feat: user avatar as public asset

lib/http_server/src/controllers/api/public_assets.rs

@@ -0,0 +1,27 @@
+use axum::{extract::{Path, State}, http::{header, HeaderMap, HeaderValue, StatusCode}, response::{Html, IntoResponse}};
+use kernel::repositories::users::get_user_asset_by_id;
+
+use crate::AppState;
+
+pub async fn get_user_asset(
+    State(app_state): State<AppState>,
+    Path(asset_id): Path<String>
+) -> impl IntoResponse {
+    let user_asset = match get_user_asset_by_id(&app_state.db, &asset_id).await {
+        Err(_) => {
+            return (
+                StatusCode::NOT_FOUND,
+                Html("Could not find user asset")
+            ).into_response();
+        },
+        Ok(ua) => ua
+    };
+
+    let mut hm = HeaderMap::new();
+    hm.insert(
+        header::CONTENT_TYPE,
+        HeaderValue::from_str(&user_asset.mime_type).expect("Constructing header value.")
+    );
+    
+    (hm, user_asset.content).into_response()
+}