I was wondering whether anyone had any recommendations regarding populating multiple view models on a screen. I have:
a) a view model that has a list of tasks
b) a view model that has a list of users
I populate these in the 2 x ajax success (separate ajax calls) something like:
success: function (data) {
masterVM.User = ko.mapping.fromJS(data, mapping);
ko.applyBindings(masterVM);
}
/* another ajax call: */
success: function (data) {
masterVM.Task = ko.mapping.fromJS(data, mapping);
ko.applyBindings(masterVM);
}
And currently calling in each ajax success call.
I hope my question is clear and concise. Please ask for further detail if required.
Regards
Phil
We currently handle this by sending all of the data to our page in a single Ajax call, then applying a ko.mapping to map the data to the view models on our main view model.
We began by making two calls just as you are but decided that it would be better to reduce the number of http requests being made, which is why we combined the data sets into a single hierarchical object structure, and it's working great.
This question and the subsequent answer contain a snippet of the approach we're taking:
Map JSON data to Knockout observableArray with specific view model type
As long as you dont notice a performance issue, I recommend making separate calls because this will keep your services loosely coupled with your presentation needs.
However, if its a perf issue, you can make your web service aggregate the data and return it in one shot. But you lose a little maintainability by this.
Related
In Sails.js, a route is set up against a controller method which can render a view. For the most part, this is straightforward, i.e. you could set up a GET /users route that points to UserController.find (which is usually set up automatically anyway).
However, say the home page of a blog renders the 10 most recent posts in the main section and a column with a list of authors and categories. The controller method has to fetch posts, authors, and categories before rendering the view and sending it back to the client. Clearly, a method like this doesn't really belong in PostController, AuthorController, or CategoryController.
What's the best thing to do in this situation? Create a controller for rendering views that rely on data from multiple models? Is there a good name for such a controller?
Thanks!
What I would do (this is purely opinion-based) is creating a PageController and create an action for each page you'd want.
For your home page example you can create a home action, get whatever you need and then render it with res.ok() (if everything is fine).
Another option would be to use Sails as a pure API and use HTTP requests (Ajax) or sockets to get your data in JSON. If you want to do so, I'd advise you to use a front end framework such as Angular, Ember, React...
By the way you could also create actions rendering HTML in your existing controllers and create a route to hit them through Ajax requests and just print them in your page. I'd prefer the 2nd solution because it takes full advantage of the Blueprint API (you don't need new controller or action whatsoever).
As Yann pointed out, this answer has to be a little opinionated. It seems that you are using the views system and not building a single page application. For the home page, I would go for an IndexController.js file with a home(req, res) action.
// api/controllers/IndexController.js
module.exports = {
home: function (req, res) {
// Retrieve all the information you need
// Take care about managing the asynchronous calls before rendering the view
return res.view('homepage');
}
};
Declare the route
// config/routes.js
module.exports.routes = {
'get /': 'IndexController.home'
}
Create the view in views/homepage.ejs.
Using web2py I am trying to use ajax to put data into a table in my database, but I'm needing a bit of help.
Here is the function I am using (it currently has dummy data in the data section, rather than being passed data from a form):
function submitData(){
$.ajax({
type: "POST",
url: "requests",
data: {
id: 1,
user_id:111,
bottle_image:'',
bottle_name:'JJjman',
bottle_description:'Lol',
request_creationDate:'2000-01-01',
request_expiryDate:'2003-08-08',
request_fulfilled:false
},
success: function(){
alert('Posted data');
}
});
}
I have a html button with this function attached to its 'onclick', but at the moment all it does is reload the page and not pass any data onto the database. The success alert is also coming up.
Firebug is saying that the POST does contain all that data, but I'm not sure if the POST is actually going anywhere..
Am I missing any steps needed to actually pass this data to the database? Or could this just be that my data isn't all the right type for the database?
Cheers guys
Simply sending a post from the browser won't do anything on the server unless you have code on the server to handle the data and insert it into the database.
I strongly recommend you read through the relevant parts of the book to learn how to do this. The Overview chapter provides an introductory tutorial, including building an image blog that involves modeling a database table and creating a form to post records to that table.
Review the DAL chapter for details on modeling your database, the section on SQLFORM for details on creating forms associated with database tables, and the sections on ajax and components for details on using Ajax to post forms.
The easiest way to do what you want would be something like this:
In /models/db.py:
db = DAL('sqlite://storage.sqlite')
db.define_table('bottle',
Field('user_id')
Field('bottle_image'),
Field('bottle_name'),
Field('bottle_description', 'text'),
Field('request_creationDate', 'date'),
Field('request_expiryDate', 'date'),
Field('request_fulfilled', 'boolean'),
format='%(bottle_name)s')
In /controllers/default.py:
def index():
return dict()
def add_bottle():
return dict(form=SQLFORM(db.bottle).process())
In /views/default/add_bottle.load:
{{=form}}
In /views/default/index.html:
{{extend 'layout.html'}}
{{=LOAD('default', 'add_bottle.load', ajax=True)}}
Then go to /yourapp/default/index, and you will see a form, which will post records to the database via Ajax.
