handle double dispense WIP

dev/double-dispense.js

@@ -0,0 +1,19 @@
+const got = require('got')
+
+const tx = {
+  sessionId: 'a9fdfedc-1d45-11e6-be13-2f68ff6306b9',
+  toAddress: '1DrK44np3gMKuvcGeFVv9Jk67zodP52eMu',
+  fiat: 10
+}
+
+const headers = {
+  'content-type': 'application/json',
+  'session-id': '36f17fbe-1d44-11e6-a1a9-bbe8a5a41617'
+}
+
+const body = JSON.stringify({tx: tx})
+got('http://localhost:3000/dispense', {body: body, json: true, headers: headers})
+.then(res => {
+  console.log(res.body)
+})
+.catch(console.log)

lib/plugins.js

@@ -829,3 +829,11 @@ exports.fetchTx = function fetchTx (session) {
 exports.requestDispense = function requestDispense (session, tx) {
   return db.addDispenseRequest(session, tx)
 }
+
+exports.cachedResponse = function (session, path, method) {
+  return db.cachedResponse(session, path, method)
+}
+
+exports.cacheResponse = function (session, path, method, body) {
+  return db.cacheResponse(session, path, method, body)
+}

lib/postgresql_interface.js

@@ -568,6 +568,7 @@ exports.addDispenseRequest = function addDispenseRequest (session, tx) {
           'dispense', 'pending')
       ], function (err) {
         done()
+
         if (err) return reject(err)
         resolve()
       })
@@ -582,7 +583,8 @@ function updateDispense (client, session, dispensed, cb) {
   var values = [dispensed, 'initial_request', 'pending', session.fingerprint, session.id, true]
   query(client, sql, values, function (err, results) {
     if (err) return cb(err)
-    if (results.rowCount === 0) return cb(new Error('No pending tx'))
+    // DEBUG10
+    // if (results.rowCount === 0) return cb(new Error('No pending tx'))
     cb()
   })
 }
@@ -768,6 +770,50 @@ exports.updateNotify = function updateNotify (tx) {
   })
 }
 
+function insertCachedRequest (session, path, method, body) {
+  const fields = [
+    'device_fingerprint',
+    'session_id',
+    'path',
+    'method',
+    'body'
+  ]
+
+  const sql = getInsertQuery('cached_requests', fields)
+  return pquery(sql, [session.fingerprint, session.id, path, method, body])
+}
+
+exports.cachedResponse = function (session, path, method) {
+  const sql = `select body from cached_requests
+  where device_fingerprint=$1
+  and session_id=$2
+  and path=$3
+  and method=$4`
+
+  const values = [session.fingerprint, session.id, path, method]
+
+  return insertCachedRequest(session, path, method, {pendingRequest: true})
+  .then(() => ({}))
+  .catch(err => {
+    if (!isUniqueViolation(err)) throw err
+    return pquery(sql, values)
+    .then(r => ({body: r.rows[0].body}))
+  })
+}
+
+exports.cacheResponse = function (session, path, method, body) {
+  const sql = `update cached_requests
+  set body=$1
+  where device_fingerprint=$2
+  and session_id=$3
+  and path=$4
+  and method=$5`
+
+  const values = [body, session.fingerprint, session.id, path, method]
+
+  return pquery(sql, values)
+}
+
 /*
 exports.init('postgres://lamassu:lamassu@localhost/lamassu')
 connect(function(err, client, done) {

lib/routes.js

@@ -283,8 +283,11 @@ function waitForDispense (req, res) {
 
 function dispense (req, res) {
   const tx = req.body.tx
+  const body = {dispense: true}
+
   return plugins.requestDispense(session(req), tx)
-  .then(() => res.json(200))
+  .then(() => cacheResponse(req, body))
+  .then(() => res.json(body))
   .catch(err => {
     logger.error(err)
     res.sendStatus(500)
@@ -318,7 +321,7 @@ function init (localConfig) {
   app.get('/phone_tx', authMiddleware, fetchPhoneTx)
   app.post('/register_redeem', authMiddleware, registerRedeem)
   app.get('/await_dispense', authMiddleware, waitForDispense)
-  app.post('/dispense', authMiddleware, dispense)
+  app.post('/dispense', authMiddleware, cachedResponse, dispense)
 
   localApp.get('/pid', function (req, res) {
     var machineFingerprint = req.query.fingerprint
@@ -354,3 +357,12 @@ function getFingerprint (req) {
   return (typeof req.connection.getPeerCertificate === 'function' &&
   req.connection.getPeerCertificate().fingerprint) || 'unknown'
 }
+
+function cachedResponse (req, res, next) {
+  return plugins.cachedResponse(session(req), req.path, req.method)
+  .then(r => r.body ? res.json(r.body) : next())
+}
+
+function cacheResponse (req, body) {
+  return plugins.cacheResponse(session(req), req.path, req.method, body)
+}

migrations/010-cached-requests.js

@@ -0,0 +1,19 @@
+'use strict'
+
+var db = require('./db')
+
+exports.up = function (next) {
+  db.query('CREATE TABLE IF NOT EXISTS cached_requests ( ' +
+    'id serial PRIMARY KEY, ' +
+    'device_fingerprint text NOT NULL, ' +
+    'session_id uuid NOT NULL, ' +
+    'path text NOT NULL, ' +
+    'method text NOT NULL, ' +
+    'body json NOT NULL, ' +
+    'UNIQUE (device_fingerprint, session_id, path, method) ' +
+    ')', next)
+}
+
+exports.down = function (next) {
+  next()
+}