embark/README.md

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What is embark
======
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Embark is a framework that allows you to easily develop and deploy DApps.
With Embark you can:
* Automatically deploy contracts and make them available in your JS code. Embark watches for changes, and if you update a contract, Embark will automatically redeploy the contracts (if needed) and the dapp.
* Use any build pipeline or tool you wish, including grunt and meteor. (for 1.x, plugins coming soon for 2.x series)
* Do Test Driven Development with Contracts using Javascript.
* Easily deploy to & use decentralized systems such as IPFS.
* Keep track of deployed contracts, deploy only when truly needed.
* Manage different chains (e.g testnet, private net, livenet)
* Quickly create advanced DApps using multiple contracts that can interact with decentralized infrastructure for storage and comunication.
Table of Contents
======
* [Installation](#installation)
* [Usage Demo](#usage---demo)
* [Dashboard](#dashboard)
* [Creating a new DApp](#creating-a-new-dapp)
* [Using and Configuring Contracts](#dapp-structure)
* [EmbarkJS](#embarkjs)
* [EmbarkJS - Storage (IPFS)](#embarkjs---storage)
* [EmbarkJS - Communication (Whisper)](#embarkjs---communication)
* [Testing Contracts](#tests)
* [Working with different chains](#working-with-different-chains)
* [Custom Application Structure](#structuring-application)
* [Deploying to IPFS](#deploying-to-ipfs)
* [LiveReload Plugin](#livereload-plugin)
* [Donations](#donations)
Installation
======
Requirements: geth (1.4.4 or higher), node (5.0.0) and npm
Optional: serpent (develop) if using contracts with Serpent, testrpc or ethersim if using the simulator or the test functionality.
Further: depending on the dapp stack you choose: [IPFS](https://ipfs.io/)
```Bash
$ npm -g install embark
# If you plan to use the simulator instead of a real ethereum node.
$ npm -g install ethereumjs-testrpc
```
See [Complete Installation Instructions](https://github.com/iurimatias/embark-framework/wiki/Installation).
**updating from embark 1**
Embark's npm package has changed from ```embark-framework``` to ```embark```, this sometimes can create conflicts. To update first uninstall embark-framework 1 to avoid any conflicts. ```npm uninstall -g embark-framework``` then ```npm install -g embark```
Usage - Demo
======
You can easily create a sample working DApp with the following:
```Bash
$ embark demo
$ cd embark_demo
```
You can run a REAL ethereum node for development purposes:
```Bash
$ embark blockchain
```
Alternatively, to use an ethereum rpc simulator simply run:
```Bash
$ embark simulator
```
By default embark blockchain will mine a minimum amount of ether and will only mine when new transactions come in. This is quite usefull to keep a low CPU. The option can be configured at config/blockchain.json
Then, in another command line:
```Bash
$ embark run
```
This will automatically deploy the contracts, update their JS bindings and deploy your DApp to a local server at http://localhost:8000
Note that if you update your code it will automatically be re-deployed, contracts included. There is no need to restart embark, refreshing the page on the browser will do.
Dashboard
=====
Embark 2 comes with a terminal dashboard.
![Dashboard](http://i.imgur.com/s4OQZpu.jpg)
The dashboard will tell you the state of your contracts, the enviroment you are using, and what embark is doing at the moment.
**available services**
Available Services will display the services available to your dapp in green, if one of these is down then it will be displayed in red.
**logs and console**
There is a console at the bottom which can be used to interact with contracts or with embark itself. type ```help``` to see a list of available commands, more commands will be added with each version of Embark.
Creating a new DApp
======
If you want to create a blank new app.
```Bash
$ embark new AppName
$ cd AppName
```
DApp Structure
======
```Bash
app/
|___ contracts/ #solidity or serpent contracts
|___ html/
|___ css/
|___ js/
config/
|___ blockchain.json #environments configuration
|___ contracts.json #contracts configuration
test/
|___ #contracts tests
```
Solidity/Serpent files in the contracts directory will automatically be deployed with embark run. Changes in any files will automatically be reflected in app, changes to contracts will result in a redeployment and update of their JS Bindings
Using Contracts
======
Embark will automatically take care of deployment for you and set all needed JS bindings. For example, the contract below:
```Javascript
# app/contracts/simple_storage.sol
contract SimpleStorage {
uint public storedData;
function SimpleStorage(uint initialValue) {
storedData = initialValue;
}
function set(uint x) {
storedData = x;
}
function get() constant returns (uint retVal) {
return storedData;
}
}
```
Will automatically be available in Javascript as:
```Javascript
# app/js/index.js
SimpleStorage.set(100);
SimpleStorage.get();
SimpleStorage.storedData();
```
You can specify for each contract and environment its gas costs and arguments:
```Json
# config/contracts.json
{
"development": {
"gas": "auto",
"contracts": {
"SimpleStorage": {
"args": [
100
]
}
}
}
}
```
If you are using multiple contracts, you can pass a reference to another contract as ```$ContractName```, Embark will automatically replace this with the correct address for the contract.
```Json
# config/contracts.json
{
...
