)).route(
+        "/api/v1/user/{:user_id}/files",
+        post(files::upload::handle_file_uploads).get(query_file_tree),
+    )
 }
 
 async fn handler() -> Html<&'static str> {