I am trying to have a reverse proxy in Golang, but I am unable to stop target ip from showing in browser ie. it is simply redirecting to wikipedia (target) rather than showing doing reverseproxy.
Can anyone tell what I am doing wrong?
package main
import (
"net/http"
"net/http/httputil"
"net/url"
"github.com/gorilla/mux"
)
func main() {
target := "https://www.wikipedia.org"
remote, err := url.Parse(target)
if err != nil {
panic(err)
}
proxy := httputil.NewSingleHostReverseProxy(remote)
r := mux.NewRouter()
r.HandleFunc("/forward/{rest:.*}", handler(remote, proxy))
http.ListenAndServe(":8080", r)
}
func handler(ur *url.URL, p *httputil.ReverseProxy) func(http.ResponseWriter, *http.Request) {
return func(w http.ResponseWriter, r *http.Request) {
r.URL.Host = ur.Host
r.URL.Scheme = ur.Scheme
r.Host = ur.Host
r.URL.Path = mux.Vars(r)["rest"]
p.ServeHTTP(w, r)
}
}
Related
I am using a basic wrapper in a web application like this:
package main
import (
"fmt"
"log"
"net/http"
"os"
"github.com/gorilla/mux"
"github.com/gorilla/sessions"
)
const (
PORT = "8083"
)
func navbarWrapper(h http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, "header")
h(w, r) // call original function
fmt.Fprintln(w, "footer")
}
}
func main() {
r := mux.NewRouter()
r.HandleFunc("/cookie_write", navbarWrapper(cookie_write))
hostname, _ := os.Hostname()
log.Printf("Listening on port %s https://%s:%s/", PORT, hostname, PORT)
http.ListenAndServe(":"+PORT, r)
}
I would like to set a cookie, but it is not being sent to the browser, but is also not providing an error
var (
key = []byte("16bytestufffffff")
store = sessions.NewCookieStore(key)
)
func cookie_write(w http.ResponseWriter, r *http.Request) {
session, _ := store.Get(r, "session-name")
session.Values["authenticated"] = true
session.Values["stuff"] = "important info"
if err := session.Save(r, w); err != nil {
fmt.Println(err)
fmt.Println("error")
} else {
fmt.Println("worked?")
}
}
If I remove the wrapper, then it works fine and I can see the cookie being generated in the browser:
r.HandleFunc("/cookie_write", cookie_write)
I know I must not be saving the session correctly, but I can't figure out how to do it.
Any mistakes in below code? Multiple directory serving is not working from the below code. When I access the localhost:9090/ide, the server will return 404 error.
package main
import (
"log"
"net/http"
)
func serveIDE(w http.ResponseWriter, r *http.Request) {
http.FileServer(http.Dir("/home/user/ide")).ServeHTTP(w, r)
}
func serveConsole(w http.ResponseWriter, r *http.Request) {
http.FileServer(http.Dir("/home/user/console")).ServeHTTP(w, r)
}
func main() {
http.HandleFunc("/ide", serveIDE)
http.HandleFunc("/console", serveConsole)
err := http.ListenAndServe(":9090", nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
When I change the code like this,
http.HandleFunc("/", serveIDE)
It will work as I expected.
One of the issues with using http.FileServer is that the request path is used to build the file name, so if you're serving from anywhere but the root you need to strip the route prefix to that handler.
The standard library includes a helpful tool for that http.StripPrefix, but that only works on http.Handlers, not http.HandleFuncs, so to use it you need to adapt your HandleFunc to a Handler.
Here is a working version that should do what you want. Note that wHandler is just an adapter from your HttpFunc methods to Hander interface:
package main
import (
"log"
"net/http"
)
func serveIDE(w http.ResponseWriter, r *http.Request) {
http.FileServer(http.Dir("/home/user/ide")).ServeHTTP(w, r)
}
func serveConsole(w http.ResponseWriter, r *http.Request) {
http.FileServer(http.Dir("/home/user/console")).ServeHTTP(w, r)
}
type wHandler struct {
fn http.HandlerFunc
}
func (h *wHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
log.Printf("Handle request: %s %s", r.Method, r.RequestURI)
defer log.Printf("Done with request: %s %s", r.Method, r.RequestURI)
h.fn(w, r)
}
func main() {
http.Handle("/ide", http.StripPrefix("/ide", &wHandler{fn: serveIDE}))
http.Handle("/console", http.StripPrefix("/console", &wHandler{fn: serveConsole}))
err := http.ListenAndServe(":9090", nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
I have put up TLS and it works. I know how to rewrite from http to https in nginx, but I do not use nginx anymore. I don't know how to do this in Go properly.
func main() {
certificate := "/srv/ssl/ssl-bundle.crt"
privateKey := "/srv/ssl/mykey.key"
http.HandleFunc("/", rootHander)
// log.Fatal(http.ListenAndServe(":80", nil))
log.Fatal(http.ListenAndServeTLS(":443", certificate, privateKey, nil))
}
func rootHander(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("To the moon!"))
}
How would I do this in a good way?
Create a handler which handles redirection to https like:
func redirectToTls(w http.ResponseWriter, r *http.Request) {
http.Redirect(w, r, "https://IPAddr:443"+r.RequestURI, http.StatusMovedPermanently)
}
Then redirect http traffic:
go func() {
if err := http.ListenAndServe(":80", http.HandlerFunc(redirectToTls)); err != nil {
log.Fatalf("ListenAndServe error: %v", err)
}
}()
The solutions posted above are a little inflexible, especially if the external hostname is different from the local host.
