feat: 文传易匿名临时文件传输站初始版本

- 后端 .NET 8 + FreeSql + 阿里云 OSS，支持共享/私密/标签三种文件模式 - 前端 Vue3 + Vite + TDesign，上传/取件/管理三页 - 取件码/二维码/海报合成（含保存二维码为图片） - deploy/ 部署文档与一键 FTP 发布脚本 - appsettings.json 含真实凭据，已 gitignore 不入库
2026-08-24 00:03:28 +08:00
commit 1bfc72f9cb
40 changed files with 6849 additions and 0 deletions
@@ -0,0 +1,68 @@
+using Aliyun.OSS;
+
+namespace WenChuanyi.Api.Services;
+
+/// <summary>OSS 存储服务：对象键构造、流式上传/下载/删除（后端中转，前端不接触凭据）</summary>
+public class OssStorageService
+{
+    private readonly OssClient _client;
+    private readonly string _bucket;
+    private readonly string _baseKey;
+    private readonly ILogger<OssStorageService> _logger;
+
+    public OssStorageService(IConfiguration cfg, ILogger<OssStorageService> logger)
+    {
+        var endpoint = cfg["Oss:Endpoint"] ?? throw new InvalidOperationException("缺少配置 Oss:Endpoint");
+        var ak = cfg["Oss:AccessKeyId"] ?? throw new InvalidOperationException("缺少配置 Oss:AccessKeyId");
+        var sk = cfg["Oss:AccessKeySecret"] ?? throw new InvalidOperationException("缺少配置 Oss:AccessKeySecret");
+        _bucket = cfg["Oss:Bucket"] ?? throw new InvalidOperationException("缺少配置 Oss:Bucket");
+        _baseKey = cfg["Oss:BaseKey"] ?? "文传易2026";
+        _client = new OssClient(endpoint, ak, sk);
+        _logger = logger;
+    }
+
+    /// <summary>构造对象键：文传易2026/{yyyyMM}/{Guid}{ext}（按上传月份建子目录）</summary>
+    public string BuildObjectKey(string originalName)
+    {
+        var month = DateTime.Now.ToString("yyyyMM");
+        var ext = Path.GetExtension(originalName).ToLowerInvariant();
+        return $"{_baseKey}/{month}/{Guid.NewGuid():N}{ext}";
+    }
+
+    /// <summary>流式上传（不落本地、不整体读内存）。ContentType 会去除参数部分（如 ";charset=utf-8"），
+    /// 因为 OSS SDK 对带参数的 Content-Type 签名会与服务端校验不一致，导致 403 签名不匹配。</summary>
+    public async Task UploadAsync(string objectKey, Stream stream, string contentType)
+    {
+        var safeContentType = (contentType ?? "application/octet-stream").Split(';')[0].Trim();
+        if (string.IsNullOrEmpty(safeContentType)) safeContentType = "application/octet-stream";
+        var req = new PutObjectRequest(_bucket, objectKey, stream);
+        req.Metadata = new ObjectMetadata { ContentType = safeContentType };
+        await Task.Run(() => _client.PutObject(req)).ConfigureAwait(false);
+    }
+
+    /// <summary>获取对象（支持 Range；end 为 -1 表示到文件末尾）</summary>
+    public OssObject GetObject(string objectKey, long? start = null, long? end = null)
+    {
+        var req = new GetObjectRequest(_bucket, objectKey);
+        if (start.HasValue || end.HasValue)
+        {
+            req.SetRange(start ?? 0, end ?? -1);
+        }
+        return _client.GetObject(req);
+    }
+
+    /// <summary>删除对象（失败不抛出，由调用方记录日志）</summary>
+    public bool TryDeleteObject(string objectKey)
+    {
+        try
+        {
+            _client.DeleteObject(_bucket, objectKey);
+            return true;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "OSS 对象删除失败：{ObjectKey}", objectKey);
+            return false;
+        }
+    }
+}