Libraries required for C# code to export files to Azure Blob Storage from websites hosted on Azure App Service

Question

We were using IIS for deploying .NET web application.

One export to excel button had been given on UI to export details from database to Excel file and then it will be downloaded to local disc storage.

We used Microsoft Office Interop Excel to export file.

It was working fine locally. But when we deployed application on Azure App service, it was not downloading files in local disk.

Now, we want to export files to Azure Blob Storage.

Which libraries is required for writing C# code for such application?

Answer 1

Microsoft Office Interop Excel will not work when hosted in Azure. the library requires office be installed on the server, and is not designed for server use. you will need to replace with another library or build a custom VM hosted in azure.

to access azure blog storage you can use the HttpClient and the azure blob rest api

https://learn.microsoft.com/en-us/rest/api/storageservices/blob-service-rest-api

or a the client library:

https://learn.microsoft.com/en-us/azure/storage/blobs/storage-quickstart-blobs-dotnet?tabs=visual-studio%2Cmanaged-identity%2Croles-azure-portal%2Csign-in-azure-cli%2Cidentity-visual-studio

Answer 2

Export from data base to browser can be done very easily without any database using below method

In you asp.net web api project, in the method
a- import data into local DTO List
b- Convert that to CSV string
c- Return with mime type CSV

To export files to Azure Blob Storage from your .NET web application, you will need to use the Azure Blob Storage client library for .NET. You can install this library by adding the "Azure.Storage.Blobs" NuGet package to your project. Here is some sample code that shows how to create a Blob container, upload a file to it, and generate a shared access signature (SAS) URI for the uploaded file. This sample code assumes that you have already obtained the file to upload and have its file path in a variable called filePath. You will also need to replace the connection string and container and file names with the appropriate values for your storage account.

using Azure.Storage.Blobs;
using Azure.Storage.Blobs.Models;
using Azure.Storage.Sas;

// Get a reference to your storage account
string connectionString = "DefaultEndpointsProtocol=https;AccountName=myaccount;AccountKey=mykey;EndpointSuffix=core.windows.net";
BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);

// Create a Blob container to store your files
string containerName = "mycontainer";
BlobContainerClient containerClient = await blobServiceClient.CreateBlobContainerAsync(containerName);

// Upload a file to the container
string fileName = "myfile.xlsx";
BlobClient blobClient = containerClient.GetBlobClient(fileName);
using (var fileStream = File.OpenRead(filePath))
{
    await blobClient.UploadAsync(fileStream, new BlobUploadOptions { HttpHeaders = new BlobHttpHeaders { ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" } });
}

// Generate a SAS URI for the uploaded file
var sasBuilder = new BlobSasBuilder
{
    BlobContainerName = containerName,
    BlobName = fileName,
    Resource = "b",
    ExpiresOn = DateTimeOffset.UtcNow.AddHours(1)
};
sasBuilder.SetPermissions(BlobSasPermissions.Read);
string sasUri = blobClient.GenerateSasUri(sasBuilder);