为什么httputil.NewSingleHostReverseProxy会在某些www站点上导致错误?
在以下示例中:为什么httputil.NewSingleHostReverseProxy会在某些www站点上导致错误?,http,go,reverse-proxy,Http,Go,Reverse Proxy,在以下示例中: package main import ( "fmt" "log" "net/http" "net/http/httputil" "net/url" ) func main() { p := new(Proxy) //host := "www.google.com" // WORKS AS EXPECTED host := "www.apple.com" // GIVES AN ERROR u, err
package main
import (
"fmt"
"log"
"net/http"
"net/http/httputil"
"net/url"
)
func main() {
p := new(Proxy)
//host := "www.google.com" // WORKS AS EXPECTED
host := "www.apple.com" // GIVES AN ERROR
u, err := url.Parse(fmt.Sprintf("http://%v/", host))
if err != nil {
log.Printf("Error parsing URL")
}
p.proxy = httputil.NewSingleHostReverseProxy(u)
http.Handle("/", p)
log.Fatal(http.ListenAndServe("localhost:8000", nil))
}
type Proxy struct {
proxy *httputil.ReverseProxy
}
func (p *Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
p.proxy.ServeHTTP(w, r)
}
将“www.google.com”替换为“www.apple.com”会在将Chrome指向“localhost:8000”时导致此错误:
无效的URL
请求的URL“/”无效。
参考#9.a61a32b8.143823668.41733295
在www.apple.com上再做一点挖掘,我得到:
➜ ~ curl --ipv4 -v localhost:8000
< HTTP/1.1 400 Bad Request
< Content-Length: 194
< Content-Type: text/html
< Date: Thu, 30 Jul 2015 05:20:38 GMT
< Expires: Thu, 30 Jul 2015 05:20:38 GMT
< Mime-Version: 1.0
* Server AkamaiGHost is not blacklisted
< Server: AkamaiGHost
<
<HTML><HEAD>
<TITLE>Invalid URL</TITLE>
</HEAD><BODY>
<H1>Invalid URL</H1>
The requested URL "/", is invalid.<p>
Reference #9.65b454b8.1438233638.1f1b8a40
</BODY></HTML>
* Connection #0 to host localhost left intact
➜ ~ curl—ipv4-v本地主机:8000
对于www.google.com:
➜ ~ curl --ipv4 -v localhost:8000
< HTTP/1.1 302 Found
< Alternate-Protocol: 80:quic,p=0
< Cache-Control: private
< Content-Length: 219
< Content-Type: text/html; charset=UTF-8
< Date: Thu, 30 Jul 2015 05:03:16 GMT
< Location: http://www.google.com/
* Server sffe is not blacklisted
< Server: sffe
< X-Content-Type-Options: nosniff
< X-Xss-Protection: 1; mode=block
<
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="http://www.google.com/">here</A>.
</BODY></HTML>
* Connection #0 to host localhost left intact
➜ ~ curl—ipv4-v本地主机:8000
找到
现在,当我使用“apple.com”而不是“www.apple.com”时,一切正常:
➜ ~ curl --ipv4 -v localhost:8000
< HTTP/1.1 301 Moved Permanently
< Content-Type: text/html
< Date:
< Location: http://www.apple.com/
< Referer:
* Server is not blacklisted
< Server:
< Content-Length: 0
<
* Connection #0 to host localhost left intact
➜ ~ curl—ipv4-v本地主机:8000
发生了什么事?这里的问题是;您连接到的某些网站不知道您请求的域(即Host
HTTP头字段设置为localhost:8000
,而不是www.apple.com
)。要解决此问题,反向代理必须重写主机头
不幸的是,httputil.NewSingleHostReverseProxy
没有提供一种简单的重写方法,因此我在下面添加的大部分内容都是从
你发布的代码甚至无法编译。请发布一个工作示例。编写自己的示例是正确的解决方案。“但是NewSingleHostReverseProxy只是一个很小的示例函数,展示了如何使用ReverseProxy。如果您想要不同的行为,您可以编写自己的控制器函数。”-BradFitz
package main
import (
"fmt"
"log"
"net/http"
"net/http/httputil"
"net/url"
"strings"
)
func main() {
host := "www.apple.com"
u, err := url.Parse(fmt.Sprintf("http://%v/", host))
if err != nil {
log.Printf("Error parsing URL")
}
targetQuery := u.RawQuery
p := &httputil.ReverseProxy{
Director: func(req *http.Request) {
req.Host = host
req.URL.Scheme = u.Scheme
req.URL.Host = u.Host
req.URL.Path = singleJoiningSlash(u.Path, req.URL.Path)
if targetQuery == "" || req.URL.RawQuery == "" {
req.URL.RawQuery = targetQuery + req.URL.RawQuery
} else {
req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
}
},
}
http.Handle("/", p)
log.Fatal(http.ListenAndServe("localhost:8000", nil))
}
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
}