"development": {
"contracts": {
"SimpleStorage": {
"args": [
100,
$MyStorage
]
},
"MyStorage": {
"args": [
"initial string"
]
},
"MyMainContract": {
"args": [
$SimpleStorage
]
}
}
}
...
}
```
You can now deploy many instances of the same contract. e.g
```Json
# config/contracts.json
{
"development": {
"contracts": {
"Currency": {
"deploy": false,
"args": [
100
]
},
"Usd": {
"instanceOf": "Currency",
"args": [
200
]
},
"MyCoin": {
"instanceOf": "Currency",
"args": [
200
]
}
}
}
}
...
```
Contracts addresses can be defined, If an address is defined the contract wouldn't be deployed but its defined address will be used instead.
```Json
# config/contracts.json
{
...
"development": {
"contracts": {
"UserStorage": {
"address": "0x123456"
},
"UserManagement": {
"args": [
"$UserStorage"
]
}
}
}
...
}
```
EmbarkJS
======
EmbarkJS is a javascript library meant to abstract and facilitate the development of DApps.
**promises**
methods in EmbarkJS contracts will be converted to promises.
```Javascript
var myContract = new EmbarkJS.Contract({abi: abiObject, address: "0x123"});
myContract.get().then(function(value) { console.log("value is " + value.toNumber) });
```
**deployment**
Client side deployment will be automatically available in Embark for existing contracts:
```Javascript
SimpleStorage.deploy().then(function(anotherSimpleStorage) {});
```
or it can be manually definied as
```Javascript
var myContract = new EmbarkJS.Contract({abi: abiObject, code: code});
myContract.deploy().then(function(anotherMyContractObject) {});
```
EmbarkJS - Storage
======
**initialization**
The current available storage is IPFS. it can be initialized as
```Javascript
EmbarkJS.Storage.setProvider('ipfs',{server: 'localhost', port: '5001'})
```
**Saving Text**
```Javascript
EmbarkJS.Storage.saveText("hello world").then(function(hash) {});
```
**Retrieving Data/Text**
```Javascript
EmbarkJS.Storage.get(hash).then(function(content) {});
```
**Uploading a file**
```HTML
<input type="file">
```
```Javascript
var input = $("input[type=file"]);
EmbarkJS.Storage.uploadFile(input).then(function(hash) {});
```
**Generate URL to file**
```Javascript
EmbarkJS.Storage.getUrl(hash);
```
EmbarkJS - Communication
======
**initialization**
The current available communication is Whisper.
**listening to messages**
```Javascript
EmbarkJS.Messages.listenTo({topic: ["achannel", "anotherchannel"]}).then(function(message) { console.log("received: " + message); })
```
**sending messages**
you can send plain text
```Javascript
EmbarkJS.Messages.sendMessage({topic: "achannel", data: 'hello world'})
```
or an object
```Javascript
EmbarkJS.Messages.sendMessage({topic: "achannel", data: {msg: 'hello world'}})
```
Tests
======
You can run specs with ```embark test```, it will run any test files under ```test/```.
Embark includes a testing lib to fastly run & test your contracts in a EVM.
```Javascript
# test/simple_storage_spec.js
var assert = require('assert');
var Embark = require('embark-framework');
var EmbarkSpec = Embark.initTests();
var web3 = EmbarkSpec.web3;
describe("SimpleStorage", function() {
before(function(done) {
var contractsConfig = {
"SimpleStorage": {
args: [100]
}
};
EmbarkSpec.deployAll(contractsConfig, done);
});
it("should set constructor value", function(done) {
SimpleStorage.storedData(function(err, result) {
assert.equal(result.toNumber(), 100);
done();
});
});
it("set storage value", function(done) {
SimpleStorage.set(150, function() {
SimpleStorage.get(function(err, result) {
assert.equal(result.toNumber(), 150);
done();
});
});
});
});
```
Embark uses [Mocha](http://mochajs.org/) by default, but you can use any testing framework you want.
Working with different chains
======
You can specify which environment to deploy to:
```$ embark blockchain production```
```$ embark run production```
The environment is a specific blockchain configuration that can be managed at config/blockchain.json
```Json
# config/blockchain.json
...
"livenet": {
"networkType": "livenet",
"rpcHost": "localhost",
"rpcPort": 8545,
"rpcCorsDomain": "http://localhost:8000",
"account": {
"password": "config/production/password"
}
},
...
```
Structuring Application
======
Embark is quite flexible and you can configure you're own directory structure using ```embark.json```
```Json
# embark.json
{
"contracts": ["app/contracts/**"],
"app": {
"css/app.css": ["app/css/**"],
"js/app.js": ["embark.js", "app/js/**"],
"index.html": "app/index.html"
},
"buildDir": "dist/",
"config": "config/"
}
```
Deploying to IPFS
======
To deploy a dapp to IPFS, all you need to do is run a local IPFS node and then run ```embark ipfs```.
If you want to deploy to the livenet then after configuring you account on ```config/blockchain.json``` on the ```production``` environment then you can deploy to that chain by specifying the environment ```embark ipfs production```.
LiveReload Plugin
======
Embark works quite well with the LiveReload Plugin
Donations
======
If you like Embark please consider donating to 0x8811FdF0F988f0CD1B7E9DE252ABfA5b18c1cDb1