Payload Cache Service

This repository provides a simple service for storing and retrieving hex-encoded payloads. It uses a keccak256 hash as the lookup key.

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Installation

1. Clone this repository:

2. Install dependencies:

   npm install

3. Set up environment variables:

   • Create a .env file in the project root and add PAYLOAD_CACHE_AUTH_TOKEN.

4. Run the server:

   npm start

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Configuration

Required Environment Variables

Variable	Description
PAYLOAD_CACHE_AUTH_TOKEN	Bearer token used to authenticate incoming requests

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Usage

After starting the server, it will listen on port 5001 by default.

• Swagger UI: Visit http://localhost:5001/docs to view API documentation.
• Authorization: All API calls must include the header Authorization: Bearer <TOKEN>, where <TOKEN> matches PAYLOAD_CACHE_AUTH_TOKEN in your .env.

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API Endpoints

POST /payload

Description
Stores a hex-encoded payload in memory by computing its keccak256 hash.

Headers

Authorization: Bearer <PAYLOAD_CACHE_AUTH_TOKEN>
Content-Type: text/plain

Request Body
A hex-encoded string representing the payload. For example:

68656c6c6f776f726c64

Response

• 200 OK: Returns a JSON object containing the hash of the payload.

  {
    "hash": "<keccak256_hash>"
  }
• 400 Bad Request: If the payload is missing, not a string, or not valid hex.
• 403 Forbidden: If the Authorization header is missing or incorrect.

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GET /payload

Description
Retrieves the original hex-encoded payload for a given keccak256 hash.

Headers

Authorization: Bearer <PAYLOAD_CACHE_AUTH_TOKEN>

Query Parameters

• hash (required): The keccak256 hash (hex string) used to look up the payload.

Response

• 200 OK: Returns the payload in plain text if found.
• 400 Bad Request: If the hash query parameter is missing.
• 404 Not Found: If no payload is stored under the provided hash.
• 403 Forbidden: If the Authorization header is missing or incorrect.

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GET /debug

Description
Returns the entire in-memory store as JSON for debugging.

Headers

Authorization: Bearer <PAYLOAD_CACHE_AUTH_TOKEN>

Response

• 200 OK: Returns a JSON object containing all hashes and their payloads.
• 403 Forbidden: If the Authorization header is missing or incorrect.

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