Add function to generate random paths

src/util/mod.rs

@@ -9,6 +9,7 @@ cfg_if! {
         pub mod auth_backend;
         pub mod redis;
         pub mod extract_field;
+        pub mod random_path;
     }
 }
 

src/util/random_path.rs

@@ -0,0 +1,36 @@
+/// Generates random paths for storing assets
+use rand::{rng, Rng};
+use std::ffi::OsStr;
+use std::path::PathBuf;
+
+/// Generate a random path for storing a new file
+/// The path will be in the format `base_path/XX/XXXXXXXXXX.extension`
+pub fn checked_random_path<P: Into<PathBuf>, E: AsRef<OsStr>>(
+    base_path: P,
+    extension: E,
+) -> PathBuf {
+    let base_path: PathBuf = base_path.into();
+    let mut rng = rng();
+
+    // Loop until we find a path that does not exist
+    // If the existance check fails, we assume the path does not exist
+    // since it is extremely unlikely to encounter a collision anyway
+    loop {
+        let random_bytes: [u8; 16] = rng.random();
+
+        let dir_part = format!("{:02x}", random_bytes[0]);
+        let file_part = random_bytes[1..]
+            .iter()
+            .map(|byte| format!("{byte:02x}"))
+            .collect::<String>();
+
+        let path = base_path
+            .join(dir_part)
+            .join(file_part)
+            .with_extension(&extension);
+
+        if !path.try_exists().unwrap_or(false) {
+            return path;
+        }
+    }
+}