GO BROKERLESS!

Free of Concern "Libre de preocupación"

Overview

In this project, we are helping you break free from broker hassles. Our distributed ledger is built upon ethereum programming in Solidity. Let's walk through this exciting process together!

Engaging Parties

Party	Address	Interpretation
Landlord	`landlord`	crypto wallet of the landloard
Tenant	`tenant`	wallet address of the candidate tenant
Previous Tenant	`previous`	wallet address of the previous tenant leaving
Us	`us`	our crypto wallet address

Escrow Account

Account	Address	Interpretation
Omnibus	`_omnibusAddress`	contract address of all deposits to earn interests from the bank

Variables

Variable	Code	Explanation
Rent	`rent`	monthly rent for bidding
Deposit	`deposit`	deposit from the higher bidder, equivalent to one-month rent
showingfeepercent	`showingfeepercent`	percent of rent for showing the property to candidate tenants
servicefeepercent	`servicefeepercent`	as a percent of monthly rent
Apartment	`apt`	a string combination of zip code, building number, and apt number

Entity Relationship Diagram

Blockchain Technologies

Solidity

Target Ethereum Virtual Machine (EVM), influenced by
- C++
- Python
- JavaScript
- Auctions
Extension installed in Visual Studio Code: Link to Github

Web3.js

See also: Web3 on Github

API in JavaScript for Ethereum
- libaries use HPPT or IPC to connect to nodes

Use web3.eth package to interact with smart contract on Ethereum blockchain

See ledger.py

Python code

def reportApt(landlord, report_uri):
  tx_hash = registerApt.functions.reportApt(landlord, report_uri).transact(
      {"from": w3.eth.accounts[0]}
  )
  receipt = w3.eth.waitForTransactionReceipt(tx_hash)
  return receipt

See record.py

Code in Python

def initContract():
    with open(Path("brokerless.json")) as json_file:
        abi = json.load(json_file)

    return w3.eth.contract(address=os.getenv("REGISTERAPT_ADDRESS"), abi=abi)

Report apartments through python: see py_dApp
- ABI acquired from compiling Solidity smart contracts in Remix
  - brokerless.json
- Environmennt setup
  Need Pinata API and secret API keys in a file .env to access URIs
```
PINATA_API_KEY=
PINATA_SECRET_API_KEY=
WEB3_PROVIDER_URI=http://127.0.0.1:8545
REGISTERAPT_ADDRESS=0x
```
- Next step: for landlord
  - Report and getting report on bidders
  - following similar process

Ganache

Personal blockchain DApp for Ethereum development
Linked with MetaMask to Localhost:8545 in this project demo
Desktop application installed

Contracts

Defined in Brokerless.sol:

Auction

Solidity code for capital distribution

      // in Constructor
        servicefeepercent = 5;
        showingfeepercent = 25;

      // within function auctionEnd() public
      // 3. Interaction
        rent = highestBid * rentPercent/100;
        deposit = highestBid * depositPercent/100;

      //leaseAddress.transfer(rent);
        omnibusAddress.transfer(deposit);
        previous.transfer(rent * showingfeepercent/100); // to previous contract to pay showingfee
        landlord.transfer(rent - (rent * showingfeepercent/100) - (rent * servicefeepercent/100));
        us.transfer(rent * servicefeepercent/100);

Lease

Solidity code for deposit return

    function returnDeposit() external 
    onlyLandlord
    {
        Omnibus omnibus = Omnibus(omnibusAddress);
        omnibus.releaseDeposit(tenant, landlord, deposit);
    }

Omnibus

Solidity code for computing fund allocation

      // in Constructor
        interestRate = 1;
        enhancedSpread = 3;
        tenantInterestSplit = 60;
        landlordInterestSplit = 20;
        usInterestSplit = 20;

      // under function releaseDeposit
        tenantInterestPayment =  (deposit * interestRate/100) + (deposit * enhancedSpread/100 * tenantInterestSplit/100);
        landlordInterestPayment = (deposit * enhancedSpread/100 * landlordInterestSplit/100);
        usInterestPayment = (deposit * enhancedSpread/100 * usInterestSplit/100);

        tenant.transfer(deposit);
        tenant.transfer(tenantInterestPayment);
        landlord.transfer(landlordInterestPayment);
        us.transfer(usInterestPayment);

BankInterest

Solidity code to generate funds in Omnibus bank account

    function generateFunds() public payable {
        
        Omnibus.transfer(msg.value);
    }

Defined under BankInterestGenerator.sol

BankInterest

NOTE: Funding through BankInterest contract in Omnibus account may be substituted by transfering funds in MetaMask under Localhost: 8545.

