allow to configure a client using var arg options

client_option.go

@@ -0,0 +1,15 @@
+package getter
+
+// A ClientOption allows to configure a client
+type ClientOption func(*Client) error
+
+// Configure configures a client with options.
+func (c *Client) Configure(opts ...ClientOption) error {
+	for _, opt := range opts {
+		err := opt(c)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

get.go

@@ -74,13 +74,17 @@ func init() {
 //
 // src is a URL, whereas dst is always just a file path to a folder. This
 // folder doesn't need to exist. It will be created if it doesn't exist.
-func Get(dst, src string) error {
-	return (&Client{
+func Get(dst, src string, opts ...ClientOption) error {
+	c := &Client{
 		Src:     src,
 		Dst:     dst,
 		Dir:     true,
 		Getters: Getters,
-	}).Get()
+	}
+	if err := c.Configure(opts...); err != nil {
+		return err
+	}
+	return c.Get()
 }
 
 // GetAny downloads a URL into the given destination. Unlike Get or
@@ -89,24 +93,32 @@ func Get(dst, src string) error {
 // dst must be a directory. If src is a file, it will be downloaded
 // into dst with the basename of the URL. If src is a directory or
 // archive, it will be unpacked directly into dst.
-func GetAny(dst, src string) error {
-	return (&Client{
+func GetAny(dst, src string, opts ...ClientOption) error {
+	c := &Client{
 		Src:     src,
 		Dst:     dst,
 		Mode:    ClientModeAny,
 		Getters: Getters,
-	}).Get()
+	}
+	if err := c.Configure(opts...); err != nil {
+		return err
+	}
+	return c.Get()
 }
 
 // GetFile downloads the file specified by src into the path specified by
 // dst.
-func GetFile(dst, src string) error {
-	return (&Client{
+func GetFile(dst, src string, opts ...ClientOption) error {
+	c := &Client{
 		Src:     src,
 		Dst:     dst,
 		Dir:     false,
 		Getters: Getters,
-	}).Get()
+	}
+	if err := c.Configure(opts...); err != nil {
+		return err
+	}
+	return c.Get()
 }
 
 // getRunCommand is a helper that will run a command and capture the output