PHP高級(jí)教程(8)-PHP安全的電子郵件

2020-03-24 18:00:15

字體：大中小

供稿：網(wǎng)友

首先，請(qǐng)看上一節(jié)中的 PHP 代碼： html
body
?php
if (isset($_REQUEST['email']))
//if email is filled out, send email
{
//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail( [email protected] , Subject: $subject ,
$message, From: $email );
echo Thank you for using our mail form
}
else
//if email is not filled out, display the form
{
echo form method='post' action='mailform.php'
Email: input name='email' type='text' / br /
Subject: input name='subject' type='text' / br /
Message: br /
textarea name='message' rows='15' cols='40'
/textarea br /
input type='submit' /
/form
}
?
/body
/html 以上代碼存在的問(wèn)題是，未經(jīng)授權(quán)的用戶可通過(guò)輸入表單在郵件頭部插入數(shù)據(jù)。假如用戶在表單中的輸入框內(nèi)加入這些文本，會(huì)出現(xiàn)什么情況呢？[email protected]%0ACc:[email protected]
%0ABcc:[email protected],[email protected],
[email protected],[email protected]
%0ABTo:[email protected]與往常一樣，mail() 函數(shù)把上面的文本放入郵件頭部，那么現(xiàn)在頭部有了額外的 Cc:, Bcc: 以及 To: 字段。當(dāng)用戶點(diǎn)擊提交按鈕時(shí)，這封 e-mail 會(huì)被發(fā)送到上面所有的地址！PHP 防止 E-mail 注入防止 e-mail 注入的最好方法是對(duì)輸入進(jìn)行驗(yàn)證。下面的代碼與上一節(jié)類似，不過(guò)我們已經(jīng)增加了檢測(cè)表單中 email 字段的輸入驗(yàn)證程序： html
body
?php
function spamcheck($field)
{
//filter_var() sanitizes the e-mail
//address using FILTER_SANITIZE_EMAIL
$field=filter_var($field, FILTER_SANITIZE_EMAIL);

//filter_var() validates the e-mail
//address using FILTER_VALIDATE_EMAIL
if(filter_var($field, FILTER_VALIDATE_EMAIL))
{
return TRUE;
}
else
{
return FALSE;
}
}
if (isset($_REQUEST['email']))
{//if email is filled out, proceed

//check if the email address is invalid
$mailcheck = spamcheck($_REQUEST['email']);
if ($mailcheck==FALSE)
{
echo Invalid input
}
else
{//send email
$email = $_REQUEST['email'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;
mail( [email protected] , Subject: $subject ,
$message, From: $email );
echo Thank you for using our mail form
}
}
else
{//if email is not filled out, display the form
echo form method='post' action='mailform.php'
Email: input name='email' type='text' / br /
Subject: input name='subject' type='text' / br /
Message: br /
textarea name='message' rows='15' cols='40'
/textarea br /
input type='submit' /
/form
}
?
/body
/html 在上面的代碼中，我們使用了 PHP 過(guò)濾器來(lái)對(duì)輸入進(jìn)行驗(yàn)證：FILTER_SANITIZE_EMAIL 從字符串中刪除電子郵件的非法字符
FILTER_VALIDATE_EMAIL 驗(yàn)證電子郵件地址html教程

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