Addresses and Variables

List of Variables and Addresses engaged in contracts

Contract	Variables	Addresses
Lease	`apt`, `rent`, `deposit`, `shwoingfeepercent`, `servicefeepercent`	landlord, tenant, us, consolidatedDeposits, previous, omnibusAddress
Omnibus	`interestRate`,`enhancedSpread`,`tenantInterestSplit`,`landlordInterestSplit`,`usInterestSplit`,`tenantInterestPayment`,`landlordInterestPayment`,`usInterestPayment`	landlord, tenant, us
Auction	`apt`,`highestBid`,`rentPercent`,`depositPercent`,`rent`,`deposit`,`servicefeepercent`,`showingfeepercent`	us, landlord, leaseAddress, omnibusAddress, previous, tenant
BankInterest	`Omnibus`	Omnibus = _omnibusAddress

State (snapshots in process)

State variable for emitted events

Contract	Variable	Value
Auction	`state`	Started, Terminated
Lease	`state`	Created, Started, Terminated

Mapping

Map a variable onto positive integers

Contract	Variable	Value	Rationale
Auction	`pendingReturns`	uint: positive integer	withdrawals of overbids

Constructors

Construct contracts by assigning values to variables

Contract	Variable	Sample Code
Auction	`omnibusAddress`,`leaseAddress`,`landlord`, `apt`,`previous`,`us`,`servicefeepercent`,`showingfeepercent`	servicefeepercent = 5;
Lease	`us`	us = msg.sender;
Omnibus	`interestRate`,`enhancedSpread`,`tenantInterestSplit`,`landlordInterestSplit`,`usInterestSplit`,`us`	usInterestSplit = 20; us = msg.sender;

Modifiers

Modify conditions

Contract	Modifier	Code
Auction	`inState`	require(state == _state);
Auction	`onlyLandlord`	require(landlord == msg.sender);
Lease	`onlyLandlord`	require(landlord == msg.sender);
Lease	`onlyTenant`	require(tenant == msg.sender);
Lease	`onlyUs`	require(us == msg.sender);
Lease	`inState`	require(state == _state);

Events

Events for dApps to listen to

Contract	Event	Code
Auction	`rentIncreased`	event rentIncreased(address bidder, uint amount);
Auction	`AuctionEnded`	event AuctionEnded(address winner, uint amount);
Lease	`landlordConfirmed`	require(landlord == msg.sender);
Lease	`tenantConfirmed`	require(tenant == msg.sender);
Lease	`paidRent`	require(us == msg.sender);
Lease	`paidDeposit`	require(state == _state);
Lease	`returnDeposit`	require(state == _state);
Lease	`paidShowingFee`	require(state == _state);
Lease	`contractTerminated`	require(state == _state);

Functions

Nested inside contracts for various purposes

Contract	Function	Purpose
Auction	`bid`	allow rent increases based on highest bid after auction starts based on State
Auction	`withdraw`	withdraw an overbid
Auction	`pendingReturn`	amount for withdraw function
Auction	`getbalance`	return balance of the address
Auction	`auctionEnd`	landlord end the auction: rent, deposit, fees transfered to landlord, omnibus, previous tenant and us
Lease	`contruct`	assign variables event-based values: _landlord, _omnibusAddress, _rent, _deposit, _apt)
Lease	`payRent`	allow tenant to pay rent to landloard after contract starts as indicated by State
Lease	`returnDeposit`	enable landlord to reutrn depost to the leaving tenant from omnibus account upon contract termination
Lease	`requestShowingFee`	pay showing fee to the previous tenant
Lease	`terminateContract`	landlord concludes the lease contract
Lease	`getbalance`	return balance of the contract
Lease	`() payable external`	required for the lease contract to be payable from an outside account
Omnibus	`releaseDeposit`	transfer interests and principal on deposit to tenant, landlord and us based on specified schedules
Omnibus	`getbalance`	return balance of the contract
Omnibus	`() payable external`	required for the lease contract to be payable from an outside account
BankInterest	`generateFunds()`	transfer funds to _omnibusAddress

Workflow

Standing on shoulders of giants

LEASEHOLD: token distribution of smart contracts on rental lease

Source: Leasehold Token - The Decentralized Money Making Through Sort Term Rental Tokenization

Step-by-step Guide

Accounts

Tune in MetaMask to Localhost 8545.
Balances of accounts are viewable in Ganache.

