sourceafButter::ErrOn5xxMiddleware.fan

** Middleware that throws a `ServerErr` when a HTTP response returns a 5xx status code, indicating a server error.
class ErrOn5xxMiddleware : ButterMiddleware {
    
    ** If set to 'true', this middleware throws a `ServerErr` on a 5xx status code. 
    ** Defaults to 'true'.
    Bool enabled    := true

    ** Do dat ting.
    override ButterResponse sendRequest(Butter butter, ButterRequest req) {
        res := butter.sendRequest(req)
        if (enabled && (500..<600).contains(res.statusCode))
            throw ServerErr(res.statusCode, res.statusMsg, ErrMsgs.serverError(res.statusCode, res.statusMsg))
        return res
    }
}

** Throw by `ErrOn5xxMiddleware` when a HTTP response returns a 5xx status code.
const class ServerErr : Err {
    ** The failing HTTP response status code
    const Int statusCode
    
    ** The failing HTTP response status message
    const Str statusMsg
    
    new make(Int statusCode, Str statusMsg, Str msg := "", Err? cause := null) : super(msg, cause) {
        this.statusCode = statusCode
        this.statusMsg  = statusMsg
    }
}