Golang：我可以删除来​​自ReverseProxy的响应头吗？

Question

我正在使用httputil.ReverseProxy将Amazon s3文件代理到我的客户端。我想隐藏所有来自亚马逊的标题 - 这是否可能而不必重新实现反向代理？

proxy := httputil.ReverseProxy{Director: func(r *http.Request) {
    r.Header = http.Header{} // Don't send client's request headers to Amazon.
    r.URL = proxyURL
    r.Host = proxyURL.Host
}}
proxy.ServeHTTP(w, r) // How do I remove w.Headers ?

Answer 1

您可以实施ReverseProxy.Transport

type MyTransport struct{
    header http.Header
}
func (t MyTransport) RoundTrip(r *Request) (*Response, error){
    resp, err := http.DefaultTransport.RoundTrip(r)
    resp.Header = t.header
    return resp, err
}
mytransport := MyTransport{
//construct Header
}
proxy := httputil.ReverseProxy{Director: func(r *http.Request) {
    r.Header = http.Header{} // Don't send client's request headers to Amazon.
    r.URL = proxyURL
    r.Host = proxyURL.Host
  },
  Transport: mytransport,
}

Answer 2

这是我删除/替换所有http.ReverseProxy响应头的解决方案：

type responseHeadersTransport http.Header

func (t responseHeadersTransport) RoundTrip(r *http.Request) (*http.Response, error) {
    resp, err := http.DefaultTransport.RoundTrip(r)
    if err != nil {
        return nil, err
    }
    resp.Header = http.Header(t)
    return resp, nil
}


func ProxyFile(w http.ResponseWriter, r *http.Request) {
    // ...

    headers := http.Header{}
    headers.Set("Content-Type", file.ContentType)
    headers.Set("Content-Length", fmt.Sprintf("%d", file.Filesize))
    headers.Set("Content-Disposition", fmt.Sprintf("inline; filename=\"%s\"", file.Filename))

    proxy := httputil.ReverseProxy{
        Director: func(r *http.Request) { // Remove request headers.
            r.Header = http.Header{}
            r.URL = proxyURL
            r.Host = proxyURL.Host
        },
        Transport: responseHeadersTransport(headers), // Replace response headers.
    }
    proxy.ServeHTTP(w, r)
}