How to List All Files with a Specific Filename Under an Amazon S3 Folder Using C

How to List All Files with a Specific Filename Under an Amazon S3 Folder Using C#

As a data scientist or software engineer, you may find yourself needing to list all files with a specific filename under an Amazon S3 folder. This task can be easily accomplished using the AWS SDK for .NET (C#). In this article, we’ll demonstrate how to achieve this.

Before we start, ensure that you have installed the AWS SDK for .NET. If not, you can install it through NuGet by searching for AWSSDK.S3.

Let’s dive in.

Setting up the AWS S3 Client

First, we need to create an Amazon S3 client. This client will handle the connection and communication with the S3 service. You’ll need your AWS Access Key and Secret Key for this.

Here’s how you do it:

using Amazon.S3;
using Amazon;

var s3Client = new AmazonS3Client("YOUR_ACCESS_KEY", "YOUR_SECRET_KEY", RegionEndpoint.USEast1);

Please replace "YOUR_ACCESS_KEY" and "YOUR_SECRET_KEY" with your actual AWS credentials. The RegionEndpoint should be the AWS region that your S3 bucket is in.

Listing the Files

Once the S3 client is set up, we can use it to list all the files in a given S3 folder. To do this, we’ll use the ListObjectsV2Async method. This method returns a ListObjectsV2Response object, which contains information about the listed objects.

using Amazon.S3.Model;

string bucketName = "your-bucket-name";
string prefix = "your-folder/";

ListObjectsV2Request request = new ListObjectsV2Request
{
    BucketName = bucketName,
    Prefix = prefix
};

ListObjectsV2Response response;
do
{
    response = await s3Client.ListObjectsV2Async(request);

    // process the response
} while (response.IsTruncated);

The Prefix property is used to specify the folder we want to list files from. Note that S3 doesn’t have real folders, but it simulates them using prefixes. The IsTruncated property indicates whether all of the objects in the bucket have been returned. If not, we need to continue listing them.

Filtering the Files

Now that we have the list of all files, we can filter them based on the filename. In this example, we’ll list all .txt files.

foreach (S3Object entry in response.S3Objects)
{
    if (entry.Key.EndsWith(".txt"))
    {
        Console.WriteLine("key = {0} size = {1}", entry.Key, entry.Size);
    }
}

In this code, entry.Key represents the object’s key, which is its name including its prefix. entry.Size represents the object’s size in bytes.

Conclusion

Using the AWS SDK for .NET (C#), we can easily list all files with a specific filename under an Amazon S3 folder. This can be useful in a variety of scenarios, such as processing log files, managing assets, and more.

Remember to handle your AWS credentials with care, as they provide access to your AWS resources. Never hard-code them into your programs. Instead, use AWS Identity and Access Management (IAM) roles, environment variables, or configuration files.

We hope this guide was helpful. If you have any questions or need further clarification, feel free to leave a comment below.

Related Keywords: C#, Amazon S3, AWS SDK for .NET, ListObjectsV2Async, S3Object

Meta Description: Learn how to list all files with a specific filename under an Amazon S3 folder using C# and the AWS SDK for .NET. This guide provides clear, step-by-step instructions on how to accomplish this task.

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