How to Upload Files using Azure Storage and Entity Framework

Question

I am using .NET Core MVC in my project. So I have a Document.cs which looks like

public class Document{
     public int DocumentId { get; set; }
     public string DocumentName { get; set; }

     public int DocumentTypeId { get; set; }
     public DocumentType DocumentType { get; set; } 

     public string DocumentFilePath { get; set; } //which contains the File Name for my File Upload function.
}

and my File Upload method is looks like:

[HttpPost]
public async Task<IActionResult> CreateDocument (DocumentModel model)
{
    string uniqueFileName = null;
    if(model.DocumentFilePath != null)
    {
        string uploadsFolder = Path.Combine(_hostingEnvironment.WebRootPath, "StoredFiles");
        uniqueFileName = model.DocumentFilePath.FileName;
        string filePath = Path.Combine(uploadsFolder, uniqueFileName);
        await model.DocumentPath.CopyToAsync(new FileStream(filePath, FileMode.Create));
    }
    var entity = new Document()
    {
        DocumentName = model.DocumentName,
        DocumentTypeId = model.DocumentTypeId,
        DocumentFilePath = uniqueFileName,        
    };

     _documentService.Create(entity); // Simple '_context.Set<Document>().Add(entity);'

     return RedirectToAction("CreateDocument");
}

As you see I have also a DocumentModel.cs comes from my View which looks like:

public class DocumentModel
{
    public int DocumentId { get; set; }

    public string DocumentName { get; set; }

    public IFormFile DocumentFilePath { get; set; }

    public int DocumentTypeId { get; set; }

    public List<DocumentType> DocumentTypes { get; set;} //For my SelectList in my View.
}

Okay, So what this actually does is, as you can simply understand that, upload a file to my "StoredFiles" under my "wwwroot" Folder, and takes the "File Name" and store it in my database.

So I want to start to use Azure Blob Storage. Because I dont want to store files in my project folder. I watched some videos about Azure Storage and how it works but I cant understand how to convert my FileUpload method to an AzureStorage method.

In my opinion I should try to do something like this

[HttpPost]
public async Task<IActionResult> CreateDocument (DocumentModel model)
{
    string uniqueFileName = null;
    if(model.DocumentFilePath != null)
    {
        //I think in this part I have to upload to Azure, then I have to get a 
        //return value for my DocumentFilePath for my "entity" object below.
    }
    var entity = new Document()
    {
        DocumentName = model.DocumentName,
        DocumentTypeId = model.DocumentTypeId,
        DocumentFilePath = uniqueFileName,        
    };

     _documentService.Create(entity); // Simple '_context.Set<Document>().Add(entity);'

     return RedirectToAction("CreateDocument");
}

or I can use seperate methods first one will uploads to azure then second one saves to my Database.

I'd be so happy if you'll help me. Thank you.

Answer 1

If using blob storage, firstly install the NuGet package: Microsoft.Azure.Storage.Blob

Then try below codes:

string storageConnection = CloudConfigurationManager.GetSetting("BlobStorageConnectionString");

CloudStorageAccount cloudStorageAccount = CloudStorageAccount.Parse(storageConnection);

CloudBlobClient cloudBlobClient = cloudStorageAccount.CreateCloudBlobClient();

CloudBlobContainer cloudBlobContainer = cloudBlobClient.GetContainerReference("appcontainer");

//create a container if it is not already exists

if (await cloudBlobContainer.CreateIfNotExistsAsync())
{

    await cloudBlobContainer.SetPermissionsAsync(new BlobContainerPermissions { PublicAccess = BlobContainerPublicAccessType.Blob });

}


//get Blob reference

CloudBlockBlob cloudBlockBlob = cloudBlobContainer.GetBlockBlobReference(model.DocumentFilePath.Name);
cloudBlockBlob.Properties.ContentType = model.DocumentFilePath.ContentType;

using (var stream = model.DocumentFilePath.OpenReadStream())
{
    await cloudBlockBlob.UploadFromStreamAsync(stream);
}

The url of the file in storage will be https://xxxxx.blob.core.windows.net/{ContainerName}/{FileName}