I have this menu that I want to make available on my layout (essentially every view on my site). I want to maintain the menu's state (whether or not tree items are opened or closed) across page requests. What I want to do is possibly have a child action that is called from my layout page that grabs some cookie or session info which contains the tree's state information so I can rebuild the tree exactly how it was the last request. My problem is, from what I read, it's bad practice to call things like Session and Cookie from within ones controller actions. What I'd like to know is what's a more elegant way to solve this problem. If I must use Cookie and Session, anyone has ideas on how to mock them? Thank you
My problem is, from what I read, it's bad practice to call things like
Session and Cookie from within ones controller actions
Interesting. And did the author of this article explain why it would be a bad practice? There's nothing wrong accessing the session and cookies from your controller actions. Actually using the session for this kind of things might not be suitable because if the user closes his browser you will not be able to persist the layout of the tree whereas with persistent cookies that would be possible.
We can have the Menu as a Partial View.
The Action to Render Partial view will accept parameters to render the state.
Each link will invoke the action with different parameters.
for Example,
public PartialViewResult RenderNavigation(int Menuroot, int subMenuItem)
{
IList<MyNavigationItem> navigationItems=GetNavigation();// Some method that'll read nvigationitems.
navigationItems.Where(n=> n.menuId.Equals(Menuroot) ||n.IsOpen.Equals(subMenuItem)).ToList().ForEach(i=> i.IsOpen=true);
return View("SomeMenuView",navigationItems);
}
public class MyNavigationItem{
int menuId{get;set;}
bool IsOpen{get;set;}
int parentMenuId{get;set;} // set default -1 for Root Items
}
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.
Spring MVC 4.1
Hi,
I have a situation where, on a single page, there are several input fields. As the users enters numbers into these fields, a bunch of calculations will occur and update various other fields on the page.
I want this whole calculation model to take place in Java on the server-side. I really want to avoid replicating this logic in Javascript on the client.
What I envision is...
User opens the page, the object that does the calculations (let's call it Calculator) is created and its initial state is set (many of its fields are pre-populated with values).
This Calculator instance is stored and available for the duration of the user's time on that page.
Whenever the user changes a value in an input field, that new value is sent to the server via ajax and plugged into our Calculator object. The Calculator, re-calculates the other fields based on the new state and returns the results to the page.
The other fields on the page are updated accordingly.
The key here is that I'm not sending the state of all fields with each ajax request. I'm only sending the current value that was updated. Essentially, I'm trying to ensure that the form state and the Calculator state on the back-end are always synchronized.
I have looked into #SessionAttributes and #ModelAttribute.
The problem with #ModelAttribute, as I understand it, is that it will be re-created with each ajax request.
The problem with #SessionAttributes is that it is a session variable. What if the user has two of these windows open? And how do I ensure the object is removed from the session when they leave the page? etc...
Maybe there's no magic Spring bullet and I just have to figure out the session variable thing. But any pointers on dealing with this would be much appreciated.
Thanks!
You have a couple of options:
.1. Like you have said using the #SessionAttributes, however yes it suffers from the issue that you have mentioned, multiple instances of the same session will see the same variable.
.2. Store state somewhere else and re-hydrate the state using #ModelAttribute annotated method. I would personally prefer this approach, essentially when you create the form, create it with a identifier for the current state:
#RequestMapping(params = "form")
public String createForm(Model uiModel) {
uiModel.addAttribute("calculationId", UUID.randomUUID().toString());
return "calculationpage/create";
}
Then for subsequent ajax requests, ensure your previous calculationId is sent across:
#ModelAttribute("calculationState")
public CalculationState rehydrateState(String calculationId) {
//retrieve current state of calculation from some persistent store..
}
#RequestMapping("/calculate")
public String handleCalculation(#ModelAttribute("calculationState") CalculationState c) {
//you will get a calculationstate with the delta's at this point..
