Uploading File to S3 via Node.js SDK Resulting is Blank File

Question

We have a S3 bucket where we upload some files.

When a user uploads a file, it is uploaded to the S3 bucket, but when checking the file's content, it is empty(blank file).

   Back End Code
   // Importing modules
   import { PutObjectCommand, S3Client } from '@aws-sdk/client-s3';
   
  // Setting up S3 client
   const s3 = new S3Client({
     credentials: {
       accessKeyId: process.env.ACCESS_KEY_ID as string,
       secretAccessKey: process.env.SECRET_ACCESS_KEY as string,
    },
    region: s3Info.S3_REGION,
   });

   const pdfContent = Buffer.from(file[0].buffer);
   const params = {
          Bucket: s3Info.S3_BUCKET_NAME,
          Key: getFilePath(fileName),
          Body: pdfContent,
          ContentType: file[0].mimetype,
   };

   // Uploading the document.
   const command = new PutObjectCommand(params);

   const res = await s3.send(command);
   return fileName;

Everything is working fine, but getting blank documents in the S3 bucket.

Answer 1

Since I am using AWS Lambda and Serverless Framework to deploy.

Now in my serverless.yml file, I was missing a part for Binary media types.

So without Binary media types in AWS API Gateway the file was getting uploaded but was blank.

After adding a plugin called serverless-apigw-binary for my serverless, and then adding apigwBinary types as application/pdf and multipart/form-data in my serverless.yml file, it worked.

# Example Serverless.yml code
plugins:
  - serverless-apigw-binary

custom:
  apigwBinary:
    types:
      - 'application/pdf'
      - 'multipart/form-data'

In API Gateway we can manually also add Media Types as shown in the below image. Just click on your API Gateway, then select API Settings, and under that, you will see Binary Media Types.