app.js

#!/usr/bin/env node

'use strict';

var os = require('os');
var path = require('path');
var dotenv = require("dotenv");
var fs = require('fs');

var configPaths = [path.join(os.homedir(), '.config', 'bch-rpc-explorer.env'), path.join(process.cwd(), '.env')];
configPaths.filter(fs.existsSync).forEach(path => {
	console.log('Loading env file:', path);
	dotenv.config({ path });
});

global.cacheStats = {};

// debug module is already loaded by the time we do dotenv.config
// so refresh the status of DEBUG env var
var debug = require("debug");
debug.enable(process.env.DEBUG || "bchexp:app,bchexp:error");

var debugLog = debug("bchexp:app");
var debugLogError = debug("bchexp:error");
var debugPerfLog = debug("bchexp:actionPerformace");

var express = require('express');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var session = require("express-session");
var csurf = require("csurf");
var config = require("./app/config.js");
var simpleGit = require('simple-git');
var utils = require("./app/utils.js");
var moment = require("moment");
var Decimal = require('decimal.js');
var bitcoinCore = require("bitcoin-core");
var pug = require("pug");
var momentDurationFormat = require("moment-duration-format");
var coreApi = require("./app/api/coreApi.js");
var coins = require("./app/coins.js");
var request = require("request");
var qrcode = require("qrcode");
var addressApi = require("./app/api/addressApi.js");
var electrumAddressApi = require("./app/api/electrumAddressApi.js");
var coreApi = require("./app/api/coreApi.js");
var auth = require('./app/auth.js');
var marked = require("marked");

var package_json = require('./package.json');
global.appVersion = package_json.version;

var crawlerBotUserAgentStrings = ["Googlebot", "Bingbot", "Slurp", "DuckDuckBot", "Baiduspider", "YandexBot", "Sogou", "Exabot", "facebot", "ia_archiver"];

var baseActionsRouter = require('./routes/baseActionsRouter.js');
var apiActionsRouter = require('./routes/apiRouter.js');
var snippetActionsRouter = require('./routes/snippetRouter.js');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));

app.set('view engine', 'pug');

// basic http authentication
if (process.env.BTCEXP_BASIC_AUTH_PASSWORD) {
	app.disable('x-powered-by');
	app.use(auth(process.env.BTCEXP_BASIC_AUTH_PASSWORD));
}

// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
//app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(session({
	secret: config.cookieSecret,
	resave: false,
	saveUninitialized: false
}));

app.use(express.static(path.join(__dirname, 'public')));

process.on("unhandledRejection", (reason, p) => {
	debugLog("Unhandled Rejection at: Promise", p, "reason:", reason, "stack:", (reason != null ? reason.stack : "null"));
});

function getSourcecodeProjectMetadata() {
	var options = {
		url: "https://api.github.com/repos/sickpig/bch-rpc-explorer",
		headers: {
			'User-Agent': 'request'
		}
	};

	request(options, function (error, response, body) {
		if (error == null && response && response.statusCode && response.statusCode == 200) {
			var responseBody = JSON.parse(body);

			global.sourcecodeProjectMetadata = responseBody;

		} else {
			utils.logError("3208fh3ew7eghfg", { error: error, response: response, body: body });
		}
	});
}

function loadChangelog() {
	var filename = "CHANGELOG.md";

	fs.readFile(path.join(__dirname, filename), 'utf8', function (err, data) {
		if (err) {
			utils.logError("2379gsd7sgd334", err);

		} else {
			global.changelogMarkdown = data;
		}
	});
}

function loadHistoricalDataForChain(chain) {
	debugLog(`Loading historical data for chain=${chain}`);

	if (global.coinConfig.historicalData) {
		global.coinConfig.historicalData.forEach(function (item) {
			if (item.chain == chain) {
				if (item.type == "blockheight") {
					global.specialBlocks[item.blockHash] = item;

				} else if (item.type == "tx") {
					global.specialTransactions[item.txid] = item;

				} else if (item.type == "address") {
					global.specialAddresses[item.address] = { type: "fun", addressInfo: item };
				}
			}
		});
	}
}

function verifyRpcConnection() {
	if (!global.activeBlockchain) {
		debugLog(`Verifying RPC connection...`);

		coreApi.getNetworkInfo().then(function (getnetworkinfo) {
			coreApi.getBlockchainInfo().then(function (getblockchaininfo) {
				global.activeBlockchain = getblockchaininfo.chain;

