With the development of the Internet, email has become one of the important ways for people to communicate in daily life. For some website developers, sending emails on the website is also particularly critical. As a server-side scripting language, PHP naturally needs to provide a way to send emails. This article will introduce how PHP uses Simple Mail Transfer Protocol (SMTP) to send emails.

SMTP Introduction

Simple Mail Transfer Protocol (SMTP) is a standard protocol for sending and receiving emails. SMTP was originally standardized in RFC821 in 1982 and has been updated to RFC5321. The SMTP protocol uses port 25 of the TCP protocol for communication, which is generally provided by the mail server.

PHP method of sending emails

SMTP class

PHP provides the SMTP class to support sending emails through the SMTP server. This class provides some interfaces to configure SMTP server parameters, such as server address, authentication method, etc.

The following is an example of sending an email:

$smtp = new SMTP();

// 設(shè)置SMTP服務(wù)器地址和端口
$smtp->setServer('smtp.example.com', 25);

// 開(kāi)啟debug模式，可以查看SMTP服務(wù)器的交互信息
$smtp->debug = true;

// SMTP認(rèn)證用戶(hù)名和密碼
$smtp->setAuth('username', 'password');

// 添加一個(gè)收件人
$smtp->addRecipient('recipient@example.com', 'Recipient Name');

// 設(shè)置郵件主題和內(nèi)容
$smtp->setSubject('Test Email');
$smtp->setMessage('This is a test email.');

// 發(fā)送郵件
$smtp->send();

As can be seen from the above example of sending an email, the method of using the SMTP class is relatively cumbersome. It is necessary to manually configure the SMTP server parameters, authentication methods, etc., and the code is lengthy and difficult to maintain.

PHPMailer Class

In response to the above-mentioned inconvenient use problems, the PHPMailer class has become an easier-to-use PHP email sending class library. The PHPMailer class encapsulates the SMTP class and provides a more friendly interface, such as using the password of the SMTP server, using SSL and TLS, etc.

The following is an example of using the PHPMailer class to send emails:

use PHPMailerPHPMailerPHPMailer;

// 創(chuàng)建PHPMailer實(shí)例
$mail = new PHPMailer();

// 配置SMTP服務(wù)器參數(shù)
$mail->isSMTP();
$mail->Host = 'smtp.example.com'; // SMTP服務(wù)器地址
$mail->SMTPAuth = true;
$mail->Username = 'username'; // SMTP認(rèn)證用戶(hù)名
$mail->Password = 'password'; // SMTP認(rèn)證密碼

// 設(shè)置SSL加密
$mail->SMTPSecure = 'ssl';
$mail->Port = 465;

// 設(shè)置發(fā)件人和收件人
$mail->setFrom('from@example.com', 'From Name');
$mail->addAddress('recipient@example.com', 'Recipient Name');

// 設(shè)置郵件主題和內(nèi)容
$mail->Subject = 'Test Email';
$mail->Body = 'This is a test email.';

// 發(fā)送郵件
if ($mail->send()) {
    echo '郵件發(fā)送成功!';
} else {
    echo '郵件發(fā)送失敗: ' . $mail->ErrorInfo;
}

Using the PHPMailer class, you can more easily configure SMTP server parameters, support SSL encryption, and provide a friendly interface. In addition, the PHPMailer class also supports SMTP server authentication error handling, attachment sending and other functions. It is one of the more commonly used class libraries for PHP email sending.

Summary

Through the introduction of this article, we know that PHP sends emails through SMTP. At the same time, PHP also provides two methods: SMTP class library and PHPMailer class library. In actual development, it is very important to choose the appropriate class library according to your needs.

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