Five accounts with the following wallet addresses engage in transactions on BrokerlessMarket (first five in Ganache):

Us: 
0x0616d31438078849D3bf66591855B3D3239a9E5c

Landlord: 
0x5DBaBe19DD1fedba1B20047059DCd755D8221BF7

Tenant: 
0x3e9D41Ec700b98C773f2599052a3590931bEa98c

Previous: 
0x8EaaBB9Fc753df2C50F0b01E99b4e0F1f2d970A6

Bank: 
0xBb2e65E2d7664E51A1547767d502169591642491

Demo Transactions

Initiate Lease Contract

In Remix, open Brokerless Contract

As Us in MetaMask:
- Scroll and choose Lease under CONTRACT
- Complile Lease Contract
- Select Injected Web3 as ENVIRONMENT and deploy Lease Contract
  
  Lease Contract Deployment
- After clicking the Deploy button, confirm on MetaMask for New Contract initiation
  - (Optional) Copy the address of the deployed Lease Contract by clicking on the page button to the right onto a .txt file: 0x0717c8C6c171E16dFE06d4df366d6fff017be521
  Notification of New Contract on MetaMask
  
  Confirmation of Deployment on MetaMask
- Check our balance on Ganache
  
  Ganache Balance for Us dropped 0.02 ETH from 134.40 ETH to 134.38 ETH following Deployment of Lease Contract

Initiate Omnibus Contract

As Us in MetaMask:
- Scroll down under CONTRACT and choose Omnibus
- Compile the Omnibus Contract
- Deploy Omnibus Contract under the same Injected Web3 ENVIRONMENT
  - (Optional) Copy the address of the deployed Omnibus Contract by clicking on the page button to the right onto a .txt file: 0x721080d169713ec439db4CaE8ED2daCEF4745B5d
  Omnibus Contract Deployment
- Check our new balance on Ganache
  
  Ganache Balance for Us dropped 0.01 ETH from 134.38 ETH to 134.37 ETH following Deployment of Omnibus Contract

Initiate Auction Contract

As Us in MetaMask:
- Scroll down under CONTRACT and choose Auction
- Compile and Deploy Auction Contract, leaving Injected Web3 ENVIRONMENT unchanged
  - (Optional) Copy the address of the deployed Auction Contract by clicking on the page button to the right onto a .txt file: 0xf3B554248FDFFc24CE7Aa14689Ed561e0350B801
  Auction Contract Deployment
  
  MetaMask Notification on Auction Contract Deployment
- Check our new balance on Ganache
  
  Ganache Balance for Us dropped 0.03 ETH from 134.37 ETH to 134.34 ETH following Deployment of Auction Contract

Bid as Tenant

As Tenant in MetaMask, i.e. the third address from the top in Ganache:
To initiate a bid, enter 10 ether as VALUE under CONTRACT Auction
- Enter wallet addresses of landord, previous tenant with lease and omnibus contract addresses under DEPLOY section (may be left unchanged from Auction deployment)
- Scroll down to unfold AUCTION under Deployed Contracts, enter 50 for _rentPercent and _depositPercent respectively for bid
  
  Tenant Bid 10 ETH with 50-50 Split on Rent and Deposit
- Compare balances on Ganache Pre and Post Tenant Bid
  
  Ganache Balance prior to Tenant's bid of 10 ether
  
  Balances on Ganache following Tenant's bid of 10 ether: a drop from 67.13 ETH to 57.13 ETH posted on the third wallet, i.e. the candidate tenant's account
- The auction would only proceed should there be a higher bid than 10 ether from this point
  
  A bid of 14 ether that is greater than the previous bid of 10 ether
  
  Balances on Ganache following Tenant's bid of 14 ether: a drop from 57.13 ETH to 43.12 ETH posted on the third wallet, i.e. the candidate tenant's account. An extra 0.01 ETH gas fee incurred for the bidding.
  
  Get Balance by pressing **getbalance** button under the Deployed Omnibus Contract: current balance is 50% of 14 ETH, i.e. 7 ETH = 7 * (10^18) Wei
  
  Should there be another bid in the valud of 14 ETH. An error message would pop up as follows:

Depost to Generate Interest on Omnibus Bank Account

As Us in MetaMask, i.e. the second address from the top in Ganache:
- Open BankInterestGenerator in Solidity
  - Expand view on Deployed Auction Contract at the bottom left-hand-side
- Complile and Deploy BankInterest contract
  - at the previously deployed address of the Omnibus Contract under Brokerless Solidity_OMNIBUSADDRESS: 0x721080d169713ec439db4CaE8ED2daCEF4745B5d
- Confirm CONTRACT DEPLOYMENT on the MetaMask pop up notification window by clicking on Confirm button
  
