遍历php的_SERVER数组键值信息

$_SERVER 是一个包含了诸如头信息(header)、路径(path)、以及脚本位置(script locations)等等信息的数组。这个数组中的项目由 Web 服务器创建。不能保证每个服务器都提供全部项目；服务器可能会忽略一些，或者提供一些没有在这里列举出来的项目。 [1]

<?php
  foreach ($_SERVER as $key => $value) {
    var_dump($key . '===' . $value. '<br/>');
  }
?>

" string(31) "DOCUMENT_ROOT===D:\CRMEB26
" string(22) "REMOTE_ADDR===::1
" string(24) "REMOTE_PORT===59715
" string(52) "SERVER_SOFTWARE===PHP 7.2.19 Development Server
" string(31) "SERVER_PROTOCOL===HTTP/1.1
" string(28) "SERVER_NAME===localhost
" string(23) "SERVER_PORT===8899
" string(20) "REQUEST_URI===/
" string(25) "REQUEST_METHOD===GET
" string(29) "SCRIPT_NAME===/index.php
" string(43) "SCRIPT_FILENAME===D:\CRMEB26\index.php
" string(26) "PHP_SELF===/index.php
" string(31) "HTTP_HOST===localhost:8899
" string(33) "HTTP_CONNECTION===keep-alive
" string(35) "HTTP_CACHE_CONTROL===max-age=0
" string(39) "HTTP_UPGRADE_INSECURE_REQUESTS===1
" string(132) "HTTP_USER_AGENT===Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36
" string(137) "HTTP_ACCEPT===text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
" string(45) "HTTP_ACCEPT_ENCODING===gzip, deflate, br
" string(51) "HTTP_ACCEPT_LANGUAGE===zh-CN,zh;q=0.9,en;q=0.8
" string(131) "HTTP_COOKIE===csrftoken=TG7fqm9L2hILFvXSBtTUTClPCytNFRJC151V209BZQ1ENL5mrSRcebdSnMtA1GfS; PHPSESSID=jsnl3bmm3ljtchbt7e2pgt7emo
" string(41) "REQUEST_TIME_FLOAT===1563240933.4171
" string(30) "REQUEST_TIME===1563240933