将中间件分配给ActionHero中的特定操作

Question

Is the anyway to add some middleware to specific actions? because as far as I know addPreProcessor adds the middleware to all the actions? lets say you don't want to have authentication or some other checks on some actions, is there any solution?

I have a short term solution but it would be nice if you could assign your specific middlewares when you're defining your action(like giving an array of middleware names that need to be run, in order)

My current solution is keeping an array of all the actions that I need to apply the middleware to them and then check it against the connection.aciton, but then still every single request goes through all the middlewares and then it gets passed around which it doesn't sound efficient to me!

exports.middlewares = function(api, next){

    var myImportantMiddleware = function(connection, actionTemplate, next) {

        var actionsToBeChecked = ['deposit'];
        var action = connection.action;

        if(actionsToBeChecked.indexOf(action) > -1) {
                /*  middleware logic 
                next(connection, true); */
        } else {
            next(connection, true);
        }
    }

    api.actions.addPreProcessor(myImportantMiddleware);

    next();
}

Thanks in advance !

Answer 1

No need to do all that! Check out this example from the docs: https://github.com/evantahler/actionhero-tutorial/blob/master/initializers/middleware.js

exports.middleware = function(api, next){

  var authenticationMiddleware = function(connection, actionTemplate, next){
    if(actionTemplate.authenticated === true){ // <-- HERE
      api.users.authenticate(connection.params.userName, connection.params.password, function(error, match){
        if(match === true){
          next(connection, true);
        }else{
          connection.error = "Authentication Failed.  userName and password required";
          next(connection, false);
        }
      });
    }else{
      next(connection, true);
    }
  }

  api.actions.addPreProcessor(authenticationMiddleware);

  next();
}

Yes, all middlewares fire for all actions, but you can tell the middleware to inspect the action's definition, and look for a specific property. In this case, we only care if the action looks like this:

exports.randomNumber = {
  name: 'randomNumber',
  description: 'I am an API method which will generate a random number',
  outputExample: {
    randomNumber: 0.123
  },

  authenticated: true // <<--- HERE

  run: function(api, connection, next){
    connection.response.randomNumber = Math.random();
    next(connection, true);
  }

};

Answer 2

Ok I think I found a better solution and I would like to know your opinion.

So I just added middlewares : ['middlewareOne', 'middlewareTwo'] to my actions, which the order of execution is equal to order of middleware names in the array and then my middlewares initialiser is like this

var async = require('async');

exports.middlewares = function(api, next){

    var middlewares = {

        authMiddleware : function(connection, next){
            /* Middleware logic */
        },

        premiumAccessMiddleware : function(connection, next){
            /* Middleware logic */
        },

        adminAccessMiddleware : function(connection, next){
            /* Middleware logic */
        }

    };


    var middlewareProcessor = function(connection, actionTemplate, next){

        var actionMiddlewares = actionTemplate.middlewares;

        async.eachSeries(actionMiddlewares, function(middlewareName, callback){

            var middleware = api.middlewares[middlewareName];

            if(!middleware) throw (new Error("Middleware '"+ middlewareName +"'doesn't exist"));  /* In case I had a typo */

            middleware(connection, function(new_connection, toRender){

                connection = new_connection;

                if(toRender){

                    callback();

                }else{

                    callback('YOU SHALL NOT PASS');
                }

            });

        }, function(err){

            // if(err) return next(connection, false); // see EDIT1

            next(connection, true);

        });

    }

    api.actions.addPreProcessor(middlewareProcessor);

    next();
} 

Any thoughts?

EDIT1: next(connection, false); don't send anything to user, I guess you always want to send an error response or something to the user even if the execution middlewares stop after one of them wasn't successful and returned a next(connection, false) . In this case in the eachSeries final callback function I guess we always have to use next(connection, true); !!