feat(wechat): Add access token refresh control and improve template message error handling

- Add forceRefresh parameter to GetServiceAccountAccessTokenAsync for cache bypass capability
- Implement automatic token refresh retry logic for HTTP 412 and token expiration error codes (40001, 42001)
- Extract SendServiceAccountTemplateMessageAsync into internal method to support retry mechanism
- Enhance logging with contextual parameters (AppId, ToUser, TemplateId, AccessToken prefix) for better diagnostics
- Add conditional logging for failed requests with full diagnostic information
- Improve error handling to distinguish between token expiration scenarios and other failures
- Add informational logging when requesting new access tokens

server/src/XiangYi.Infrastructure/WeChat/IWeChatService.cs

@@ -67,8 +67,9 @@ public interface IWeChatService
     /// <summary>
     /// 获取服务号AccessToken
     /// </summary>
+    /// <param name="forceRefresh">是否强制刷新（忽略缓存）</param>
     /// <returns>AccessToken</returns>
-    Task<string?> GetServiceAccountAccessTokenAsync();
+    Task<string?> GetServiceAccountAccessTokenAsync(bool forceRefresh = false);
 
     /// <summary>
     /// 获取服务号关注用户信息（包含UnionId）

server/src/XiangYi.Infrastructure/WeChat/WeChatService.cs

@@ -371,7 +371,7 @@ public class WeChatService : IWeChatService
 
     private const string ServiceAccountAccessTokenCacheKey = "wechat:service_account:access_token";
 
-    public async Task<string?> GetServiceAccountAccessTokenAsync()
+    public async Task<string?> GetServiceAccountAccessTokenAsync(bool forceRefresh = false)
     {
         // 检查服务号配置
         if (string.IsNullOrEmpty(_options.ServiceAccount?.AppId) || 
@@ -381,10 +381,13 @@ public class WeChatService : IWeChatService
             return null;
         }
 
-        // 先从缓存获取
-        var cached = await _cache.GetStringAsync(ServiceAccountAccessTokenCacheKey);
-        if (!string.IsNullOrEmpty(cached))
-            return cached;
+        // 先从缓存获取（非强制刷新时）
+        if (!forceRefresh)
+        {
+            var cached = await _cache.GetStringAsync(ServiceAccountAccessTokenCacheKey);
+            if (!string.IsNullOrEmpty(cached))
+                return cached;
+        }
 
         // 请求新的AccessToken
         var url = $"https://api.weixin.qq.com/cgi-bin/token" +
@@ -392,6 +395,8 @@ public class WeChatService : IWeChatService
                   $"&appid={_options.ServiceAccount.AppId}" +
                   $"&secret={_options.ServiceAccount.AppSecret}";
 
+        _logger.LogInformation("请求服务号AccessToken: AppId={AppId}", _options.ServiceAccount.AppId);
+
         var httpResponse = await _httpClient.GetAsync(url);
         var responseContent = await httpResponse.Content.ReadAsStringAsync();
         var response = JsonSerializer.Deserialize<AccessTokenResponse>(responseContent);
@@ -402,6 +407,8 @@ public class WeChatService : IWeChatService
             return null;
         }
 
+        _logger.LogInformation("获取服务号AccessToken成功");
+
         // 缓存AccessToken，提前5分钟过期
         var expireSeconds = response.ExpiresIn - 300;
         await _cache.SetStringAsync(
@@ -416,13 +423,20 @@ public class WeChatService : IWeChatService
     }
 
     public async Task<bool> SendServiceAccountTemplateMessageAsync(ServiceAccountTemplateMessageRequest request)
+    {
+        return await SendServiceAccountTemplateMessageInternalAsync(request, isRetry: false);
+    }
+
+    private async Task<bool> SendServiceAccountTemplateMessageInternalAsync(
+        ServiceAccountTemplateMessageRequest request, bool isRetry)
     {
         try
         {
             var accessToken = await GetServiceAccountAccessTokenAsync();
             if (string.IsNullOrEmpty(accessToken))
             {
-                _logger.LogError("获取服务号AccessToken失败");
+                _logger.LogError("获取服务号AccessToken失败, AppId={AppId}, ToUser={ToUser}, TemplateId={TemplateId}",
+                    _options.ServiceAccount?.AppId, request.ToUser, request.TemplateId);
                 return false;
             }
 
