php基础知识(四)－cookie使用
php基础知识(4)－cookie使用
php基础知识－cookie使用
示例代码下载页http://xieye.iteye.com/blog/1336095（在附件）
cookie简单定义：浏览器发送请求给服务器时额外传送的数据。
cookie原理：web协议规定，服务器返回请求时可以将一小部分数据存在浏览器客户端，浏览器在下次往同域名服务器请求信息时，会
同时自动把该段信息再发送给服务器，而这一切是对用户透明的，用户不需要理解这些东西可以照常上网。
cookie的一个特点是，服务器存客户端时可以带有时间参数，浏览器会根据这个参数决定cookie是否过期来处理，如果过期了，这个cookie就
不会到服务端。
假如服务端不对cookie做处理，则每次浏览器发送请求到服务端总会自动传送相同内容的cookie。
cookie的另一个特点是多个名称和值的组合。
例子：自动登录。
有3个页面，一个首页，一个是登录页
必须先添加一个用户
insert into test.member(username,password)values('admin', md5('1') );
9.php,10.php,11quit.php 是没有自动登录的例子。
19.php,20.php,21quit.php 是自动登录的例子。
演示
首先是一个普通的登录例子
http://localhost/command/peixun/cookie/9.php,提示登录
进入10.php,输入admin，1则跳转到9.php,显示出当前用户名，如果愿意可以退出。
如果没有点击“退出”按钮，则直接关闭浏览器，再打开浏览器输入http://localhost/command/peixun/cookie/9.php，发现并没有处于登录状态。
然后是一个通过cookie的自动登录例子。
http://localhost/command/peixun/cookie/19.php,提示登录
进入10.php发现多了一个复选框,不勾选的情况下和上面的例子效果完全一样，输入admin，1则跳转到19.php,显示出当前用户名，如果愿意可以退出。
如果勾选后输入admin，1则跳转到19.php，此时不能点击“退出”链接，直接关闭浏览器。
双击桌面的浏览器图标再次打开浏览器，发现处于已登录状态，这就是cookie的效果。
重要说明：本例子只用于演示cookie的用法，实际应用中为安全起见，最好隐藏cooikie的字段含义，程序也因此需要做修改。
代码可下载，只显示第2个例子的代码
19.php
<?php//会话的第2个例子,首页//9.php,简单例子，首页//10.php，简单例子，登录页//11quit.php,简单例子，退出页//19.php, 复杂例子，首页//20.php， 复杂例子，登录页//21quit.php, 复杂例子，退出页require_once('../Public/CommandLine.php');session_start();//逻辑是如果未登录，则显示“请登录”，如果已登录，显示欢迎某某某$html = '';if (isset($_SESSION['islogin']) && $_SESSION['islogin'] == 1 ) { //已登录 $html .= '欢迎您，' . $_SESSION['username'] . " <a href='11quit.php'>退出</a>"; } else { //未登录分：有cookie的记住我，且为1 if (isset($_COOKIE['rememberme']) && $_COOKIE['rememberme']==1 ) { $username = strval($_COOKIE['username']); $password = strval($_COOKIE['password']); $db = Sys::getdb(); $select = $db->select(); $select->from('test.member', 'count(*)' ) ->where('username=?', $username) ->where('password=?', $password); $result = $db->fetchOne($select); if ($result) { //如果是对的 $_SESSION['islogin'] = 1; $_SESSION['username'] = $username; $html .= '欢迎您，' . $_SESSION['username'] . " <a href='21quit.php'>退出</a>"; } }}if(!( isset($_SESSION['islogin']) && $_SESSION['islogin'] == 1 ) ){ $html .= '<a href="20.php">请登录</a>';} $html .= "<br><h1>这是首页<h1>";echo $html;20.php
<?php//自动登录的登录页require_once('../Public/CommandLine.php');session_start();$isget = ($_SERVER['REQUEST_METHOD'] == 'GET') ? 1 : 0;if ($isget) { $html = <<<longs<html> <body> <form method="post"> 请输入用户名：<input type="text" name="username" value=''><br> 请输入密码：<input type="text" name="password" value=''><br> <input type="checkbox" name="rememberme" value="1" />下次自动登录<br> <input type="submit" value="登录" > </form></body> </html> longs; echo $html; } else { //echo $_POST['name1']; $username = $_POST['username']; $password = $_POST['password']; $db = Sys::getdb(); $select = $db->select(); $select->from('test.member', 'count(*)' ) ->where('username=?', $username) ->where('password=?', md5($password)); $result = $db->fetchOne($select); if ($result) { $_SESSION['islogin'] = 1; $_SESSION['username'] = $username; $time = time() + 3600 * 24 * 365; setcookie('rememberme', intval($_POST['rememberme']), $time, "/"); setcookie('password', md5($password), $time, "/"); setcookie('username', $username, $time, "/"); header('Location: 19.php'); }else { $html = <<<longs<html> <body> 请输入正确的用户名和密码 <form method="post"> 请输入用户名：<input type="text" name="username" value='{$username}'><br> 请输入密码：<input type="text" name="password" value='{$password}'><br> <input type="checkbox" name="rememberme" value="1" />下次自动登录<br> <input type="submit" value="登录" > </form></body> </html> longs; echo $html; } }21quit.php
<?php//第2个例子,自动登录的退出页require_once('../Public/CommandLine.php');session_start();$_SESSION['islogin'] =0;$date = time() - 3600 * 24 * 365;foreach($_COOKIE as $key => $ko){ if ($key != 'PHPSESSID') { setcookie($key, "", $date, "/"); //删除cookie的写法 }}header('Location: 19.php');
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