feat: custom JSON marshal/unmarshal functions (#1162)

components.go

@@ -70,7 +70,7 @@ type ActionsRow struct {
 func (r ActionsRow) MarshalJSON() ([]byte, error) {
 	type actionsRow ActionsRow
 
-	return json.Marshal(struct {
+	return Marshal(struct {
 		actionsRow
 		Type ComponentType `json:"type"`
 	}{
@@ -145,7 +145,7 @@ func (b Button) MarshalJSON() ([]byte, error) {
 		b.Style = PrimaryButton
 	}
 
-	return json.Marshal(struct {
+	return Marshal(struct {
 		button
 		Type ComponentType `json:"type"`
 	}{
@@ -192,7 +192,7 @@ func (SelectMenu) Type() ComponentType {
 func (m SelectMenu) MarshalJSON() ([]byte, error) {
 	type selectMenu SelectMenu
 
-	return json.Marshal(struct {
+	return Marshal(struct {
 		selectMenu
 		Type ComponentType `json:"type"`
 	}{
@@ -222,7 +222,7 @@ func (TextInput) Type() ComponentType {
 func (m TextInput) MarshalJSON() ([]byte, error) {
 	type inputText TextInput
 
-	return json.Marshal(struct {
+	return Marshal(struct {
 		inputText
 		Type ComponentType `json:"type"`
 	}{

restapi.go

@@ -39,6 +39,13 @@ var (
 	ErrUnauthorized            = errors.New("HTTP request was unauthorized. This could be because the provided token was not a bot token. Please add \"Bot \" to the start of your token. https://discord.com/developers/docs/reference#authentication-example-bot-token-authorization-header")
 )
 
+var (
+	// Marshal defines function used to encode JSON payloads
+	Marshal func(v interface{}) ([]byte, error) = json.Marshal
+	// Unmarshal defines function used to decode JSON payloads
+	Unmarshal func(src []byte, v interface{}) error = json.Unmarshal
+)
+
 // RESTError stores error information about a request with a bad response code.
 // Message is not always present, there are cases where api calls can fail
 // without returning a json message.
@@ -60,7 +67,7 @@ func newRestError(req *http.Request, resp *http.Response, body []byte) *RESTErro
 
 	// Attempt to decode the error and assume no message was provided if it fails
 	var msg *APIErrorMessage
-	err := json.Unmarshal(body, &msg)
+	err := Unmarshal(body, &msg)
 	if err == nil {
 		restErr.Message = msg
 	}
@@ -94,7 +101,7 @@ func (s *Session) Request(method, urlStr string, data interface{}) (response []b
 func (s *Session) RequestWithBucketID(method, urlStr string, data interface{}, bucketID string) (response []byte, err error) {
 	var body []byte
 	if data != nil {
-		body, err = json.Marshal(data)
+		body, err = Marshal(data)
 		if err != nil {
 			return
 		}
@@ -193,7 +200,7 @@ func (s *Session) RequestWithLockedBucket(method, urlStr, contentType string, b
 		}
 	case 429: // TOO MANY REQUESTS - Rate limiting
 		rl := TooManyRequests{}
-		err = json.Unmarshal(response, &rl)
+		err = Unmarshal(response, &rl)
 		if err != nil {
 			s.log(LogError, "rate limit unmarshal error, %s", err)
 			return
@@ -225,7 +232,7 @@ func (s *Session) RequestWithLockedBucket(method, urlStr, contentType string, b
 }
 
 func unmarshal(data []byte, v interface{}) error {
-	err := json.Unmarshal(data, v)
+	err := Unmarshal(data, v)
 	if err != nil {
 		return fmt.Errorf("%w: %s", ErrJSONUnmarshal, err)
 	}
@@ -2292,7 +2299,7 @@ func (s *Session) WebhookMessage(webhookID, token, messageID string) (message *M
 		return
 	}
 
-	err = json.Unmarshal(body, &message)
+	err = Unmarshal(body, &message)
 
 	return
 }

structs.go

@@ -878,7 +878,7 @@ func (p GuildScheduledEventParams) MarshalJSON() ([]byte, error) {
 	type guildScheduledEventParams GuildScheduledEventParams
 
 	if p.EntityType == GuildScheduledEventEntityTypeExternal && p.ChannelID == "" {
-		return json.Marshal(struct {
+		return Marshal(struct {
 			guildScheduledEventParams
 			ChannelID json.RawMessage `json:"channel_id"`
 		}{
@@ -887,7 +887,7 @@ func (p GuildScheduledEventParams) MarshalJSON() ([]byte, error) {
 		})
 	}
 
-	return json.Marshal(guildScheduledEventParams(p))
+	return Marshal(guildScheduledEventParams(p))
 }
 
 // GuildScheduledEventEntityMetadata holds additional metadata for guild scheduled event.
@@ -1129,7 +1129,7 @@ func (t *TimeStamps) UnmarshalJSON(b []byte) error {
 		End   float64 `json:"end,omitempty"`
 		Start float64 `json:"start,omitempty"`
 	}{}
-	err := json.Unmarshal(b, &temp)
+	err := Unmarshal(b, &temp)
 	if err != nil {
 		return err
 	}
@@ -1267,7 +1267,7 @@ func (t *TooManyRequests) UnmarshalJSON(b []byte) error {
 		Message    string  `json:"message"`
 		RetryAfter float64 `json:"retry_after"`
 	}{}
-	err := json.Unmarshal(b, &u)
+	err := Unmarshal(b, &u)
 	if err != nil {
 		return err
 	}
@@ -1687,7 +1687,7 @@ func (activity *Activity) UnmarshalJSON(b []byte) error {
 		Instance      bool         `json:"instance,omitempty"`
 		Flags         int          `json:"flags,omitempty"`
 	}{}
-	err := json.Unmarshal(b, &temp)
+	err := Unmarshal(b, &temp)
 	if err != nil {
 		return err
 	}

util.go

@@ -2,7 +2,6 @@ package discordgo
 
 import (
 	"bytes"
-	"encoding/json"
 	"fmt"
 	"io"
 	"mime/multipart"
@@ -30,7 +29,7 @@ func MultipartBodyWithJSON(data interface{}, files []*File) (requestContentType
 	body := &bytes.Buffer{}
 	bodywriter := multipart.NewWriter(body)
 
-	payload, err := json.Marshal(data)
+	payload, err := Marshal(data)
 	if err != nil {
 		return
 	}