7天入门php-超全局

小灰灰 2022-07-16 03:46 149阅读 0赞

一、所有超全局

*  $GLOBALS
 *  $\_SERVER
 *  $\_REQUEST
 *  $\_POST
 *  $\_GET
 *  $\_FILES
 *  $\_ENV
 *  $\_COOKIE
 *  $\_SESSION

二、点滴

**1、$\_GLOBALS**

用于php脚本中任意位置访问所有全局变量。例：

<?php 
    $x = 75; 
    $y = 25;
     
    function addition() { 
      $GLOBALS['z'] = $GLOBALS['x'] + $GLOBALS['y']; 
    }
     
    addition(); 
    echo $z; 
    ?>

**2、$\_SERVER **

重要元素：

<table style="margin:10px 0px 0px; padding:0px; border:1px solid rgb(170,170,170); border-collapse:collapse; width:708.75px; color:rgb(0,0,0); font-family:Verdana,Arial,宋体; font-size:15px; background-color:rgb(249,249,249)"> 
 <tbody style="margin:0px; padding:0px; border:0px"> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['PHP_SELF']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前执行脚本的文件名。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['GATEWAY_INTERFACE']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回服务器使用的 CGI 规范的版本。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_ADDR']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前运行脚本所在的服务器的 IP 地址。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_NAME']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前运行脚本所在的服务器的主机名（比如 www.w3school.com.cn）。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_SOFTWARE']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回服务器标识字符串（比如 Apache/2.2.24）。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_PROTOCOL']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回请求页面时通信协议的名称和版本（例如，“HTTP/1.0”）。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['REQUEST_METHOD']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回访问页面使用的请求方法（例如 POST）。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['REQUEST_TIME']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回请求开始时的时间戳（例如 1577687494）。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['QUERY_STRING']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回查询字符串，如果是通过查询字符串访问此页面。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['HTTP_ACCEPT']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回来自当前请求的请求头。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['HTTP_ACCEPT_CHARSET']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回来自当前请求的 Accept_Charset 头（ 例如 utf-8,ISO-8859-1）</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['HTTP_HOST']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回来自当前请求的 Host 头。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['HTTP_REFERER']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前页面的完整 URL（不可靠，因为不是所有用户代理都支持）。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['HTTPS']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 是否通过安全 HTTP 协议查询脚本。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['REMOTE_ADDR']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回浏览当前页面的用户的 IP 地址。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['REMOTE_HOST']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回浏览当前页面的用户的主机名。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['REMOTE_PORT']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回用户机器上连接到 Web 服务器所使用的端口号。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SCRIPT_FILENAME']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前执行脚本的绝对路径。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_ADMIN']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 该值指明了 Apache 服务器配置文件中的 SERVER_ADMIN 参数。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_PORT']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> Web 服务器使用的端口。默认值为 “80”。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SERVER_SIGNATURE']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回服务器版本和虚拟主机名。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['PATH_TRANSLATED']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 当前脚本所在文件系统（非文档根目录）的基本路径。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SCRIPT_NAME']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前脚本的路径。</td> 
  </tr> 
  <tr style="margin:0px; padding:0px; border:0px"> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> $_SERVER['SCRIPT_URI']</td> 
   <td style="margin:0px; padding:6px 15px 6px 6px; border:1px solid rgb(170,170,170); vertical-align:text-top; background-color:rgb(239,239,239)"> 返回当前页面的 URI。</td> 
  </tr> 
 </tbody> 
</table>

**3、$\_REQUEST**

用于收集表单上传的数据，方法与$\_GET 和$\_POST 相同。但$\_REQUEST 能收集任意method的表单数据，而不仅限于GET 或 POST。

**4、$\_GET 与$\_POST**

用于取表单提交的数据。

**5、$\_FILES**

php全局数组，用于取出表单上传的文件。

基础属性：

*  $\_FILES\["file"\]\["name"\] - 被上传文件的名称
 *  $\_FILES\["file"\]\["type"\] - 被上传文件的类型
 *  $\_FILES\["file"\]\["size"\] - 被上传文件的大小，以字节计
 *  $\_FILES\["file"\]\["tmp\_name"\] - 存储在服务器的文件的临时副本的名称
 *  $\_FILES\["file"\]\["error"\] - 由文件上传导致的错误代码

说明：其中file为文件上传控件的name属性值。

**注意：应该控制上传文件的用户权限，因为可能存在巨大风险。**

具体文件上传查看文件上传小节！

**6、$\_ENV**

**7、$\_COOKIE**

**8、$\_SESSION**