There is a sort of "trick" that I've seen around more than once, in order to clear the cache for an MVC app by calling a specific url similar to
http://somewebsite.com/Misc/ClearCache
I used it a couple of times, but honestly I didn't understand exactly how it works and I haven't found any documentation or post about it.
Is there anyone that could explain it a bit, possibly with some related documentation?
Many thanks.
I am not sure if you are using some plugin or 3rd party library for that. But it is as simple as :
write a web method to clearcache like:
public void Clearcache()
{
HttpContext.Current.Response.Cache.SetExpires(DateTime.UtcNow.AddDays(-1));
HttpContext.Current.Response.Cache.SetValidUntilExpires(false);
HttpContext.Current.Response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache);
HttpContext.Current.Response.Cache.SetNoStore();
}
Call method from browser with like controller/actionname :http://somewebsite.com/Controller/ClearCache
If cache is 3rd party you can delete as required in same method
I was wrong in my comment, no Ajax needed.
Here would be your JQuery:
$("#clearCache").click(function () {
if (!$(this).disabled) {
$('<iframe id="cacheCleared" src="../../Misc/ClearCache"></iframe>').appendTo('body').hide();
}
});
Then in your Misc Controller you would have:
public ActionResult ClearCache()
{
foreach (System.Collections.DictionaryEntry entry in HttpContext.Cache)
{
HttpContext.Cache.Remove((entry.Key).ToString());
}
return View();
}
Once you append your iframe, it will attempt to load the content from that source. When it tries to load that source, it will hit your ClearCache in your controller and should clear everything.
EDIT:
Add this before you return View(); if you want to avoid building a view for it.
System.Web.HttpContext.Current.Response.End();
Related
In my controller, via service, I get from DB a list of the names of widgets (eg. chart, calendar, etc). Every widget implements WidgetInterface and may need other services as its own dependencies. The list of widgets can be different for each user, so I don't know which widgets / dependencies I will need in my controller. Generally, I put dependencies via DI, using factories, but in this case I don't know dependencies at the time of controller initialization.
I want to avoid using service locator directly in controller. How can I manage that issue? Should I get a list of the names of widgets in controller factory? And depending on widgets list get all dependencies and put them to controller?
Thanks, Tom
Solution
I solved my issue in a way that suggested Kwido and Sven Buis, it means, I built my own Plugin Manager.
Advantages: I do not need use service locator directly in controller and I have clear and extensible way to get different kinds of widgets.
Thank you.
Create your own Manager, like some sort of ServiceManager, for your widgets.
class WidgetManager extends AbstractPluginManager
Take a look at: Samsonik tutorial - pluginManager. So this way you can inject the WidgetManager and only retrieve the widgets from this manager as your function: validatePlugin, checks whether or not the fetched instance is using the WidgetInterface. Keep in mind that you can still call the parent ServiceManager.
Or keep it simple and build a plugin for your controller that maps your widget names to the service. This plugin can then use the serviceLocator/Manager to retrieve your widget(s), whether they're created by factories or invokableFactories. So you dont inject all the widget directly but only fetch them when they're requested. Something realy simplistic:
protected $map = [
// Widget name within the plugin => Name or class to call from the serviceManager
'Charts' => Widget\Charts::class,
];
public function load($name)
{
if (array_key_exists($name, $this->map)) {
return $this->getServiceManager()->get($this->map[$name]);
}
return null;
}
Injecting all the Widgets might be bad for your performance so you might consider something else, as when the list of your widgets grow so will the time to handle your request.
Hope this helped you and pushed you in some direction.
This indeed is a interesting question. You could consider using Plugins for the widgets, which can be loaded on the fly.
Depency injection is a good practise, but sometimes, with dynamic content, impossible to implement.
Another way to do this, is to make your own widget-manager. This manager then can load the specific widgets you need. The widget-manager can be injected into the controller.
Edit:
As you can see above, same idea from #kwido.
I would use a separate service and inject that into the controller.
interface UserWidgetServiceInterface
{
public function __construct(array $widgets);
public function getWidget($name);
}
The controller factory
class MyControllerFactory
{
public function __invoke(ControllerManager $controllerManager, $name, $requestedName)
{
$serviceLocator = $controllerManager->getServiceLocator();
$userWidgetService = $serviceLocator->get('UserWidgetService');
return new MyController($userWidgetService);
}
}
Then the logic to load the widgets would be moved to the UserWidgetServiceFactory.
public function UserWidgetServiceFactory
{
public function __invoke(ServiceManager $serviceLocator, $name, $requestedName)
{
$userId = 123; // Load from somewhere e.g session, auth service.
$widgetNames = $this->getWidgetNames($serviceLocator, $userId);
$widgets = $this->loadWidgets($serviceManager, $widgetNames);
return new UserWidgetService($widgets);
}
public function getWidgetNames(ServiceManager $sm, $userId)
{
return ['foo','bar'];
}
public function loadWidgets(serviceManager $sm, array $widgets)
{
$w = [];
foreach($widgets as $widgetName) {
$w[$widgetName] = $sm->get($widgetName);
}
return $w;
}
}
The call to loadWidgets() would eager load all the widgets; should you wish to optimise this you could register your widgets as LazyServices
I have a solution which makes use of many class libraries (optional plugins). It is actually very similar in design to nopCommerce. Anyway, I have the following interface:
public interface IOwinStartupConfiguration
{
void Configuration(IAppBuilder app);
}
Obviously what happens is that in my Startup class in the web project, I get a list of all registered IOwinStartupConfiguration instances in all plugins and then proceed to iterate over each one.
