ABP框架系列之二十四：(Email-Sending-EF-电子邮件发送)

Introduction

Email sending is a pretty common task for almost every application. ASP.NET Boilerplate provides a basic infrastructure to simply send emails and seperate email server configuration from sending emails.

IEmailSender

IEmailSender is a service to simply send emails without knowing details. Example usage:

public class TaskManager : IDomainService
{
    private readonly IEmailSender _emailSender;

    public TaskManager(IEmailSender emailSender)
    {
        _emailSender = emailSender;
    }

    public void Assign(Task task, Person person)
    {
        //Assign task to the person
        task.AssignedTo = person;

        //Send a notification email
        _emailSender.Send(
            to: person.EmailAddress,
            subject: "You have a new task!",
            body: $"A new task is assigned for you: <b>{task.Title}</b>",
            isBodyHtml: true
        );
    }
}

We simply injected IEmailSender and used Send method. Send method has a few more overloads. It can also get a MailMessage object (not available for .net core since .net core does not include SmtpClient and MailMessage).

我们简单用注射IEmailSender和发送方法。发送方法有更多重载。它也可以让一个MailMessage对象（不可用。NET的核心从.NET核心不包括SmtpClient和邮件）。

ISmtpEmailSender

There is also ISmtpEmailSender which extends IEmailSender and adds BuildClient method to create an SmtpClient to directly use it (not available for .net core since .net core does not include SmtpClient and MailMessage). Using IEmailSender will be enough for most cases.

也有ismtpemailsender继承 iemailsender和添加方法用于创建在一buildclient SmtpClient直接使用它（不可用，因为.NET .NET核心的核心不包含MailMessage和SmtpClient）。使用iemailsender要足够的大多数例子。

NullEmailSender

There is also a null object pattern implementation of IEmailSender as NullEmailSender. You can use it in unit tests or injecting IEmalSender with property injection pattern.

Configuration

Email Sender uses setting management system to read emal sending configuration. All setting names are defined in Abp.Net.Mail.EmailSettingNames class as constant strings. Their values and descriptions:

电子邮件发件人使用设置管理系统读取邮件发送配置。所有设定的名字是在类的定义abp.net.mail.emailsettingnames常量字符串。他们的值和描述：

• Abp.Net.Mail.DefaultFromAddress: Used as sender email address when you don't specify a sender while sending emails (as like in the sample above).
• Abp.Net.Mail.DefaultFromDisplayName: Used as sender display name when you don't specify a sender while sending emails (as like in the sample above).
• Abp.Net.Mail.Smtp.Host: IP/Domain of the SMTP server (default: 127.0.0.1).
• Abp.Net.Mail.Smtp.Port: Port of the SMTP server (default: 25).
• Abp.Net.Mail.Smtp.UserName: Username, if SMTP server requires authentication.
• Abp.Net.Mail.Smtp.Password: Password, if SMTP server requires authentication.
• Abp.Net.Mail.Smtp.Domain: Domain for the username, if SMTP server requires authentication.
• Abp.Net.Mail.Smtp.EnableSsl: A value indicates that SMTP server uses SSL or not ("true" or "false". Default: "false").
• Abp.Net.Mail.Smtp.UseDefaultCredentials: True, to use default credentials instead of provided username and password ("true" or "false". Default: "true").

MailKit Integration

Since .net core does not support standard System.Net.Mail.SmtpClient, so we need a 3rd-party vendor to send emails. Fortunately, MailKit provides a good replacement for default SmtpClient. It's also suggested by Microsoft.

Abp.MailKit package gracefully integrates to ABP's email sending system. So, you can still use IEmailSender as described above to send emails via MailKit.

Installation

First, install Abp.MailKit nuget package to your project:

Install-Package Abp.MailKit

Integration

Add AbpMailKitModule to dependencies of your module:

[DependsOn(typeof(AbpMailKitModule))]
public class MyProjectModule : AbpModule
{
    //...
}

Usage

You can use IEmailSender as described before since Abp.MailKit package registers MailKit implementation for it. It also uses the same configuration defined above.

Customization

You may need to make additional configuration or customization while creating MailKit's SmtpClient. In that case, you can replace IMailKitSmtpBuilder interface with your own implementation. You can derive from DefaultMailKitSmtpBuilder to make it easier. For instance, you may want to accept all SSL certificates. In that case, you can override ConfigureClient method as shown below:

你可能需要进行额外的配置或定制的同时创造MailKit SmtpClient。在这种情况下，你可以用你自己的imailkitsmtpbuilder接口实现替换。你可以从defaultmailkitsmtpbuilder更容易。例如，您可能希望接受所有SSL证书。在这种情况下，您可以重写configureclient方法如下图所示：

public class MyMailKitSmtpBuilder : DefaultMailKitSmtpBuilder
{
    public MyMailKitSmtpBuilder(ISmtpEmailSenderConfiguration smtpEmailSenderConfiguration) 
        : base(smtpEmailSenderConfiguration)
    {
    }

    protected override void ConfigureClient(SmtpClient client)
    {
        client.ServerCertificateValidationCallback = (sender, certificate, chain, errors) => true;

        base.ConfigureClient(client);
    }
}

Then you can replace IMailKitSmtpBuilder interface with your implementation in PreInitialize method of your module:

[DependsOn(typeof(AbpMailKitModule))]
public class MyProjectModule : AbpModule
{
    public override void PreInitialize()
    {
        Configuration.ReplaceService<IMailKitSmtpBuilder, MyMailKitSmtpBuilder>();
    }

    //...
}

(remember to add "using Abp.Configuration.Startup;" statement since ReplaceService extension method is defined in that namespace)

（记得添加“使用ABP。配置。启动；”声明后，replaceservice扩展方法是定义在命名空间）