Azure Functions：是否有机会在不使用 azure 包的情况下附加 blob 存储？

Question

我使用 blob 存储作为输出。但我只能创建新文件，但不能追加。有机会追加吗？

Answer 1

有机会追加吗？

是的，您可以将数据附加到 blob。我们重现了相同的场景。

使用以下示例代码将数据附加到 blob。

Azure Function 代码示例

using Azure.Storage.Blobs;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.Extensions.Logging;
using System;
using System.IO;
using System.Threading.Tasks;
using Newtonsoft.Json;
using System.Collections.Generic;
using Azure.Storage.Blobs.Models;
using Azure.Storage.Blobs.Specialized;

namespace AF_append_blob_file
{
    public static class Function1
    {
        [FunctionName("Function1")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            string con = Environment.GetEnvironmentVariable("AzureWebJobsStorage");
            string containername = Environment.GetEnvironmentVariable("ContainerName");

            string localpath = "C:/Users/v-pusharma/Desktop/2question.txt";
            
            var filename = Path.GetFileName(localpath);
            BlobContainerClient blobContainerClient = new BlobContainerClient(con, containername);

            AppendBlobClient appendBlobClient = blobContainerClient.GetAppendBlobClient(containername);
            appendBlobClient.CreateIfNotExists();
            
            var maxblobsize = appendBlobClient.AppendBlobMaxAppendBlockBytes;
            var buffer = new byte[maxblobsize];
            byte[] buffer2 = File.ReadAllBytes(localpath);
            MemoryStream memoryStream = new MemoryStream(buffer2);
            
            if (memoryStream.Length <= maxblobsize)
            {
               appendBlobClient.AppendBlock(memoryStream);
            }
            else
            {
                var byteleft = (memoryStream.Length - memoryStream.Position);
                while (byteleft > 0)
                {
                    if (byteleft >= maxblobsize)
                    {
                        buffer = new byte[maxblobsize];
                        await memoryStream.ReadAsync(buffer, 0, maxblobsize);
                    }
                    else
                    {
                        buffer = new byte[byteleft];
                        await memoryStream.ReadAsync
                            (buffer, 0, Convert.ToInt32(byteleft));
                    }
                    appendBlobClient.AppendBlock(new MemoryStream(buffer));

                    byteleft = (memoryStream.Length - memoryStream.Position);
                }
            }
            return new OkObjectResult("Ok");
        }
    }
}

附加前的 Blob 文件，大小 (20B)

追加前的结果

第一次运行

后追加 blob 的结果，Size(40B)

第二次跑

附加输出后

请参阅 Microsoft Documentation 以将数据附加到 Azure 存储中的 blob。