}
.3. Another potential approach may be to use session but disambiguate different instances within the session with a custom id:
public String handleCalculation(HttpSession session, #RequestParam("calcId") String calcId) {
CalculationState calcState = (CalculationState) session.getAttribute("calculation" + calcId);
}
You need any sort of persistent store outside session to store and retrieve the state of your calculator model. Like Biju said, I will go for solutions like No 2.
I have a task in my controller that I call from an URL in the view, like this:
echo JRoute::_('index.php?option=com_mycomponent&task=myComponent.myFunction');
The task gets the model and actions one of the model's methods, which should return a list of objects based on state variables set from a form in the view's POST. It seems when I click the anchor and the task is loaded - the state disappears.
Can anyone tell me why?
Many Thanks!
Since it is a new request your post data is no longer available.
You need to store information in session (setUserState) or somewhere else (db?) if you want to keep it across calls.
setUserState is a convenient feature of Joomla to store (small) pieces of info into session in an easy way: http://docs.joomla.org/How_to_use_user_state_variables
I suspect I'm doing this wrong.
For various reasons, my app forces the user to make some choices right after login. In order to ensure that they enter the necessary data, I override the OnActionExecuting method in a base controller class to intercept any attempt at executing an action before this data has been entered, and redirect the user to the necessary page. I preserve the url of the action they were attempting to execute with the following code:
url = Url.RouteUrl("Default", filterContext.RouteData.Values);
(filterContext is an ActionExecutingContext object, and a parameter of OnActionExecuting.)
The problem I'm having is that, if the action was associated with a controller in an area, the url I get doesn't reflect the area.
I understand from other posts that I can get the area name from the DataTokens collection of RouteData. But I'm uncertain of the best way to pass it. I suppose I could retrieve it and use the RouteValueDictionary.Add method to add it to RouteData.Values (assuming Values is not read-only at that point; I don't know), but that feels a bit ... odd, like somehow the point is being missed.
Is this really the way this is supposed to be done? Is there something wrong elsewhere, that Area is absent from my RouteData.Values?
I would just take it out of the data tokens in the filter and add it to route values. You can do it with RouteValues.Add:
if (filterContext.RouteData.DataTokens.ContainsKey("area"))
filterContext.RouteData.Values.Add("area",
filterContext.RouteData.DataTokens["area"]);
The areas feature was added in MVC2, and I imagine this is a side effect of it not being in MVC1. However, as long as your RouteValues contains an "area" key, UrlHelper.RouteUrl should generate the correct URL for the area.
Is there a method for specifically hiding the routing parameters in ASP.NET MVC from the users. Specifically, I'd like a link
http://sitename.com/Do?title = 2
to simply become
http://sitename.com/Do
but internally pass the titleId to my controller.
Is that do able?
Thanks
Update: yes, there are buttons on my webpage that currently have such as their href, but I'd rather hide all the parameters so users dont go to other parts of the page directly by trying differnt parameters. #Moshe, no its not a from submit or post else I'd have used a strongly typed view. Thanks
As long as your parameters are on the client, they are never 'hidden' unless you encrypt them. You could store the parameter in a hidden field and set the action method to post, then the value is not visible in the URL. But a user with a little bit of knowlegde about web could still manipulate the hidden field (unless you encrypt the value in some way).
EDIT: If it has to be save you have to check the user's credentials on the server. Otherwise you can obscure the data like in the other sample or you can use encryption, e.g. with ProtectData.Protect(...).
For simple numeric values that have to be passed back and forth to a view you can write two private methods in your controller:
private int Obscure(int source) {
return (source*source) * 3; //or something clever you come up with
}
private int DeObscure(int obscuredValue) {
return (int)Math.Sqrt(obscuredValue / 3); //inverse the Obscure method
}
You can use these to obscure values before you pass them to a view, and de-obscure them after you get them posted back. Mind you, this is really not a good way to implement security, as is explained in this stackoverflow post.
Another option is to create an Obscure/DeObscure procedure that takes in the entire querystring and somehow mangles that back and forth. This would required writing a custom ViewEngine though. Sounds interesting...