ethereum

I installed truffle through npm with the following: sudo npm install -g truffle but when I run truffle list on the console it just gives me bash: truffle: command not found Please make sure you have the latest version of npm and node installed. I had the same issue, I updated npm and node to latest version and it worked. npm install -g truffle works. I had a similar problem. I ran npm i -g truffle and then when I tried to run truffle init I got an error: zsh: command not found: truffle . What solved it for me is to create a local node_modules with truffle installed in it, and then run that

I want to make simple smart contract that has a list, can set item, and can get the list. Code in solidity: contract lister { mapping(int => string) list; int id = 0; function getList() returns ( /*HERE*/ ) { return list; } function setItemToList(string str) { list[id] = str; id++; } } I want to make getList() return the list, but return type is not compatible. How can I do that? Bulk access to lists/arrays/etc is painful in Solidity. You rarely see it in contracts. In your case, a possible solution is to provide a function to access one item, using its index, and to let the caller loops from

创建项目文件夹 首先创建一个项目文件夹。你可以通过你喜欢的文件资源管理器或在命令行中执行以下命令： $ mkdir myproject 初始化你的项目 接下来，初始化你的 Truffle 项目通过在命令行执行以下命令： $ cd myproject $ truffle init 一旦执行完成，你将拥有一个如下项目结构的项目： app/ - 你的应用程序默认目录。这里包含推荐的 Javascript 和 stylesheets 文件夹，但是你完全可以自由支配这些文件的使用。 contracts/ - Truffle 项目的 solidity 合约目录。 environments/ - 放置应用程序构建文件的目录，在这里你可以重写每个环境变量配置。 test/ - 用于测试你的应用程序和智能合约的测试文件目录。 truffle.js - Truffle 项目主配置文件。 默认项目：MetaCoin 默认情况下，Truffle 给你初始化一个 MetaCoin 演示应用程序，它就像一个以太坊构建的 alt-coin 系统。你可以使用这个项目并通过浏览入门指南来快速学习 Truffle 的使用，或者删除这些文件，建立一个属于自己的项目。 英文原文： http://truffle.readthedocs.io/en/latest/getting_started/project/ 来源：

how display balance of token through Ethereum RPC? $id = 0; $data = array(); $data['jsonrpc'] = '2.0'; $data['id'] = $id++; $data['method'] = 'eth_call'; $data['params'] = [['from' => '0x0...', 'to' => '0x0...', 'data' => 'contract byte code here 0x0...'], 'latest']; $ch = curl_init(); ... Return: {"jsonrpc":"2.0","id":0,"result":"0x"} What to do next? Call contract method balanceOf? How to do that? Kris Roofe To get token balance with eth_call you need to and data parameter. to is contract address, here we need to generate the data parameter. As the doc eth_call says, data: DATA - (optional)

I'm getting this error: CONNECTION ERROR: Couldn't connect to node http://localhost:8545, is it running? I'm currently trying to use a Meteor app with a node on a private test network. I've also tried running it on a real node on the real network as well. I am able to access the web3.eth objects, but I can't seem to connect to my node! It's so frustrating! My app runs on http://localhost:3000 I've tried the following in launching my nodes, neither of them work (they launch okay, but I cannot connect to them through my browser): geth --networkid 8545 --genesis ~/genesis_block.json --datadir ~/