x/smalltrip/exceptions/exceptions.go

package exceptions

import (
	"errors"
	"fmt"
	"net/http"
)

type Exception struct {
	Status   int            `json:"status"`          // HTTP Status Code
	Code     string         `json:"code"`            // Application error code
	Message  string         `json:"message"`         // User friendly message
	Err      error          `json:"error,omitempty"` // Go error
	Data     map[string]any `json:"data,omitempty"`  // Additional contextual data
	Severity Severity       `json:"severity"`        // Exception level

	// Handler to be used. This is normally provided by a middleware via the
	// request context. Setting this field overrides any provided by the middleware
	// and can be used to add a handler when using a middleware is not possible.
	handler HandlerFunc `json:"-"`
}

var (
	_ fmt.Stringer = Exception{}
	_ error        = Exception{}
	_ http.Handler = Exception{}
)

func (e Exception) String() string {
	return fmt.Sprintf("%s %3d %s Exception %q", e.Severity, e.Status, e.Code, e.Message)
}

func (e Exception) Error() string {
	return e.String()
}

func (e Exception) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if e.handler != nil {
		e.handler(e, w, r)
	}

	e.handler = HandlerJSON(HandlerText)

	handler, ok := r.Context().Value(handlerFuncCtxKey).(HandlerFunc)
	if !ok {
		e.handler(e, w, r)
	}

	handler(e, w, r)
}