Allow custom error types through a macro and allow them to be used with Result

gotham_restful/src/result/result.rs

@@ -0,0 +1,59 @@
+use super::{ResourceResult, handle_error, into_response_helper};
+use crate::{
+	result::ResourceError,
+	Response, ResponseBody, StatusCode
+};
+#[cfg(feature = "openapi")]
+use crate::OpenapiSchema;
+use futures_core::future::Future;
+use mime::{Mime, APPLICATION_JSON};
+use std::{
+	error::Error,
+	fmt::Display,
+	pin::Pin
+};
+
+pub trait IntoResponseError
+{
+	type Err : Error + Send + 'static;
+	
+	fn into_response_error(self) -> Result<Response, Self::Err>;
+}
+
+impl<E : Error> IntoResponseError for E
+{
+	type Err = serde_json::Error;
+	
+	fn into_response_error(self) -> Result<Response, Self::Err>
+	{
+		let err : ResourceError = self.into();
+		Ok(Response::json(StatusCode::INTERNAL_SERVER_ERROR, serde_json::to_string(&err)?))
+	}
+}
+
+impl<R, E> ResourceResult for Result<R, E>
+where
+	R : ResponseBody,
+	E : Display + IntoResponseError<Err = serde_json::Error>
+{
+	type Err = E::Err;
+	
+	fn into_response(self) -> Pin<Box<dyn Future<Output = Result<Response, E::Err>> + Send>>
+	{
+		match self {
+			Ok(r) => into_response_helper(|| Ok(Response::json(StatusCode::OK, serde_json::to_string(&r)?))),
+			Err(e) => handle_error(e)
+		}
+	}
+	
+	fn accepted_types() -> Option<Vec<Mime>>
+	{
+		Some(vec![APPLICATION_JSON])
+	}
+	
+	#[cfg(feature = "openapi")]
+	fn schema() -> OpenapiSchema
+	{
+		R::schema()
+	}
+}