Here is the code I use for HTTP->HTTPS redirects:
package main
import (
"net"
"log"
"net/http"
)
var httpAddr ":8080"
var httpsAddr ":8443"
func main() {
srv := http.Server{
Addr: httpsAddr,
}
_, tlsPort, err := net.SplitHostPort(httpsAddr)
if err != nil {
return err
}
go redirectToHTTPS(tlsPort)
srv.ListenAndServeTLS("cert.pem", "key.pem")
}
func redirectToHTTPS(tlsPort string) {
httpSrv := http.Server{
Addr: httpAddr,
Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request){
host, _, _ := net.SplitHostPort(r.Host)
u := r.URL
u.Host = net.JoinHostPort(host, tlsPort)
u.Scheme="https"
log.Println(u.String())
http.Redirect(w,r,u.String(), http.StatusMovedPermanently)
}),
}
log.Println(httpSrv.ListenAndServe())
}
If you are using standard ports (80,443) the splitting of joining of the adresses is not rquired and just setting the scheme on the URL is sufficient.
package main
import (
"fmt"
"net/http"
)
func redirectToHttps(w http.ResponseWriter, r *http.Request) {
// Redirect the incoming HTTP request. Note that "127.0.0.1:443" will only work if you are accessing the server from your local machine.
http.Redirect(w, r, "https://127.0.0.1:443"+r.RequestURI, http.StatusMovedPermanently)
}
func handler(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "Hi there!")
fmt.Println(r.RequestURI)
}
func main() {
http.HandleFunc("/", handler)
// Start the HTTPS server in a goroutine
go http.ListenAndServeTLS(":443", "cert.pem", "key.pem", nil)
// Start the HTTP server and redirect all incoming connections to HTTPS
http.ListenAndServe(":8080", http.HandlerFunc(redirectToHttps))
}
There is another great example and discussion here if you are using your own mux:
https://gist.github.com/d-schmidt/587ceec34ce1334a5e60
I want to create global err handler to send it by email.
package main
import (
"github.com/gorilla/mux"
"log"
"net/http"
)
func main() {
rtr := mux.NewRouter()
rtr.HandleFunc("/", withPanic).Methods("GET")
http.Handle("/", rtr)
log.Println("Listening...")
http.ListenAndServe(":3001", http.DefaultServeMux)
}
func withPanic(w http.ResponseWriter, r *http.Request) {
panic("somewhere here will be panic, but I don't know where exactly")
}
How to make it global. It would be easy if I know where error will occur
if err != nil {
sendMeMail(err)
}
But what to do in cases when I don't know exactly where an error will occur? So I should add a global recoverish handler. But how to do it exactly I don't know.
Update
I added defer recover to beginning of main but it never executes on requesting http://localhost:3001. So panic is not emailed.
package main
import (
"errors"
"fmt"
"github.com/gorilla/mux"
"log"
"net/http"
)
func main() {
defer func() {
if r := recover(); r != nil {
fmt.Println("Recovered in f", r)
// find out exactly what the error was and set err
var err error
switch x := r.(type) {
case string:
err = errors.New(x)
case error:
err = x
default:
err = errors.New("Unknown panic")
}
if err != nil {
// sendMeMail(err)
fmt.Println("sendMeMail")
}
}
}()
rtr := mux.NewRouter()
rtr.HandleFunc("/", withPanic).Methods("GET")
http.Handle("/", rtr)
log.Println("Listening...")
http.ListenAndServe(":3001", http.DefaultServeMux)
}
func withPanic(w http.ResponseWriter, r *http.Request) {
panic("somewhere here will be panic, but I don't know where exactly")
}
You can wrap your handlers in a recovery middleware
package main
import (
"errors"
"github.com/gorilla/mux"
"log"
"net/http"
)
func main() {
m := mux.NewRouter()
m.Handle("/", RecoverWrap(http.HandlerFunc(handler))).Methods("GET")
http.Handle("/", m)
log.Println("Listening...")
http.ListenAndServe(":3001", nil)
}
func handler(w http.ResponseWriter, r *http.Request) {
panic(errors.New("panicing from error"))
}
func RecoverWrap(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
defer func() {
r := recover()
if r != nil {
var err error
switch t := r.(type) {
case string:
err = errors.New(t)
case error:
err = t
default:
err = errors.New("Unknown error")
}
sendMeMail(err)
http.Error(w, err.Error(), http.StatusInternalServerError)
}
}()
h.ServeHTTP(w, r)
})
}
func sendMeMail(err error) {
// send mail
}
You can take a a look at codahale recovery handler or negroni middleware for more details.
I believe that is what the gorilla recovery handler is for
I can not get the gorilla mux to work..
When requesting http://www.localhost:9000 this is returned by the web server 404 page not found
But this works http://localhost:9000/ and prints Hello world
package main
import (
"net/http"
"fmt"
"log"
"github.com/gorilla/mux"
)
func Handler(w http.ResponseWriter, r *http.Request){
fmt.Fprint(w, "Hello world")
}
func main(){
r := mux.NewRouter()
r.Host("www.localhost")
r.HandleFunc("/", Handler)
err := http.ListenAndServe(":9000", r)
if err != nil {
log.Fatal("ListenAndServe error: ", err)
}
}
You want to be able to support both localhost and www.localhost
package main
import (
"fmt"
"log"
"net/http"
"github.com/gorilla/mux"
)
func Handler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, "Hello world")
}
func main() {
r := mux.NewRouter()
r.Host("www.localhost").Path("/").HandlerFunc(Handler)
r.HandleFunc("/", Handler)
err := http.ListenAndServe(":9000", r)
if err != nil {
log.Fatal("ListenAndServe error: ", err)
}
}
If you read the documentation carefully, you'll notice that r.Host() is just another pattern matching function. It doesn't set any global rule for that router.
if you want to make that rule to be inherited you'll need to use a subrouter:
subrouter := r.Host("www.localhost").Subrouter()
then you use "subrouter" in place of "r"