Setting up proxy for HTTP client - http

Question

I'm trying to setup the HTTP client so that it uses a proxy, however I cannot quite understand how to do it. The documentation has multiple reference to "proxy" but none of the functions seem to allow to define the proxy. What I need is something like this:
client := &http.Client{}
client.SetProxy("someip:someport") // pseudo code
resp, err := client.Get("http://example.com") // do request through proxy
Any idea how to do this in Go?

Answer 1

lukad is correct, you could set the HTTP_PROXY environment variable, if you do this Go will use it by default.
Bash:
export HTTP_PROXY="http://proxyIp:proxyPort"
Go:
os.Setenv("HTTP_PROXY", "http://proxyIp:proxyPort")
You could also construct your own http.Client that MUST use a proxy regardless of the environment's configuration:
proxyUrl, err := url.Parse("http://proxyIp:proxyPort")
myClient := &http.Client{Transport: &http.Transport{Proxy: http.ProxyURL(proxyUrl)}}
This is useful if you can not depend on the environment's configuration, or do not want to modify it.
You could also modify the default transport used by the "net/http" package. This would affect your entire program (including the default HTTP client).
proxyUrl, err := url.Parse("http://proxyIp:proxyPort")
http.DefaultTransport = &http.Transport{Proxy: http.ProxyURL(proxyUrl)}

Answer 2

Go will use the the proxy defined in the environment variable HTTP_PROXY if it's set. Otherwise it will use no proxy.
You could do it like this:
os.Setenv("HTTP_PROXY", "http://someip:someport")
resp, err := http.Get("http://example.com")
if err != nil {
panic(err)
}

Answer 3

May you could also try this:
url_i := url.URL{}
url_proxy, _ := url_i.Parse(proxy_addr)
transport := http.Transport{}
transport.Proxy = http.ProxyURL(url_proxy)// set proxy
transport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true} //set ssl
client := &http.Client{}
client.Transport = transport
resp, err := client.Get("http://example.com") // do request through proxy

Answer 4

The Go built-in proxy use is briefly documented in the DefaultTransport:
// DefaultTransport .... It uses HTTP proxies
// as directed by the $HTTP_PROXY and $NO_PROXY (or $http_proxy and
// $no_proxy) environment variables.
var DefaultTransport RoundTripper = &Transport{
Proxy: ProxyFromEnvironment,
This points to the usefulness of creating custom Transports from DefaultTransport vs. from scratch to take advantage of the built-in ProxyFromEnvironment function

Answer 5

If you run something like this:
HTTP_PROXY=89.x.y.z path_to_program
Then the HTTP_PROXY setting is set for that command only, which is useful if you don't want to set it for the whole shell session.
Note: there's no ; between the setting and the path; if you put a semicolon, it would set (but not export) HTTP_PROXY for that shell

Answer 6

For an alternative way, you can also use GoRequest which has a feature that you can set proxy easily for any single request.
request := gorequest.New()
resp, body, errs:= request.Proxy("http://proxy:999").Get("http://example.com").End()
resp2, body2, errs2 := request.Proxy("http://proxy2:999").Get("http://example2.com").End()
Or you can set for the whole at once.
request := gorequest.New().Proxy("http://proxy:999")
resp, body, errs:= request.Get("http://example.com").End()
resp2, body2, errs2 := request.Get("http://example2.com").End()