tsviewer/response/response.go

package response

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

	"git.cliffbreak.de/Cliffbreak/tsviewer/request/meta"
)

type HandlerFunc func() (int, error)

// Responder is a service for responses
type Responder interface {
	Send(http.ResponseWriter, int)
}

// Response data type
type Response struct {
	Content interface{}
	Pretty  bool
}

type Envelope struct {
	Data interface{} `json:"data,omitempty"`
}

// New creates a new Response
func New(content interface{}, r *http.Request) *Response {
	var resp Response

	meta := meta.NewFromRequest(r)

	if meta.Envelope {
		resp = Response{
			Content: Envelope{
				Data: content,
			},
		}
	} else {
		resp = Response{
			Content: content,
		}
	}

	resp.Pretty = meta.Pretty

	return &resp
}

// Send sends the response
func (resp Response) Send(w http.ResponseWriter, status int) (int, error) {
	var (
		rawJSON []byte
		err     error
	)

	if resp.Pretty {
		rawJSON, err = json.MarshalIndent(resp.Content, "", "    ")
	} else {
		rawJSON, err = json.Marshal(resp.Content)
	}

	if err != nil {
		return http.StatusInternalServerError, err
	} else if string(rawJSON) == "null" {
		rawJSON = make([]byte, 0)
	}

	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	w.Write(rawJSON)

	return status, nil
}

func Handler(w http.ResponseWriter, r *http.Request, hf HandlerFunc) {
	status, err := hf()
	if err == nil {
		return
	}

	log.Printf("HTTP %d: %q", status, err)
	if status, err = New(NewError(status, err), r).Send(w, status); err != nil {
		http.Error(w, http.StatusText(status), status)
	}
}