handle double dispense WIP

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) {