Auto re-login if session is expired.

* if config.AUTO_LOGIN is true, user password will be saved
  locally and used to re-login w/o manually intervened.
* if config.AUTO_LOGIN is false, user password will not be
  saved. If session expired, user need to manually login again.

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

Author: skygragon

lib/config.js

@@ -14,8 +14,9 @@ var defaultConfig = {
   VERIFY_URL:   'https://leetcode.com/submissions/detail/$id/check/',
 
   // but you will want change these
-  LANG:      'cpp', // avail: [c,cpp,csharp,golang,java,javascript,python,ruby,swift]
-  USE_COLOR: true
+  LANG:       'cpp', // avail: [c,cpp,csharp,golang,java,javascript,python,ruby,swift]
+  USE_COLOR:  true,
+  AUTO_LOGIN: true
 };
 
 function initConfig() {

lib/core.js

@@ -1,6 +1,7 @@
 var _ = require('underscore');
 
 var cache = require('./cache');
+var config = require('./config');
 var client = require('./leetcode_client');
 
 var core = {};
@@ -69,7 +70,12 @@ core.login = function(user, cb) {
 
     self.logout();
 
-    cache.set('.user', _.omit(user, 'pass'));
+    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'));
+
     return cb(null, user);
   });
 };

lib/leetcode_client.js

@@ -4,15 +4,17 @@ var request = require('request');
 var config = require('./config');
 var h = require('./helper');
 
+// update options with user credentials
+function signOpts(opts, user) {
+  opts.headers.Cookie = 'PHPSESSID=' + user.sessionId +
+                        ';csrftoken=' + user.sessionCSRF + ';';
+  opts.headers['X-CSRFToken'] = user.sessionCSRF;
+}
+
 function makeOpts(url) {
-  var opts = {url: url, headers: {}};
+  var opts = {url: url, headers: {}, _expectedStatus: 200};
   var core = require('./core');
-  if (core.isLogin()) {
-    var user = core.getUser();
-    opts.headers.Cookie = 'PHPSESSID=' + user.sessionId +
-                             ';csrftoken=' + user.sessionCSRF + ';';
-    opts.headers['X-CSRFToken'] = user.sessionCSRF;
-  }
+  if (core.isLogin()) signOpts(opts, core.getUser());
   return opts;
 }
 
@@ -34,10 +36,44 @@ function checkError(e, resp, expectedStatus, msg) {
   }
 }
 
+// leetcode.com is limiting one session alive in the same time,
+// which means once you login on web, your cli session will get
+// expired immediately. In that case we will try to re-login in
+// the backend to give a seamless user experience.
+function requestWithReLogin(opts, cb) {
+  if (!config.AUTO_LOGIN)
+    return request(opts, cb);
+
+  var core = require('./core');
+  var user = core.getUser();
+
+  request(opts, function(e, resp, body) {
+    e = checkError(e, resp, opts._expectedStatus);
+
+    // not 403: transparently pass down
+    if (!e || e.statusCode !== 403)
+      return cb(e, resp, body);
+
+    // if 403: try re-login
+    console.log('session expired, auto re-login...');
+
+    core.login(user, function(e2, user) {
+      if (e2) return cb(e, resp, body);
+
+      console.log('login successfully, cont\'d...');
+      signOpts(opts, user);
+
+      request(opts, cb);
+    });
+  });
+}
+
 var leetcodeClient = {};
 
 leetcodeClient.getProblems = function(cb) {
-  request(makeOpts(config.PROBLEMS_URL), function(e, resp, body) {
+  var opts = makeOpts(config.PROBLEMS_URL);
+
+  requestWithReLogin(opts, function(e, resp, body) {
     e = checkError(e, resp, 200);
     if (e) return cb(e);
 
@@ -135,8 +171,10 @@ function verifyResult(opts, jobs, results, cb) {
   if (jobs.length === 0)
     return cb(null, results);
 
+  opts.method = 'GET';
   opts.url = config.VERIFY_URL.replace('$id', jobs[0].id);
-  request.get(opts, function(e, resp, body) {
+
+  requestWithReLogin(opts, function(e, resp, body) {
     e = checkError(e, resp, 200);
     if (e) return cb(e);
 
@@ -153,6 +191,7 @@ function verifyResult(opts, jobs, results, cb) {
 
 leetcodeClient.testProblem = function(problem, cb) {
   var opts = makeOpts();
+  opts.method = 'POST';
   opts.url = config.TEST_URL.replace('$key', problem.key);
   opts.headers.Origin = config.BASE_URL;
   opts.headers.Referer = problem.link;
@@ -166,7 +205,7 @@ leetcodeClient.testProblem = function(problem, cb) {
     'typed_code':  h.getFileData(problem.file)
   };
 
-  request.post(opts, function(e, resp, body) {
+  requestWithReLogin(opts, function(e, resp, body) {
     e = checkError(e, resp, 200);
     if (e) return cb(e);
 
@@ -183,6 +222,7 @@ leetcodeClient.testProblem = function(problem, cb) {
 
 leetcodeClient.submitProblem = function(problem, cb) {
   var opts = makeOpts();
+  opts.method = 'POST';
   opts.url = config.SUBMIT_URL.replace('$key', problem.key);
   opts.headers.Origin = config.BASE_URL;
   opts.headers.Referer = problem.link;
@@ -196,7 +236,7 @@ leetcodeClient.submitProblem = function(problem, cb) {
     'typed_code':  h.getFileData(problem.file)
   };
 
-  request.post(opts, function(e, resp, body) {
+  requestWithReLogin(opts, function(e, resp, body) {
     e = checkError(e, resp, 200);
     if (e) return cb(e);