Error Handler allow recording error and formatting error response, it receives a context and an error that returns by middleware or final handler.

    1. type ErrorHandler struct {
    2.     tmpl *template.Template
    3. }
    5. func NewErrorHandler(tmpl *template.Template) *ErrorHandler {
    6.     return &ErrorHandler{
    7.         tmpl: tmpl,
    8.     }
    9. }
    11. func (h *ErrorHandler) Handle(ctx *clevergo.Context, err error) {
    12.     // write error to log.
    13.     log.Println(err)
    15.     format := ctx.DefaultQuery("format", "html")
    16.     switch format {
    17.     case "json":
    18.         ctx.JSON(http.StatusOK, map[string]interface{}{
    19.             "message": err.Error(),
    20.         })
    21.     default:
    22.         h.tmpl.Execute(ctx.Response, err)
    23.     }
    24. }
    26. tmpl := template.Must(template.New("error").Parse(`<html><body><h1>{{ .Error }}</h1></body></html>`))
    27. router.ErrorHandler = NewErrorHandler(tmpl)
    1. $ curl http://localhost:8080/404             
    2. <html><body><h1>404 page not found</h1></body></html>                                                
    4. $ curl "http://localhost:8080/404?format=json"
    5. {"message":"404 page not found"}