package http import ( "encoding/json" "fmt" "html/template" "path/filepath" "github.com/mpolden/ipd/iputil" "github.com/mpolden/ipd/iputil/geo" "github.com/mpolden/ipd/useragent" "net" "net/http" "strconv" ) const ( jsonMediaType = "application/json" textMediaType = "text/plain" ) type Server struct { Template string IPHeaders []string LookupAddr func(net.IP) (string, error) LookupPort func(net.IP, uint64) error gr geo.Reader } type Response struct { IP net.IP `json:"ip"` IPDecimal uint64 `json:"ip_decimal"` Country string `json:"country,omitempty"` CountryISO string `json:"country_iso,omitempty"` City string `json:"city,omitempty"` Hostname string `json:"hostname,omitempty"` } type PortResponse struct { IP net.IP `json:"ip"` Port uint64 `json:"port"` Reachable bool `json:"reachable"` } func New(db geo.Reader) *Server { return &Server{gr: db} } func ipFromRequest(headers []string, r *http.Request) (net.IP, error) { remoteIP := "" for _, header := range headers { remoteIP = r.Header.Get(header) if remoteIP != "" { break } } if remoteIP == "" { host, _, err := net.SplitHostPort(r.RemoteAddr) if err != nil { return nil, err } remoteIP = host } ip := net.ParseIP(remoteIP) if ip == nil { return nil, fmt.Errorf("could not parse IP: %s", remoteIP) } return ip, nil } func (s *Server) newResponse(r *http.Request) (Response, error) { ip, err := ipFromRequest(s.IPHeaders, r) if err != nil { return Response{}, err } ipDecimal := iputil.ToDecimal(ip) country, _ := s.gr.Country(ip) city, _ := s.gr.City(ip) var hostname string if s.LookupAddr != nil { hostname, _ = s.LookupAddr(ip) } return Response{ IP: ip, IPDecimal: ipDecimal, Country: country.Name, CountryISO: country.ISO, City: city, Hostname: hostname, }, nil } func (s *Server) newPortResponse(r *http.Request) (PortResponse, error) { lastElement := filepath.Base(r.URL.Path) port, err := strconv.ParseUint(lastElement, 10, 16) if err != nil || port < 1 || port > 65355 { return PortResponse{Port: port}, fmt.Errorf("invalid port: %d", port) } ip, err := ipFromRequest(s.IPHeaders, r) if err != nil { return PortResponse{Port: port}, err } err = s.LookupPort(ip, port) return PortResponse{ IP: ip, Port: port, Reachable: err == nil, }, nil } func (s *Server) CLIHandler(w http.ResponseWriter, r *http.Request) *appError { ip, err := ipFromRequest(s.IPHeaders, r) if err != nil { return internalServerError(err) } fmt.Fprintln(w, ip.String()) return nil } func (s *Server) CLICountryHandler(w http.ResponseWriter, r *http.Request) *appError { response, err := s.newResponse(r) if err != nil { return internalServerError(err) } fmt.Fprintln(w, response.Country) return nil } func (s *Server) CLICountryISOHandler(w http.ResponseWriter, r *http.Request) *appError { response, err := s.newResponse(r) if err != nil { return internalServerError(err) } fmt.Fprintln(w, response.CountryISO) return nil } func (s *Server) CLICityHandler(w http.ResponseWriter, r *http.Request) *appError { response, err := s.newResponse(r) if err != nil { return internalServerError(err) } fmt.Fprintln(w, response.City) return nil } func (s *Server) JSONHandler(w http.ResponseWriter, r *http.Request) *appError { response, err := s.newResponse(r) if err != nil { return internalServerError(err).AsJSON() } b, err := json.Marshal(response) if err != nil { return internalServerError(err).AsJSON() } w.Header().Set("Content-Type", jsonMediaType) w.Write(b) return nil } func (s *Server) HealthHandler(w http.ResponseWriter, r *http.Request) *appError { w.Header().Set("Content-Type", jsonMediaType) w.Write([]byte(`{"status":"OK"}`)) return nil } func (s *Server) PortHandler(w http.ResponseWriter, r *http.Request) *appError { response, err := s.newPortResponse(r) if err != nil { return badRequest(err).WithMessage(fmt.Sprintf("Invalid port: %d", response.Port)).AsJSON() } b, err := json.Marshal(response) if err != nil { return internalServerError(err).AsJSON() } w.Header().Set("Content-Type", jsonMediaType) w.Write(b) return nil } func (s *Server) DefaultHandler(w http.ResponseWriter, r *http.Request) *appError { response, err := s.newResponse(r) if err != nil { return internalServerError(err) } t, err := template.ParseFiles(s.Template) if err != nil { return internalServerError(err) } json, err := json.MarshalIndent(response, "", " ") if err != nil { return internalServerError(err) } var data = struct { Response Host string JSON string Port bool }{ response, r.Host, string(json), s.LookupPort != nil, } if err := t.Execute(w, &data); err != nil { return internalServerError(err) } return nil } func NotFoundHandler(w http.ResponseWriter, r *http.Request) *appError { err := notFound(nil).WithMessage("404 page not found") if r.Header.Get("accept") == jsonMediaType { err = err.AsJSON() } return err } func cliMatcher(r *http.Request) bool { ua := useragent.Parse(r.UserAgent()) switch ua.Product { case "curl", "HTTPie", "Wget", "fetch libfetch", "Go", "Go-http-client", "ddclient": return true } return false } type appHandler func(http.ResponseWriter, *http.Request) *appError func (fn appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) { if e := fn(w, r); e != nil { // e is *appError // When Content-Type for error is JSON, we need to marshal the response into JSON if e.IsJSON() { var data = struct { Error string `json:"error"` }{e.Message} b, err := json.Marshal(data) if err != nil { panic(err) } e.Message = string(b) } // Set Content-Type of response if set in error if e.ContentType != "" { w.Header().Set("Content-Type", e.ContentType) } w.WriteHeader(e.Code) fmt.Fprint(w, e.Message) } } func (s *Server) Handler() http.Handler { r := NewRouter() // Health r.Route("GET", "/health", s.HealthHandler) // JSON r.Route("GET", "/", s.JSONHandler).Header("Accept", jsonMediaType) r.Route("GET", "/json", s.JSONHandler) // CLI r.Route("GET", "/", s.CLIHandler).MatcherFunc(cliMatcher) r.Route("GET", "/", s.CLIHandler).Header("Accept", textMediaType) r.Route("GET", "/ip", s.CLIHandler) if !s.gr.IsEmpty() { r.Route("GET", "/country", s.CLICountryHandler) r.Route("GET", "/country-iso", s.CLICountryISOHandler) r.Route("GET", "/city", s.CLICityHandler) } // Browser r.Route("GET", "/", s.DefaultHandler) // Port testing if s.LookupPort != nil { r.RoutePrefix("GET", "/port/", s.PortHandler) } return r.Handler() } func (s *Server) ListenAndServe(addr string) error { return http.ListenAndServe(addr, s.Handler()) }