1// Code in this file is based on net/http/httputil/reverseproxy.go from the Go

2// standard library, and covered by licenses/golang.org/x/sys/LICENSE.

3

4package http

5

6import (

7 "net/http"

8 "net/http/httputil"

9 "net/url"

10 "strings"

11)

12

13func newSingleHostReverseProxy(target *url.URL) *httputil.ReverseProxy {

14 director := func(req *http.Request) {

15 rewriteRequestURL(req, target)

16 }

17 return &httputil.ReverseProxy{Director: director}

18}

19

20func rewriteRequestURL(req *http.Request, target *url.URL) {

21 targetQuery := target.RawQuery

22 req.URL.Scheme = target.Scheme

23 req.URL.Host = target.Host

24 req.URL.Path, req.URL.RawPath = joinURLPath(target, req.URL)

25 if targetQuery == "" || req.URL.RawQuery == "" {

26 req.URL.RawQuery = targetQuery + req.URL.RawQuery

27 } else {

28 req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery

29 }

30}

31

32// Like in httputil, but we won't add a trailing slash if the original request did

33// not have one.

34func joinURLPath(a, b *url.URL) (path, rawpath string) {

35 if a.RawPath == "" && b.RawPath == "" {

36 return singleJoiningSlash(a.Path, b.Path), ""

37 }

38 // Same as singleJoiningSlash, but uses EscapedPath to determine

39 // whether a slash should be added

40 apath := a.EscapedPath()

41 bpath := b.EscapedPath()

42

43 aslash := strings.HasSuffix(apath, "/")

44 bslash := strings.HasPrefix(bpath, "/")

45

46 switch {

47 case aslash && bslash:

48 return a.Path + b.Path[1:], apath + bpath[1:]

49 case !aslash && !bslash && bpath != "":

50 return a.Path + "/" + b.Path, apath + "/" + bpath

51 }

52 return a.Path + b.Path, apath + bpath

53}

54

55func singleJoiningSlash(a, b string) string {

56 aslash := strings.HasSuffix(a, "/")

57 bslash := strings.HasPrefix(b, "/")

58 switch {

59 case aslash && bslash:

60 return a + b[1:]

61 case !aslash && !bslash && b != "":

62 return a + "/" + b

63 }

64 return a + b

65}

66