first commot

Service/EmailFetchService.cs

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+using MailKit;
+using MailKit.Net.Imap;
+using MailKit.Search;
+using MailKit.Security;
+using MimeKit;
+
+namespace Service;
+
+/// <summary>
+/// 邮件抓取服务接口
+/// </summary>
+public interface IEmailFetchService
+{
+    /// <summary>
+    /// 连接状态
+    /// </summary>
+    bool IsConnected { get; }
+    
+    /// <summary>
+    /// 连接到邮件服务器
+    /// </summary>
+    Task<bool> ConnectAsync(string host, int port, bool useSsl, string email, string password);
+
+    /// <summary>
+    /// 从收件箱获取未读邮件
+    /// </summary>
+    Task<List<(MimeMessage Message, UniqueId Uid)>> FetchUnreadMessagesAsync();
+
+    /// <summary>
+    /// 获取所有邮件
+    /// </summary>
+    Task<List<(MimeMessage Message, UniqueId Uid)>> FetchAllMessagesAsync();
+    
+    /// <summary>
+    /// 断开与邮件服务器的连接
+    /// </summary>
+    Task DisconnectAsync();
+
+    /// <summary>
+    /// 标记邮件为已读
+    /// </summary>
+    Task MarkAsReadAsync(UniqueId uid);
+    
+    /// <summary>
+    /// 确保连接有效，如断开则自动重连
+    /// </summary>
+    Task<bool> EnsureConnectedAsync();
+}
+
+/// <summary>
+/// 邮件抓取服务实现
+/// </summary>
+public class EmailFetchService(ILogger<EmailFetchService> logger) : IEmailFetchService
+{
+    private ImapClient? _imapClient;
+    private string _host = string.Empty;
+    private int _port;
+    private bool _useSsl;
+    private string _email = string.Empty;
+    private string _password = string.Empty;
+    private DateTime _lastKeepAlive = DateTime.MinValue;
+    private const int KeepAliveIntervalSeconds = 300; // 5分钟发送一次KeepAlive
+    private readonly ILogger<EmailFetchService> _logger = logger;
+    
+    public bool IsConnected => _imapClient?.IsConnected == true;
+
+    public async Task<bool> ConnectAsync(string host, int port, bool useSsl, string email, string password)
+    {
+        try
+        {
+            // 保存连接信息用于自动重连
+            _host = host;
+            _port = port;
+            _useSsl = useSsl;
+            _email = email;
+            _password = password;
+            
+            // 如果已连接，先断开
+            if (_imapClient?.IsConnected == true)
+            {
+                await DisconnectAsync();
+            }
+            
+            _imapClient = new ImapClient();
+
+            if (useSsl)
+            {
+                await _imapClient.ConnectAsync(host, port, SecureSocketOptions.SslOnConnect);
+            }
+            else
+            {
+                await _imapClient.ConnectAsync(host, port, SecureSocketOptions.StartTlsWhenAvailable);
+            }
+
+            await _imapClient.AuthenticateAsync(email, password);
+            _logger.LogInformation("邮箱 {Email} 连接成功", email);
+            _lastKeepAlive = DateTime.UtcNow;
+            return true;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "邮件连接失败 ({Email}): {Message}", email, ex.Message);
+            return false;
+        }
+    }
+
+    public async Task<List<(MimeMessage Message, UniqueId Uid)>> FetchUnreadMessagesAsync()
+    {
+        var result = new List<(MimeMessage, UniqueId)>();
+
+        try
+        {
+            // 确保连接有效
+            if (!await EnsureConnectedAsync())
+                return result;
+
+            var inbox = _imapClient?.Inbox;
+            if (inbox == null)
+                return result;
+
+            await inbox.OpenAsync(FolderAccess.ReadWrite);
+
+            // 查询未读邮件
+            var unreadUids = await inbox.SearchAsync(SearchQuery.NotSeen);
+
+            foreach (var uid in unreadUids)
+            {
+                var message = await inbox.GetMessageAsync(uid);
+                result.Add((message, uid));
+            }
+
+            return result;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "获取未读邮件失败: {Message}", ex.Message);
+            return result;
+        }
+    }
+
+    public async Task<List<(MimeMessage Message, UniqueId Uid)>> FetchAllMessagesAsync()
+    {
+        var result = new List<(MimeMessage, UniqueId)>();
+
+        try
+        {
+            // 确保连接有效
+            if (!await EnsureConnectedAsync())
+                return result;
+
+            var inbox = _imapClient?.Inbox;
+            if (inbox == null)
+                return result;
+
+            await inbox.OpenAsync(FolderAccess.ReadWrite);
+
+            var uids = await inbox.SearchAsync(SearchQuery.All);
+
+            foreach (var uid in uids)
+            {
+                var message = await inbox.GetMessageAsync(uid);
+                result.Add((message, uid));
+            }
+
+            return result;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "获取所有邮件失败: {Message}", ex.Message);
+            return result;
+        }
+    }
+
+    public async Task DisconnectAsync()
+    {
+        try
+        {
+            if (_imapClient?.IsConnected == true)
+            {
+                await _imapClient.DisconnectAsync(true);
+                _logger.LogInformation("邮箱 {Email} 已断开连接", _email);
+            }
+
+            _imapClient?.Dispose();
+            _imapClient = null;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "断开连接失败 ({Email}): {Message}", _email, ex.Message);
+        }
+    }
+
+    public async Task MarkAsReadAsync(UniqueId uid)
+    {
+        try
+        {
+            if (!await EnsureConnectedAsync())
+                return;
+
+            var inbox = _imapClient?.Inbox;
+            if (inbox == null)
+                return;
+
+            // 打开收件箱以读写模式
+            await inbox.OpenAsync(FolderAccess.ReadWrite);
+
+            // 标记邮件为已读（设置Seen标记）
+            await inbox.AddFlagsAsync(uid, MessageFlags.Seen, silent: false);
+            
+            _logger.LogDebug("邮件 {Uid} 标记已读操作已提交", uid);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "标记邮件为已读失败: {Message}", ex.Message);
+        }
+    }
+    
+    /// <summary>
+    /// 确保连接有效，如果断开则自动重连
+    /// </summary>
+    public async Task<bool> EnsureConnectedAsync()
+    {
+        if (_imapClient?.IsConnected == true)
+        {
+            // 定期发送NOOP保持连接活跃（防止超时断开）
+            var timeSinceLastKeepAlive = (DateTime.UtcNow - _lastKeepAlive).TotalSeconds;
+            if (timeSinceLastKeepAlive > KeepAliveIntervalSeconds)
+            {
+                try
+                {
+                    await _imapClient.NoOpAsync();
+                    _lastKeepAlive = DateTime.UtcNow;
+                    _logger.LogDebug("邮箱 {Email} KeepAlive 保活信号已发送", _email);
+                }
+                catch (Exception ex)
+                {
+                    // NOOP失败，说明连接已断开，继续重连逻辑
+                    _logger.LogWarning(ex, "KeepAlive 失败，连接已断开: {Message}", ex.Message);
+                }
+            }
+            return _imapClient?.IsConnected == true;
+        }
+            
+        if (string.IsNullOrEmpty(_host) || string.IsNullOrEmpty(_email))
+        {
+            _logger.LogWarning("未初始化连接信息，无法自动重连");
+            return false;
+        }
+        
+        _logger.LogInformation("检测到连接断开，尝试重新连接到 {Email}...", _email);
+        return await ConnectAsync(_host, _port, _useSsl, _email, _password);
+    }
+}