@@ -454,33 +468,51 @@ public class WeChatService : IWeChatService
             var response = await _httpClient.PostAsJsonAsync(url, requestBody);
             var responseContent = await response.Content.ReadAsStringAsync();
 
-            _logger.LogInformation("发送服务号模板消息: StatusCode={StatusCode}, Response={Response}", 
-                (int)response.StatusCode, responseContent);
+            // 非200时打印完整诊断信息
+            if (!response.IsSuccessStatusCode || string.IsNullOrWhiteSpace(responseContent))
+            {
+                _logger.LogWarning("发送服务号模板消息失败: StatusCode={StatusCode}, AppId={AppId}, ToUser={ToUser}, TemplateId={TemplateId}, AccessToken={AccessToken}, IsRetry={IsRetry}, Response={Response}",
+                    (int)response.StatusCode, _options.ServiceAccount?.AppId, request.ToUser, request.TemplateId,
+                    accessToken?[..Math.Min(accessToken.Length, 20)] + "...", isRetry, responseContent);
+            }
 
-            // 打印请求体方便排查
-            var requestJson = System.Text.Json.JsonSerializer.Serialize(requestBody);
-            _logger.LogInformation("发送服务号模板消息请求体: {RequestBody}", requestJson);
+            // HTTP 412 表示 access_token 失效，强制刷新后重试一次
+            if ((int)response.StatusCode == 412 && !isRetry)
+            {
+                _logger.LogWarning("服务号AccessToken可能已失效(412)，强制刷新后重试");
+                await _cache.RemoveAsync(ServiceAccountAccessTokenCacheKey);
+                return await SendServiceAccountTemplateMessageInternalAsync(request, isRetry: true);
+            }
 
             if (string.IsNullOrWhiteSpace(responseContent))
             {
-                _logger.LogWarning("发送服务号模板消息失败: 微信返回空响应");
                 return false;
             }
 
             var result = System.Text.Json.JsonSerializer.Deserialize<WeChatApiResponse>(responseContent);
 
+            // errcode 40001/42001 也是 token 失效，重试
+            if (result != null && (result.ErrCode == 40001 || result.ErrCode == 42001) && !isRetry)
+            {
+                _logger.LogWarning("服务号AccessToken失效({ErrCode})，强制刷新后重试, AppId={AppId}", result.ErrCode, _options.ServiceAccount?.AppId);
+                await _cache.RemoveAsync(ServiceAccountAccessTokenCacheKey);
+                return await SendServiceAccountTemplateMessageInternalAsync(request, isRetry: true);
+            }
+
             if (result?.ErrCode != 0)
             {
-                _logger.LogWarning("发送服务号模板消息失败: {ErrCode} - {ErrMsg}", result?.ErrCode, result?.ErrMsg);
+                _logger.LogWarning("发送服务号模板消息失败: ErrCode={ErrCode}, ErrMsg={ErrMsg}, AppId={AppId}, ToUser={ToUser}, TemplateId={TemplateId}",
+                    result?.ErrCode, result?.ErrMsg, _options.ServiceAccount?.AppId, request.ToUser, request.TemplateId);
                 return false;
             }
 
-            _logger.LogInformation("发送服务号模板消息成功: {ToUser}", request.ToUser);
+            _logger.LogInformation("发送服务号模板消息成功: ToUser={ToUser}, TemplateId={TemplateId}", request.ToUser, request.TemplateId);
             return true;
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "发送服务号模板消息异常");
+            _logger.LogError(ex, "发送服务号模板消息异常: AppId={AppId}, ToUser={ToUser}, TemplateId={TemplateId}",
+                _options.ServiceAccount?.AppId, request.ToUser, request.TemplateId);
             return false;
         }
     }