Renting Platform

A blockchain-based renting platform proof-of-concept (PoC) built with Daml. This project demonstrates a decentralized lease management system featuring automated rent payments, maintenance issue reporting, and dispute resolution via arbitrators.

Features

• Lease Agreements: Manage rental contracts between landlords and tenants.
• Time Oracle: Automates time-dependent actions like rent due dates.
• Arbitration: Resolves disputes (e.g., maintenance issues) through designated arbitrators.
• User Interface: Java-based clients for users and arbitrators to interact with the ledger.

Prerequisites

Ensure you have the following installed:

• Daml SDK
• Java Development Kit (JDK) (Compatible with your Maven setup)
• Maven
• Python 3 (Used for fetching party IDs in scripts)

Getting Started

1. Build and Start the Ledger

The sandbox.sh script automates the build process, generates Java bindings, and starts the Daml Sandbox (Ledger).

./sandbox.sh

What this does:

• Builds the Daml project (rentingPlatform.dar).
• Generates Java code from Daml templates into Time/, Arbitrators/, and User/ directories.
• Starts the Daml Sandbox with the Test.Main:initialize init script.
• Generates parties.json containing the IDs of allocated parties.

2. Run Components

Open separate terminal windows to run the different components of the system.

Time Oracle

Starts the Time Provider service which handles time-based events on the ledger.

# Run Time Provider 1
./time.sh 1

# Run Time Provider 2
./time.sh 2

User Client

Runs the client application for tenants and landlords.

# Run as Bob (Tenant)
./user.sh 1

# Run as Alice (Landlord)
./user.sh 2

Arbitrator Client

Runs the client application for arbitrators to view and resolve disputes.

# Run as Arbitrator 1
./arbitrator.sh 1

# Run as Arbitrator 2
./arbitrator.sh 2

Project Structure

• daml/: Contains the Daml source code (Smart Contracts).
  • User.daml: User and Message templates.
  • Test/Main.daml: Initialization script and main test definitions.
• Time/: Java application for the Time Oracle.
• Arbitrators/: Java application for the Arbitrator interface.
• User/: Java application for the User interface.
• manifests/: (If applicable) Deployment manifests.
• scripts:
  • sandbox.sh: Lifecycle management (Build, Codegen, Start).
  • time.sh, user.sh, arbitrator.sh: Launchers for respective Java apps.

Troubleshooting

• Parties not found: Ensure parties.json exists in the root directory. It is generated when daml start runs (via ./sandbox.sh).
• Port conflicts: The scripts assume the ledger runs on localhost:6865. Ensure this port is free.