doomer/server/server.go

package server

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

type ApiError struct {
	Err    string
	Status int
}

func (e ApiError) Error() string {
	return e.Err
}

type Api struct {
	mux  *http.ServeMux
	host string
}

func NewApi(host string) Api {
	return Api{
		mux:  http.NewServeMux(),
		host: host,
	}
}

func (a Api) Run() error {
	log.Println("Server is running at ", a.host)
	return http.ListenAndServe(a.host, a.mux)
}

func (a Api) Group(path string) group {
	return group{path: path, api: &a}
}

type group struct {
	api  *Api
	path string
}

func (g group) Group(path string) group {
	p, _ := url.JoinPath(g.path, path)
	return group{path: p, api: g.api}
}

type apiFunc func(http.ResponseWriter, *http.Request) error

func (g group) Endpoint(path string, f apiFunc) *group {
	p, _ := url.JoinPath(g.path, path)
	log.Println("New path registered: ", p, f)
	g.api.mux.HandleFunc(p, func(w http.ResponseWriter, r *http.Request) {
		if err := f(w, r); err != nil {
			if e, ok := err.(ApiError); ok {
				WriteJSON(w, e.Status, e)
				return
			}
			WriteJSON(w, 500, ApiError{Err: err.Error(), Status: http.StatusInternalServerError})
			return
		}
	})
	return &g
}

func StatusAndContent(w http.ResponseWriter, status int, contentType string) {
	w.Header().Add("Content-Type", contentType)
	w.WriteHeader(status)
}

func WriteJSON(w http.ResponseWriter, status int, v any) error {
	StatusAndContent(w, status, "application/json")
	return json.NewEncoder(w).Encode(v)
}

func WritePlain(w http.ResponseWriter, status int, text string) error {
	StatusAndContent(w, status, "text/plain")
	_, err := w.Write([]byte(text))
	return err
}

func WriteBlob(w http.ResponseWriter, status int, contentType string, blob []byte) error {
	StatusAndContent(w, status, contentType)
	_, err := w.Write(blob)
	return err
}