				// we've verified rpc connection, no need to keep trying
				clearInterval(global.verifyRpcConnectionIntervalId);

				onRpcConnectionVerified(getnetworkinfo, getblockchaininfo);

			}).catch(function (err) {
				utils.logError("329u0wsdgewg6ed", err);
			});
		}).catch(function (err) {
			utils.logError("32ugegdfsde", err);
		});
	}
}

function onRpcConnectionVerified(getnetworkinfo, getblockchaininfo) {
	// localservicenames introduced in 0.19
	var services = getnetworkinfo.localservicesnames ? ("[" + getnetworkinfo.localservicesnames.join(", ") + "]") : getnetworkinfo.localservices;

	global.getnetworkinfo = getnetworkinfo;

	var bitcoinCoreVersionRegex = /^.*\/BCH Unlimited\:(.*)\/.*$/;

	var match = bitcoinCoreVersionRegex.exec(getnetworkinfo.subversion);
	if (match) {
		global.btcNodeVersion = match[1];

		var semver4PartRegex = /^([0-9]+)\.([0-9]+)\.([0-9]+)\.([0-9]+)$/;

		var semver4PartMatch = semver4PartRegex.exec(global.btcNodeVersion);
		if (semver4PartMatch) {
			var p0 = semver4PartMatch[1];
			var p1 = semver4PartMatch[2];
			var p2 = semver4PartMatch[3];
			var p3 = semver4PartMatch[4];

			// drop last segment, which usually indicates a bug fix release which is (hopefully) irrelevant for RPC API versioning concerns
			global.btcNodeSemver = `${p0}.${p1}.${p2}`;

		} else {
			var semver3PartRegex = /^([0-9]+)\.([0-9]+)\.([0-9]+)$/;

			var semver3PartMatch = semver3PartRegex.exec(global.btcNodeVersion);
			if (semver3PartMatch) {
				var p0 = semver3PartMatch[1];
				var p1 = semver3PartMatch[2];
				var p2 = semver3PartMatch[3];

				global.btcNodeSemver = `${p0}.${p1}.${p2}`;

			} else {
				// short-circuit: force all RPC calls to pass their version checks - this will likely lead to errors / instability / unexpected results
				global.btcNodeSemver = "1000.1000.0"
			}
		}
	} else {
		// short-circuit: force all RPC calls to pass their version checks - this will likely lead to errors / instability / unexpected results
		global.btcNodeSemver = "1000.1000.0"

		debugLogError(`Unable to parse node version string: ${getnetworkinfo.subversion} - RPC versioning will likely be unreliable. Is your node a version of Bitcoin Core?`);
	}

	debugLog(`RPC Connected: version=${getnetworkinfo.version} subversion=${getnetworkinfo.subversion}, parsedVersion(used for RPC versioning)=${global.btcNodeSemver}, protocolversion=${getnetworkinfo.protocolversion}, chain=${getblockchaininfo.chain}, services=${services}`);

	// load historical/fun items for this chain
	loadHistoricalDataForChain(global.activeBlockchain);

	if (global.activeBlockchain == "main") {
		if (global.exchangeRates == null) {
			utils.refreshExchangeRates();
		}

		// refresh exchange rate periodically
		setInterval(utils.refreshExchangeRates, 1800000);

		// UTXO pull
		refreshUtxoSetSummary();
		setInterval(refreshUtxoSetSummary, 30 * 60 * 1000);

		// 1d / 7d volume
		refreshNetworkVolumes();
		setInterval(refreshNetworkVolumes, 30 * 60 * 1000);
	}
}

function refreshUtxoSetSummary() {
	if (config.slowDeviceMode) {
		global.utxoSetSummary = null;
		global.utxoSetSummaryPending = false;

		debugLog("Skipping performance-intensive task: fetch UTXO set summary. This is skipped due to the flag 'slowDeviceMode' which defaults to 'true' to protect slow nodes. Set this flag to 'false' to enjoy UTXO set summary details.");

		return;
	}

	// flag that we're working on calculating UTXO details (to differentiate cases where we don't have the details and we're not going to try computing them)
	global.utxoSetSummaryPending = true;

