From bd8904c07514efad75764538034b9c2d64a16f7b Mon Sep 17 00:00:00 2001
From: Andrey Zverev <andrey.zverev@sbermarket.ru>
Date: Mon, 11 Dec 2023 22:22:24 +0300
Subject: [PATCH] Implement WithJsonMarshalFunc which allow us to implement own
 Marshal function

---
 client.go  | 14 ++++++++++++++
 request.go | 15 ++++++++++++---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/client.go b/client.go
index cd0325c..ada4889 100644
--- a/client.go
+++ b/client.go
@@ -22,6 +22,9 @@ type Client struct {
 	HttpClient       *http.Client
 	HttpRetryTimeout time.Duration
 
+	// Store custom JSON Unmarshal function
+	jsonMarshalFunc JsonMarshalFunc
+
 	// Option to specify extra headers like User-Agent
 	ExtraHeader map[string]string
 }
@@ -42,8 +45,19 @@ type FormOptions struct {
 	GrantType    string `url:"grant_type"`
 }
 
+type JsonMarshalFunc func(v any) ([]byte, error)
+
 type Option func(*Client)
 
+// WithJsonMarshalFunc allow override (encoding/json) json.Marshal function with own implementation
+// while keep original function signature.
+func WithJsonMarshalFunc(f JsonMarshalFunc) Option {
+	return func(c *Client) {
+		c.jsonMarshalFunc = f
+
+	}
+}
+
 // WithHttpClient sets the http client to use for requests
 func WithHttpClient(client *http.Client) Option {
 	return func(c *Client) {
diff --git a/request.go b/request.go
index b858eb8..c0e3be4 100644
--- a/request.go
+++ b/request.go
@@ -177,9 +177,18 @@ func (c *Client) createRequest(method, api string, params *url.Values, reqbody i
 			}
 			bodyReader = strings.NewReader(b.Encode())
 		} else {
-			b, err := json.Marshal(reqbody)
-			if err != nil {
-				return nil, err
+			var b []byte
+			var err error
+			if c.jsonMarshalFunc == nil {
+				b, err = json.Marshal(reqbody)
+				if err != nil {
+					return nil, err
+				}
+			} else {
+				b, err = c.jsonMarshalFunc(reqbody)
+				if err != nil {
+					return nil, err
+				}
 			}
 			bodyReader = bytes.NewReader(b)
 		}