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package api
import (
"encoding/json"
"fmt"
"html/template"
"io"
"log"
"net"
"net/http"
"path/filepath"
"regexp"
"strconv"
"strings"
"github.com/gorilla/mux"
)
const APPLICATION_JSON = "application/json"
var USER_AGENT_RE = regexp.MustCompile(
`^(?:curl|Wget|fetch\slibfetch|Go-http-client|HTTPie)\/.*|Go\s1\.1\spackage\shttp$`,
)
type API struct {
Template string
oracle Oracle
ipFromRequest func(*http.Request) (net.IP, error)
}
type Response struct {
IP net.IP `json:"ip"`
Country string `json:"country,omitempty"`
City string `json:"city,omitempty"`
Hostname string `json:"hostname,omitempty"`
}
type TestPortResponse struct {
IP net.IP `json:"ip"`
Port uint64 `json:"port"`
Reachable bool `json:"reachable"`
}
func New(oracle Oracle) *API {
return &API{
oracle: oracle,
ipFromRequest: ipFromRequest,
}
}
func ipFromRequest(r *http.Request) (net.IP, error) {
remoteIP := r.Header.Get("X-Real-IP")
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 (a *API) newResponse(r *http.Request) (Response, error) {
ip, err := a.ipFromRequest(r)
if err != nil {
return Response{}, err
}
country, err := a.oracle.LookupCountry(ip)
if err != nil {
log.Print(err)
}
city, err := a.oracle.LookupCity(ip)
if err != nil {
log.Print(err)
}
hostnames, err := a.oracle.LookupAddr(ip.String())
if err != nil {
log.Print(err)
}
return Response{
IP: ip,
Country: country,
City: city,
Hostname: strings.Join(hostnames, " "),
}, nil
}
func (a *API) CLIHandler(w http.ResponseWriter, r *http.Request) *appError {
ip, err := a.ipFromRequest(r)
if err != nil {
return internalServerError(err)
}
io.WriteString(w, ip.String()+"\n")
return nil
}
func (a *API) CLICountryHandler(w http.ResponseWriter, r *http.Request) *appError {
response, err := a.newResponse(r)
if err != nil {
return internalServerError(err)
}
io.WriteString(w, response.Country+"\n")
return nil
}
func (a *API) CLICityHandler(w http.ResponseWriter, r *http.Request) *appError {
response, err := a.newResponse(r)
if err != nil {
return internalServerError(err)
}
io.WriteString(w, response.City+"\n")
return nil
}
func (a *API) JSONHandler(w http.ResponseWriter, r *http.Request) *appError {
response, err := a.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", APPLICATION_JSON)
w.Write(b)
return nil
}
func (a *API) PortHandler(w http.ResponseWriter, r *http.Request) *appError {
vars := mux.Vars(r)
port, err := strconv.ParseUint(vars["port"], 10, 16)
if err != nil {
return badRequest(err).WithMessage("Invalid port: " + vars["port"]).AsJSON()
}
if port < 1 || port > 65355 {
return badRequest(nil).WithMessage("Invalid port: " + vars["port"]).AsJSON()
}
ip, err := a.ipFromRequest(r)
if err != nil {
return internalServerError(err).AsJSON()
}
err = a.oracle.LookupPort(ip, port)
response := TestPortResponse{
IP: ip,
Port: port,
Reachable: err == nil,
}
b, err := json.Marshal(response)
if err != nil {
return internalServerError(err).AsJSON()
}
w.Header().Set("Content-Type", APPLICATION_JSON)
w.Write(b)
return nil
}
func (a *API) DefaultHandler(w http.ResponseWriter, r *http.Request) *appError {
response, err := a.newResponse(r)
if err != nil {
return internalServerError(err)
}
t, err := template.New(filepath.Base(a.Template)).ParseFiles(a.Template)
if err != nil {
return internalServerError(err)
}
var data = struct {
Response
Oracle
}{response, a.oracle}
if err := t.Execute(w, &data); err != nil {
return internalServerError(err)
}
return nil
}
func (a *API) NotFoundHandler(w http.ResponseWriter, r *http.Request) *appError {
err := notFound(nil).WithMessage("404 page not found")
if r.Header.Get("accept") == APPLICATION_JSON {
err = err.AsJSON()
}
return err
}
func cliMatcher(r *http.Request, rm *mux.RouteMatch) bool {
return USER_AGENT_RE.MatchString(r.UserAgent())
}
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
if e.Error != nil {
log.Print(e.Error)
}
// 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)
io.WriteString(w, e.Message)
}
}
func (a *API) Handlers() http.Handler {
r := mux.NewRouter()
// JSON
r.Handle("/", appHandler(a.JSONHandler)).Methods("GET").Headers("Accept", APPLICATION_JSON)
r.Handle("/json", appHandler(a.JSONHandler)).Methods("GET")
// CLI
r.Handle("/", appHandler(a.CLIHandler)).Methods("GET").MatcherFunc(cliMatcher)
r.Handle("/ip", appHandler(a.CLIHandler)).Methods("GET").MatcherFunc(cliMatcher)
r.Handle("/country", appHandler(a.CLICountryHandler)).Methods("GET").MatcherFunc(cliMatcher)
r.Handle("/city", appHandler(a.CLICityHandler)).Methods("GET").MatcherFunc(cliMatcher)
// Browser
r.Handle("/", appHandler(a.DefaultHandler)).Methods("GET")
// Port testing
r.Handle("/port/{port:[0-9]+}", appHandler(a.PortHandler)).Methods("GET")
// Not found handler which returns JSON when appropriate
r.NotFoundHandler = appHandler(a.NotFoundHandler)
return r
}
func (a *API) ListenAndServe(addr string) error {
http.Handle("/", a.Handlers())
return http.ListenAndServe(addr, nil)
}
|
