Remove user specific info from single cache

Signed-off-by: Eric Wang <skygragon@gmail.com>

Author: skygragon

lib/core.js

@@ -10,13 +10,28 @@ var config = require('./config');
 var client = require('./leetcode_client');
 var h = require('./helper');
 
+function saveProblem(problem) {
+  // it would be better to leave specific problem cache being user
+  // independent, thus try to reuse existing cache as much as possible
+  // after changing user.
+  var p = _.omit(problem, ['locked', 'state', 'starred']);
+  return cache.set(p.key, p);
+}
+
+function saveUser(user) {
+  // when auto login enabled, have to save password to re-login later
+  // otherwise don't dump password for the sake of security.
+  var u = _.omit(user, config.AUTO_LOGIN ? [] : ['pass']);
+  cache.set('.user', u);
+}
+
 var core = {};
 
 core.getProblems = function(cb) {
-  var cached = cache.get('all');
-  if (cached) {
+  var problems = cache.get('all');
+  if (problems) {
     log.debug('loading from all.json');
-    return cb(null, cached);
+    return cb(null, problems);
   }
 
   client.getProblems(function(e, problems) {
@@ -39,16 +54,17 @@ core.getProblem = function(keyword, cb) {
     if (!problem)
       return cb('Problem not found!');
 
-    var cached = cache.get(problem.key);
-    if (cached) {
+    var problemDetail = cache.get(problem.key);
+    if (problemDetail) {
       log.debug('loading from ' + problem.key + '.json');
-      return cb(null, cached);
+      _.extendOwn(problem, problemDetail);
+      return cb(null, problem);
     }
 
     client.getProblem(problem, function(e, problem) {
       if (e) return cb(e);
 
-      cache.set(problem.key, problem);
+      saveProblem(problem);
       return cb(null, problem);
     });
   });
@@ -82,7 +98,7 @@ core.updateProblem = function(problem, kv) {
   _.extend(oldProblem, kv);
   _.extend(problem, kv);
 
-  var singleUpdated = cache.set(problem.key, problem);
+  var singleUpdated = saveProblem(problem);
   var allUpdated = cache.set('all', problems);
   return singleUpdated && allUpdated;
 };
@@ -129,12 +145,7 @@ core.login = function(user, cb) {
 
     self.logout();
 
-    if (config.AUTO_LOGIN)
-      // need save password thus we can auto re-login later
-      cache.set('.user', user);
-    else
-      cache.set('.user', _.omit(user, 'pass'));
-
+    saveUser(user);
     return cb(null, user);
   });
 };