add "check Validate" support

yggdrasil/validate.go

@@ -0,0 +1,21 @@
+package yggdrasil
+
+import "fmt"
+
+// Validate checks if an accessToken is usable for authentication with a Minecraft server.
+func (a *Access) Validate() (bool, error) {
+	pl := struct {
+		AccessToken string `json:"accessToken"`
+		ClientToken string `json:"clientToken"`
+	}{
+		AccessToken: a.ar.AccessToken,
+		ClientToken: a.ar.ClientToken,
+	}
+
+	resp, err := rowPost("/validate", pl)
+	if err != nil {
+		return false, fmt.Errorf("request fail: %v", err)
+	}
+
+	return resp.StatusCode == 204, resp.Body.Close()
+}