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package http
import (
"context"
"encoding/json"
"net"
"net/http"
"time"
"github.com/mpolden/zdns/dns"
"github.com/mpolden/zdns/log"
)
// A Server defines paramaters for running an HTTP server. The HTTP server serves an API for inspecting cache contents
// and request log.
type Server struct {
server *http.Server
logger *log.Logger
}
type logEntry struct {
Time string `json:"time"`
RemoteAddr net.IP `json:"remote_addr"`
Qtype string `json:"type"`
Question string `json:"question"`
Answers []string `json:"answers"`
}
type httpError struct {
err error
Status int `json:"status"`
Message string `json:"message"`
}
// NewServer creates a new HTTP server, serving logs from the given logger and listening on listenAddr.
func NewServer(logger *log.Logger, listenAddr string) *Server {
server := &http.Server{Addr: listenAddr}
s := &Server{logger: logger, server: server}
s.server.Handler = s.handler()
return s
}
func (s *Server) handler() http.Handler {
mux := http.NewServeMux()
mux.Handle("/log/v1/", appHandler(s.logHandler))
//mux.Handle("/cache/v1")
mux.Handle("/", appHandler(notFoundHandler))
return requestFilter(mux)
}
type appHandler func(http.ResponseWriter, *http.Request) (interface{}, *httpError)
func (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
data, e := fn(w, r)
if e != nil { // e is *Error, not os.Error.
if e.Message == "" {
e.Message = e.err.Error()
}
out, err := json.Marshal(e)
if err != nil {
panic(err)
}
w.WriteHeader(e.Status)
w.Write(out)
} else if data != nil {
out, err := json.Marshal(data)
if err != nil {
panic(err)
}
w.Write(out)
}
}
func requestFilter(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/json")
next.ServeHTTP(w, r)
})
}
func notFoundHandler(w http.ResponseWriter, r *http.Request) (interface{}, *httpError) {
return nil, &httpError{
Status: http.StatusNotFound,
Message: "Resource not found",
}
}
func (s *Server) logHandler(w http.ResponseWriter, r *http.Request) (interface{}, *httpError) {
logEntries, err := s.logger.Get(100)
if err != nil {
return nil, &httpError{
err: err,
Status: http.StatusInternalServerError,
}
}
entries := make([]logEntry, 0, len(logEntries))
for _, entry := range logEntries {
dnsType := ""
switch entry.Qtype {
case dns.TypeA:
dnsType = "A"
case dns.TypeAAAA:
dnsType = "AAAA"
case dns.TypeMX:
dnsType = "MX"
}
e := logEntry{
Time: entry.Time.UTC().Format(time.RFC3339),
RemoteAddr: entry.RemoteAddr,
Qtype: dnsType,
Question: entry.Question,
Answers: entry.Answers,
}
entries = append(entries, e)
}
return entries, nil
}
// Close shuts down the HTTP server.
func (s *Server) Close() error { return s.server.Shutdown(context.Background()) }
// ListenAndServe starts the HTTP server listening on the configured address.
func (s *Server) ListenAndServe() error {
s.logger.Printf("http server listening on http://%s", s.server.Addr)
err := s.server.ListenAndServe()
if err == http.ErrServerClosed {
return nil // Do not treat server closing as an error
}
return err
}
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