	coreApi.getUtxoSetSummary().then(function (result) {
		global.utxoSetSummary = result;

		result.lastUpdated = Date.now();

		debugLog("Refreshed utxo summary: " + JSON.stringify(result));
	});
}

function refreshNetworkVolumes() {
	if (config.slowDeviceMode) {
		debugLog("Skipping performance-intensive task: fetch last 24 hrs of blockstats to calculate transaction volume. This is skipped due to the flag 'slowDeviceMode' which defaults to 'true' to protect slow nodes. Set this flag to 'false' to enjoy UTXO set summary details.");

		return;
	}

	var cutoff1d = new Date().getTime() - (60 * 60 * 24 * 1000);
	var cutoff7d = new Date().getTime() - (60 * 60 * 24 * 7 * 1000);

	coreApi.getBlockchainInfo().then(function (result) {
		var promises = [];

		var blocksPerDay = 144 + 20; // 20 block padding

		for (var i = 0; i < (blocksPerDay * 1); i++) {
			if (result.blocks - i >= 0) {
				promises.push(coreApi.getBlockStatsByHeight(result.blocks - i));
			}
		}

		var startBlock = result.blocks;

		var endBlock1d = result.blocks;
		var endBlock7d = result.blocks;

		var endBlockTime1d = 0;
		var endBlockTime7d = 0;

		Promise.all(promises).then(function (results) {
			var volume1d = new Decimal(0);
			var volume7d = new Decimal(0);

			var blocks1d = 0;
			var blocks7d = 0;

			if (results && results.length > 0 && results[0] != null) {
				for (var i = 0; i < results.length; i++) {
					if (results[i].time * 1000 > cutoff1d) {
						volume1d = volume1d.plus(new Decimal(results[i].total_out));
						volume1d = volume1d.plus(new Decimal(results[i].subsidy));
						volume1d = volume1d.plus(new Decimal(results[i].totalfee));
						blocks1d++;

						endBlock1d = results[i].height;
						endBlockTime1d = results[i].time;
					}

					if (results[i].time * 1000 > cutoff7d) {
						volume7d = volume7d.plus(new Decimal(results[i].total_out));
						volume7d = volume7d.plus(new Decimal(results[i].subsidy));
						volume7d = volume7d.plus(new Decimal(results[i].totalfee));
						blocks7d++;

						endBlock7d = results[i].height;
						endBlockTime7d = results[i].time;
					}
				}

				debugLog("Volume 1d", volume1d);
				debugLog("Volume 7d", volume7d);

				global.networkVolume = { d1: { amt: volume1d, blocks: blocks1d, startBlock: startBlock, endBlock: endBlock1d, startTime: results[0].time, endTime: endBlockTime1d } };

				debugLog(`Network volume: ${JSON.stringify(global.networkVolume)}`);

			} else {
				debugLog("Unable to load network volume, likely due to bitcoind version older than BCH Unlimited 1.8.0 (the first version to support getblockstats).");
			}
		});
	});
}


app.onStartup = function () {
	global.appStartTime = new Date().getTime();
	global.config = config;
	global.coinConfig = coins[config.coin];
	global.coinConfigs = coins;

	global.specialTransactions = {};
	global.specialBlocks = {};
	global.specialAddresses = {};

	// TODO: move the explorer list out to an external JSON file to decouple codebase from any one branding/provider
	let allExplorers = new Map([
		["mainnet", new utils.ExplorerLink("mainnet", "Mainnet Explorer", "https://explorer.bitcoincash.org")],
		["testnet", new utils.ExplorerLink("testnet", "Testnet Explorer", "https://texplorer.bitcoincash.org")],
		["activationTestnet", new utils.ExplorerLink("activationTestnet", "Activation Testnet Explorer", "https://upgrade-explorer.bitcoincash.org")],
	]);

