bloc makes building applications for the Ethereum blockchain as easy. Bloc uses the blockapps api and provides:
- Application scaffoldig and generated UI based on smart contracts methods to test interactions
- Generated Smart Contract APIs to make working with Ethereum smart contracts easy in any language
- Ethereum Account key management
The easiest way to get started is to install
bloc from NPM:
npm install -g blockapps-bloc
You can also check out the github repo and build it by running
git clone https://github.com/blockapps/bloccd bloc; npm install -g
Generate a new blockchain app
You can use
bloc init to create a sample app.
bloc init builds a base structure for your blockchain app as well as sets some default parameters values for creating transactions. These can be edited in the
config.yaml file in your app directory.
config.yaml file also holds the app's
apiURL. This can be configured to point to an isolated test network, or the real Ethereum network. You can change this link, which will allow you to build and test in a sandboxed environment, and later re-deploy on the real Ethereum blockchain.
You will find the following files in your newly created app directory:
/app /components /contracts /lib /meta /routes /static /users app.js bower.json config.yaml gulpfile.js marko-taglib.json node_modules package.json
The "contracts" directory holds Ethereum blockchain code, written in the Solidity language, which you can learn about here- https://solidity.readthedocs.org/en/latest/. This is the code that will run on the blockchain. Samples contracts have been provided to get you started.
Key management to handle account keys for users and signing transactions with bloc.
Once contracts are deployed
blocprovides a RESTful interface for interacting with deployed contracts. Simply call contract methods with an address and pass the password to decrypt your key.
Creating a Sample Account
After initing your app, run the following to download the dependencies for the app:
Once this is finished run
This generates a new user with name
admin as well as a private key and fills it with test-ether (note- free sample Ether is only available on the test network, of course). You can view the address information in the newly created
app/users/admin/<address>.json file. Also, beware that this file contains your private key, so if you intend to use this address on the live network, make sure you keep this file secure and hidden.
The new account has also been created on the blockchain, and you can view account information by using our REST API directly in a browser by visiting http://strato-dev4.blockapps.net/eth/v1.2/account?address= < fill in your address here >
An example output is:
Getting a contract live on the blockchain is a two step process
- Compile the contract
- Upload the contract
To compile a smartcontract, run
bloc compile <ContractName>
If there are any bugs in your contract code, this is where you will be allowed to fix them.
Upload a contract using
bloc upload <ContractName>
You will now see that Ether has been deducted from your account
Also, the newly created contract has been given its own address, which you can view in the data in the
app/users/<username> folder. Viewing contract information, including compiled bytecode for your Solidity contract can be done using the same URL that you use to view your own account information.
Running The Local Webserver
Bloc ships with a node server. To get the server up and running
Now you can visit one of the contracts in your application, for example http://localhost:3000/contracts/Payout. Note
that the local webserver relies on dynamically generated templates, founds in the
bloc will run through three contract status checks
- Does the contract exist in the project
- Has the contract been compiled
- Has the contract been uploaded to the network
This will be reflected in the application as well as at the terminal
Keyserver & Contract API
Once you have a deployed contract
bloc will provide a simple REST API for interacting with the contract. The API has routes for viewing contract methods, symbols, calling contract methods. The keyserver and contract API documentation can be viewed here
Usage: /usr/local/bin/bloc <command> (options) Commands: init [appName] start a new project compile [contract] compile contract in contract folder upload contract upload contract to blockchain genkey [user] generate a new private key and fill it at the faucet, namespaced by user send start prompt, transfer (amount*unit) to (address) start start bloc as a webserver with live reload Options: -u [default: "admin"]
bloc uses blockapps-js, our library for interfacing with the blockchain in a simple way.