首页语言自动重定向异常：URL重复添加语言前缀问题求助

我用JavaScript实现了基于浏览器语言的自动重定向功能，除首页外所有页面运行正常，但首页在语言为英语（English）或阿拉伯语（Arabic）时，URL会出现en/en或ar/ar的重复语言前缀问题。

原代码如下：

window.addEventListener("DOMContentLoaded", function() {
  console.log("DOMContentLoaded event triggered");

  var excludedUrls = ["/customer-center", "/en/customer-center", "/ar/customer-center", "/make-payment", "/make-payment/1", "/make-payment/2", "/make-payment/3", "/make-payment/4", "/make-payment/5", "/make-payment/6", "/en/make-payment", "/en/make-payment/1", "/en/make-payment/2", "/en/make-payment/3", "/en/make-payment/4", "/en/make-payment/5", "/en/make-payment/6", "/ar/make-payment", "/ar/make-payment/1", "/ar/make-payment/2", "/ar/make-payment/3", "/ar/make-payment/4", "/ar/make-payment/5", "/ar/make-payment/6", "/cart", "/en/cart", "/ar/cart"]; // Exclude these URLs from redirection
  var storedLang = localStorage.getItem('lang');
  var userLang;
  
  if (storedLang) {
    userLang = storedLang;
  } else {
    userLang = navigator.language || navigator.userLanguage; 
    userLang = userLang.substr(0,2).toLowerCase();
    localStorage.setItem('lang', userLang);
  }
  
  console.log("Chosen language:", userLang);

  var currentUrl = window.location.href;
  var baseUrl = currentUrl.split("/")[0] + "//" + currentUrl.split("/")[2];
  var path = currentUrl.substring(baseUrl.length);

  // Check if the current path is in the list of excluded URLs
  if (!excludedUrls.includes(path)) {
    if (userLang === "tr") {
      if (path.includes("/en/") || path === "/en") {
        window.location.href = baseUrl + path.replace("/en", "/");
      } else if (path.includes("/ar/") || path === "/ar") {
        window.location.href = baseUrl + path.replace("/ar", "/");
      } 
    } else if (userLang === "en") {
      if (path.includes("/ar/")) {
        window.location.href = baseUrl + path.replace("/ar/", "/en/");
      } else if (!path.includes("/en/")) {
        if (path === "/ar" || path === "/") {
          window.location.href = baseUrl + "/en/";
        } else {
          window.location.href = baseUrl + "/en" + path;
        }
      }
    } else if (userLang === "ar") {
      if (path.includes("/en/")) {
        window.location.href = baseUrl + path.replace("/en/", "/ar/");
      } else if (!path.includes("/ar/")) {
        if (path === "/en" || path === "/") {
          window.location.href = baseUrl + "/ar/";
        } else {
          window.location.href = baseUrl + "/ar" + path;
        }
      }
    }
  }
});

问题原因 #

核心问题出在路径判断逻辑的漏洞：

• 当首页重定向到/en（部分服务器会自动去掉URL末尾的斜杠）时，原代码中!path.includes("/en/")的判断会返回true（因为/en不包含/en/这个带斜杠的子串），进而进入else分支执行baseUrl + "/en" + path，最终拼接出/en/en的重复路径。
• 阿拉伯语的/ar路径同理会触发重复前缀问题。

修复后的代码 #

window.addEventListener("DOMContentLoaded", function() {
  console.log("DOMContentLoaded event triggered");

  var excludedUrls = ["/customer-center", "/en/customer-center", "/ar/customer-center", "/make-payment", "/make-payment/1", "/make-payment/2", "/make-payment/3", "/make-payment/4", "/make-payment/5", "/make-payment/6", "/en/make-payment", "/en/make-payment/1", "/en/make-payment/2", "/en/make-payment/3", "/en/make-payment/4", "/en/make-payment/5", "/en/make-payment/6", "/ar/make-payment", "/ar/make-payment/1", "/ar/make-payment/2", "/ar/make-payment/3", "/ar/make-payment/4", "/ar/make-payment/5", "/ar/make-payment/6", "/cart", "/en/cart", "/ar/cart"]; // Exclude these URLs from redirection
  var storedLang = localStorage.getItem('lang');
  var userLang;
  
  if (storedLang) {
    userLang = storedLang;
  } else {
    userLang = navigator.language || navigator.userLanguage; 
    userLang = userLang.substr(0,2).toLowerCase();
    localStorage.setItem('lang', userLang);
  }
  
  console.log("Chosen language:", userLang);

  var currentUrl = window.location.href;
  var baseUrl = currentUrl.split("/")[0] + "//" + currentUrl.split("/")[2];
  var path = currentUrl.substring(baseUrl.length);

  // Check if the current path is in the list of excluded URLs
  if (!excludedUrls.includes(path)) {
    if (userLang === "tr") {
      if (path.includes("/en/") || path === "/en") {
        window.location.href = baseUrl + path.replace("/en", "/");
      } else if (path.includes("/ar/") || path === "/ar") {
        window.location.href = baseUrl + path.replace("/ar", "/");
      } 
    } else if (userLang === "en") {
      if (path.includes("/ar/")) {
        window.location.href = baseUrl + path.replace("/ar/", "/en/");
      } else if (!path.includes("/en/") && path !== "/en") {
        if (path === "/ar" || path === "/") {
          window.location.href = baseUrl + "/en/";
        } else {
          window.location.href = baseUrl + "/en" + path;
        }
      }
    } else if (userLang === "ar") {
      if (path.includes("/en/")) {
        window.location.href = baseUrl + path.replace("/en/", "/ar/");
      } else if (!path.includes("/ar/") && path !== "/ar") {
        if (path === "/en" || path === "/") {
          window.location.href = baseUrl + "/ar/";
        } else {
          window.location.href = baseUrl + "/ar" + path;
        }
      }
    }
  }
});

修复说明 #

主要修改了两处判断逻辑：

1. 针对英语分支，将!path.includes("/en/")改为!path.includes("/en/") && path !== "/en"，确保路径已经是/en时不会触发额外重定向；
2. 针对阿拉伯语分支，同理将!path.includes("/ar/")改为!path.includes("/ar/") && path !== "/ar"；
3. 保留了土耳其语分支中对/en、/ar纯路径的判断，确保逻辑一致性。

修改后，首页会正确重定向到/en或/ar，不会出现重复前缀的问题，其他页面的重定向逻辑保持正常。

内容的提问来源于stack exchange，提问作者Resul Yigit OCAK