在中间件中设置标题 [英] set header in middleware

问题描述

我试图在中间件中设置标头，以避免Google漫游器将诸如登录页面之类的内容编入索引.我实际上使它起作用，但是遇到了我无法理解的错误.

I tried to set a header in a middleware to avoid Google bot for indexing something like a login page. And I actually made it work but came across this error which I cannot understand.

public function handle($request, Closure $next)
{

    $next($request)->header('x-robots-tag', 'none', false);

    return $next($request);
}

上面的代码不会在下面的代码中添加此标头x-robots-tag: none.

The code above won't add this header x-robots-tag: none while the below code does.

 public function handle($request, Closure $next)
{
    $response = $next($request);

    $response->header('x-robots-tag', 'none', false);

    return $response;
}

基本上不是同一回事吗?唯一的区别是将$next($request)放入变量还是不放入变量.为什么会这样?

Isn't it basically the same thing? The only difference is putting $next($request) in a variable or not. Why is this?

推荐答案

让我们逐步了解第二个版本:

Let's walk through the second version:

 public function handle($request, Closure $next)
{
    $response = $next($request); //You get the Response instance and store it

    $response->header('x-robots-tag', 'none', false); //you set the header

    return $response; //and then you return it
}

而

public function handle($request, Closure $next)
{

    $next($request)->header('x-robots-tag', 'none', false);//You set the header to the response

    return $next($request);// Here you get another instance thus the previous result is lost
}

想象一下$next($request)的行为就像一个工厂.

Imagine that $next($request) behaves like a factory.

这篇关于在中间件中设置标题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！