⭐️ manual client creation (with proxy) (#25)

* manual client creation (with proxy)

Keep DefaultHttpClient() the way it is, but introduce a new HttpClient()
that will allow specifying non-default values for the client.

Specifically, allow passing in a proxy string that will used for
connections.

Signed-off-by: Joel Diaz <[email protected]>

httpclient.go

@@ -3,6 +3,7 @@ package ranger
 import (
 	"net"
 	"net/http"
+	"net/url"
 	"time"
 )
 
@@ -12,9 +13,14 @@ var (
 	DefaultTLSHandshakeTimeout = 10 * time.Second
 )
 
-func DefaultHttpClient() *http.Client {
+func newHttpTransport(proxy *url.URL) *http.Transport {
+	proxyFn := http.ProxyFromEnvironment
+	if proxy != nil {
+		proxyFn = http.ProxyURL(proxy)
+	}
+
 	tr := &http.Transport{
-		Proxy: http.ProxyFromEnvironment,
+		Proxy: proxyFn,
 		DialContext: (&net.Dialer{
 			Timeout:   DefaultHttpTimeout,
 			KeepAlive: 30 * time.Second,
@@ -25,9 +31,40 @@ func DefaultHttpClient() *http.Client {
 		ExpectContinueTimeout: 1 * time.Second,
 	}
 
-	httpClient := &http.Client{
+	return tr
+}
+
+func newHttpClient(tr *http.Transport) *http.Client {
+	return &http.Client{
 		Transport: tr,
 		Timeout:   DefaultHttpTimeout,
 	}
-	return httpClient
+}
+
+// DefaultHttpClient will set up a basic client
+// with default timeouts/proxies/etc.
+func DefaultHttpClient() *http.Client {
+	tr := newHttpTransport(nil)
+
+	return newHttpClient(tr)
+}
+
+type HttpClientOpts struct {
+	// Proxy is the string representation of the proxy the client
+	// should use for connections.
+	Proxy string
+}
+
+func NewHttpClient(opts *HttpClientOpts) (*http.Client, error) {
+	var proxy *url.URL
+	if opts.Proxy != "" {
+		var err error
+		proxy, err = url.Parse(opts.Proxy)
+		if err != nil {
+			return nil, err
+		}
+	}
+	tr := newHttpTransport(proxy)
+
+	return newHttpClient(tr), nil
 }