node.js – 如何在Heroku上使用带有多个dyno的node-openid？

我正在尝试使用 node-openid(通过 passport-google)使用他们的Google凭据对我的用户进行身份验证.它在我的开发机器上工作正常但是当我用2个dynos将它部署到Heroku时,当一个dyno处理整个OpenID会话时它会起作用,而当一个dyno上启动会话并且在第二个dyno上完成会话时失败.在这种情况下,我收到以下错误：

2013-01-15T15:18:24+00:00 app[web.2]: Failed to verify assertion (message: Invalid association handle)
2013-01-15T15:18:24+00:00 app[web.2]:     at Strategy.authenticate.identifier (/app/node_modules/passport-google/node_modules/passport-openid/lib/passport-openid/strategy.js:143:36)
...

处理这个问题的正确方法是什么？我是否应该以某种方式在数据库中保存对话状态,以便两个dynos都可以访问它？

更新：

这是我用来通过在MongoDB中存储关联来解决问题的代码.

var
  GoogleStrategy = require('passport-google').Strategy;

// We have to save the OpenID state in the database so it's available to both
// dynos.

db.collection('OpenID').ensureIndex({expires: 1},{expireAfterSeconds: 0},function(err,result) {
        if (err) {
            throw new Error('Error setting TTL index on OpenID collection.');
        }
    });

// Use the GoogleStrategy within Passport.
//   Strategies in passport require a `validate` function,which accept
//   credentials (in this case,an OpenID identifier and profile),and invoke a
//   callback with a user object.
strategy = new GoogleStrategy({
    returnURL: 'http://localhost:3000/auth/google/return',realm: 'http://localhost:3000/'
  },function(identifier,profile,done) {
    // asynchronous verification,for effect...
    process.nextTick(function () {

      // To keep the example simple,the user's Google profile is returned to
      // represent the logged-in user.  In a typical application,you would want
      // to associate the Google account with a user record in your database,// and return that user instead.
      profile.identifier = identifier;
      return done(null,profile);
    });
  }
);

strategy.saveAssociation(function(handle,provider,algorithm,secret,expiresIn,done) {
    db.collection("OpenID").insert({
        handle: handle,provider: provider,algorithm: algorithm,secret: secret,expires: new Date(Date.Now() + 1000 * expiresIn)
    },done);
});

strategy.loadAssociation(function(handle,done) {
    db.collection("OpenID").findOne({handle: handle},function (error,result) {
        if (error)
            return done(error);
        else
            return done(null,result.provider,result.algorithm,result.secret);
    });
});