How do you upload a PDF received from an API to AWS S3?

Problem

How do you upload a PDF file generated by a 3rd party API to an AWS S3 bucket and protect it using server-side encryption?

Solution

Let's assume that we have got the pdf as a stream from calling our API endpoint.

Stream pdfStream = api.GetPdfAsStream();

Snippet

Let's see the code before talking about what is happening.

var s3Client = new AmazonS3Client(RegionEndpoint.USEast1);
var s3Request = new PutObjectRequest
{
    BucketName = "Bucket Name",
    Key = Guid.NewGuid().ToString(),
    InputStream = pdfStream,
    ServerSideEncryptionMethod = ServerSideEncryptionMethod.AWSKMS,
    ContentType = "application/pdf",
    Headers = { ContentDisposition = $"attachment; \"filename=\"File Name\"" },
};

var s3Response = await s3Client.PutObjectAsync(s3Request);

• Line 1: Setup the S3 client with the region we want to connect to
• Line 2: Create a new PutObjectRequest because we want to upload a file to S3.
• Line 4: BucketName: Set the bucket name to which the PDF needs to be uploaded.
• Line 5: Key: Create a unique key to identify the object in S3.
• Line 6: InputStream: Set the inputStream to the PDF stream we received from the API.
• Line 7: ServerSideEncryptionMethod: Use the AWS Key Management Service to encrypt the PDF.
• Line 8: ContentType: Set the content type to application/pdf so the browser can show the file as a PDF.
• Line 9: Headers: Add some common headers
  • ContentDisposition to attachment to indicate that the file should be downloaded.
  • filename to the name of the file.
• Line 12: Start the asynchronous execution of the PutObject operation.

Conclusion

We can upload a PDF to an S3 bucket using this snippet and encrypt it using server-side encryption.