Refactor auto login.

* prepare for some cases that session is expired, but still 200 ok returned.

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

Author: skygragon

lib/leetcode_client.js

@@ -20,52 +20,82 @@ function makeOpts(url, expectedStatus) {
   opts.url = url;
   opts.headers = {};
   opts.expectedStatus = expectedStatus || 200;
+  opts.retry = 0;
 
   var core = require('./core');
   if (core.isLogin()) signOpts(opts, core.getUser());
   return opts;
 }
 
-function checkError(e, resp, expectedStatus, msg) {
-  if (e) return e;
+var EXPIRED_ERROR = {
+  msg:        'session expired, please login again',
+  statusCode: -1
+};
 
-  var code = resp.statusCode;
-  if (resp && code !== expectedStatus) {
+function checkError(e, resp, expectedStatus, msg) {
+  if (!e && resp && resp.statusCode !== expectedStatus) {
+    var code = resp.statusCode;
     if (code === 403 || code === 401) {
-      msg = msg || 'session expired, please login again';
+      e = EXPIRED_ERROR;
+      log.debug('session expired:' + code);
+    } else {
+      e = {msg: msg || 'http error', statusCode: code};
     }
-    e = {msg: msg || 'http error', statusCode: code};
   }
   return e;
 }
 
+function relogin(opts, cb) {
+  log.debug('session expired, try to re-login...');
+  ++opts.retry;
+
+  var core = require('./core');
+  var user = core.getUser();
+  if (!user) {
+    log.debug('login failed: no user found, please login again');
+    return cb();
+  }
+
+  core.login(user, function(e, user) {
+    if (e) {
+      log.debug('login failed:' + e);
+    } else {
+      log.debug('login successfully, cont\'d...');
+      signOpts(opts, user);
+    }
+    // for now we don't care result, just blindly retry
+    return cb();
+  });
+}
+
 // 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 (opts.retry > 1) return cb(EXPIRED_ERROR);
+
   var req = request(opts, function(e, resp, body) {
     e = checkError(e, resp, opts.expectedStatus);
 
-    // not session expired: transparently pass down
-    if (!config.AUTO_LOGIN || !e) return cb(e, resp, body, req);
-    if (e.statusCode !== 403 && e.statusCode !== 401) return cb(e, resp, body, req);
-
-    log.debug('session expired, auto re-login...');
-
-    var core = require('./core');
-    var user = core.getUser();
-    core.login(user, function(e2, user) {
-      if (e2) return cb(e, resp, body, req);
-
-      log.debug('login successfully, cont\'d...');
-      signOpts(opts, user);
-
-      req = request(opts, function(e, resp, body) {
-        e = checkError(e, resp, opts.expectedStatus);
-        return cb(e, resp, body, req);
+    if (e === EXPIRED_ERROR && config.AUTO_LOGIN) {
+      relogin(opts, function() {
+        requestWithReLogin(opts, cb);
       });
-    });
+      return;
+    }
+
+    try {
+      return cb(e, resp, body, req);
+    } catch (e2) {
+      if (e2 === EXPIRED_ERROR && config.AUTO_LOGIN) {
+        relogin(opts, function() {
+          requestWithReLogin(opts, cb);
+        });
+        return;
+      }
+      return cb(e2);
+    }
   });
 }
 
@@ -81,8 +111,10 @@ leetcodeClient.getProblems = function(cb) {
 
     // leetcode permits anonymous access to the problem list
     // while we require login first to make a better experience.
-    if (json.user_name.length === 0)
-      return cb('session expired, please login again');
+    if (json.user_name.length === 0) {
+      log.debug('no user info in list response, maybe session expired...');
+      throw EXPIRED_ERROR;
+    }
 
     var problems = json.stat_status_pairs
         .filter(function(p) {

test/test_leetcode_client.js

@@ -16,6 +16,10 @@ describe('leetcode_client', function() {
     locked: false,
     file:   '/dev/null'
   };
+  var EXPIRED_ERROR = {
+    msg:        'session expired, please login again',
+    statusCode: -1
+  };
 
   before(function() {
     config.init();
@@ -57,11 +61,7 @@ describe('leetcode_client', function() {
       nock(config.URL_PROBLEMS).get('/').reply(403);
 
       client.getProblems(function(e, problems) {
-        var expected = {
-          msg:        'session expired, please login again',
-          statusCode: 403
-        };
-        assert.deepEqual(e, expected);
+        assert.deepEqual(e, EXPIRED_ERROR);
         done();
       });
     });
@@ -83,17 +83,13 @@ describe('leetcode_client', function() {
     it('should fail if http error in relogin', function(done) {
       config.AUTO_LOGIN = true;
       nock(config.URL_PROBLEMS).get('/').reply(403);
+      nock(config.URL_PROBLEMS).get('/').reply(403);
       core.login = function(user, cb) {
         return cb('unknown error!');
       };
 
-      // the original error will be returned instead
-      var expected = {
-        msg:        'session expired, please login again',
-        statusCode: 403
-      };
       client.getProblems(function(e, problems) {
-        assert.deepEqual(e, expected);
+        assert.deepEqual(e, EXPIRED_ERROR);
         done();
       });
     });
@@ -111,10 +107,11 @@ describe('leetcode_client', function() {
     });
 
     it('should fail if not login', function(done) {
+      config.AUTO_LOGIN = false;
       nock(config.URL_PROBLEMS).get('/').replyWithFile(200, './test/mock/problems.nologin.json.20161015');
 
       client.getProblems(function(e, problems) {
-        assert.equal(e, 'session expired, please login again');
+        assert.deepEqual(e, EXPIRED_ERROR);
         done();
       });
     });