perf: fast-path default 404 and 405 responses

engine.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/WJQSERVER-STUDIO/httpc"
 	"github.com/fenthope/reco"
+	"github.com/go-json-experiment/json"
 )
 
 // Last 返回链中的最后一个处理函数
@@ -132,6 +133,32 @@ type defaultErrorResponse struct {
 	Error   string `json:"error"`
 }
 
+var defaultNotFoundBody = mustMarshalDefaultErrorBody(http.StatusNotFound, errNotFound.Error())
+var defaultMethodNotAllowedBody = mustMarshalDefaultErrorBody(http.StatusMethodNotAllowed, errMethodNotAllowed.Error())
+
+func mustMarshalDefaultErrorBody(code int, errMsg string) []byte {
+	body, err := json.Marshal(defaultErrorResponse{
+		Code:    code,
+		Message: http.StatusText(code),
+		Error:   errMsg,
+	})
+	if err != nil {
+		panic(err)
+	}
+	return body
+}
+
+func writeDefaultErrorJSON(c *Context, code int, body []byte) {
+	if c == nil || c.Writer == nil {
+		return
+	}
+	c.Writer.Header().Set("Content-Type", "application/json; charset=utf-8")
+	c.Writer.WriteHeader(code)
+	_, _ = c.Writer.Write(body)
+	c.Writer.Flush()
+	c.Abort()
+}
+
 var methodNotAllowedHandler HandlerFunc = func(c *Context) {
 	httpMethod := c.Request.Method
 	requestPath := routeLookupPath(c.Request)
@@ -191,6 +218,16 @@ func defaultErrorHandle(c *Context, code int, err error) { // 检查客户端是
 		if c.Writer.Written() {
 			return
 		}
+		if len(c.Errors) == 0 {
+			switch {
+			case code == http.StatusNotFound && errors.Is(err, errNotFound):
+				writeDefaultErrorJSON(c, code, defaultNotFoundBody)
+				return
+			case code == http.StatusMethodNotAllowed && errors.Is(err, errMethodNotAllowed):
+				writeDefaultErrorJSON(c, code, defaultMethodNotAllowedBody)
+				return
+			}
+		}
 		// 输出json 状态码与状态码对应描述
 		var errMsg string
 		if err != nil {

engine_test.go

@@ -139,3 +139,49 @@ func TestDefaultErrorHandleJSONShape(t *testing.T) {
 		t.Fatalf("unexpected error payload: %+v", body)
 	}
 }
+
+func TestDefaultMethodNotAllowedJSONShape(t *testing.T) {
+	engine := New()
+	engine.GET("/users", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+
+	rr := PerformRequest(engine, http.MethodDelete, "/users", nil, nil)
+	if rr.Code != http.StatusMethodNotAllowed {
+		t.Fatalf("expected status %d, got %d", http.StatusMethodNotAllowed, rr.Code)
+	}
+
+	var body struct {
+		Code    int    `json:"code"`
+		Message string `json:"message"`
+		Error   string `json:"error"`
+	}
+	if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
+		t.Fatalf("expected JSON error body, got %q: %v", rr.Body.String(), err)
+	}
+	if body.Code != http.StatusMethodNotAllowed || body.Message != http.StatusText(http.StatusMethodNotAllowed) || body.Error != "method not allowed" {
+		t.Fatalf("unexpected error payload: %+v", body)
+	}
+}
+
+func TestCustomErrorHandlerStillOverridesDefaultFastPath(t *testing.T) {
+	engine := New()
+	engine.SetErrorHandler(func(c *Context, code int, err error) {
+		c.Writer.Header().Set("X-Custom-Error", "1")
+		c.String(code, "custom:%v", err)
+	})
+	engine.GET("/users", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+
+	rr := PerformRequest(engine, http.MethodDelete, "/users", nil, nil)
+	if rr.Code != http.StatusMethodNotAllowed {
+		t.Fatalf("expected status %d, got %d", http.StatusMethodNotAllowed, rr.Code)
+	}
+	if got := rr.Header().Get("X-Custom-Error"); got != "1" {
+		t.Fatalf("expected custom error header, got %q", got)
+	}
+	if rr.Body.String() != "custom:method not allowed" {
+		t.Fatalf("expected custom error body, got %q", rr.Body.String())
+	}
+}