Here is what I'm tyrnig to do:
Make ajax request to retrieve JSON data from a PHP script
Insert that information into DataStore Models
Store those models within a controller
Display the information using {{#each}} with a handlebars template
Does ember-data have a built in way of retrieving data? If not, where
should the AJAX request be implemented?
What is the best way to insert the JSON data into the DS model?
What is the best way to then sync the models up with a Controller?
Any examples that implement all of the 4 steps would also be very helpful, since I can't seem to find any.
<edit>
Like I said in the comments, this questions asks a lot at once, so to follow up, here's a work in progress fiddle: http://jsfiddle.net/schawaska/dWcUp/
This is not 100%, but covers some of your questions. It uses the FixtureAdapter.
I'll be updating it as I find time.
</edit>
1 Make ajax request to retrieve JSON data from a PHP script
Ember-Data will take care of that for you. Consider the following:
window.App = Em.Application.create();
App.Store = DS.Store.extend({
revision: 12,
adapter: 'DS.RESTAdapter'
});
App.Product = DS.Model.extend({
name: DS.attr('string'),
imageUrl: DS.attr('string')
})
The code above defines a data store (almost like an ORM) within your client app. Ember uses convention over configuration (heavily), so as per configuration this code expects your backend to have a resource in the same domain as /products which talks to GET, POST, PUT and DELETE.
2 Insert that information into DataStore Models
Considering what I said above, by calling one of the following:
App.store.find(App.Product) or App.Product.find()
EmberData will fire a GET request through AJAX targeting your resource /products, and if you say App.Product.find(1), it will target /products/1.
Your app store will use its adapter and the adapter's serializer to translate the JSON result and materialize its data into your App.Product model.
3 Store those models within a controller
This is done when defining your application router. Regardless of what you do, Ember will run its own workflow, but it provides you several hooks, giving you the control of that specific action. Consider the following:
App.Router.map(function() {
this.resource('products');
});
App.ProductsRoute = Ember.Route.extend({
model: function() {
return App.Product.find();
}
});
The code above populates the model used in the products route (which you would access at http://yourdomain.com/#/products). Internally it will generate the code for your ProductsController, or you can define your own, which should extend ArrayController.
Controllers will have a content property which is an alias to the model or model collection. Again, convention over configuration.
4 Display the information using {{#each}} with a handlebars template
Providing you're following the conventions, in your handlebars template, you should iterate through your collection like this:
{{#each product in controller}}
{{#linkTo 'product' product}}
{{product.name}}
{{/linkTo}}
{{/each}}
Does ember-data have a built in way of retrieving data? If not, where
should the AJAX request be implemented?
Yes, simply call App.Product.find() for a product model and it return you a blank ModelArray while firing the AJAX request to the products resource in your backend, then materialize/populate your data into each model once it receives the data back from the server.
What is the best way to insert the JSON data into the DS model?
You shouldn't be concerned about this if you're using ember-data. The framework does that for you in most cases. That's why we love it. You might, however, have to configure mapping, namespace and plurals depending on your backend.
What is the best way to then sync the models up with a Controller?
Something similar to this:
var product = App.Product.createRecord({
name: 'laptop',
imageUrl: 'path/to/image.png'
});
product.save();
This should fire a POST or PUT request to your backend API.
You should definitely check:
http://emberjs.com/guides/
https://peepcode.com/products/emberjs
http://toranbillups.com/blog/archive/2013/01/03/Intro-to-ember-js-and-the-new-router-api/
Making the AJAX request
// Find all pets.
var pets = App.Pet.find();
// Find pet with ID of 1.
var pet = App.Pet.find(1);
Into DataStore Models
pets above will be a DS.RecordArray containing many App.Pet models, whereas pet is just one App.Pet.
Store in Controller
App.IndexRoute = Ember.Route.extend({
model: function() {
return App.Pet.find(4);
}
});
The router is used to setup the controller, and so we specify here that the IndexController should hold one App.Pet with the ID of 4. This can of course be dynamic. Since your controller represents only one model, it should be of the type ObjectController, but if it was used to store many pets, then it should be of the type ArrayController.
By specify the model, you will have access to it in your IndexController and index view (data-template-name="index"). This is because when you move into your index route, the IndexController is located/instantiated, IndexView is instantiated and placed into the DOM, all after consulting the IndexRoute for setting up the controller.
You can now do something like this in your template (although model. is not necessary): {{model.name}}, which will get you your pet's name.
Display using #each
Find all your pets using a modified version of the above code, but returning all of the pets. Remember, this is done by specifying no arguments to your find method:
App.IndexRoute = Ember.Route.extend({
model: function() {
return App.Pet.find();
}
});
Now we can do loop through all of the pets in the index template. Whilst there are many ways to loop, such as including content./model., excluding .content/model, using this, controller, et cetera..., it's not necessary, but that's for another day. What matters at the moment is that this will work for you, and will be the most self-intuitive:
{{#each pet in controller}}
{{pet.name}}
{{/each}}
I'll put together a jsFiddle for this if you would like. Please let me know.
