這是我的用例我們有一個服務(wù)“foobar”，它有兩個版本legacy 和version_2_of_doom （都在運行中）為了進行從legacy到的轉(zhuǎn)換version_2_of_doom，我們希望第一次將兩個版本放在一起，并在兩個版本上都收到 POST 請求（因為這里只有一個 POST api 調(diào)用）。我看到如何去做的方式。將是修改legacy 處理程序開頭的代碼，以便將請求復(fù)制到version_2_of_doom func(w http.ResponseWriter, req *http.Request) { req.URL.Host = "v2ofdoom.local:8081" req.Host = "v2ofdoom.local:8081" client := &http.Client{} client.Do(req) // legacy code 但似乎沒有這么簡單它失敗了 http: Request.RequestURI can't be set in client requests.是否有一種眾所周知的方法來執(zhí)行這種操作（即在不接觸的情況下傳輸）ahttp.Request到其他服務(wù)器？
3 回答
慕妹3146593
TA貢獻1820條經(jīng)驗 獲得超9個贊
您需要將所需的值復(fù)制到新請求中。由于這與反向代理的作用非常相似，您可能需要查看“net/http/httputil”對ReverseProxy.
創(chuàng)建一個新請求，并僅復(fù)制要發(fā)送到下一個服務(wù)器的請求部分。如果您打算在兩個地方使用它，您還需要讀取和緩沖請求正文：
func handler(w http.ResponseWriter, req *http.Request) {
// we need to buffer the body if we want to read it here and send it
// in the request.
body, err := ioutil.ReadAll(req.Body)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
// you can reassign the body if you need to parse it as multipart
req.Body = ioutil.NopCloser(bytes.NewReader(body))
// create a new url from the raw RequestURI sent by the client
url := fmt.Sprintf("%s://%s%s", proxyScheme, proxyHost, req.RequestURI)
proxyReq, err := http.NewRequest(req.Method, url, bytes.NewReader(body))
// We may want to filter some headers, otherwise we could just use a shallow copy
// proxyReq.Header = req.Header
proxyReq.Header = make(http.Header)
for h, val := range req.Header {
proxyReq.Header[h] = val
}
resp, err := httpClient.Do(proxyReq)
if err != nil {
http.Error(w, err.Error(), http.StatusBadGateway)
return
}
defer resp.Body.Close()
// legacy code
}
狐的傳說
TA貢獻1804條經(jīng)驗 獲得超3個贊
根據(jù)我的經(jīng)驗，實現(xiàn)這一點的最簡單方法是簡單地創(chuàng)建一個新請求并將您需要的所有請求屬性復(fù)制到新的請求對象中：
func(rw http.ResponseWriter, req *http.Request) {
url := req.URL
url.Host = "v2ofdoom.local:8081"
proxyReq, err := http.NewRequest(req.Method, url.String(), req.Body)
if err != nil {
// handle error
}
proxyReq.Header.Set("Host", req.Host)
proxyReq.Header.Set("X-Forwarded-For", req.RemoteAddr)
for header, values := range req.Header {
for _, value := range values {
proxyReq.Header.Add(header, value)
}
}
client := &http.Client{}
proxyRes, err := client.Do(proxyReq)
// and so on...
這種方法的好處是不修改原始請求對象（也許您的處理程序函數(shù)或存在于堆棧中的任何中間件函數(shù)仍然需要原始對象？）。
明月笑刀無情
TA貢獻1828條經(jīng)驗 獲得超4個贊
使用原始請求（僅在原始請求仍需要時才復(fù)制或復(fù)制）：
func handler(w http.ResponseWriter, r *http.Request) {
// Step 1: rewrite URL
URL, _ := url.Parse("https://full_generic_url:123/x/y")
r.URL.Scheme = URL.Scheme
r.URL.Host = URL.Host
r.URL.Path = singleJoiningSlash(URL.Path, r.URL.Path)
r.RequestURI = ""
// Step 2: adjust Header
r.Header.Set("X-Forwarded-For", r.RemoteAddr)
// note: client should be created outside the current handler()
client := &http.Client{}
// Step 3: execute request
resp, err := client.Do(r)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
// Step 4: copy payload to response writer
copyHeader(w.Header(), resp.Header)
w.WriteHeader(resp.StatusCode)
io.Copy(w, resp.Body)
resp.Body.Close()
}
// copyHeader and singleJoiningSlash are copy from "/net/http/httputil/reverseproxy.go"
func copyHeader(dst, src http.Header) {
for k, vv := range src {
for _, v := range vv {
dst.Add(k, v)
}
}
}
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
}
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