响应头重复（流明）

Question

Continuation of: Setting response headers with middleware in Lumen

When using the following exception handler in Lumen, the X-Powered-By header is duplicated, even though $replace (the third parameter of the header() method) defaults to true (even setting it manually, as below, does not work).

public function render($request, Exception $e)
{
    if ($e instanceof \Symfony\Component\HttpKernel\Exception\NotFoundHttpException)
    {
        return response(view('not-found'), 404)->header('X-Powered-By', env('APP_NAME')."/".env('APP_VER'), true);
    }

    return parent::render($e);
}

The response header:

HTTP/1.0 404 Not Found
Date: Sat, 23 May 2015 08:05:13 GMT
Server: Apache
X-Powered-By: PHP/5.6.3
Cache-Control: no-cache
X-Powered-By: AppName/1.0.0
Connection: close
Content-Type: text/html; charset=UTF-8

The only thing that works is to use header_remove('X-Powered-By') just before the call to ->header. I should not have to do this, due to the $replace parameter being set accordingly.

Are there any better ways to prevent the duplication of the X-Powered-By header?

Answer 1

I couldn't get this to work with method chaining, however, if I did this:

header('X-Powered-By: '.env('APP_NAME')."/".env('APP_VER'));
return response(view('not-found'), 404);

... it worked as you desire. But please do notice there is only one argument in the header per the PHP manual:

void header ( string $string [, bool $replace = true [, int $http_response_code ]] )

The optional replace parameter indicates whether the header should replace a previous similar header, or add a second header of the same type. By default it will replace, but if you pass in FALSE as the second argument you can force multiple headers of the same type.

Source: http://php.net/manual/en/function.header.php

... meaning, it's not a "replace this with that" type of item like str_replace. If the string you type into the first argument is similar to another header item, it will replace it with whatever you've typed automatically.

Side note: I also tried setting the third argument of the response function to an array including the X-Powered-By header to no avail.