php-gpioを使ってWEBから操作してみる [Thu Mar 14 00:39:00.764008 2019] [:error] [pid 935] [client ***.***.***.***] PHP Warning: file_put_contents(/sys/class/gpio/gpio21/direction): failed to open stream: Permission denied in /var/www/html/lib/src/PhpGpio/Gpio.php on line 103, referer: http://raspi3p-01.local/gpio-php-gpio.php