S3 Presign Generator

Generate AWS S3 pre-signed URLs from a CSV file input.

This tool reads a CSV file containing folder and filename columns, generates pre-signed S3 URLs for each file, and writes the result into an output CSV. It's useful for temporary access to private S3 files without exposing AWS credentials.

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✨ Features

• 🔐 Uses AWS pre-signed URLs with customizable expiration.
• 📂 Reads CSV with headers like identifier, folder_name, filename.
• 📄 Writes output CSV with columns: identifier,presigned_url.
• ⚙️ All configurations are via .env or system environment variables.

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🚀 Getting Started

1. Install Dependencies

  mix deps.get

2. Set Environment Variables

Create a .env file by copying the provided example:

  cp .env.example .env

Then, edit .env and set the required values:

AWS_ACCESS_KEY_ID=your_access_key
AWS_SECRET_ACCESS_KEY=your_secret_key
AWS_REGION=ap-southeast-1
AWS_BUCKET=your_bucket_name
AWS_EXPIRES=3600
AWS_BASE_FOLDER=private

FILE_INPUT=input.csv
FILE_OUTPUT=output.csv
FILE_IDENTIFIER_HEADER=identifier

3. Run App You can run the tool using the provided Makefile:

  make run

📂 Input and Output CSV

The CSV file should include the following headers:

  user_id,folder_name,filename
  aksjdh312gj,folder1,document.pdf

An output CSV file will be generated (default: output.csv) with columns like:

  user_id,presigned_url
  aksjdh312gj,https://s3.ap-southeast-1.amazonaws.com/your_bucket/private/...