585 lines
16 KiB
Markdown
585 lines
16 KiB
Markdown
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[](https://npmjs.com/package/embark)
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[](https://gitter.im/iurimatias/embark-framework)
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[](https://travis-ci.org/iurimatias/embark-framework)
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What is Embark
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======
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Embark is a framework that allows you to easily develop and deploy Decentralized Applications (DApps).
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A Decentralized Application is a serverless html5 application that uses one or more decentralized technologies.
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Embark currently integrates with EVM blockchains (Ethereum), Decentralized Storages (IPFS), and Decentralized communication platforms (Whisper and Orbit). Swarm is supported for deployment.
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With Embark you can:
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**Blockchain (Ethereum)**
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* 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.
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* Contracts are available in JS with Promises.
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* Do Test Driven Development with Contracts using Javascript.
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* Keep track of deployed contracts; deploy only when truly needed.
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* Manage different chains (e.g testnet, private net, livenet)
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* Easily manage complex systems of interdependent contracts.
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**Decentralized Storage (IPFS)**
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* Easily Store & Retrieve Data on the DApp through EmbarkJS. Including uploading and retrieving files.
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* Deploy the full application to IPFS or Swarm.
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**Decentralized Communication (Whisper, Orbit)**
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* Easily send/receive messages through channels in P2P through Whisper or Orbit.
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**Web Technologies**
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* Integrate with any web technology including React, Foundation, etc..
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* Use any build pipeline or tool you wish, including grunt, gulp and webpack.
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Table of Contents
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======
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* [Installation](#installation)
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* [Usage Demo](#usage---demo)
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* [Dashboard](#dashboard)
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* [Creating a new DApp](#creating-a-new-dapp)
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* [Libraries and APIs available](#libraries-and-languages-available)
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* [Using and Configuring Contracts](#using-contracts)
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* [EmbarkJS](#embarkjs)
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* [EmbarkJS - Storage (IPFS)](#embarkjs---storage)
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* [EmbarkJS - Communication (Whisper/Orbit)](#embarkjs---communication)
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* [Testing Contracts](#tests)
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* [Working with different chains](#working-with-different-chains)
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* [Custom Application Structure](#structuring-application)
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* [Deploying to IPFS](#deploying-to-ipfs-and-swarm)
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* [Extending Functionality with Plugins](#plugins)
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* [Donations](#donations)
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Installation
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======
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Requirements: geth (1.6.7 or higher recommended), node (6.9.1 or higher is recommended) and npm
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Optional: testrpc (3.0 or higher) if using the simulator
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Further: depending on the dapp stack you choose: [IPFS](https://ipfs.io/)
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```Bash
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$ npm -g install embark
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# If you plan to use the simulator instead of a real ethereum node.
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$ npm -g install ethereumjs-testrpc
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```
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See [Complete Installation Instructions](https://github.com/iurimatias/embark-framework/wiki/Installation).
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**updating from Embark 1**
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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```
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Usage - Demo
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======
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You can easily create a sample working DApp with the following:
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```Bash
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$ embark demo
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$ cd embark_demo
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```
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You can run a REAL ethereum node for development purposes:
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```Bash
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$ embark blockchain
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```
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Alternatively, to use an ethereum rpc simulator simply run:
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```Bash
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$ embark simulator
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```
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By default Embark blockchain will mine a minimum amount of ether and will only mine when new transactions come in. This is quite useful to keep a low CPU. The option can be configured at ```config/blockchain.json```. Note that running a real node requires at least 2GB of free ram, please take this into account if running it in a VM.
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Then, in another command line:
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```Bash
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$ embark run
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```
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This will automatically deploy the contracts, update their JS bindings and deploy your DApp to a local server at http://localhost:8000
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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.
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Dashboard
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=====
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Embark 2 comes with a terminal dashboard.
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The dashboard will tell you the state of your contracts, the environment you are using, and what Embark is doing at the moment.
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**available services**
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Available Services will display the services available to your dapp in green. If a service is down, then it will be displayed in red.
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**logs and console**
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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.
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Creating a new DApp
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======
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If you want to create a blank new app:
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```Bash
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$ embark new AppName
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$ cd AppName
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```
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DApp Structure
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======
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```Bash
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app/
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|___ contracts/ #solidity or serpent contracts
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|___ html/
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|___ css/
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|___ js/
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config/
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|___ blockchain.json #rpc and blockchain configuration
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|___ contracts.json #ethereum contracts configuration
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|___ storage.json #ipfs configuration
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|___ communication.json #whisper/orbit configuration
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|___ webserver.json #dev webserver configuration
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test/
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|___ #contracts tests
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```
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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
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Libraries and languages available
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======
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Embark can build and deploy contracts coded in Solidity. It will make them available on the client side using EmbarkJS and Web3.js.
