add new ErrorMessage type

catalyst-gateway/bin/src/service/common/objects/error_message.rs

@@ -0,0 +1,11 @@
+//! Define `ErrorMessage` type.
+
+use poem_openapi::Object;
+
+/// Common error message type.
+#[derive(Object)]
+pub(crate) struct ErrorMessage {
+    /// Error message
+    #[oai(validator(max_length = "100"))]
+    pub(crate) message: String,
+}

catalyst-gateway/bin/src/service/common/objects/mod.rs

@@ -1,4 +1,5 @@
 //! This module contains common and re-usable objects.
 
 pub(crate) mod cardano;
+pub(crate) mod error_message;
 pub(crate) mod legacy;

catalyst-gateway/bin/src/service/common/responses/resp_4xx.rs

@@ -2,7 +2,9 @@
 
 use poem::IntoResponse;
 use poem_extensions::OneResponse;
-use poem_openapi::payload::{Payload, PlainText};
+use poem_openapi::payload::{Json, Payload};
+
+use crate::service::common::objects::error_message::ErrorMessage;
 
 #[derive(OneResponse)]
 #[oai(status = 400)]
@@ -13,12 +15,12 @@ pub(crate) struct BadRequest<T: IntoResponse + Payload>(T);
 #[oai(status = 400)]
 /// This error means that the request was malformed.
 /// It has failed to pass validation, as specified by the `OpenAPI` schema.
-pub(crate) struct ApiValidationError(PlainText<String>);
+pub(crate) struct ApiValidationError(Json<ErrorMessage>);
 
 impl ApiValidationError {
     /// Create new `ApiValidationError`
-    pub(crate) fn new(error: String) -> Self {
-        Self(PlainText(error))
+    pub(crate) fn new(message: String) -> Self {
+        Self(Json(ErrorMessage { message }))
     }
 }