aws-http-provider.js

/////////////////////////////////////////////////////
// Authored by Carl Youngblood
// Senior Blockchain Solutions Architect, AWS
// Adapted from web3 npm package v1.3.0
// licensed under GNU Lesser General Public License
// https://github.com/ethereum/web3.js
/////////////////////////////////////////////////////

import AWS from 'aws-sdk';
import HttpProvider from 'web3-providers-http';
import XHR2 from 'xhr2';

export default class AWSHttpProvider extends HttpProvider {
	send(payload, callback) {
		const self = this;
		const request = new XHR2(); // eslint-disable-line

		request.timeout = self.timeout;
		request.open('POST', self.host, true);
		request.setRequestHeader('Content-Type', 'application/json');

		request.onreadystatechange = () => {
			if (request.readyState === 4 && request.timeout !== 1) {
				let result = request.responseText; // eslint-disable-line
				let error = null; // eslint-disable-line

				try {
					result = JSON.parse(result);
				} catch (jsonError) {
					let message;
					if (!!result && !!result.error && !!result.error.message) {
						message = `[aws-ethjs-provider-http] ${result.error.message}`;
					} else  {
						message = `[aws-ethjs-provider-http] Invalid JSON RPC response from host provider ${self.host}: ` +
							`${JSON.stringify(result, null, 2)}`;
					}
					error = new Error(message);
				}

				callback(error, result);
			}
		};

		request.ontimeout = () => {
			callback(`[aws-ethjs-provider-http] CONNECTION TIMEOUT: http request timeout after ${self.timeout} ` +
				`ms. (i.e. your connect has timed out for whatever reason, check your provider).`, null);
		};

		try {
			const strPayload = JSON.stringify(payload);
			const region = process.env.AWS_DEFAULT_REGION || 'us-east-1';
			const credentials = new AWS.EnvironmentCredentials('AWS');
			const endpoint = new AWS.Endpoint(self.host);
			const req = new AWS.HttpRequest(endpoint, region);
			req.method = request._method;
			req.body = strPayload;
			req.headers['host'] = request._url.host;
			const signer = new AWS.Signers.V4(req, 'managedblockchain');
			signer.addAuthorization(credentials, new Date());
			request.setRequestHeader('Authorization', req.headers['Authorization']);
			request.setRequestHeader('X-Amz-Date', req.headers['X-Amz-Date']);
			request.send(strPayload);
		} catch (error) {
			callback(`[aws-ethjs-provider-http] CONNECTION ERROR: Couldn't connect to node '${self.host}': ` +
				`${JSON.stringify(error, null, 2)}`, null);
		}
	}
}