78 lines
1.9 KiB
JavaScript
78 lines
1.9 KiB
JavaScript
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// Copyright 2015, 2016 Ethcore (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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import EventEmitter from 'eventemitter3';
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const defaults = {
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from: 0, // TODO
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to: 'latest',
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timeout: null,
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filter: () => true
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};
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const subscribeToEvent = (contract, name, opt = {}) => {
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opt = Object.assign({}, defaults, opt);
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let subscription = null;
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let timeout = null;
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const unsubscribe = () => {
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if (subscription) {
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contract.unsubscribe(subscription);
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subscription = null;
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}
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if (timeout) {
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clearTimeout(timeout);
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timeout = null;
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}
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};
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const emitter = new EventEmitter();
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emitter.unsubscribe = unsubscribe;
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if (typeof opt.timeout === 'number') {
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timeout = setTimeout(() => {
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unsubscribe();
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emitter.emit('timeout');
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}, opt.timeout);
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}
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const callback = (err, logs) => {
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if (err) {
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return emitter.emit('error', err);
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}
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for (let log of logs) {
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if (opt.filter(log)) {
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emitter.emit('log', log);
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}
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}
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};
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contract.subscribe(name, {
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fromBlock: opt.from, toBlock: opt.to
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}, callback)
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.then((_subscription) => {
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subscription = _subscription;
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})
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.catch((err) => {
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emitter.emit('error', err);
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});
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return emitter;
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};
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export default subscribeToEvent;
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