refactor: ⚡ Improved context

Author: roshangade

context.go

@@ -15,55 +15,57 @@ type Context interface {
 	Status(int) Context
 	Header(string, string) Context
 	Set(string, any)
-	Get(string) any
-	Metadata() map[string]any
+	Get(string) (any, bool)
+	Unset(string)
 	Throw(string, error)
-	JSON(interface{})
-	XML(interface{})
+	JSON(any)
+	XML(any)
 	Text(string)
 	Write([]byte)
 	End()
 }
 
-var (
+const (
 	ErrCodeInvalidJSON = "INVALID_JSON"
 	ErrCodeInvalidXML  = "INVALID_XML"
 )
 
-var (
+const HeaderContentType = "Content-Type"
+
+const (
 	headerText = "text/plain"
 	headerJSON = "application/json"
 	headerXML  = "text/xml"
 )
 
 type context struct {
-	w http.ResponseWriter
-	r *http.Request
+	w    http.ResponseWriter
+	r    *http.Request
+	meta sync.Map
 
 	// for internal purpose
-	params   map[string]string
-	headers  map[string]string
-	metadata map[string]any
-	process  *sync.Mutex
-	end      bool
-	status   int
-	code     string
-	err      error
+	params  map[string]string
+	headers map[string]string
+	end     bool
+	status  int
+	code    string
+	err     error
 }
 
 func (ctx *context) init() {
 	ctx.headers = make(map[string]string)
-	ctx.metadata = make(map[string]any)
-	ctx.process = new(sync.Mutex)
 }
 
 func (ctx *context) destroy() {
 	ctx.w = nil
 	ctx.r = nil
-	ctx.headers = nil
+	ctx.meta = sync.Map{}
 	ctx.params = nil
+	ctx.headers = nil
+	ctx.end = true
+	ctx.status = 0
+	ctx.code = ""
 	ctx.err = nil
-	ctx.metadata = nil
 }
 
 func (ctx *context) reset() {
@@ -89,17 +91,15 @@ func (ctx *context) Header(key string, value string) Context {
 }
 
 func (ctx *context) Set(key string, value any) {
-	ctx.process.Lock()
-	ctx.metadata[key] = value
-	ctx.process.Unlock()
+	ctx.meta.Store(key, value)
 }
 
-func (ctx *context) Get(key string) any {
-	return ctx.metadata[key]
+func (ctx *context) Get(key string) (any, bool) {
+	return ctx.meta.Load(key)
 }
 
-func (ctx *context) Metadata() map[string]any {
-	return ctx.metadata
+func (ctx *context) Unset(key string) {
+	ctx.meta.Delete(key)
 }
 
 func (ctx *context) Throw(code string, err error) {
@@ -114,35 +114,41 @@ func (ctx *context) JSON(data any) {
 		ctx.Throw(ErrCodeInvalidJSON, err)
 		return
 	}
-	ctx.Header("Content-Type", headerJSON)
+	if _, exists := ctx.headers[HeaderContentType]; !exists {
+		ctx.Header(HeaderContentType, headerJSON)
+	}
 	ctx.write(body)
 }
 
-func (ctx *context) XML(data interface{}) {
+func (ctx *context) XML(data any) {
 	body, err := xmlToBytes(data)
 	if err != nil {
 		ctx.Throw(ErrCodeInvalidXML, err)
 		return
 	}
-	ctx.Header("Content-Type", headerXML)
+	if _, exists := ctx.headers[HeaderContentType]; !exists {
+		ctx.Header(HeaderContentType, headerXML)
+	}
 	ctx.write(body)
 }
 
 // send Raw
 func (ctx *context) Text(data string) {
-	ctx.Header("Content-Type", headerText)
+	if _, exists := ctx.headers[HeaderContentType]; !exists {
+		ctx.Header(HeaderContentType, headerText)
+	}
 	ctx.write([]byte(data))
 }
 
+func (ctx *context) Write(data []byte) {
+	ctx.write(data)
+}
+
 // send blank
 func (ctx *context) End() {
 	ctx.write(nil)
 }
 
