How to download and read Azure blob container files

Question

I need to download all files from the Azure blob container and then read file one by one to find the sum of all ASCII character values.

Answer 1

Here is the example to download and read Azure Blobs Container Files in C#. You will need to make function async-await to connect Azure Blobs Container and download the blob files locally to read and "do something" with these file. In the example, we are finding the joker file that size exactly 11K bytes and making sum of ASCII value of each character in the joker file and other files and at the last multiplying sum of ASCII value of joker file with other files ASCII value.

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Azure.Storage.Blobs;
using Azure.Storage.Blobs.Models;

namespace myApp
{
    class Program
    {
        static async Task Main(string[] args)
        {   /**********************************************************************************************
            * Sum the ASCII value - find the joker (228326687915660 = 329081602*693830)
            ***********************************************************************************************/
            Uri blobContainerUri = new Uri("blob-container-uri-find-the-joker");
            BlobContainerClient blobContainerClient = new BlobContainerClient(blobContainerUri, null);
            string localPath = "./data/";
            ulong sumASCIIValue = 0ul;
            ulong sumJokerASCIIValue = 0ul;

            await foreach (var blob in blobContainerClient.GetBlobsAsync())
            {
                string fileName = blob.Name;
                string localFilePath = Path.Combine(localPath, fileName);

                using (var file = File.Open(localFilePath, FileMode.OpenOrCreate, FileAccess.ReadWrite))
                {
                    var blobClient = blobContainerClient.GetBlobClient(blob.Name);
                    await blobClient.DownloadToAsync(file);

                    if (file.CanRead)
                    {
                        file.Position = 0;

                        byte[] readBytes = new byte[file.Length];

                        // Detect joker file
                        if (file.Length >= 11000)
                        {
                            while (file.Read(readBytes, 0, readBytes.Length) > 0)
                            {
                                string asciiString = System.Text.Encoding.ASCII.GetString(readBytes);
                                foreach (Char chr in asciiString)
                                {
                                    sumJokerASCIIValue += (ulong)chr;
                                }
                            }
                        }
                        else
                        {
                            while (file.Read(readBytes, 0, readBytes.Length) > 0)
                            {
                                string asciiString = System.Text.Encoding.ASCII.GetString(readBytes);
                                foreach (Char chr in asciiString)
                                {
                                    sumASCIIValue += (ulong)chr;
                                }
                            }
                        }
                    }
                }

                Console.WriteLine("File Read: {0} sumASCIIValue: {1}, sumJokerASCIIValue: {2}", fileName, sumASCIIValue, sumJokerASCIIValue);
            }

            Console.WriteLine("ASCII value: {0}", sumASCIIValue * sumJokerASCIIValue);
        }
    }
}