Config holds configuration for HTTP proxy settings. See FromEnvironment for details.
type Config struct {
// HTTPProxy represents the value of the HTTP_PROXY or
// http_proxy environment variable. It will be used as the proxy
// URL for HTTP requests and HTTPS requests unless overridden by
// HTTPSProxy or NoProxy.
HTTPProxy string
// HTTPSProxy represents the HTTPS_PROXY or https_proxy
// environment variable. It will be used as the proxy URL for
// HTTPS requests unless overridden by NoProxy.
HTTPSProxy string
// NoProxy represents the NO_PROXY or no_proxy environment
// variable. It specifies a string that contains comma-separated values
// specifying hosts that should be excluded from proxying. Each value is
// represented by an IP address prefix (1.2.3.4), an IP address prefix in
// CIDR notation (1.2.3.4/8), a domain name, or a special DNS label (*).
// An IP address prefix and domain name can also include a literal port
// number (1.2.3.4:80).
// A domain name matches that name and all subdomains. A domain name with
// a leading "." matches subdomains only. For example "foo.com" matches
// "foo.com" and "bar.foo.com"; ".y.com" matches "x.y.com" but not "y.com".
// A single asterisk (*) indicates that no proxying should be done.
// A best effort is made to parse the string and errors are
// ignored.
NoProxy string
// CGI holds whether the current process is running
// as a CGI handler (FromEnvironment infers this from the
// presence of a REQUEST_METHOD environment variable).
// When this is set, ProxyForURL will return an error
// when HTTPProxy applies, because a client could be
// setting HTTP_PROXY maliciously. See https://golang.org/s/cgihttpproxy.
CGI bool
}
func FromEnvironment() *Config
FromEnvironment returns a Config instance populated from the environment variables HTTP_PROXY, HTTPS_PROXY and NO_PROXY (or the lowercase versions thereof). HTTPS_PROXY takes precedence over HTTP_PROXY for https requests.
The environment values may be either a complete URL or a "host[:port]", in which case the "http" scheme is assumed. An error is returned if the value is a different form.
func (cfg *Config) ProxyFunc() func(reqURL *url.URL) (*url.URL, error)
ProxyFunc returns a function that determines the proxy URL to use for a given request URL. Changing the contents of cfg will not affect proxy functions created earlier.
A nil URL and nil error are returned if no proxy is defined in the environment, or a proxy should not be used for the given request, as defined by NO_PROXY.
As a special case, if req.URL.Host is "localhost" (with or without a port number), then a nil URL and nil error will be returned.