Plugin to enable middleware on a class

Example

var Mammal = define(comb.plugins.Middleware, {
 instance : {

   constructor: function(options) {
       options = options || {};
       this.super(arguments);
       this._type = options.type || "mammal";
   },

   speak : function() {
       var ret = new comb.Promise();
       this._hook("pre", "speak")
               .then(comb.hitch(this, "_hook", "post", "speak"), hitch(ret, "errback"))
               .then(comb.hitch(ret, "callback"), comb.hitch(ret, "errback"));
       return ret;
   }
 }
});

 Mammal.pre('speak', function(next){
    //do something meaningful
    next();
 });
 var m = new Mammal({color : "gold"});
 m.speak();
            

Constructor

Defined plugins/Middleware.js Source

function (){
   this.__hooks = obj.merge({}, this.__hooks);
   this._super(arguments);
           
}
            

post Static Function Public

---

Defined plugins/Middleware.js

Use to listen to after an event has occurred i.e. post save

NOTE:

• You must call next in order for the middleware chain to complete
• This connects to events on ALL instances of an object
• Hooks are called in the order they are received!
• When connecting your callback will be called in the scope of the class
  if you want a certain scope use comb.hitch

Example

Class.post("save", function(next){
              ...
              //you must call next
         });
        

Arguments

• name :
• cb :

Source

function (name,cb){
   var hooks = this.prototype.__hooks;
   var hook = hooks.post[name];
   if (!hook) {
       hook = hooks.post[name] = [];
   }
   hook.push(cb);
           
}
    

pre Static Function Public

---

Defined plugins/Middleware.js

Use to listen to after an event has occurred i.e. post save

NOTE:

• You must call next in order for the middleware chain to complete
• This connects to events on ALL instances of an object
• Hooks are called in the order they are received!
• When connecting your callback will be called in the scope of the class
  if you want a certain scope use comb.hitch

Example

Class.pre("save", function(next){
              ...
              //you must call next
         });
        

Arguments

• name :
• cb :

Source

function (name,cb){
   var hooks = this.prototype.__hooks;
   var hook = hooks.pre[name];
   if (!hook) {
       hook = hooks.pre[name] = [];
   }
   hook.push(cb);
           
}
    

_hook Function Public

---

Defined plugins/Middleware.js

Protected!

Call to initiate middleware for the topic

NOTE: this function takes a variable number of arguments whatever comes after the op param will be passed into the listening function, with the last argument to the listenting function being the next function

Arguments

• state :

  the state in which the hook should be called

• op :

  the operation that is being acted upong

• args :

  arguments to be passed into the listening functions.

Returns

• comb.Promise

  a promise to use after middleware chain completes

Source

function (state,op,args){
   args = args || [];
   var promise = new Promise();
   var funcs, length;
   if (this.__hooks[state] && (funcs = this.__hooks[state][op]) != null && (length = funcs.length) > 0) {
       var count = 0;
       var next = func.hitch(this, function (err) {
           if (err) {
               promise.errback(err);
           } else {
               nextTick(func.hitch(this, function () {
                   //if Ive looped through all of them callback
                   if (count === length) {
                       promise.callback();
                   } else {
                       //call next
                       var nextArgs = args.slice(0);
                       nextArgs.unshift(next);
                       funcs[count++].apply(this, nextArgs);
                   }
               }));
           }
       });
       next();
   } else {
       promise.callback();
   }
   return promise.promise();
           
}
    

post Function Public

---

Defined plugins/Middleware.js

Use to listen to after an event has occurred i.e. post save

NOTE:

• You must call next in order for the middleware chain to complete
• This connects to events on the instance of an object, NOT all instances!
• Hooks are called in the order they are received!
• When connecting your callback will be called in the scope of the class
  if you want a certain scope use comb.hitch

Example

instance.post("save", function(next){
               //do something...
                //you have to call next!!!!!
                next();
         });
        

Arguments

• fun :
• callback :

Source

function (fun,callback){
   var hook = this.__hooks.post[fun];
   //if I havent initialized it create it;
   if (hook === undefined) {
       hook = this.__hooks.post[fun] = [];
   }
   hook.push(callback);
           
}
    

pre Function Public

---

Defined plugins/Middleware.js

Use to listen to before an event occurred i.e. pre save

NOTE:

• You must call next in order for the middleware chain to complete
• This connects to events on the instance of an object, not all instances!
• Hooks are called in the order they are received!
• When connecting your callback will be called in the scope of the class
  if you want a certain scope use comb.hitch

Example

instance.pre("save", function(args,...., next){
         //do something...
         //you have to call next!!!!!
         next();
     });
        

Arguments

• fun :
• callback :

Source

function (fun,callback){
   var hook = this.__hooks.pre[fun];
   if (!hook) {
       hook = this.__hooks.pre[fun] = [];
   }
   hook.push(callback);
           
}
    

---

License

MIT https://github.com/C2FO/comb/raw/master/LICENSE

Meta

• Code: git clone git://github.com/C2FO/comb.git
• Website: http://c2fo.com
• Twitter: http://twitter.com/c2fo - 877.465.4045