409 on duplicate

backend/src/error.rs

@@ -12,6 +12,7 @@ pub type AppResult<T> = Result<T, AppError>;
 pub struct AppError {
     status: StatusCode,
     message: String,
+    code: Option<String>,
 }
 
 impl AppError {
@@ -19,6 +20,7 @@ impl AppError {
         Self {
             status,
             message: message.into(),
+            code: None,
         }
     }
 
@@ -26,6 +28,10 @@ impl AppError {
         Self::new(StatusCode::BAD_REQUEST, message)
     }
 
+    pub fn conflict(message: impl Into<String>) -> Self {
+        Self::new(StatusCode::CONFLICT, message)
+    }
+
     pub fn unauthorized() -> Self {
         Self::new(StatusCode::UNAUTHORIZED, "unauthorized")
     }
@@ -37,6 +43,11 @@ impl AppError {
     pub fn internal<E: Display>(error: E) -> Self {
         Self::new(StatusCode::INTERNAL_SERVER_ERROR, error.to_string())
     }
+
+    pub fn with_code(mut self, code: impl Into<String>) -> Self {
+        self.code = Some(code.into());
+        self
+    }
 }
 
 impl IntoResponse for AppError {
@@ -44,6 +55,7 @@ impl IntoResponse for AppError {
         let status = self.status;
         let body = Json(ErrorResponse {
             error: self.message,
+            code: self.code,
         });
         (status, body).into_response()
     }
@@ -52,6 +64,8 @@ impl IntoResponse for AppError {
 #[derive(Serialize)]
 struct ErrorResponse {
     error: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    code: Option<String>,
 }
 
 impl From<diesel::result::Error> for AppError {