-func (ctx *context) Write(data []byte) {
-	ctx.write(data)
-}
-
 // write bytes in response
 func (ctx *context) write(body []byte) {
 
@@ -179,7 +185,7 @@ func (ctx *context) unhandledException() {
 	if ctx.err != nil {
 		ctx.reset()
 
-		ctx.Header("Content-Type", headerText)
+		ctx.Header(HeaderContentType, headerText)
 
 		if ctx.code == ErrCodeNotFound {
 			ctx.Status(http.StatusNotFound)

context_test.go

@@ -29,7 +29,7 @@ func TestContext_init(t *testing.T) {
 func TestContext_destroy(t *testing.T) {
 	ctx.destroy()
 
-	if ctx.w != nil || ctx.r != nil || ctx.headers != nil {
+	if ctx.w != nil || ctx.r != nil {
 		t.Error("context.destroy() should destroy the context")
 	}
 }
@@ -90,7 +90,7 @@ func TestContext_Throw(t *testing.T) {
 }
 
 func TestContext_JSON(t *testing.T) {
-	res := "{\"message\":\"Hello, World!\"}"
+	res := map[string]any{"message": "Hello, World!"}
 	r := httptest.NewRequest(http.MethodGet, "/", nil)
 	w := httptest.NewRecorder()
 	ctx = &context{
@@ -103,8 +103,8 @@ func TestContext_JSON(t *testing.T) {
 	ctx.JSON(res)
 
 	body, err := ioutil.ReadAll(w.Body)
-
-	if err != nil || string(body) != res {
+	var expected = `{"message":"Hello, World!"}`
+	if err != nil || string(body) != expected {
 		t.Error("context.JSON() should write a response in JSON format")
 	}
 
@@ -114,7 +114,10 @@ func TestContext_JSON(t *testing.T) {
 }
 
 func TestContext_XML(t *testing.T) {
-	res := "<message>Hello, World!</message>"
+	type Message struct {
+		Data string `xml:"data"`
+	}
+
 	r := httptest.NewRequest(http.MethodGet, "/", nil)
 	w := httptest.NewRecorder()
 	ctx = &context{
@@ -124,11 +127,12 @@ func TestContext_XML(t *testing.T) {
 	ctx.init()
 	defer ctx.destroy()
 
-	ctx.XML(res)
+	ctx.XML(&Message{Data: "Hello, World!"})
 
 	body, err := ioutil.ReadAll(w.Body)
+	var expected = "<Message><data>Hello, World!</data></Message>"
 
-	if err != nil || string(body) != res {
+	if err != nil || string(body) != expected {
 		t.Error("context.XML() should write a response in XML format")
 	}
 

examples/hello-world/main.go

@@ -62,13 +62,14 @@ func main() {
 	//==========================Error Handling==================================
 
 	api.Get("/test", func(ctx rest.Context) {
-		ctx.Set("Hi", "There")
+		ctx.Set("Hi", "{\"a\": 1}")
 		ctx.Throw("CUSTOM_ERROR", errors.New("custom error"))
 	})
 
 	api.CatchError("CUSTOM_ERROR", func(err error, ctx rest.Context) {
 		//ctx.Status(412).JSON("{\"a\": 1}")
-		ctx.Status(412).JSON(ctx.Metadata())
+		text, _ := ctx.Get("Hi")
+		ctx.Status(412).Header("Content-Type", "application/json; charset=utf-8").Text(text.(string))
 	})
 
 	http.ListenAndServe(":8080", api)

helper.go

@@ -89,17 +89,10 @@ func trim(str string) string {
 }
 
 func jsonToBytes(data any) ([]byte, error) {
-	if body, isString := data.(string); isString {
-		return json.RawMessage(body).MarshalJSON()
-	}
-
 	//standard JSON as per RFC 7159
 	return json.Marshal(data)
 }
 
-func xmlToBytes(data interface{}) ([]byte, error) {
-	if body, isString := data.(string); isString {
-		return []byte(body), nil
-	}
+func xmlToBytes(data any) ([]byte, error) {
 	return xml.Marshal(data)
 }