go-ethereum/lib/contract.js

144 lines
4.7 KiB
JavaScript

/*
This file is part of ethereum.js.
ethereum.js is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
ethereum.js is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with ethereum.js. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file contract.js
* @authors:
* Marek Kotewicz <marek@ethdev.com>
* @date 2014
*/
var web3 = require('./web3'); // jshint ignore:line
var abi = require('./abi');
/**
* This method should be called when we want to call / transact some solidity method from javascript
* it returns an object which has same methods available as solidity contract description
* usage example:
*
* var abi = [{
* name: 'myMethod',
* inputs: [{ name: 'a', type: 'string' }],
* outputs: [{name: 'd', type: 'string' }]
* }]; // contract abi
*
* var myContract = web3.eth.contract('0x0123123121', abi); // creation of contract object
*
* myContract.myMethod('this is test string param for call'); // myMethod call (implicit, default)
* myContract.call().myMethod('this is test string param for call'); // myMethod call (explicit)
* myContract.transact().myMethod('this is test string param for transact'); // myMethod transact
*
* @param address - address of the contract, which should be called
* @param desc - abi json description of the contract, which is being created
* @returns contract object
*/
var contract = function (address, desc) {
desc.forEach(function (method) {
// workaround for invalid assumption that method.name is the full anonymous prototype of the method.
// it's not. it's just the name. the rest of the code assumes it's actually the anonymous
// prototype, so we make it so as a workaround.
if (method.name.indexOf('(') === -1) {
var displayName = method.name;
var typeName = method.inputs.map(function(i){return i.type}).join();
method.name = displayName + '(' + typeName + ')';
}
});
var inputParser = abi.inputParser(desc);
var outputParser = abi.outputParser(desc);
var result = {};
result.call = function (options) {
result._isTransact = false;
result._options = options;
return result;
};
result.transact = function (options) {
result._isTransact = true;
result._options = options;
return result;
};
result._options = {};
['gas', 'gasPrice', 'value', 'from'].forEach(function(p) {
result[p] = function (v) {
result._options[p] = v;
return result;
};
});
desc.forEach(function (method) {
var displayName = abi.methodDisplayName(method.name);
var typeName = abi.methodTypeName(method.name);
var impl = function () {
var params = Array.prototype.slice.call(arguments);
var signature = abi.methodSignature(method.name);
var parsed = inputParser[displayName][typeName].apply(null, params);
var options = result._options || {};
options.to = address;
options.data = signature + parsed;
var isTransact = result._isTransact === true || (result._isTransact !== false && !method.constant);
var collapse = options.collapse !== false;
// reset
result._options = {};
result._isTransact = null;
if (isTransact) {
// it's used byt natspec.js
// TODO: figure out better way to solve this
web3._currentContractAbi = desc;
web3._currentContractAddress = address;
// transactions do not have any output, cause we do not know, when they will be processed
web3.eth.transact(options);
return;
}
var output = web3.eth.call(options);
var ret = outputParser[displayName][typeName](output);
if (collapse)
{
if (ret.length == 1)
ret = ret[0];
else if (ret.length == 0)
ret = null;
}
return ret;
};
if (result[displayName] === undefined) {
result[displayName] = impl;
}
result[displayName][typeName] = impl;
});
return result;
};
module.exports = contract;