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Simple Ethereum contract to act as a shop
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| <html> | |
| <head> | |
| <script src="https://code.jquery.com/jquery-3.1.1.min.js"></script> | |
| <script src="./web3.min.js"></script> | |
| <title>Web3 test</title> | |
| <meta charset='utf-8'> | |
| </head> | |
| <body> | |
| <div id="main"> | |
| <div id="coinbase-val"></div> | |
| <div id="balance">Balance: <span id="balance-val"></span></div> | |
| <ul id="items"></ul> | |
| </div> | |
| <script> | |
| window.addEventListener('load', function() { | |
| // Checking if Web3 has been injected by the browser (Mist/MetaMask) | |
| if (typeof web3 !== 'undefined') { | |
| // Use Mist/MetaMask's provider | |
| web3 = new Web3(web3.currentProvider); | |
| } else { | |
| console.log('No web3? You should consider trying MetaMask!') | |
| // fallback - use your fallback strategy (local node / hosted node + in-dapp id mgmt / fail) | |
| web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545")); | |
| } | |
| var kobyshop = web3.eth.contract([{"constant":false,"inputs":[],"name":"withdraw","outputs":[{"name":"","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"_itemId","type":"bytes32"}],"name":"details","outputs":[{"name":"","type":"string"},{"name":"","type":"uint256"},{"name":"","type":"address"},{"name":"","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"_itemId","type":"bytes32"}],"name":"buy","outputs":[],"payable":true,"type":"function"},{"constant":false,"inputs":[{"name":"_name","type":"string"},{"name":"_price","type":"uint256"}],"name":"sell","outputs":[],"payable":false,"type":"function"},{"anonymous":false,"inputs":[{"indexed":false,"name":"itemId","type":"bytes32"},{"indexed":false,"name":"seller","type":"address"}],"name":"NewSale","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"itemId","type":"bytes32"},{"indexed":false,"name":"buyer","type":"address"}],"name":"NewPurchase","type":"event"}]).at("0x1d7C28F5075c102daE1588fBFFbb303B04852b49"); | |
| startApp(kobyshop); | |
| $("#items").on("click", "li", function(){ | |
| var itmId = $(this).data("item-id"); | |
| var price = $(this).data("price"); | |
| kobyshop.buy(itmId, {value: price, from: web3.eth.accounts[0]}, function(rep){ | |
| console.log(rep) | |
| }); | |
| }); | |
| }); | |
| function startApp(ks){ | |
| watchBalance(); | |
| listItems(ks); | |
| } | |
| function listItems(ks){ | |
| var ul = document.getElementById("items"); | |
| ks.NewSale({}, {fromBlock:0, toBlock:'latest'}, function(err, log){ | |
| ks.details(log.args.itemId, function(err, itm){ | |
| if(itm[3] === true){ | |
| ul.innerHTML += "<li data-price='"+ itm[1] +"' data-item-id='"+ log.args.itemId +"'>"+ itm[0] +" - <b>"+ web3.fromWei(itm[1], "ether") +" ETH</b><br><i>owner: "+ itm[2] +"</i></li>"; | |
| } | |
| }) | |
| }); | |
| } | |
| function watchBalance(){ | |
| var cb = web3.eth.coinbase; | |
| var cb_div = document.getElementById("coinbase-val"); | |
| var bal_div = document.getElementById("balance-val"); | |
| cb_div.innerHTML = cb; | |
| web3.eth.getBalance(cb, function(e, bal){ | |
| bal_div.innerHTML = web3.fromWei(bal, "ether").toNumber(); | |
| }); | |
| web3.eth.filter('latest').watch(function() { | |
| web3.eth.getBalance(cb, function(e, bal){ | |
| bal_div.innerText = web3.fromWei(bal, "ether").toNumber(); | |
| }); | |
| }); | |
| } | |
| </script> | |
| </body> | |
| </html> |
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| pragma solidity ^0.4.6; | |
| contract KobyShop { | |
| struct Item { | |
| string name; | |
| uint price; | |
| bool forSale; | |
| address owner; | |
| bool initialized; | |
| } | |
| mapping(bytes32 => Item) private items; | |
| mapping(address => uint) private pendingWithdrawals; | |
| event NewSale(bytes32 itemId, address seller); | |
| event NewPurchase(bytes32 itemId, address buyer); | |
| function sell(string _name, uint _price){ | |
| var itemId = keccak256(_name); | |
| // if item already exists we just update it if same owner | |
| if(items[itemId].initialized){ | |
| if(items[itemId].owner != msg.sender) throw; | |
| items[itemId].price = _price; | |
| items[itemId].forSale = true; | |
| }else{ | |
| items[itemId] = Item({ | |
| name: _name, | |
| price: _price, | |
| forSale: true, | |
| owner: msg.sender, | |
| initialized: true | |
| }); | |
| } | |
| NewSale(itemId, msg.sender); | |
| } | |
| function buy(bytes32 _itemId) payable { | |
| var itm = items[_itemId]; | |
| if(!itm.initialized) throw; | |
| if(!itm.forSale) throw; | |
| if(msg.value < itm.price) throw; | |
| pendingWithdrawals[itm.owner] += itm.price; | |
| itm.owner = msg.sender; | |
| itm.forSale = false; | |
| // Send any excess back | |
| if (msg.value > itm.price){ | |
| if(!msg.sender.send(msg.value - itm.price)){ | |
| throw; | |
| } | |
| } | |
| NewPurchase(_itemId, msg.sender); | |
| } | |
| function details(bytes32 _itemId) constant returns (string, uint, address, bool){ | |
| return ( | |
| items[_itemId].name, | |
| items[_itemId].price, | |
| items[_itemId].owner, | |
| items[_itemId].forSale | |
| ); | |
| } | |
| function withdraw() returns (bool) { | |
| uint amount = pendingWithdrawals[msg.sender]; | |
| // Remember to zero the pending refund before | |
| // sending to prevent re-entrancy attacks | |
| pendingWithdrawals[msg.sender] = 0; | |
| if (msg.sender.send(amount)) { | |
| return true; | |
| } else { | |
| pendingWithdrawals[msg.sender] = amount; | |
| return false; | |
| } | |
| } | |
| } |
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