  Confirm Deployment of BankInterest Contract

Get Funds from Omnibus Bank Account

As Bank in MetaMask, i.e. the fifth address from the top in Ganache:
- Enter 50 ether as VALUE on the Remix Deployment page
  - Keep BankInterest under CONTRACT selection
  - Keep _OMNIBUSADDRESS the same as the address of the previously deployed Omnibus Contract from Brokerless Solidity: 0x721080d169713ec439db4CaE8ED2daCEF4745B5d
- Expaned view of the deployed BankInterest Contract and click on generateFunds button
- Confirm CONTRACT INTERACTION on the MetaMask notification by clicking on Confirm button
  
  Omnibus Bank Account balance dropped from 100 ETH to 49.9994 ETH. The difference is resulted from gas fee.
  
  Balances on Ganache before and after the balance transfer of 50 ether are show below:

Return Deposit

As Landlord in MetaMask, i.e. the second address from the top in Ganache:
- Expand view of the deployed Lease Contract
- Click on returnDeposit button
- Confirm on the MetaMask via Confirm button
  
  The balance of Tenant's account went up 7 ETH from 43 ETH to 50 ETH approximately.

Conclude Auction

As Landlord in MetaMask, i.e. the second address from the top in Ganache:
To conclude an auction, under Auction Contract on Deployment page
- Expand view on Deployed Auction Contract at the bottom left-hand-side
- Press auctionEnd button
- Confirm AUCTION END on the MetaMask pop up notification window by clicking on Confirm button
  
  Terminate Auction by Landlord
  
  Balances on Ganache following Tenant's bid of 10 ether: a drop from 67.13 ETH to 57.13 ETH posted on the third wallet, i.e. the candidate tenant's account

Archived Process for Previous Versions

--------------------------------------
********CONTRACT DEPLOYMENT***********
--------------------------------------
* As Landlord deploys Auction contract 
* As Us deploy Lease contract
* As Us deploy the Omnibus contract
--------------------------------------
** Insert bank interest 5%
--------------------------------------


--------------------------------------
*********LEASE CONTRACT**************
--------------------------------------
* Set leaseAddress contract
* Set omnibusAddress contract
* As potentialTenant 1 enter bid Value and split Value between 
  rent percent and deposit percent
* As potentialTenant 2 enter higher bid Value and split Value
  between rent percent and deposit percent
* As potentialTenant 1 withdraw bid to get back money
* As Landlord end auction and accept highest bid. Resulting in the rent being transferred
  to lease contract and deposit gets transferred to the Omnibus contract
--------------------------------------
** Navigate to the Lease contract. As Landlord confirm lease contract
** As Tenant confirm lease contract
--------------------------------------


--------------------------------------
**********OMNIBUS CONTRACT***********
--------------------------------------

* Set Omnibus contract
* Set Previous contract
* Click initialPayout
* Rent payment is transferred to Landlord and Previous Tenant for showing
 the house and Us for offering the platform
--------------------------------------
** In the Previous Tenant Agreement set 
** Click PayRent 
** After duration press requestDeposit
--------------------------------------

Results

Wix Frontend + Backend View

Hakuna matata! This is how it appears!

Frontend: Set up a Webpage on Github

Step 1: Click on `Settings` on the Github repository

Step 2: On Github Pages, select `master branch ` as `Source` and select a theme under `Theme Chooser`

Step 3: Open the link to the webpage published highlighted in green to view this page

Step 4: Click on the link `here` under Demo App from the previous step to bid on BrokerlessMarket

Step 5: Register an apartment by entering Apartment name, Pinata API and Secret API Key

Next Steps

We would like to elaborate on the following aspects on our project:

Duration of contract
Auction contract should create brokerless contract.
- Or contract factory for may empty lease contracts to exist in waiting.
Vetting with machine learning
- Invest deposit with machine learning
Add damage report
- for landlord, require picture submission, allow withdrawal of deposit funds
- for bidders, from perspectives of a landlord
Rather than auction process:
- bidders should offer rent and deposit fee
- Landlord should be able to choose which to accept
- Landlord to set minimum
Add “paper” contract as URI
- json
- pdf
- png
Allow tenants to offer a higher security deposit that the landlord is allowed to invest (전세) -> more security for the landlord (better tenants)
Link with property listing platform
Late fee (require payRent function even month)
Events in place for javascript Dapps to listen to
- For user friendly UI
Hosting a factory of contracts for multiple apartments: Example on Github

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LICENSE		LICENSE
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josephpasik/theblock-web3

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