ExpressJS-Flash

The flash is a special area of the session used for storing messages. Messages are written to the flash and cleared after being displayed to the user. The flash is typically used in combination with redirects, ensuring that the message is available to the next page that is to be rendered.

This is inspired by connect-flash module used for ExpressJS>=3.x.

But I felt that the connect-flash was too basic. I made a new module to include some more features that I felt were sorely needed for many workflows.

Install

$ npm install connect-flash

Usage

Express

Flash messages are stored in the session. First, setup sessions as usual by enabling cookieParser and session middleware. Then, use flash middleware provided by connect-flash.

var flash = require('connect-flash');
var app = express();

app.configure(function() {
  app.use(express.session({ 
    secret: 'keyboard cat',
    cookie: { maxAge: 60000 }
  }));
  app.use(flash());
});

Options for Middleware

You can pass options to the middleware.

  app.use(flash({
    passToView : true  //This enables you to use the getFlash() and setFlash() in the view directly, Default: true
  }));
});

With the flash middleware in place, all requests will have a req.getFlash() and a req.getFlash() function that can be used for flash messages.

app.get('/flash', function(req, res){
  // Set a flash message by passing the key, followed by the value, to req.flash().
  req.setFlash('info', 'Flash is here!');
  res.redirect('/');
});

app.get('/', function(req, res){
  messages=req.getFlash('info');
  res.render('index', { messages: req.getFlash('info') });
});

Options for the functions

You can pass options to the get and set functions

app.get('/flash', function(req, res){
  // Set a flash message by passing the key, followed by the value, to req.flash().
  req.setFlash('info', 'Flash is back!',{
    maxReads: 4,   //The number of times this message can be read, default: 1
    reqCount: 8    //The number of requests through which this message persists, default: null, This means that the middleware does not keep track of this. Note: a redirect counts as a request and decreases this counter
  });
  res.redirect('/');
});

app.get('/', function(req, res){
  messages=req.getFlash('info',{
    reflash: true, //This stops it being counted as a read, Useful when needing to read in a middleware
  });
  res.render('index', { messages: req.getFlash('info') });
});

Examples

For an example using connect-flash in an Express app, refer to the express3 example.

Feature Requests and Contributions

If you want a Feature to be added to this module, you can either open an issue or contribute yourself to the package on dev branch

Tests

$ npm install --dev
$ make test

Credits

• Vaibhav Agarwal

License

The MIT License

Copyright (c) 2012-2013 Vaibhav Agarwal