Today we are going to make our first simple decentralized app using the blockchain.
The app is going to be a simple micro blog service.
ethereumjs-testrc is for running a local dev blockchain
web3 is the ethereum js client
solc is for compiling smart contracts
http-server for running the web app in a dev env
Creating the smart contract
Read more about solidity
Compiling the smart contract and deploying the code to the blockchain
Run the test blockchain by executing ./node_modules/.bin/testrpc
Then execute ‘node compile.js’ and save the outputs.
Building the web app
app.js (Use the outputs from the compile.js)
Difference between contract.getMessages() and contract.getMessages.call()
call() is for read operations, doesn’t cost gas and doesn’t write in the blockchain.
Calling a method directly, like getMessages(), is for writing in the blockchain and costs gas.
Read more about gas
Run the website http-server -a localhost -p 8000 -c-1 .
Download the full code at github