Questions
Does ember-data have a built in way of retrieving data? If not, where
should the AJAX request be implemented?
Yes, that's Ember Data module which has some good guides on EmberJS.com.
What is the best way to insert the JSON data into the DS model?
Using Ember Data as per the examples up above.
What is the best way to then sync the models up with a Controller?
Using the model hook in the appropriate route to specify which model(s) your controller represents.
I am currently trying to convert a controller action into Ajax requests in order to let the page load in sections rather than all at once. Before I started making changes, the page loaded in about 8 seconds (it has to process a lot of information).
Since I've changed it to loading up Partial Views via ajax, the page now takes about 35 seconds to load up the same information.
The process is as follows:
The initial request processes and then returns a viewmodel (a generic list) as json
I then use the returned data to create two partial views
I just wonder if there is a better way of laying out the jquery to get it to work faster. I'm aware the amount of data being passed could be a factor - although I can't find the exact size of the object in the debugger, when I dump the json out to a text file it is about 70kb.
jQuery
$.ajax({
type: 'GET',
dataType: "json",
url: '#Url.Action("GetMapDetails")',
success: function (data) {
$.ajax({
type: 'POST',
contentType: 'application/json',
url: '#Url.Action("GetMapItems")',
data: JSON.stringify({
list: data
}),
success: function (result) {
$("#mapContainer").html(result);
}
});
$.ajax({
type: 'POST',
contentType: 'application/json',
url: '#Url.Action("GetAreaPoints")',
data: JSON.stringify({
list: data
}),
success: function (result) {
$("#areaPointsContainer").html(result);
}
});
}
});
Controller
public JsonResult GetMapDetails()
{
List<ViewModel> vm = new List<ViewModel>();
//create viewmodel here
return Json(vm.ToArray(), JsonRequestBehavior.AllowGet);
}
public ActionResult GetMapItems(List<ViewModel> list)
{
return PartialView("_MapItemsPartial", list);
}
public PartialViewResult GetAreaPoints(List<ViewModel> list)
{
return PartialView("_AreaPointsPartial", list);
}
If anyone can offer some optimization advice, that would be great thanks
You could look into rendering partial views into strings. That way you could return both HTML strings from GetMapDetails, and you'd be able to achieve the same result in one AJAX call instead of three.
If would also rid you the need of serializing the viewmodel back and forth, so there might be some performance gain there.
Install the Stackexchange Miniprofiler and hook it into your database requests as well, this will help you find which bit is taking the most time. I suspect it could well be your data and processing on the server (depending on how you have written your controller you could be hitting your data load+process 4 times in the AJAX version, resulting in the 4 times page load).
If this is true then the problem is not going to be fixed by AJAXing your page but caching the processed data on the server (to keep it up to date your choices are a short cache duration or have the process that updates your data remove the cache, the correct answer depends on what your data is).
Since I think that your goal is to be able to load partial views only when they are needed, putting them all in one markup string isn't going to work.
The performance problem you are having is probably due to the fact that ajax-calls are indeed more performance expensive then to load a result stream from a server.
Caching will only help when you retrieve the same data into the same page - not your case either.
From what it seems to me, you should load up the initial view to the user, and immediately start background pre-loading of the views you are probably going to need soon. Just placing them onto the DOM as an indivisible elements, so one requested, they will be immediately loaded. Of course you pre-load only those which you are most likely to need soon.
Other, probably more effective way, would be to use an MVVM framework on the client, like KnockoutJS. Define your views in a simple html markup, without the actual need for the server to render the partial view with the model. This would allow an html to transfer faster. Separate REST calls from your client would be retrieving only the model data from the server in JSON format, and you will apply data binding to the view (lightweight html you've loaded previously). This way the burden of heavy-rendering will be on the client and the server will be able to service more clients in a long run + you are most likely to get the performance gain.
Also try to use $.ajax cache option to true to improve further calls jQuery ajax method
I assume that infomation don't change fast then it would improve the performance.
For example I work with statistics pages loading asynchronously 7-8 plots there cache saves me a lot of time.
From jQuery Api:
On the other hand if the posted data content changes fast it's not recommended to cache it but also take into account that EVERY browser caches that request in it's own cache. To avoid browsers caching use timestamps on every request as query strings just as $.ajax does automatically.
I have a form where user is able to choose search options. When user clicks "Search" button,
an appropriate GET controller's action is invoked:
public ActionResult Search(SearcherViewModel model, int pageNo=1)
{
var results = xService.GetSearchResults(model);
return View("Index", results);
}
GetSearchResults method does not connect to the database, but instead it call some third party web service. This however is not the main issue.
Therefore, the url can look as follows:
http://localhost/Search?startDate=20120210&offerType=3&foodId=4&&Destination=456
How can I implement a pagination of search results? In particular, how should I construct the page numbers and how to use my model?
Kinda depends on how much stuff you are paginating. If it is small then you can hold the whole thing in javascript memory using preloading and then paginate based on the javascript objects. If you are looking at potentially tens of thousands or more of items to paginate, then you may consider preloading part of that and then using ajax to load pages later on depending on how the user navigates.