Class comb.plugins.Middleware

Plugin to enable middleware on a class
Defined in: Middleware.js.

Class Detail

comb.plugins.Middleware()

Example 1 :

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();

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

Method Detail

{comb.Promise} _hook(state, op, args)

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

Parameters:
{"pre"|"post"} state: the state in which the hook should be called
{String} 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

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() {
        
        if (count == length) {
            promise.callback();
        } else {
            
            var nextArgs = args.slice(0);
            nextArgs.unshift(next);
            funcs[count++].apply(this, nextArgs);
        }
    });
    next();
} else {
    promise.callback();
}
return promise;

post(fun, callback)

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 1 :

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

Parameters:
fun
callback

var hook = this.__hooks.post[fun];

if (hook == undefined) {
    hook = this.__hooks.post[fun] = [];
}
hook.push(callback);

<static> comb.plugins.Middleware.post(name, cb)

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 1 :

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

Parameters:
name
cb

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

<static> comb.plugins.Middleware.pre(name, cb)

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 1 :

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

Parameters:
name
cb

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

pre(fun, callback)

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 1 :

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

Parameters:
fun
callback

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

Documentation generated by JsDoc Toolkit 2.4.0 on Tue Jan 31 2012 16:14:12 GMT-0600 (CST)