public function hasHeader($name)
    {
        $name = $this->normalizeHeaderName($name);

        return isset($this->_environment[$name]);
    }
public function hasHeader($name)
    {
        $name = $this->normalizeHeaderName($name);

        return isset($this->_environment[$name]);
    }
public function hasHeader ( $ name ) { $ name = $ this -> normalizeHeaderName ( $ name ) ; return isset ( $ this -> _environment [ $ name ] ) ; }
Check if a header is set in the request.

@param string $name The header you want to get (case-insensitive)
@return bool Whether or not the header is defined.
@link http://www.php-fig.org/psr/psr-7/ This method is part of the PSR-7 server request interface.
Check if a header is set in the request .