【原创】使用阿里云存放一个临时共享的文件

在某些场合，需要临时将一个文件存储到一个可被公网访问的地方，某个服务需要访问一下这个文件。这个文件基本上就是一次寿命，也就是你上传一下，然后被访问一下，这个文件的寿命就结束了。

对于这种需求，自建服务程序，太麻烦。刚好，阿里云提供了这样的服务。其实就三个步骤：
1、创建一个临时存放的位置
2、上传文件
3、获取这个临时存放的位置对应的公网URL
然后将这个URL提供给某个服务就可以了 ，文件大约保存1个小时。那么这个文件的有效期也就是一个小时，基本上够用了。

接下来，按照如下编码，即可使用此功能。

获取临时文件上传地址

private static Client CreateHbrClient()
{
    return new Client(new Config
    {
        AccessKeyId = Environment.GetEnvironmentVariable("ALIBABA_CLOUD_ACCESS_KEY_ID"),
        AccessKeySecret = Environment.GetEnvironmentVariable("ALIBABA_CLOUD_ACCESS_KEY_SECRET"),
        Endpoint = "hbr.cn-hangzhou.aliyuncs.com"
    });
}
        
 private static CreateTempFileUploadUrlResponse? UploadFileToTempStorage(string filePath)
 {
     Client client = CreateHbrClient();

     try
     {
         return client.CreateTempFileUploadUrlWithOptions(new CreateTempFileUploadUrlRequest
         {
             FileName = Path.GetFileName(filePath)
         },
         new RuntimeOptions()
         );
     }
     catch (Exception error)
     {
         Console.WriteLine(error.Message);
         Console.WriteLine(error.Data["Recommend"]);
     }
     return null;
 }

上载临时文件

正在实现C#代码(这里试了很多次(HttpClient、WebClient)，都没搞定，最后用最原始的方式组装数据才能用)。但是Python代码不会遇到问题。

 public static void PostFile1(string filePath, CreateTempFileUploadUrlResponse data)
 {
     //提交文件
     Console.WriteLine("curl -X POST ^");
     Console.WriteLine("-F \"OSSAccessKeyId=" + data.Body.OssAccessKeyId + "\" ^");
     Console.WriteLine("-F \"Signature=" + data.Body.Signature + "\" ^");
     Console.WriteLine("-F \"Policy=" + data.Body.Policy + "\" ^");
     Console.WriteLine("-F \"key=" + data.Body.TempFileKey + "\" ^");
     Console.WriteLine("-F \"file=@" + filePath + "\" ^");
     Console.WriteLine($"https://{data.Body.BucketName}.{data.Body.Endpoint}/");
     Console.WriteLine("");

     Console.ReadLine();
 }
 public static void PostFileAsync(string filePath, CreateTempFileUploadUrlResponse data)
 {
     //PostFile1(filePath, data);

     var uploadUrl = $"https://{data.Body.BucketName}.{data.Body.Endpoint}/";
     string host = $"{data.Body.BucketName}.{data.Body.Endpoint}";
     string boundary = "---------------------------boundary";
     string contentType = "multipart/form-data; boundary=" + boundary;

     // 构造请求头
     string requestHeader = $"POST / HTTP/1.1\r\n";
     requestHeader += $"Host: {host}\r\n";
     requestHeader += $"Content-Type: {contentType}\r\n";
     requestHeader += "Connection: close\r\n";

     // 构造请求体
     StringBuilder requestBody = new StringBuilder();
     requestBody.AppendLine($"--{boundary}");
     requestBody.AppendLine("Content-Disposition: form-data; name=\"OSSAccessKeyId\"");
     requestBody.AppendLine();
     requestBody.AppendLine(data.Body.OssAccessKeyId);
     requestBody.AppendLine($"--{boundary}");
     requestBody.AppendLine("Content-Disposition: form-data; name=\"Signature\"");
     requestBody.AppendLine();
     requestBody.AppendLine(data.Body.Signature);
     requestBody.AppendLine($"--{boundary}");
     requestBody.AppendLine("Content-Disposition: form-data; name=\"Policy\"");
     requestBody.AppendLine();
     requestBody.AppendLine(data.Body.Policy);
     requestBody.AppendLine($"--{boundary}");
     requestBody.AppendLine("Content-Disposition: form-data; name=\"key\"");
     requestBody.AppendLine();
     requestBody.AppendLine(data.Body.TempFileKey);
     requestBody.AppendLine($"--{boundary}");
     requestBody.AppendLine("Content-Disposition: form-data; name=\"file\"; filename=\"" + Path.GetFileName(filePath) + "\"");
     requestBody.AppendLine("Content-Type: audio/m4a");
     requestBody.AppendLine();

     byte[] requestBodyBytes = Encoding.UTF8.GetBytes(requestBody.ToString());

     // 读取文件内容
     byte[] fileBytes = File.ReadAllBytes(filePath);

     // 构造完整的请求数据
     byte[] requestBytes = new byte[requestBodyBytes.Length + fileBytes.Length + Encoding.UTF8.GetBytes($"\r\n--{boundary}--\r\n").Length];
     requestBodyBytes.CopyTo(requestBytes, 0);
     fileBytes.CopyTo(requestBytes, requestBodyBytes.Length);
     Encoding.UTF8.GetBytes($"\r\n--{boundary}--\r\n").CopyTo(requestBytes, requestBodyBytes.Length + fileBytes.Length);

     // 发送请求
     using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
     {
         IPAddress ipAddress = Dns.GetHostEntry(host).AddressList[0];
         IPEndPoint remoteEP = new IPEndPoint(ipAddress, 443);

         socket.Connect(remoteEP);

         // 使用SslStream封装Socket连接
         using (SslStream sslStream = new SslStream(new NetworkStream(socket), false, (object sender, X509Certificate? certificate, X509Chain? chain, SslPolicyErrors sslPolicyErrors)=>true))
         {
             sslStream.AuthenticateAsClient(host);

             // 发送请求头
             byte[] headerBytes = Encoding.UTF8.GetBytes(requestHeader + $"Content-Length: {requestBytes.Length}\r\n\r\n");
             sslStream.Write(headerBytes);

             // 发送请求体
             sslStream.Write(requestBytes);

             // 接收响应
             byte[] buffer = new byte[1024];
             int bytesRead;
             StringBuilder response = new StringBuilder();
             while ((bytesRead = sslStream.Read(buffer, 0, buffer.Length)) > 0)
             {
                 response.Append(Encoding.UTF8.GetString(buffer, 0, bytesRead));
             }

             Console.WriteLine("Response:");
             Console.WriteLine(response.ToString());
         }
     }
 }

获取文件路径

    public static string? GetUrl(string filePath, CreateTempFileUploadUrlResponse data)
    {
        Client client = CreateHbrClient();

        try
        {
            return client.GetTempFileDownloadLinkWithOptions(new GetTempFileDownloadLinkRequest
            {
                TempFileKey = data.Body.TempFileKey,
            },
            new RuntimeOptions()
            ).Body.Url;
        }
        catch (Exception error)
        {
            Console.WriteLine(error.Message);
            Console.WriteLine(error.Data["Recommend"]);
        }
        return null;
    }
}

执行代码

const string filePath = "C:\\Users\\Zmrbak\\Documents\\Camtasia\\声线20250513-26.m4a";

//获取临时文件上传地址
var urlResponse = UploadFileToTempStorage(filePath);
if (urlResponse == null) return;

//上载临时文件
await PostFileAsync(filePath, urlResponse);

//获取文件路径
var url = GetUrl(filePath, urlResponse);
Console.WriteLine(url);