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Further documentation for these can be found below:
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* Smart Contracts: [Solidity](https://solidity.readthedocs.io/en/develop/) and [Serpent](https://github.com/ethereum/wiki/wiki/Serpent)
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* Client Side: [Web3.js](https://github.com/ethereum/wiki/wiki/JavaScript-API) and [EmbarkJS](#embarkjs)
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Using Contracts
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======
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Embark will automatically take care of deployment for you and set all needed JS bindings. For example, the contract below:
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```Javascript
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# app/contracts/simple_storage.sol
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pragma solidity ^0.4.17;
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contract SimpleStorage {
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uint public storedData;
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function SimpleStorage(uint initialValue) public {
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storedData = initialValue;
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}
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function set(uint x) public {
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storedData = x;
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}
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function get() view returns (uint retVal) {
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return storedData;
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}
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}
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```
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Will automatically be available in Javascript as:
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```Javascript
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# app/js/index.js
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SimpleStorage.methods.set(100).send({from: web3.eth.defaultAccount});
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SimpleStorage.methods.get().call().then(function(value) { console.log(value.toNumber()) });
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SimpleStorage.methods.storedData().then(function(value) { console.log(value.toNumber()) });
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```
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You can specify for each contract and environment its gas costs and arguments:
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```Json
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# config/contracts.json
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{
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"development": {
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"gas": "auto",
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"contracts": {
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"SimpleStorage": {
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"args": [
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100
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]
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}
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}
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}
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}
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```
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If you are using multiple contracts, you can pass a reference to another contract as ```$ContractName```, Embark will automatically replace this with the correct address for the contract.
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```Json
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# config/contracts.json
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{
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...
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"development": {
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"contracts": {
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"SimpleStorage": {
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"args": [
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100,
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"$MyStorage"
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]
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},
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"MyStorage": {
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"args": [
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"initial string"
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]
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},
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"MyMainContract": {
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"args": [
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"$SimpleStorage"
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]
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}
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}
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}
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...
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}
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```
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You can now deploy many instances of the same contract. e.g
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```Json
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# config/contracts.json
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{
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"development": {
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"contracts": {
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"Currency": {
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"deploy": false,
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"args": [
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100
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]
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},
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"Usd": {
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"instanceOf": "Currency",
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"args": [
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200
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]
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},
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"MyCoin": {
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"instanceOf": "Currency",
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"args": [
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200
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]
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}
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}
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}
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}
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...
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```
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Contracts addresses can be defined. If an address is defined, Embark uses the defined address instead of deploying the contract.
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```Json
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# config/contracts.json
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{
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...
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"development": {
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"contracts": {
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"UserStorage": {
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"address": "0x123456"
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},
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"UserManagement": {
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"args": [
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"$UserStorage"
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]
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}
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}
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}
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...
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}
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```
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You can Also specify which versions of solc and web3.js to use:
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```Json
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# config/contracts.json
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{
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...
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"development": {
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"versions": {
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"web3.js": "1.0.0-beta",
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"solc": "0.4.17"
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}
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}
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...
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}
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```
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You specify which node the contracts should be deploy to and the order of nodes
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the dapp should connect to. $WEB3 means the dapp will try to use an existing
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web3 object first if available.
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```Json
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# config/contracts.json
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{
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...
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"development": {
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"deployment": {
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"host": "localhost",
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"port": 8545,
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"type": "rpc"
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},
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"dappConnection": [
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"$WEB3",
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"http://localhost:8545"
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]
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}
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...
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}
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```
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EmbarkJS
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======
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EmbarkJS is a javascript library meant to abstract and facilitate the development of DApps.
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**promises**
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```Javascript
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var myContract = new EmbarkJS.Contract({abi: abiObject, address: "0x123"});
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myContract.methods.get().call().then(function(value) { console.log("value is " + value.toNumber) });
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```
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events:
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```Javascript
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myContract.events.eventName({from: web3.eth.accounts}, 'latest').then(function(event) { console.log(event) });
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```
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**deployment**
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Client side deployment will be automatically available in Embark for existing contracts:
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```Javascript
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SimpleStorage.deploy([args], {options}).then(function(anotherSimpleStorage) {});
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```
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or it can be manually definied as
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```Javascript
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var myContract = new EmbarkJS.Contract({abi: abiObject, code: code});
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myContract.deploy([args], {options}).then(function(anotherMyContractObject) {});
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```
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so you can define your gas as
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```Javascript
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myContract.deploy([100, "seconde argument"], {gas: 800000}).then(function(anotherMyContractObject) {});
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```
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EmbarkJS - Storage
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======
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**initialization**
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The current available storage is IPFS. It can be initialized as
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```Javascript
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EmbarkJS.Storage.setProvider('ipfs',{server: 'localhost', port: '5001'})
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```
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**Saving Text**
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```Javascript
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EmbarkJS.Storage.saveText("hello world").then(function(hash) {});
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```
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**Retrieving Data/Text**
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```Javascript
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EmbarkJS.Storage.get(hash).then(function(content) {});
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```
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**Uploading a file**
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```HTML
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<input type="file">
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```
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```Javascript
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var input = $("input[type=file"]);
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EmbarkJS.Storage.uploadFile(input).then(function(hash) {});
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```
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**Generate URL to file**
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```Javascript
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EmbarkJS.Storage.getUrl(hash);
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```
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note: if not using localhost, the cors needs to be set as ```ipfs --json API.HTTPHeaders.Access-Control-Allow-Origin '["your-host-name-port"]```
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EmbarkJS - Communication
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======
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**initialization**
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For Whisper (note: currently requires geth 1.6.0 or higher):
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```Javascript
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EmbarkJS.Messages.setProvider('whisper')
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```
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For Orbit:
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You'll need to use IPFS from master and run it as: ```ipfs daemon --enable-pubsub-experiment```
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then set the provider:
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```Javascript
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EmbarkJS.Messages.setProvider('orbit', {server: 'localhost', port: 5001})
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```
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**listening to messages**
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```Javascript
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EmbarkJS.Messages.listenTo({topic: ["topic1", "topic2"]}).then(function(message) { console.log("received: " + message); })
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```
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**sending messages**
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you can send plain text
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```Javascript
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EmbarkJS.Messages.sendMessage({topic: "sometopic", data: 'hello world'})
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```
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or an object
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```Javascript
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EmbarkJS.Messages.sendMessage({topic: "sometopic", data: {msg: 'hello world'}})
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```
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note: array of topics are considered an AND. In Whisper you can use another array for OR combinations of several topics e.g ```["topic1", ["topic2", "topic3"]]``` => ```topic1 AND (topic2 OR topic 3)```
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Tests
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======
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You can run specs with ```embark test```, it will run any test files under ```test/```.
