Merge pull request #1121 from yquansah/yq-override-json

feat: add definition for overridable json engine

app.go

@@ -12,6 +12,7 @@ package fiber
 import (
 	"bufio"
 	"crypto/tls"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"net"
@@ -272,6 +273,13 @@ type Config struct {
 	//
 	// Default: false
 	// RedirectFixedPath bool
+
+	// When set by an external client of Fiber it will use the provided implementation of a
+	// JSONMarshal
+	//
+	// Allowing for flexibility in using another json library for encoding
+	// Default: json.Marshal
+	JSONEncoder utils.JSONMarshal `json:"-"`
 }
 
 // Static defines configuration options when defining static assets.
@@ -385,6 +393,9 @@ func New(config ...Config) *App {
 	if app.config.ErrorHandler == nil {
 		app.config.ErrorHandler = DefaultErrorHandler
 	}
+	if app.config.JSONEncoder == nil {
+		app.config.JSONEncoder = json.Marshal
+	}
 
 	// Init app
 	app.init()

ctx.go

@@ -536,7 +536,7 @@ func (c *Ctx) Is(extension string) bool {
 // and a nil slice encodes as the null JSON value.
 // This method also sets the content header to application/json.
 func (c *Ctx) JSON(data interface{}) error {
-	raw, err := json.Marshal(data)
+	raw, err := c.app.config.JSONEncoder(data)
 	if err != nil {
 		return err
 	}

utils/json_marshal.go

@@ -0,0 +1,5 @@
+package utils
+
+// JSONMarshal is the standard definition of representing a Go structure in
+// json format
+type JSONMarshal func(interface{}) ([]byte, error)

utils/json_marshal_test.go

@@ -0,0 +1,26 @@
+package utils
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestDefaultJSONEncoder(t *testing.T) {
+	type SampleStructure struct {
+		ImportantString string `json:"important_string"`
+	}
+
+	var (
+		sampleStructure = &SampleStructure{
+			ImportantString: "Hello World",
+		}
+		importantString = `{"important_string":"Hello World"}`
+
+		jsonEncoder JSONMarshal = json.Marshal
+	)
+
+	raw, err := jsonEncoder(sampleStructure)
+	AssertEqual(t, err, nil)
+
+	AssertEqual(t, string(raw), importantString)
+}