	// Get selected explorer info, remove it from list of siblings to link to
	const selectedExplorerKey = process.env.BTCEXP_EXPLORER_INSTANCE;
	global.selectedExplorer = allExplorers.get(selectedExplorerKey);
	if (!allExplorers.delete(selectedExplorerKey)) {
		// an invalid explorer-instance was configured, it's better to exit than proceed with a default
		debugLog(`Invalid explorer-instance \`${selectedExplorerKey}\` configured, please use --help and pick a valid one:`);
		process.exit(1);
	}

	global.siblingExplorers = undefined;
	// Only if running on sibling explorer mode
	if (process.env.BTCEXP_SIBLING_EXPLORER) {
		// Populate array with the remaining explorers
		let otherExplorers = []
		for (const [key, value] of allExplorers) {
			otherExplorers.push(value);
		}
		global.siblingExplorers = otherExplorers;
	}

	if (global.selectedExplorer.identifier == 'activationTestnet') {
		const activationTimestamp = process.env.BTCEXP_ACTIVATION_TIMESTAMP;
		// need a timestamp if this is an activationTestnet explorer
		if (activationTimestamp == undefined) {
			debugLog(`Running in post-upgrade mode.`);
			global.currentActivation = -1;
		} else {
			global.currentActivation = moment.unix(activationTimestamp);
			global.nextActivation = moment.unix(activationTimestamp).add(1, 'day');
		}
	}

	loadChangelog();

	if (global.sourcecodeVersion == null && fs.existsSync('.git')) {
		simpleGit(".").log(["-n 1"], function (err, log) {
			if (err) {
				utils.logError("3fehge9ee", err, { desc: "Error accessing git repo" });

				debugLog(`Starting ${global.coinConfig.ticker} RPC Explorer, v${global.appVersion} (code: unknown commit)`);

			} else {
				global.sourcecodeVersion = log.all[0].hash.substring(0, 10);
				global.sourcecodeDate = log.all[0].date.substring(0, "0000-00-00".length);

				debugLog(`Starting ${global.coinConfig.ticker} RPC Explorer, v${global.appVersion} (commit: '${global.sourcecodeVersion}', date: ${global.sourcecodeDate})`);
			}

			app.continueStartup();
		});

	} else {
		debugLog(`Starting ${global.coinConfig.ticker} RPC Explorer, v${global.appVersion}`);

		app.continueStartup();
	}
}

app.continueStartup = function () {
	var rpcCred = config.credentials.rpc;
	debugLog(`Connecting to RPC node at ${rpcCred.host}:${rpcCred.port}`);

	var rpcClientProperties = {
		host: rpcCred.host,
		port: rpcCred.port,
		username: rpcCred.username,
		password: rpcCred.password,
		timeout: rpcCred.timeout
	};

	global.rpcClient = new bitcoinCore(rpcClientProperties);

	var rpcClientNoTimeoutProperties = {
		host: rpcCred.host,
		port: rpcCred.port,
		username: rpcCred.username,
		password: rpcCred.password,
		timeout: 0
	};

	global.rpcClientNoTimeout = new bitcoinCore(rpcClientNoTimeoutProperties);


	// keep trying to verify rpc connection until we succeed
	// note: see verifyRpcConnection() for associated clearInterval() after success
	verifyRpcConnection();
	global.verifyRpcConnectionIntervalId = setInterval(verifyRpcConnection, 30000);


	if (config.addressApi) {
		var supportedAddressApis = addressApi.getSupportedAddressApis();
		if (!supportedAddressApis.includes(config.addressApi)) {
			utils.logError("32907ghsd0ge", `Unrecognized value for BTCEXP_ADDRESS_API: '${config.addressApi}'. Valid options are: ${supportedAddressApis}`);
		}

		if (config.addressApi == "electrumx") {
			if (config.electrumXServers && config.electrumXServers.length > 0) {
				electrumAddressApi.connectToServers().then(function () {
					global.electrumAddressApi = electrumAddressApi;

				}).catch(function (err) {
					utils.logError("31207ugf4e0fed", err, { electrumXServers: config.electrumXServers });
				});
			} else {
				utils.logError("327hs0gde", "You must set the 'BTCEXP_ELECTRUMX_SERVERS' environment variable when BTCEXP_ADDRESS_API=electrumx.");
			}
		}
	}


	getSourcecodeProjectMetadata();
	if (config.demoSite) {
		setInterval(getSourcecodeProjectMetadata, 3600000);
	}

	utils.logMemoryUsage();
	setInterval(utils.logMemoryUsage, 5000);
};

app.use(function (req, res, next) {
	req.startTime = Date.now();
	req.startMem = process.memoryUsage().heapUsed;

	next();
});

app.use(function (req, res, next) {
	// make session available in templates
	res.locals.session = req.session;

	if (config.credentials.rpc && req.session.host == null) {
		req.session.host = config.credentials.rpc.host;
		req.session.port = config.credentials.rpc.port;
		req.session.username = config.credentials.rpc.username;
	}

	var userAgent = req.headers['user-agent'];
	for (var i = 0; i < crawlerBotUserAgentStrings.length; i++) {
		if (userAgent.indexOf(crawlerBotUserAgentStrings[i]) != -1) {
			res.locals.crawlerBot = true;
		}
	}

