telebit/internal/http01proxy/proxy.go

106 lines
3.0 KiB
Go

package http01proxy
import (
"net/http"
"net/http/httputil"
"net/url"
"strings"
"time"
)
// ListenAndServe will start the HTTP-01 proxy
func ListenAndServe(target string, timeout time.Duration) error {
target = strings.TrimSuffix(target, "/")
// TODO accept listener?
targetURL, err := url.Parse(target)
if nil != err {
panic(err)
}
//proxyHandler := httputil.NewSingleHostReverseProxy(targetURL)
proxyHandler := &httputil.ReverseProxy{
Director: func(req *http.Request) {
req.Header.Del("X-Forwarded-For")
req.Header.Del("X-Forwarded-Proto")
req.Header.Del("X-Forwarded-Host")
req.Header.Del("X-Forwarded-Port")
// We want the incoming host header to remain unchanged,
// which is the domain name that is being challenged
// This is the ORIGINAL req.Header.Host
//log.Printf("[debug] Incoming Host: %q", req.Host)
// This will always be an empty string ""
//log.Printf("[debug] Incoming URL.Host: %q", req.URL.Host)
// This will always be an empty string ""
//log.Printf("[debug] Incoming Header.Host: %q", req.Header.Get("Host"))
// This will become the HTTP Host header
//req.Host
targetQuery := targetURL.RawQuery
// This will change the scheme (http/s) used to connect to the target
req.URL.Scheme = targetURL.Scheme
//log.Printf("[debug] Target URL.Scheme: %q", req.URL.Scheme)
// This will change the network host target
// but will NOT change the HTTP Host header
req.URL.Host = targetURL.Host
//log.Printf("[debug] Target URL.Host: %q", req.URL.Host)
// This will add the target prefix to the original url
req.URL.Path, req.URL.RawPath = joinURLPath(targetURL, req.URL)
//log.Printf("[debug] Target URL.Path: %q", req.URL.Path)
//log.Printf("[debug] Target URL.RawPath: %q", req.URL.Path)
if targetQuery == "" || req.URL.RawQuery == "" {
req.URL.RawQuery = targetQuery + req.URL.RawQuery
} else {
req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
}
if _, ok := req.Header["User-Agent"]; !ok {
// explicitly disable User-Agent so it's not set to default value
req.Header.Set("User-Agent", "")
}
},
}
return http.ListenAndServe(":80", proxyHandler)
}
// Taken from https://golang.org/src/net/http/httputil/reverseproxy.go
func joinURLPath(a, b *url.URL) (path, rawpath string) {
if a.RawPath == "" && b.RawPath == "" {
return singleJoiningSlash(a.Path, b.Path), ""
}
// Same as singleJoiningSlash, but uses EscapedPath to determine
// whether a slash should be added
apath := a.EscapedPath()
bpath := b.EscapedPath()
aslash := strings.HasSuffix(apath, "/")
bslash := strings.HasPrefix(bpath, "/")
switch {
case aslash && bslash:
return a.Path + b.Path[1:], apath + bpath[1:]
case !aslash && !bslash:
return a.Path + "/" + b.Path, apath + "/" + bpath
}
return a.Path + b.Path, apath + bpath
}
func singleJoiningSlash(a, b string) string {
aslash := strings.HasSuffix(a, "/")
bslash := strings.HasPrefix(b, "/")
switch {
case aslash && bslash:
return a + b[1:]
case !aslash && !bslash:
return a + "/" + b
}
return a + b
}