node.JS - express framework create session and check if session exist

This is my server code, please take a look at the comments in the code.

var app = express.createServer();
app.get('/', function(req, res){
    // create a session with the value of an email for example: me@gmail.com
});

// down here I want to check the session if the se开发者_StackOverflow社区ssion exist
if( there is a session with value me@gmail.com){
    //do stuff  
}

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The way sessions are implemented in Connect / Express doesn't allow for a custom session ID. This is partly because of security. So there's a bunch of things you can do.

• Store everything in the session. Create an index somewhere (perhaps in a database) that maps email addresses to session IDs, so you can look up sessions by email.

• Store only the email in the session. Keep the actual session data elsewhere (perhaps in a database), where you can fetch it by email address.

• Create your own session middleware, perhaps based off Connect's code. The actual session code in Connect is a mere 300 lines. But be very careful to keep security features intact.