coke/lib/middleware/flash.js

A full stack MVC framework that speeds up your web development.

/**
 * Module dependencies.
 */
var format  = require( 'util' ).format;
var isArray = require( 'util' ).isArray;

/**
 * Expose `flash()` function on requests.
 *
 * @return {Function}
 * @api public
 */
module.exports = function flash( options ){
  options = options || {};
  var safe = ( options.unsafe === undefined ) ? true : !options.unsafe;

  return function ( req, res, next ){
    if( req.flash && safe ) return next();

    req.flash = _flash;
    res.locals.messages = function (){
      var buf      = [];
      var messages = req.flash();
      var types    = Object.keys( messages );
      var len      = types.length;

      if( !len ) return '';

      buf.push( '<div id="messages">' );

      for( var i = 0; i < len; ++i ){
        var type = types[ i ];
        var msgs = messages[ type ];

        if( msgs ){
          buf.push( '  <ul class="' + type + '">' );

          for( var j = 0, l = msgs.length; j < l; ++j ){
            var msg = msgs[ j ];

            buf.push( '    <li>' + msg + '</li>' );
          }

          buf.push( '  </ul>' );
        }
      }

      buf.push( '</div>' );

      return buf.join( '\n' );
    };

    next();
  }
}

/**
 * Queue flash `msg` of the given `type`.
 *
 * Examples:
 *
 *      req.flash( 'info', 'email sent' );
 *      req.flash( 'error', 'email delivery failed' );
 *      req.flash( 'info', 'email re-sent' );
 *      // => 2
 *
 *      req.flash( 'info' );
 *      // => [ 'email sent', 'email re-sent' ]
 *
 *      req.flash( 'info' );
 *      // => []
 *
 *      req.flash();
 *      // => { error: [ 'email delivery failed' ], info: [] }
 *
 * Formatting:
 *
 * Flash notifications also support arbitrary formatting support.
 * For example you may pass variable arguments to `req.flash()`
 * and use the %s specifier to be replaced by the associated argument:
 *
 *     req.flash( 'info', 'email has been sent to %s.', userName );
 *
 * Formatting uses `util.format()`, which is available on Node 0.6+.
 *
 * @param {String} type
 * @param {String} msg
 * @return {Array|Object|Number}
 * @api public
 */
function _flash( type, msg ){
  if( this.session === undefined ) throw Error( 'req.flash() requires sessions' );

  var msgs = this.session.flash = this.session.flash || {};

  if( type && msg ){
    // util.format is available in Node.js 0.6+
    if( arguments.length > 2 && format ){
      var args = Array.prototype.slice.call( arguments, 1 );
      msg = format.apply( undefined, args );

    }else if( isArray( msg )){
      msg.forEach( function ( val ){
        ( msgs[ type ] = msgs[ type ] || []).push( val );
      });

      return msgs[ type ].length;
    }

    return ( msgs[ type ] = msgs[ type ] || []).push( msg );
  }else if( type ){
    var arr = msgs[ type ];

    delete msgs[ type ];

    return arr || [];
  }else {
    this.session.flash = {};

    return msgs;
  }
}