YUI.add('model-sync-rest', function (Y, NAME) {

/**

An extension which provides a RESTful XHR sync implementation that can be mixed

into a Model or ModelList subclass.

@module app

@submodule model-sync-rest

@since 3.6.0

**/

var Lang = Y.Lang;

/**

An extension which provides a RESTful XHR sync implementation that can be mixed

into a Model or ModelList subclass.

This makes it trivial for your Model or ModelList subclasses communicate and

transmit their data via RESTful XHRs. In most cases you'll only need to provide

a value for `root` when sub-classing `Y.Model`.

    Y.User = Y.Base.create('user', Y.Model, [Y.ModelSync.REST], {

        root: '/users'

    });

    Y.Users = Y.Base.create('users', Y.ModelList, [Y.ModelSync.REST], {

        // By convention `Y.User`'s `root` will be used for the lists' URL.

        model: Y.User

    });

    var users = new Y.Users();

    // GET users list from: "/users"

    users.load(function () {

        var firstUser = users.item(0);

        firstUser.get('id'); // => "1"

        // PUT updated user data at: "/users/1"

        firstUser.set('name', 'Eric').save();

    });

@class ModelSync.REST

@extensionfor Model

@extensionfor ModelList

@since 3.6.0

**/

function RESTSync() {}

/**

A request authenticity token to validate HTTP requests made by this extension

with the server when the request results in changing persistent state. This

allows you to protect your server from Cross-Site Request Forgery attacks.

A CSRF token provided by the server can be embedded in the HTML document and

assigned to `YUI.Env.CSRF_TOKEN` like this:

    <script>

        YUI.Env.CSRF_TOKEN = {{session.authenticityToken}};

    </script>

The above should come after YUI seed file so that `YUI.Env` will be defined.

**Note:** This can be overridden on a per-request basis. See `sync()` method.

When a value for the CSRF token is provided, either statically or via `options`

passed to the `save()` and `destroy()` methods, the applicable HTTP requests

will have a `X-CSRF-Token` header added with the token value.

@property CSRF_TOKEN

@type String

@default YUI.Env.CSRF_TOKEN

@static

@since 3.6.0

**/

RESTSync.CSRF_TOKEN = YUI.Env.CSRF_TOKEN;

/**

Static flag to use the HTTP POST method instead of PUT or DELETE.

If the server-side HTTP framework isn't RESTful, setting this flag to `true`

will cause all PUT and DELETE requests to instead use the POST HTTP method, and

add a `X-HTTP-Method-Override` HTTP header with the value of the method type

which was overridden.

@property EMULATE_HTTP

@type Boolean

@default false

@static

@since 3.6.0

**/

RESTSync.EMULATE_HTTP = false;

/**

Default headers used with all XHRs.

By default the `Accept` and `Content-Type` headers are set to

"application/json", this signals to the HTTP server to process the request

bodies as JSON and send JSON responses. If you're sending and receiving content

other than JSON, you can override these headers and the `parse()` and

`serialize()` methods.

**Note:** These headers will be merged with any request-specific headers, and

the request-specific headers will take precedence.

@property HTTP_HEADERS

@type Object

@default

    {

        "Accept"      : "application/json",

        "Content-Type": "application/json"

    }

@static

@since 3.6.0

**/

RESTSync.HTTP_HEADERS = {

    'Accept'      : 'application/json',

    'Content-Type': 'application/json'

};

/**

Static mapping of RESTful HTTP methods corresponding to CRUD actions.

@property HTTP_METHODS

@type Object

@default

    {

        "create": "POST",

        "read"  : "GET",

        "update": "PUT",

        "delete": "DELETE"

    }

@static

@since 3.6.0

**/

RESTSync.HTTP_METHODS = {

    'create': 'POST',

    'read'  : 'GET',

    'update': 'PUT',

    'delete': 'DELETE'

};

/**

The number of milliseconds before the XHRs will timeout/abort. This defaults to

30 seconds.

**Note:** This can be overridden on a per-request basis. See `sync()` method.

@property HTTP_TIMEOUT

@type Number

@default 30000

@static

@since 3.6.0

**/

RESTSync.HTTP_TIMEOUT = 30000;

/**

Properties that shouldn't be turned into ad-hoc attributes when passed to a

Model or ModelList constructor.

@property _NON_ATTRS_CFG

@type Array

@default ["root", "url"]

@static

@protected

@since 3.6.0

**/

RESTSync._NON_ATTRS_CFG = ['root', 'url'];

RESTSync.prototype = {

    // -- Public Properties ----------------------------------------------------

    /**

    A string which represents the root or collection part of the URL which

    relates to a Model or ModelList. Usually this value should be same for all

    instances of a specific Model/ModelList subclass.

