add json and xml body parser

app.go

@@ -318,13 +318,27 @@ type Config struct {
 	// Default: json.Marshal
 	JSONEncoder utils.JSONMarshal `json:"-"`
 
+	// When set by an external client of Fiber it will use the provided implementation of a
+	// JSONUnmarshal
+	//
+	// Allowing for flexibility in using another json library for decoding
+	// Default: json.Unmarshal
+	JSONDecoder utils.JSONUnmarshal `json:"-"`
+
 	// XMLEncoder set by an external client of Fiber it will use the provided implementation of a
 	// XMLMarshal
 	//
 	// Allowing for flexibility in using another XML library for encoding
 	// Default: xml.Marshal
 	XMLEncoder utils.XMLMarshal `json:"-"`
 
+	// XMLDecoder set by an external client of Fiber it will use the provided implementation of a
+	// XMLUnmarshal
+	//
+	// Allowing for flexibility in using another XML library for encoding
+	// Default: utils.XMLUnmarshal
+	XMLDecoder utils.XMLUnmarshal `json:"-"`
+
 	// App validate. if nil, and context.Validate will always return a error.
 	// Default: nil
 	Validator Validator
@@ -510,10 +524,17 @@ func New(config ...Config) *App {
 	if app.config.JSONEncoder == nil {
 		app.config.JSONEncoder = json.Marshal
 	}
+	if app.config.JSONDecoder == nil {
+		app.config.JSONDecoder = json.Unmarshal
+	}
 
 	if app.config.XMLEncoder == nil {
 		app.config.XMLEncoder = xml.Marshal
 	}
+	if app.config.XMLDecoder == nil {
+		app.config.XMLDecoder = xml.Unmarshal
+	}
+
 	if app.config.Network == "" {
 		app.config.Network = NetworkTCP4
 	}

ctx.go

@@ -284,6 +284,22 @@ func (c *DefaultCtx) Body() []byte {
 	return body
 }
 
+func (c *DefaultCtx) BodyJSON(v any) error {
+	if !bytes.HasPrefix(c.Request().Header.ContentType(), utils.UnsafeBytes(MIMEApplicationJSON)) {
+		return NewError(http.StatusUnsupportedMediaType, "expecting content-type \"application/json\"")
+	}
+
+	return c.app.config.JSONDecoder(c.Body(), v)
+}
+
+func (c *DefaultCtx) BodyXML(v any) error {
+	if !bytes.HasPrefix(c.Request().Header.ContentType(), utils.UnsafeBytes(MIMEApplicationXML)) {
+		return NewError(http.StatusUnsupportedMediaType, "expecting content-type \"application/xml\"")
+	}
+
+	return c.app.config.XMLDecoder(c.Body(), v)
+}
+
 // ClearCookie expires a specific cookie by key on the client side.
 // If no key is provided it expires all cookies that came with the request.
 func (c *DefaultCtx) ClearCookie(key ...string) {

ctx_interface.go

@@ -58,6 +58,12 @@ type Ctx interface {
 	// Make copies or use the Immutable setting instead.
 	Body() []byte
 
+	// BodyJSON will check the content-type and unmarshal request body with Config.JSONDecoder
+	BodyJSON(v any) error
+
+	// BodyXML will check the content-type and unmarshal request body with Config.XMLDecoder
+	BodyXML(v any) error
+
 	// ClearCookie expires a specific cookie by key on the client side.
 	// If no key is provided it expires all cookies that came with the request.
 	ClearCookie(key ...string)