Documentation about OpenAPI errors content types is confusing

[cortopy]

In the documentation about error handling with OpenAPI, it appears as if StatusError will be automatically generated as an application/json content type. However, it's by default a string since StatusError doesn't implement any Derive traits.

With the following code:

use salvo::http::{StatusCode, StatusError};
use salvo::oapi::{self, EndpointOutRegister, ToSchema};
use salvo::prelude::*;
use thiserror::Error;

#[derive(Error, Debug)]
pub enum ApiError {
    #[error("Unexpected error")]
    Unexpected,
}

#[async_trait]
impl Writer for ApiError {
    async fn write(mut self, _req: &mut Request, depot: &mut Depot, res: &mut Response) {
        res.render(StatusError::internal_server_error());
    }
}

impl EndpointOutRegister for ApiError {
    fn register(components: &mut oapi::Components, operation: &mut oapi::Operation) {
        operation.responses.insert(
            StatusCode::INTERNAL_SERVER_ERROR.as_str(),
            oapi::Response::new("Internal server error")
                .add_content("application/json", StatusError::to_schema(components)),
        );
    }
}

if the endpoint handler returns an error, the clients gets a plain/text response with the following body:

code: 500

name: Internal Server Error

brief: The server encountered an internal error while processing this request.

cause: There is no more detailed explanation.

This makes the OpenAPI specs inavlid since they say that 500 status code should come with json, but it doesn't. Is there anything I'm missing?

[chrislearn]

If you add http header accept="application/json" to the request, will it still return plain text?

[cortopy]

ah! that was it. Thanks @chrislearn. My endpoint returns String and Swagger UI was sending Content-Type: plain/text