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dns/internal/server/server.go
2026-05-12 22:54:32 +03:00

146 lines
3.7 KiB
Go

package server
import (
"encoding/json"
"errors"
"log/slog"
"net/http"
"time"
"github.com/wzray/dns/internal/resolv"
)
type Server struct {
mgr *resolv.Manager
log *slog.Logger
mux *http.ServeMux
}
func New(mgr *resolv.Manager, log *slog.Logger) *Server {
s := &Server{mgr: mgr, log: log, mux: http.NewServeMux()}
s.routes()
return s
}
func (s *Server) Handler() http.Handler {
return s.withLogging(s.mux)
}
func (s *Server) routes() {
s.mux.HandleFunc("GET /health", s.handleHealth)
s.mux.HandleFunc("GET /dns", s.handleList)
s.mux.HandleFunc("POST /dns", s.handleAdd)
s.mux.HandleFunc("DELETE /dns/{address}", s.handleRemove)
}
type listResponse struct {
Servers []string `json:"servers"`
}
type addRequest struct {
Address string `json:"address"`
}
type errorResponse struct {
Error string `json:"error"`
}
func (s *Server) handleHealth(w http.ResponseWriter, _ *http.Request) {
writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}
func (s *Server) handleList(w http.ResponseWriter, r *http.Request) {
servers, err := s.mgr.List()
if err != nil {
s.log.Error("list nameservers", "err", err)
writeError(w, http.StatusInternalServerError, "failed to read nameservers")
return
}
if servers == nil {
servers = []string{}
}
writeJSON(w, http.StatusOK, listResponse{Servers: servers})
}
func (s *Server) handleAdd(w http.ResponseWriter, r *http.Request) {
var req addRequest
dec := json.NewDecoder(r.Body)
dec.DisallowUnknownFields()
if err := dec.Decode(&req); err != nil {
writeError(w, http.StatusBadRequest, "invalid JSON body")
return
}
if req.Address == "" {
writeError(w, http.StatusBadRequest, "address is required")
return
}
err := s.mgr.Add(req.Address)
switch {
case err == nil:
writeJSON(w, http.StatusCreated, map[string]string{"address": req.Address})
case errors.Is(err, resolv.ErrInvalidAddress):
writeError(w, http.StatusBadRequest, err.Error())
case errors.Is(err, resolv.ErrAlreadyExists):
writeError(w, http.StatusConflict, err.Error())
default:
s.log.Error("add nameserver", "addr", req.Address, "err", err)
writeError(w, http.StatusInternalServerError, "failed to add nameserver")
}
}
func (s *Server) handleRemove(w http.ResponseWriter, r *http.Request) {
addr := r.PathValue("address")
if addr == "" {
writeError(w, http.StatusBadRequest, "address is required")
return
}
err := s.mgr.Remove(addr)
switch {
case err == nil:
w.WriteHeader(http.StatusNoContent)
case errors.Is(err, resolv.ErrInvalidAddress):
writeError(w, http.StatusBadRequest, err.Error())
case errors.Is(err, resolv.ErrNotFound):
writeError(w, http.StatusNotFound, err.Error())
default:
s.log.Error("remove nameserver", "addr", addr, "err", err)
writeError(w, http.StatusInternalServerError, "failed to remove nameserver")
}
}
func writeJSON(w http.ResponseWriter, status int, body any) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(status)
_ = json.NewEncoder(w).Encode(body)
}
func writeError(w http.ResponseWriter, status int, msg string) {
writeJSON(w, status, errorResponse{Error: msg})
}
type statusRecorder struct {
http.ResponseWriter
status int
}
func (r *statusRecorder) WriteHeader(code int) {
r.status = code
r.ResponseWriter.WriteHeader(code)
}
func (s *Server) withLogging(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
start := time.Now()
rec := &statusRecorder{ResponseWriter: w, status: http.StatusOK}
next.ServeHTTP(rec, r)
s.log.Info("http request",
"method", r.Method,
"path", r.URL.Path,
"status", rec.status,
"duration_ms", time.Since(start).Milliseconds(),
"remote", r.RemoteAddr,
)
})
}