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Embark includes a testing lib to rapidly run & test your contracts in a EVM.
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```Javascript
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# test/simple_storage_spec.js
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describe("SimpleStorage", function() {
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before(function(done) {
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this.timeout(0);
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var contractsConfig = {
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"SimpleStorage": {
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args: [100]
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}
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};
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EmbarkSpec.deployAll(contractsConfig, done);
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});
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it("should set constructor value", function(done) {
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SimpleStorage.storedData(function(err, result) {
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assert.equal(result.toNumber(), 100);
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done();
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});
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});
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it("set storage value", function(done) {
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SimpleStorage.set(150, function() {
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SimpleStorage.get(function(err, result) {
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assert.equal(result.toNumber(), 150);
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done();
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});
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});
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});
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});
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```
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Embark uses [Mocha](http://mochajs.org/) by default, but you can use any testing framework you want.
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Working with different chains
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======
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You can specify which environment to deploy to:
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```$ embark blockchain livenet```
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```$ embark run livenet```
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The environment is a specific blockchain configuration that can be managed at config/blockchain.json
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```Json
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# config/blockchain.json
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...
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"livenet": {
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"networkType": "livenet",
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"rpcHost": "localhost",
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"rpcPort": 8545,
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"rpcCorsDomain": "http://localhost:8000",
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"account": {
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"password": "config/livenet/password"
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}
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},
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...
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```
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Structuring Application
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======
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Embark is quite flexible and you can configure your own directory structure using ```embark.json```
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```Json
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# embark.json
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{
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"contracts": ["app/contracts/**"],
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"app": {
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"css/app.css": ["app/css/**"],
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"images/": ["app/images/**"],
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"js/app.js": ["embark.js", "app/js/**"],
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"index.html": "app/index.html"
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},
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"buildDir": "dist/",
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"config": "config/",
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"plugins": {}
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}
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```
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Deploying to IPFS and Swarm
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======
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To deploy a dapp to IPFS, all you need to do is run a local IPFS node and then run ```embark upload ipfs```.
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If you want to deploy to the livenet then after configuring you account on ```config/blockchain.json``` on the ```livenet``` environment then you can deploy to that chain by specifying the environment ```embark ipfs livenet```.
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To deploy a dapp to SWARM, all you need to do is run a local SWARM node and then run ```embark upload swarm```.
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Plugins
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======
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It's possible to extend Embark's functionality with plugins. For example, the following is possible:
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* plugin to add support for es6, jsx, coffescript, etc (``embark.registerPipeline``)
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* plugin to add standard contracts or a contract framework (``embark.registerContractConfiguration`` and ``embark.addContractFile``)
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* plugin to make some contracts available in all environments for use by other contracts or the dapp itself e.g a Token, a DAO, ENS, etc.. (``embark.registerContractConfiguration`` and ``embark.addContractFile``)
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* plugin to add a libraries such as react or bootstrap (``embark.addFileToPipeline``)
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* plugin to specify a particular web3 initialization for special provider uses (``embark.registerClientWeb3Provider``)
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* plugin to create a different contract wrapper (``embark.registerContractsGeneration``)
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* plugin to add new console commands (``embark.registerConsoleCommand``)
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* plugin to add support for another contract language such as viper, LLL, etc (``embark.registerCompiler``)
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For more information on how to develop your own plugin, please see the [plugin documentation](http://embark.readthedocs.io/en/latest/plugins.html)
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Donations
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If you like Embark, please consider donating to 0xFA239D14c7117C3D2370B2a4c4238534391fadd9
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