From 1923834e07fcd90047d02a25833a06bcd15479fe Mon Sep 17 00:00:00 2001
From: Chris Troutner <chris.troutner@gmail.com>
Date: Mon, 6 Apr 2020 12:30:10 -0700
Subject: [PATCH] fix(electrum): Added route library for working with ElectrumX
 servers

---
 src/routes/v3/electrum.js | 162 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 162 insertions(+)
 create mode 100644 src/routes/v3/electrum.js

diff --git a/src/routes/v3/electrum.js b/src/routes/v3/electrum.js
new file mode 100644
index 0000000..919cf0e
--- /dev/null
+++ b/src/routes/v3/electrum.js
@@ -0,0 +1,162 @@
+/*
+  Electrum API route
+*/
+
+'use strict'
+
+const express = require('express')
+const axios = require('axios')
+const wlogger = require('../../util/winston-logging')
+
+const RouteUtils = require('../../util/route-utils')
+const routeUtils = new RouteUtils()
+
+const router = express.Router()
+
+// Used for processing error messages before sending them to the user.
+const util = require('util')
+util.inspect.defaultOptions = { depth: 1 }
+
+const BCHJS = require('@chris.troutner/bch-js')
+const bchjs = new BCHJS()
+
+let _this
+
+class Electrum {
+  constructor () {
+    _this = this
+
+    _this.axios = axios
+    _this.routeUtils = routeUtils
+    _this.bchjs = bchjs
+
+    _this.router = router
+    _this.router.get('/', _this.root)
+    // _this.router.get('/balance/:address', _this.balanceSingle)
+    // _this.router.post('/balance', _this.balanceBulk)
+    // _this.router.get('/utxos/:address', _this.utxosSingle)
+    // _this.router.post('/utxos', _this.utxosBulk)
+    // _this.router.get('/tx/:txid', _this.txSingle)
+    // _this.router.post('/tx', _this.txBulk)
+  }
+
+  // DRY error handler.
+  errorHandler (err, res) {
+    // Attempt to decode the error message.
+    const { msg, status } = _this.routeUtils.decodeError(err)
+    if (msg) {
+      res.status(status)
+      return res.json({ error: msg })
+    }
+
+    res.status(500)
+    return res.json({ error: util.inspect(err) })
+  }
+
+  // Root API endpoint. Simply acknowledges that it exists.
+  root (req, res, next) {
+    return res.json({ status: 'address' })
+  }
+
+  // Query the Blockbook Node API for a balance on a single BCH address.
+  // Returns a Promise.
+  async balanceFromBlockbook (thisAddress) {
+    try {
+      // console.log(`BLOCKBOOK_URL: ${BLOCKBOOK_URL}`)
+
+      // Convert the address to a cashaddr without a prefix.
+      const addr = _this.bchjs.Address.toCashAddress(thisAddress)
+
+      const path = `${_this.BLOCKBOOKPATH.addrPath}${addr}`
+      // console.log(`path: ${path}`)
+
+      // Query the Blockbook Node API.
+      const options = {
+        method: 'get',
+        baseURL: path
+      }
+
+      const axiosResponse = await _this.axios.request(options)
+      const retData = axiosResponse.data
+      // console.log(`retData: ${util.inspect(retData)}`)
+
+      return retData
+    } catch (err) {
+      // Dev Note: Do not log error messages here. Throw them instead and let the
+      // parent function handle it.
+      wlogger.debug('Error in blockbook.js/balanceFromBlockbook()')
+      throw err
+    }
+  }
+
+  /**
+   * @api {get} /blockbook/balance/{addr} Get balance for a single address.
+   * @apiName Balance for a single address
+   * @apiGroup Blockbook
+   * @apiDescription Returns an object with balance and details about an address.
+   *
+   *
+   * @apiExample Example usage:
+   * curl -X GET "https://api.fullstack.cash/v3/blockbook/balance/bitcoincash:qrdka2205f4hyukutc2g0s6lykperc8nsu5u2ddpqf" -H "accept: application/json"
+   *
+   */
+  // GET handler for single balance
+  async balanceSingle (req, res, next) {
+    try {
+      const address = req.params.address
+
+      if (!address || address === '') {
+        res.status(400)
+        return res.json({ error: 'address can not be empty' })
+      }
+
+      // Reject if address is an array.
+      if (Array.isArray(address)) {
+        res.status(400)
+        return res.json({
+          error: 'address can not be an array. Use POST for bulk upload.'
+        })
+      }
+
+      wlogger.debug(
+        'Executing blockbook/balanceSingle with this address: ',
+        address
+      )
+
+      // Ensure the input is a valid BCH address.
+      try {
+        // const legacyAddr = bchjs.Address.toLegacyAddress(address)
+        _this.bchjs.Address.toLegacyAddress(address)
+      } catch (err) {
+        res.status(400)
+        return res.json({
+          error: `Invalid BCH address. Double check your address is valid: ${address}`
+        })
+      }
+
+      // Prevent a common user error. Ensure they are using the correct network address.
+      const networkIsValid = _this.routeUtils.validateNetwork(address)
+      if (!networkIsValid) {
+        res.status(400)
+        return res.json({
+          error:
+            'Invalid network. Trying to use a testnet address on mainnet, or vice versa.'
+        })
+      }
+
+      // Query the Blockbook Node API.
+      const retData = await _this.balanceFromBlockbook(address)
+
+      // Return the retrieved address information.
+      res.status(200)
+      return res.json(retData)
+    } catch (err) {
+      // Write out error to error log.
+      wlogger.error('Error in blockbook.js/balanceSingle().', err)
+
+      return _this.errorHandler(err, res)
+    }
+  }
+}
+
+module.exports = Electrum