From 5af63ce03a85985981166527b9604b8a0226fed8 Mon Sep 17 00:00:00 2001
From: Ray Schamp <ray@scratch.mit.edu>
Date: Fri, 2 Oct 2015 15:27:57 -0400
Subject: [PATCH] Handle errors by retrying with exponential backoff

---
 src/mixins/api.jsx |  8 +++++++-
 src/session.js     | 13 ++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/mixins/api.jsx b/src/mixins/api.jsx
index cdb54b360..d542f5e05 100644
--- a/src/mixins/api.jsx
+++ b/src/mixins/api.jsx
@@ -1,14 +1,20 @@
 var xhr = require('xhr');
 
 module.exports = {
+    ERR_500: 500,
     api: function (opts, callback) {
         xhr(opts, function (err, res, body) {
             if (err) {
                 // emit global "error" event
                 return callback(err);
             }
+
+            if (res.statusCode == 500) {
+                return callback(this.ERR_500);
+            }
+
             // @todo Global error handler
             callback(err, body);
-        });
+        }.bind(this));
     }
 };
diff --git a/src/session.js b/src/session.js
index bff716391..ebcfd9066 100644
--- a/src/session.js
+++ b/src/session.js
@@ -9,12 +9,19 @@ window.updateSession = function (session) {
     window.dispatchEvent(sessionEvent);
 };
 
-window.refreshSession = function () {
+window.refreshSession = function (iteration) {
+    if (!iteration) iteration = 1;
     api({
         uri: '/session/',
         responseType: 'json'
-    }, function (err, res) {
-        if (!err) window.updateSession(res);
+    }, function (err, body) {
+        if (err) {
+            var timeout = Math.floor(Math.pow(Math.E, iteration));
+            if (!isFinite(timeout)) return;
+            window.setTimeout(window.refreshSession.bind(window, iteration+1), timeout);
+        } else {
+            window.updateSession(body);
+        }
     });
 };