handler.go

package phi

import (
	"encoding/json"
	"errors"
	"log"
	"net/http"
)

// Defines a function which accepts a ResponseWriter, Request and a phi.Error
// this function is used to handle errors thrown by any handler/route
//
// can be set by SetErrorHandler
var ErrorHandler = defaultErrorHandler

func defaultErrorHandler(w http.ResponseWriter, r *http.Request, e *Error) {
	if w.Header().Get("Content-Type") == "" {
		w.Header().Set("Content-Type", "application/json")
	}

	parsed, err := json.Marshal(Map{
		"error":   e.Error,
		"message": e.Message,
	})
	if err == nil {
		if _, err = w.Write(parsed); err != nil {
			log.Printf("#> defaultHandler: %v", err)
		}

		return
	}

	if e.StatusCode != 0 {
		w.WriteHeader(e.StatusCode)
	}

	if _, err = w.Write(parsed); err != nil {
		log.Printf("#> defaultHandler: %v", err)
	}
}

type Handler func(w *Response, r *Request) *Error

func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if err := h(
		&Response{
			ResponseWriter: w,
		},
		&Request{
			Request: r,
		},
	); err != nil {
		ErrorHandler(w, r, err)
	}
}

// set custom error handler
type ErrorHandlerFunc func(w http.ResponseWriter, r *http.Request, e *Error)

func SetErrorHandler(fn ErrorHandlerFunc) error {
	if fn == nil {
		return errors.New("couldn't set empty error handling function")
	}

	ErrorHandler = fn
	return nil
}