Building a .NET Core Web Application with AWS S3 Integration

 Proof of Concept: Building a .NET Core Web Application with AWS S3 Integration

In this article, we will explore how to build a Proof of Concept (POC) web application using .NET Core and integrate it with Amazon Web Services (AWS) Simple Storage Service (S3). This POC will demonstrate how to upload files to AWS S3 and retrieve them from the application.

Prerequisites

To follow along with this POC, you will need the following:

• Visual Studio Code or Visual Studio
• .NET Core SDK
• AWS account
• AWS S3 bucket
• AWS SDK for .NET

Creating a .NET Core Web Application

First, we will create a new .NET Core web application using Visual Studio or Visual Studio Code. In this POC, we will use Visual Studio Code.

Open Visual Studio Code and create a new folder for your project. Open a terminal and navigate to the folder.

Next, create a new .NET Core web application by running the following command in the terminal:

javascript
dotnet new web -n POCApplication

This will create a new .NET Core web application with the name "POCApplication."

Integrating with AWS S3

Next, we will integrate our .NET Core web application with AWS S3. To do this, we need to install the AWS SDK for .NET.

In the terminal, run the following command to install the AWS SDK for .NET:

java
dotnet add package AWSSDK.S3

Next, we need to add our AWS S3 credentials to the application. In the root folder of the application, create a new file called "appsettings.json." Add the following JSON to the file, replacing the placeholders with your AWS S3 credentials:

json
{
  "AWS": {
    "Region": "us-east-1",
    "Profile": "default"
  },
  "S3": {
    "BucketName": "<your-bucket-name>",
    "AccessKey": "<your-access-key>",
    "SecretKey": "<your-secret-key>"
  }
}

This will add the AWS S3 credentials to our application.

Uploading and Retrieving Files from AWS S3

Next, we will create two methods to upload and retrieve files from AWS S3.

In the "HomeController.cs" file, add the following methods:

csharp
[HttpPost]
public async Task<IActionResult> UploadFile(IFormFile file)
{
  var s3Client = new AmazonS3Client();

  using (var fileStream = file.OpenReadStream())
  {
    var putRequest = new PutObjectRequest
    {
      BucketName = Configuration.GetSection("S3:BucketName").Value,
      Key = file.FileName,
      InputStream = fileStream
    };

    await s3Client.PutObjectAsync(putRequest);
  }

  return RedirectToAction("Index");
}

public async Task<IActionResult> DownloadFile(string fileName)
{
  var s3Client = new AmazonS3Client();
  var getRequest = new GetObjectRequest
  {
    BucketName = Configuration.GetSection("S3:BucketName").Value,
    Key = fileName
  };

  var response = await s3Client.GetObjectAsync(getRequest);

  return File(response.ResponseStream, response.Headers.ContentType);
}

The "UploadFile" method uploads a file to AWS S3, and the "DownloadFile" method retrieves a file from AWS S3.

Finally, we need to create a view to upload files. In the "Views/Home" folder, create a new file called "Upload.cshtml." Add the following code to the file:

python
@{
    ViewData["Title"] = "Upload";
}