使用身份验证进行HTTP代理

Question

I need to use a proxy with auth using PostForm method. If I use something like (simplified):

request, err := http.NewRequest("GET", url.String(), nil)
response, err := client.Do(request)

I can with ease do request.Header.Add("Proxy-Authorization", basicAuth) and it works fine. But now, I am editing third-party package, and I try to add proxy to the existing code:

    proxyStr := "http://proxy.com:8080"
    proxyURL, _ := url.Parse(proxyStr)

    transport := &http.Transport{
        Proxy: http.ProxyURL(proxyURL),
    }
    bot.Client = &http.Client{
        Transport: transport,
    }

    resp, err := bot.Client.PostForm(method, params)

    auth := "username:password"
    basicAuth := "Basic " + base64.StdEncoding.EncodeToString([]byte(auth)) 
    resp.Header.Add("Proxy-Authorization", basicAuth)

It does not work, and it fails, to my mind, at string resp.Header.Add("Proxy-Authorization", basicAuth). Proxy without auth works fine, in this example. Does anybody know, can I use proxy with auth in this case?

Answer 1

You are trying to add a header to a response, which isn't what you send to the server but what you receive. You have to add headers and data to the request, which you have to assemble first and then execute it like this:

data := url.Values{} // the form data
data.Add("foo-key", "some data")
req, err := http.NewRequest("POST","https://yoururl", strings.NewReader(data.Encode()))
auth := "username:password"
basicAuth := "Basic " + base64.StdEncoding.EncodeToString([]byte(auth))
req.Header.Add("Proxy-Authorization", basicAuth)
req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
resp, err := bot.Client.Do(req)

Then you just use the response (resp)