	// make a bunch of globals available to templates
	res.locals.config = global.config;
	res.locals.coinConfig = global.coinConfig;
	res.locals.activeBlockchain = global.activeBlockchain;
	res.locals.exchangeRates = global.exchangeRates;
	res.locals.utxoSetSummary = global.utxoSetSummary;
	res.locals.utxoSetSummaryPending = global.utxoSetSummaryPending;
	res.locals.networkVolume = global.networkVolume;

	res.locals.host = req.session.host;
	res.locals.port = req.session.port;

	res.locals.genesisBlockHash = coreApi.getGenesisBlockHash();
	res.locals.genesisCoinbaseTransactionId = coreApi.getGenesisCoinbaseTransactionId();

	res.locals.pageErrors = [];

	res.locals.allExplorers = global.allExplorers;
	res.locals.siblingExplorers = global.siblingExplorers

	// make currentActivation and nextActivation timestamp available to templates
	res.locals.currentActivation = global.currentActivation;
	res.locals.nextActivation = global.nextActivation;

	// currency format type
	if (!req.session.currencyFormatType) {
		var cookieValue = req.cookies['user-setting-currencyFormatType'];

		if (cookieValue) {
			req.session.currencyFormatType = cookieValue;

		} else {
			req.session.currencyFormatType = "";
		}
	}

	// blockPage.showTechSummary
	if (!req.session.blockPageShowTechSummary) {
		var cookieValue = req.cookies['user-setting-blockPageShowTechSummary'];

		if (cookieValue) {
			req.session.blockPageShowTechSummary = cookieValue;

		} else {
			req.session.blockPageShowTechSummary = "true";
		}
	}

	// homepage banner
	req.session.hideHomepageBanner = "true";

	res.locals.currencyFormatType = req.session.currencyFormatType;
	global.currencyFormatType = req.session.currencyFormatType;


	if (!["/", "/connect"].includes(req.originalUrl)) {
		if (utils.redirectToConnectPageIfNeeded(req, res)) {
			return;
		}
	}

	if (req.session.userMessage) {
		res.locals.userMessage = req.session.userMessage;

		if (req.session.userMessageType) {
			res.locals.userMessageType = req.session.userMessageType;

		} else {
			res.locals.userMessageType = "warning";
		}

		req.session.userMessage = null;
		req.session.userMessageType = null;
	}

	if (req.session.query) {
		res.locals.query = req.session.query;

		req.session.query = null;
	}

	// make some var available to all request
	// ex: req.cheeseStr = "cheese";

	next();
});

app.use(csurf(), (req, res, next) => {
	res.locals.csrfToken = req.csrfToken();
	next();
});

app.use('/', baseActionsRouter);
app.use('/api/', apiActionsRouter);
app.use('/snippet/', snippetActionsRouter);

app.use(function (req, res, next) {
	var time = Date.now() - req.startTime;
	var memdiff = process.memoryUsage().heapUsed - req.startMem;

	debugPerfLog("Finished action '%s' in %d ms", req.path, time);
	next();
});

/// catch 404 and forwarding to error handler
app.use(function (req, res, next) {
	res.status(404);
	res.format({
		html: function () {
			res.render('404', { url: req.url })
		},
		json: function () {
			res.json({ error: 'Not found' })
		},
		default: function () {
			res.type('txt').send('Not found')
		}
	})
});

/// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
	app.use(function (err, req, res, next) {
		res.status(err.status || 500);
		res.render('error', {
			message: err.message,
			error: err
		});
	});
}

// production error handler
// no stacktraces leaked to user
app.use(function (err, req, res, next) {
	res.status(err.status || 500);
	res.render('error', {
		message: err.message,
		error: {}
	});
});

app.locals.moment = moment;
app.locals.Decimal = Decimal;
app.locals.utils = utils;
app.locals.marked = marked;



module.exports = app;