build your own blockchain application in less than an hour

Edward Ciggaar
developer advocate
IBM

I’ve been looking forward to this one for a while now :D
starting with an example of a game (coffee with blockchain) the hyperledger platform was explained

– a map was shown on the screen showing network data for coffee producers and coffee sellers and coffee consumers.
– the idea is that you need to be invited to become a part of the network
– once you are a member, your transactions are shown on the map
– you select the role – farmer, buyer, consumer, etc

basically its a nice little UI for creating the parameters around a smart contract
once the smart contract is created it is sent to the blockchain
the buyer and the grower create separate contracts (eg the seller saying I want at least £1 and the buyer saying I will pay max £1.50).

if there is a match on the system, a transaction is created and the two contracts (from buyer and seller are fulfulled).
its a nice example of a closed network which can be expanded by invitation

‘efficiency through smart contracts’ was the theme of this.
———————–

On with the build your own blockchain application on hyperledger fabric.
– invite network
– no cryptocurrency involved
– confidential transactions
– can specify business logic in the smart contract

—–

Actors:
developer
– the application
– building the client side app for the end user
– how does it interact with the ledger
– events being raised
– how does it interact with traditional systems

Using the composer (npm) framework to build the application
– framework speeds up dev time
– dont have to worry about ledger things, confirmations, etc
– you can focus on the business logic

hyperledger:
open source + open dev toolchain
yeoman
hyperledger-composer
npm
composer-playground

this generates all the boilerplate code, which is agreat starting point.
you can emit events when transactions happen (using webhooks)
till here, we have some business logic, model, acl etc but nothing is running in the blockchain.
the next step is to package the dapp and deploy to the blockchain. (with npm install)

(will be good to go through the build your own blockchain application in less than an hour slides later on and actually make something)

[
– separately, its good to get confirmation from others that using the frameworks with the CLI is a valid way to do it
– also, webhooks seem to be huge now, so safe to put them everywhere
– ibm have lots of ‘call patterns’ that we can use and see for different scenarios
]