apache_event_php-fpm 示意圖：

nginx-php-fpm示意圖：

Worker-Master-Server

 TCP-Nginx_PHP

Nginx-FastCGI

1、使用$_GET 獲取所有引數，php7 會多出一個引數：_url ，例如訪問的地址

http://127.0.0.1/Home/String/index2?a=12&b=19

 此時的的引數_url = "Home/String/index2"

2、在PHP7 中為一個Error：PHP Notice: Undefined index: HTTP_USER_AGENT in line 2 

　　php5.9則為一個notice 

2017/03/27 10:58:09 [error] 5286#0: *851 FastCGI sent in stderr: "PHP message: PHP Notice:  Undefined index: HTTP_USER_AGENT in /home/UserAgent.php on line 9" while reading response header from upstream

if(!empty($_SERVER['HTTP_USER_AGENT'])){
  $user_agent = $_SERVER['HTTP_USER_AGENT'];    
} 
 
else {
  $user_agent = ''; 
}

3、NULL 合併運算子 ，PHP7才正式加入了??這個運算子：

// 獲取user引數的值(如果為空，則用'nobody')
$username = $_GET['user'] ?? 'nobody';
// 等價於:
$username = isset($_GET['user']) ? $_GET['user'] : 'nobody';

 4、php-fpm 沒有啟動的後果

2017/03/31 20:56:19 [crit] 19288#0: *1 connect() to unix:/var/run/php7.0.9-fpm.sock failed
 
 (2: No such file or directory) while connecting to upstream, client: 127.0.0.1, 
server: www.phalcon3.com, request: "GET /index.php HTTP/1.1", upstream: "fastcgi://unix:/var/run/php7.0.9-fpm.sock:", host: "127.0.0.1"

[email protected]:/usr/local/nginx/logs$ ll /var/run/php7.0.9-fpm.sock
ls: 無法訪問'/var/run/php7.0.9-fpm.sock': 沒有那個檔案或目錄

搞了半天，原來php-fmp 沒有啟動，