使用自定义传输时，如何编程去使用代理？

您可以使用 http.ProxyFromEnvironment 方法

  var PTransport = & http.Transport { Proxy: http.ProxyFromEnvironment }  client: = http.Client { Transport: PTransport }

ProxyFromEnvironment返回用于给定请求的代理的URL，如环境变量HTTP_PROXY，HTTPS_PROXY和NO_PROXY（或其小写版本）所指示。对于HTTPS请求，HTTPS_PROXY优先于HTTP_PROXY。

我试过下面的代码，它的工作原理，只需在终端中添加您的代理详细信息。

export http_proxy='http://user:password@prox-server:3128'export https_proxy='http://user:password@prox-server:3128'export HTTP_PROXY='http://user:password@prox-server:3128'export HTTPS_PROXY='http://user:password@prox-server:3128'package mainimport (  "fmt"  "net/http"  "io/ioutil")func main() {  var PTransport = & http.Transport {    Proxy: http.ProxyFromEnvironment  }  client: = http.Client {    Transport: PTransport  }  req, err: = http.NewRequest("GET", "https://jsonplaceholder.typipre.com/todos/1", nil)  req.Header.Add("If-None-Match", `some value`)  resp, err: = client.Do(req)  if err != nil {    panic(err)  }  defer resp.Body.Close()  bodyBytes, err: = ioutil.ReadAll(resp.Body)  if err != nil {    panic(err)  }  bodyString: = string(bodyBytes)  fmt.Printf("GET Response = %s n", string(bodyString))}