Revert "Revert "V0.4.0 imporve error response""

This reverts commit 9744f45e86.

backend/errors/errors.go

@@ -0,0 +1,55 @@
+package errors
+
+import (
+	"fmt"
+	"net/http"
+)
+
+type Scope int
+
+const (
+	ScopeSystem   Scope = 1
+	ScopeBusiness Scope = 2
+)
+
+type OPError struct {
+	HttpCode int
+	Message  string
+	Code     int
+	Scope    Scope
+}
+
+func (O OPError) Error() string {
+	var scope string
+	switch O.Scope {
+	case ScopeSystem:
+		scope = "system"
+		break
+	case ScopeBusiness:
+		scope = "business"
+	}
+	return fmt.Sprintf("%s error: [%d]%s.", scope, O.Code, O.Message)
+}
+
+func NewSystemOPError(code int, message string, httpCodes ...int) *OPError {
+	httpCode := http.StatusOK
+	if len(httpCodes) > 0 {
+		httpCode = httpCodes[0]
+	}
+	return NewOpError(code, message, ScopeSystem, httpCode)
+}
+func NewOpError(code int, message string, scope Scope, httpCode int) *OPError {
+	return &OPError{
+		Message:  message,
+		Code:     code,
+		Scope:    scope,
+		HttpCode: httpCode,
+	}
+}
+func NewBusinessError(code int, message string, httpCodes ...int) *OPError {
+	httpCode := http.StatusOK
+	if len(httpCodes) > 0 {
+		httpCode = httpCodes[0]
+	}
+	return NewOpError(code, message, ScopeBusiness, httpCode)
+}