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

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  • snippet
  • AWS
  • S3


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


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

Stream pdfStream = api.GetPdfAsStream();


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 an unique key to identify the object in S3.
  • Line 6: InputStream: Set the the inputStream to the PDF stream that 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 that 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.


Using this snippet, we are able to upload a PDF to a S3 bucket and encrypt it using server-side encryption.

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