state-channels-poc

This repository is a monorepo managed by lerna.

It contains the following packages:

• channel-contracts: Solidity contracts for the state channel
• loopback-connector-web3: Web3 Connector for LoopBack 3.x
• sc-demo-app: A demo application (clicks demo)
• sc-hub: The hub
• sc-app-server-demo3: The payment channel impression demo server
• sc-app-frontend-demo3: The payment channel impression demo frontend

Getting started

Check out the project and install dependencies

git clone [email protected]:levelk/payment-channel-demo.git
cd statechannels
git submodule init
git submodule update
npm i

Compile and migrate solidity contracts

Compile contracts

cd packages/channel-contracts
npm run truffle:compile

Start a local ganache

To start a local ganache in a different terminal window/tab:

npm run ganache

Run migration

cd packages/channel-contracts
npm run truffle:migrate

Start the demo application

cd packages/sc-demo-app
npm start
``

Open http://localhost:3000/explorer and play!

Demos

A number of scenarios have been created to show the following progression:

• demo 1: an indirect interaciton with a smart contract by someone with no ETH value
• demo 2: an etherless relay
• demo 3: state channels
• demo 4: account abstraction

demo #1

goal

to demo a baseline scenario where users interacting with a hub as an intermediary can update a smartcontract if they have value in their account

players

raymond is the advertiser james is a publisher al is a publisher

hub

hub is a marketplace that brings advertisers together with publishers hub keeps track of clicks through the blockchain hub hosts /clicks API through LB hub interacts with the smartcontract that keeps track of global counter of clicks

initial account balances

hub has account hub.eth with 5 eth

steps

step 1

raymond wants to sign up to advertise with the hub james agrees to publish raymond's ads and informs the hub on each click al agrees to publish raymond's ads and informs the hub on each click

step 2

james invokes POST /clicks API

hub receives the request with signed message from james

hub pays the gas to update the smart contract

hub updates state: increments the clicks counter in the smartcontract from 0 to 1

hub ETH goes down to 4.999 ETH

james receives the clicks counter state as a string - 1 from the api call

step 2

al invokes POST /clicks API

hub recives the request with signed message from al

hub pays the gas to update the smart contract

hub updates the state: increments the clicks counter in the smartcontract form 1 to 2

hub ETH goes down to 4.998 ETH

al receives the clicks counter state as a string - 2 from the api call

demo #2

goal

to demo a baseline scenario where users interacting with a hub as an intermediary can update a smartcontract without value in their account

players

raymond is the advertiser james is the publisher al is a publisher

hub

hub is a marketplace that brings advertisers together with publishers hub keeps track of clicks through the blockchain hub hosts /clicks/<user> API through LB hub interacts with the smartcontract that keeps track of global counter of clicks hub interacts with the smartcontract that keeps track of user counter of clicks

initial account balances

hub has account hub.eth with 5 eth james has account james.eth with 0 eth and just a set of keys al has account al.eth with 0 ETH and just a set of keys

steps

step 1

james invokes POST /clicks/james API

hub receives the request with signed message from james

hub updates state:

• increments the global clicks counter in the smartcontract from 0 to 1
• increments the james clicks counter in the smartcontract from 0 to 1

hub ETH goes down to 4.998 ETH

james receives the clicks counter state as a string - 1 from the api call

step 2

al invokes POST /clicks/al API

hub recives the request with signed message from al

hub ETH goes down to 4.996 ETH

hub updates state:

• increments the global clicks counter in the smartcontract from 1 to 2
• increments the al clicks counter in the smartcontract from 0 to 1

al receives the clicks counter state as a string - 1 from the api call

demo #3

goal

to demo state channels where sender has ETH and receiver has no ETH

players

raymond is the advertiser james is the publisher al is a publisher

hub

hub is a marketplace that brings advertisers together with publishers hub keeps track of clicks through the blockchain hub hosts /clicks/<user> API through LB hub interacts with the smartcontract that keeps track of global counter of clicks hub interacts with the smartcontract that keeps track of user counter of clicks

initial account balances

hub has account hub.eth with 5 eth james has account james.eth with 5 eth and just a set of keys al has account al.eth with 0 ETH and just a set of keys

steps

step 1

james desposits 5 eth directly to smart contract

james invokes POST /clicks/james API

hub receives the request with signed message from james

hub updates state:

• increments the james clicks counter in the smartcontract from 0 to 1

james channel ETH goes down to 4.998 ETH

james receives the clicks counter state as a string - 1 from the api call

al invokes POST /clicks/james API

al receives the clicks counter state as a string - 1 and a signed message from james for 0.002 ETH from the api call

step 2

james invokes POST /clicks/james API

hub receives the request with signed message from james

hub updates state:

• increments the james clicks counter in the smartcontract from 1 to 2

james channel ETH goes down to 4.996 ETH

al channel ETH goes up to 0.004 ETH

james receives the clicks counter state as a string - 2 from the api call

al invokes POST /clicks/james API

al receives the clicks counter state as a string - 2 and a signed message from james for 0.004 ETH from the api call

step 3

al invokes POST /withdraw API

hub receives al's request with signed message from james

hub closes channel with al

hub sends al 0.004 ETH

Demo 5

Instructions

In terminal 1, start testrpc

make start/testrpc

In terminal 2, deploy contracts

make deploy/contracts

In terminal 2, start hub

make start/hub

In terminal 3, start alice server

make start/server/demo5

In terminal 3, start hub frontend

make start/frontend/demo5