feat: complete contract-driven business development and MySQL integration

httpx/metadata.go

@@ -0,0 +1,22 @@
+package httpx
+
+import "context"
+
+// RequestMetadata is a value snapshot for Logic. It excludes credentials,
+// query strings, headers and bodies. ClientIP is resolved by App's proxy policy.
+type RequestMetadata struct{ ClientIP, Method, Route string }
+type metadataKey struct{}
+
+func WithRequestMetadata(ctx context.Context, value RequestMetadata) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, metadataKey{}, value)
+}
+func Metadata(ctx context.Context) RequestMetadata {
+	if ctx == nil {
+		return RequestMetadata{}
+	}
+	value, _ := ctx.Value(metadataKey{}).(RequestMetadata)
+	return value
+}