    When sub-classing `Y.Model`, usually you'll only need to override this

    property, which lets the URLs for the XHRs be generated by convention. If

    the `root` string ends with a trailing-slash, XHR URLs will also end with a

    "/", and if the `root` does not end with a slash, neither will the XHR URLs.

    @example

        Y.User = Y.Base.create('user', Y.Model, [Y.ModelSync.REST], {

            root: '/users'

        });

        var currentUser, newUser;

        // GET the user data from: "/users/123"

        currentUser = new Y.User({id: '123'}).load();

        // POST the new user data to: "/users"

        newUser = new Y.User({name: 'Eric Ferraiuolo'}).save();

    When sub-classing `Y.ModelList`, usually you'll want to ignore configuring

    the `root` and simply rely on the build-in convention of the list's

    generated URLs defaulting to the `root` specified by the list's `model`.

    @property root

    @type String

    @default ""

    @since 3.6.0

    **/

    root: '',

    /**

    A string which specifies the URL to use when making XHRs, if not value is

    provided, the URLs used to make XHRs will be generated by convention.

    While a `url` can be provided for each Model/ModelList instance, usually

    you'll want to either rely on the default convention or provide a tokenized

    string on the prototype which can be used for all instances.

    When sub-classing `Y.Model`, you will probably be able to rely on the

    default convention of generating URLs in conjunction with the `root`

    property and whether the model is new or not (i.e. has an `id`). If the

    `root` property ends with a trailing-slash, the generated URL for the

    specific model will also end with a trailing-slash.

    @example

        Y.User = Y.Base.create('user', Y.Model, [Y.ModelSync.REST], {

            root: '/users/'

        });

        var currentUser, newUser;

        // GET the user data from: "/users/123/"

        currentUser = new Y.User({id: '123'}).load();

        // POST the new user data to: "/users/"

        newUser = new Y.User({name: 'Eric Ferraiuolo'}).save();

    If a `url` is specified, it will be processed by `Y.Lang.sub()`, which is

    useful when the URLs for a Model/ModelList subclass match a specific pattern

    and can use simple replacement tokens; e.g.:

    @example

        Y.User = Y.Base.create('user', Y.Model, [Y.ModelSync.REST], {

            root: '/users',

            url : '/users/{username}'

        });

    **Note:** String subsitituion of the `url` only use string an number values

    provided by this object's attribute and/or the `options` passed to the

    `getURL()` method. Do not expect something fancy to happen with Object,

    Array, or Boolean values, they will simply be ignored.

    If your URLs have plural roots or collection URLs, while the specific item

    resources are under a singular name, e.g. "/users" (plural) and "/user/123"

    (singular), you'll probably want to configure the `root` and `url`

    properties like this:

    @example

        Y.User = Y.Base.create('user', Y.Model, [Y.ModelSync.REST], {

            root: '/users',

            url : '/user/{id}'

        });

        var currentUser, newUser;

        // GET the user data from: "/user/123"

        currentUser = new Y.User({id: '123'}).load();

        // POST the new user data to: "/users"

        newUser = new Y.User({name: 'Eric Ferraiuolo'}).save();

    When sub-classing `Y.ModelList`, usually you'll be able to rely on the

    associated `model` to supply its `root` to be used as the model list's URL.

    If this needs to be customized, you can provide a simple string for the

    `url` property.

    @example

        Y.Users = Y.Base.create('users', Y.ModelList, [Y.ModelSync.REST], {

            // Leverages `Y.User`'s `root`, which is "/users".

            model: Y.User

        });

        // Or specified explicitly...

        Y.Users = Y.Base.create('users', Y.ModelList, [Y.ModelSync.REST], {

            model: Y.User,

            url  : '/users'

        });

    @property url

    @type String

    @default ""

    @since 3.6.0

    **/

    url: '',

    // -- Lifecycle Methods ----------------------------------------------------

    initializer: function (config) {

        config || (config = {});

        // Overrides `root` at the instance level.

        if ('root' in config) {

            this.root = config.root || '';

        }

        // Overrides `url` at the instance level.

        if ('url' in config) {

            this.url = config.url || '';

        }

    },

    // -- Public Methods -------------------------------------------------------

    /**

    Returns the URL for this model or model list for the given `action` and

    `options`, if specified.

    This method correctly handles the variations of `root` and `url` values and

    is called by the `sync()` method to get the URLs used to make the XHRs.

    You can override this method if you need to provide a specific

    implementation for how the URLs of your Model and ModelList subclasses need

    to be generated.

    @method getURL

    @param {String} [action] Optional `sync()` action for which to generate the

        URL.

    @param {Object} [options] Optional options which may be used to help

        generate the URL.

    @return {String} this model's or model list's URL for the the given

        `action` and `options`.

