S3 Uploader API (AWS CDK Deployment)

This project provides a serverless API to generate pre-signed S3 upload URLs using AWS Lambda, API Gateway, and S3.
It allows secure file uploads of any type while enforcing API key authentication.

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Features

✅ Secure Signed URL Uploads (AWS SDK v3)
✅ Supports All File Types (PNG, PDF, MP4, etc.)
✅ API Gateway Throttling & API Key Security
✅ Built with AWS CDK (Python) for easy deployment

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Setup & Deployment

Prerequisites

• AWS CLI Installed → Install Guide
• AWS CDK Installed → Run:

  npm install -g aws-cdk

• Python 3.9+ Installed
• AWS Credentials Configured

  aws configure

Clone the Repo

git clone https://github.com/YOUR-ORG/s3-uploader-api.git
cd s3-uploader-api

Install Python Dependencies

python -m venv .venv
source .venv/bin/activate  # (Mac/Linux) or .venv\Scripts\activate (Windows)
pip install -r requirements.txt

Install Lambda Dependencies

cd s3UploaderFunction
npm install
cd ..

Deploy the CDK Stack

cdk deploy

After deployment, note the API Gateway URL and API Key from the output.

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How to Use the API

Get a Signed Upload URL

Use API Gateway to request a pre-signed URL:

curl -H "x-api-key: YOUR_API_KEY" \
     "https://your-api-id.execute-api.us-east-1.amazonaws.com/prod/upload?contentType=image/png"

Response Example:

{
  "uploadURL": "https://your-bucket.s3.amazonaws.com/abc12345?AWSAccessKeyId=...",
  "photoFilename": "abc12345"
}

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Upload a File Using the Signed URL

Once you receive the uploadURL, upload a file using curl:

curl -X PUT -H "Content-Type: image/png" --upload-file test-image.png "UPLOAD_URL_FROM_STEP_1"

✅ If successful, you will not see any output.

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Verify the File in S3

Check if the file exists:

aws s3 ls s3://YOUR_BUCKET_NAME/

Or download it:

aws s3 cp s3://YOUR_BUCKET_NAME/abc12345 downloaded-file.png

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Debugging & Troubleshooting

Issue	Solution
403 Forbidden on API Gateway	Ensure API Key is correct and included in the request headers.
403 Forbidden on S3 Upload	Check IAM permissions for Lambda, ensure correct S3 bucket policy.
500 Internal Server Error	Check AWS CloudWatch logs for Lambda errors.

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Cleanup

To remove all AWS resources:

cdk destroy