chore: import upstream snapshot with attribution

internal/base/handler/lang.go

@@ -0,0 +1,47 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package handler
+
+import (
+	"context"
+
+	"github.com/apache/answer/internal/base/constant"
+	"github.com/gin-gonic/gin"
+	"github.com/segmentfault/pacman/i18n"
+)
+
+// GetLangByCtx get language from header
+func GetLangByCtx(ctx context.Context) i18n.Language {
+	if ginCtx, ok := ctx.(*gin.Context); ok {
+		acceptLanguage, ok := ginCtx.Get(constant.AcceptLanguageFlag)
+		if ok {
+			if acceptLanguage, ok := acceptLanguage.(i18n.Language); ok {
+				return acceptLanguage
+			}
+			return i18n.DefaultLanguage
+		}
+	}
+
+	acceptLanguage, ok := ctx.Value(constant.AcceptLanguageContextKey).(i18n.Language)
+	if ok {
+		return acceptLanguage
+	}
+	return i18n.DefaultLanguage
+}