    @since 3.6.0

    **/

    getURL: function (action, options) {

        var root = this.root,

            url  = this.url;

        // If this is a model list, use its `url` and substitute placeholders,

        // but default to the `root` of its `model`. By convention a model's

        // `root` is the location to a collection resource.

        if (this._isYUIModelList) {

            if (!url) {

                return this.model.prototype.root;

            }

            return this._substituteURL(url, Y.merge(this.getAttrs(), options));

        }

        // Assume `this` is a model.

        // When a model is new, i.e. has no `id`, the `root` should be used. By

        // convention a model's `root` is the location to a collection resource.

        // The model's `url` will be used as a fallback if `root` isn't defined.

        if (root && (action === 'create' || this.isNew())) {

            return root;

        }

        // When a model's `url` is not provided, we'll generate a URL to use by

        // convention. This will combine the model's `id` with its configured

        // `root` and add a trailing-slash if the root ends with "/".

        if (!url) {

            return this._joinURL(this.getAsURL('id') || '');

        }

        // Substitute placeholders in the `url` with URL-encoded values from the

        // model's attribute values or the specified `options`.

        return this._substituteURL(url, Y.merge(this.getAttrs(), options));

    },

    /**

    Called to parse the response object returned from `Y.io()`. This method

    receives the full response object and is expected to "prep" a response which

    is suitable to pass to the `parse()` method.

    By default the response body is returned (`responseText`), because it

    usually represents the entire entity of this model on the server.

    If you need to parse data out of the response's headers you should do so by

    overriding this method. If you'd like the entire response object from the

    XHR to be passed to your `parse()` method, you can simply assign this

    property to `false`.

    @method parseIOResponse

    @param {Object} response Response object from `Y.io()`.

    @return {Any} The modified response to pass along to the `parse()` method.

    @since 3.7.0

    **/

    parseIOResponse: function (response) {

        return response.responseText;

    },

    /**

    Serializes `this` model to be used as the HTTP request entity body.

    By default this model will be serialized to a JSON string via its `toJSON()`

    method.

    You can override this method when the HTTP server expects a different

    representation of this model's data that is different from the default JSON

    serialization. If you're sending and receive content other than JSON, be

    sure change the `Accept` and `Content-Type` `HTTP_HEADERS` as well.

    **Note:** A model's `toJSON()` method can also be overridden. If you only

    need to modify which attributes are serialized to JSON, that's a better

    place to start.

    @method serialize

    @param {String} [action] Optional `sync()` action for which to generate the

        the serialized representation of this model.

    @return {String} serialized HTTP request entity body.

    @since 3.6.0

    **/

    serialize: function (action) {

        return Y.JSON.stringify(this);

    },

    /**

    Communicates with a RESTful HTTP server by sending and receiving data via

    XHRs. This method is called internally by load(), save(), and destroy().

    The URL used for each XHR will be retrieved by calling the `getURL()` method

    and passing it the specified `action` and `options`.

    This method relies heavily on standard RESTful HTTP conventions

    @method sync

    @param {String} action Sync action to perform. May be one of the following:

      * `create`: Store a newly-created model for the first time.

      * `delete`: Delete an existing model.

      * `read`  : Load an existing model.

      * `update`: Update an existing model.

    @param {Object} [options] Sync options:

      @param {String} [options.csrfToken] The authenticity token used by the

        server to verify the validity of this request and protected against CSRF

        attacks. This overrides the default value provided by the static

        `CSRF_TOKEN` property.

      @param {Object} [options.headers] The HTTP headers to mix with the default

        headers specified by the static `HTTP_HEADERS` property.

      @param {Number} [options.timeout] The number of milliseconds before the

        request will timeout and be aborted. This overrides the default provided

        by the static `HTTP_TIMEOUT` property.

    @param {Function} [callback] Called when the sync operation finishes.

      @param {Error|null} callback.err If an error occurred, this parameter will

        contain the error. If the sync operation succeeded, _err_ will be

        falsy.

      @param {Any} [callback.response] The server's response.

    **/

    sync: function (action, options, callback) {

        options || (options = {});

        var url       = this.getURL(action, options),

            method    = RESTSync.HTTP_METHODS[action],

            headers   = Y.merge(RESTSync.HTTP_HEADERS, options.headers),

            timeout   = options.timeout || RESTSync.HTTP_TIMEOUT,

            csrfToken = options.csrfToken || RESTSync.CSRF_TOKEN,

            entity;

        // Prepare the content if we are sending data to the server.

        if (method === 'POST' || method === 'PUT') {

            entity = this.serialize(action);

        } else {

            // Remove header, no content is being sent.

            delete headers['Content-Type'];

        }

        // Setup HTTP emulation for older servers if we need it.

        if (RESTSync.EMULATE_HTTP &&