Automatically create admin on first start

src/data/entity_manager.rs

@@ -0,0 +1,43 @@
+use std::path::{Path, PathBuf};
+
+use crate::utils::err::Res;
+
+pub struct EntityManager<E> {
+    file_path: PathBuf,
+    list: Vec<E>,
+}
+
+impl<E> EntityManager<E> where E: rocket::serde::Serialize + rocket::serde::DeserializeOwned + Eq + Clone {
+    /// Open entity
+    pub fn open_or_create<A: AsRef<Path>>(path: A) -> Res<Self> {
+        if !path.as_ref().is_file() {
+            log::warn!("Entities at {:?} does not point to a file, creating a new empty entity container...", path.as_ref());
+            return Ok(Self {
+                file_path: path.as_ref().to_path_buf(),
+                list: vec![],
+            });
+        }
+
+        log::info!("Open existing entity file {:?}", path.as_ref());
+        Ok(Self {
+            file_path: path.as_ref().to_path_buf(),
+            list: serde_json::from_str(&std::fs::read_to_string(path.as_ref())?)?,
+        })
+    }
+
+    /// Get the number of entries in the list
+    pub fn len(&self) -> usize {
+        self.list.len()
+    }
+
+    /// Save the list
+    fn save(&self) -> Res {
+        Ok(std::fs::write(&self.file_path, serde_json::to_string(&self.list)?)?)
+    }
+
+    /// Insert a new element in the list
+    pub fn insert(&mut self, el: E) -> Res {
+        self.list.push(el);
+        self.save()
+    }
+}