So far I only have one plugin using this, but that may change later. The thing I'm worried about is the possibility of more than 1 plugin calling something like:
app.MapSignalR();
Acccording to this page:
http://www.asp.net/signalr/overview/testing-and-debugging/troubleshooting
doing so would cause an error like
"A route named 'signalr.hubs' is already in the route collection"
Is it possible to see what's in the OWIN pipeline?
Ideally I would like to do something like this:
if (!app.IsSignalRMapped)
{
app.MapSignalR();
}
or
if (!app.HasMappedService("SignalR"))
{
app.MapSignalR();
}
Obviously I cannot find any such thing on the IAppBuilder interface. So what can I do in this situation?
I just stumbled upon MapWhen(), but it seemed a bit pointless. I was going to try something like this:
app.MapWhen(x => !existingConfigurations.Contains("SignalR"), x => app.MapSignalR());
where existingConfigurations is a new ICollection<string> passed in the modified method:
void Configuration(IAppBuilder app, ICollection<string> existingConfigurations)
However, I found it made more sense to simply do this:
if (!existingConfigurations.Contains("SignalR"))
{
app.MapSignalR();
existingConfigurations.Add("SignalR");
}
It's not a perfect solution, since someone could misspell "SignalR", for example. But since there's no IsSignalRMapped() method, it will have to suffice.
I haven't tried this but this might work:
var hub = GlobalHost.ConnectionManager.GetHubContext<MySignalRHub>();
if (hub == null)
{
app.MapSignalR();
}
In ASP.NET MVC, when we call a post action with some data, we check ModelState and in case some validation error, it would be falst. For a big Enter User Information form, it is annoying to expand each Value and look at the count to see which Key (9 in attached example image) has validation error. Wondering if someone knows an easy way to figure out which element is causing validation error.
In VS2015+, you can use LINQ in the Immediate Window, which means you can just run the following:
ModelState.SelectMany(
x => x.Value.Errors,
(state, error) => $"{state.Key}: {error.ErrorMessage}"
)
I propose to write a method:
namespace System.Web
{
using Mvc;
public static class ModelStateExtensions
{
public static Tuple<string, string> GetFirstError(this ModelStateDictionary modelState)
{
if (modelState.IsValid)
{
return null;
}
foreach (var key in modelState.Keys)
{
if (modelState[key].Errors.Count != 0)
{
return new Tuple<string, string>(key, modelState[key].Errors[0].ErrorMessage);
}
}
return null;
}
}
}
Then during debugging open Immediate Window and enter:
ModelState.GetFirstError()
Sounds like you're looking for debugger enhancements. I recently came across this product in the visual studio gallery.
http://visualstudiogallery.msdn.microsoft.com/16acdc63-c4f1-43a7-866a-67ff7022a0ac
I have no affiliation with them, and haven't used it. It's also a trial version and have no idea how much it costs for the full thing.
If you're more focused on the debugger side of things, have a go with the trial copy of OzCode. It enhances the Visual Studio IDE by replacing the usual debugging tooltip with it's own, more powerful, debugging tooltip. It's hard to epxlain with words, check out their website, they have a gallery of features on there.
I've been playing around with the beta for a few weeks, and it's proved a very valuable tool. You can query against data in the debugger using OzCode. For example, you could query items in the ModelState by filtering against the Values collection.
I'm using the HotTowel SPA template which makes use of Durandal. In my Durandal ViewModels I am using Breeze to get some data from the database.
I have a datacontext class that I put all my breeze queries in and the queries all follow the pattern like the following:
getAthletes: function (queryCompleted) {
var query = breeze.EntityQuery.from("Athletes");
return manager
.executeQuery(query)
.then(queryCompleted)
.fail(queryFailed)
}
Since I'm doing an asynchronous call in the activate method of the view model, I have to return the promise that comes back from these calls in the activate method.
Using a single query works great like this:
function activate() {
datacontext.getAthlete(loadAthlete);
}
However, if I need to perform two queries I run into problems, but only in the release version of my application. I have tried doing this with the following syntax:
function activate() {
datacontext.getAthlete(loadAthlete).then(datacontext.getOtherData(loadOtherData));
}
This will work fine in debug mode, but when I deploy it out to the server and my scripts get bundled, I get an exception which isn't very clear.
t is not a function
I've also tried chaining them together in my datacontext class like below, but I still get the same error.
getAthleteAndEfforts: function (athleteId, athleteQueryCompleted, effortsQueryCompleted) {
var athleteQuery = breeze.EntityQuery.from("Athletes").where("id", "==", athleteId);
var effortsQuery = breeze.EntityQuery.from("BestEfforts").where("athleteId", "==", athleteId);
return manager.executeQuery(athleteQuery).then(athleteQueryCompleted)
.then(manager.executeQuery(effortsQuery).then(effortsQueryCompleted))
.fail(queryFailed);
}
So I'm assuming I just don't understand the Q.defer() enough to use it properly or there is something else going on.
What is the correct syntax to accomplish this?
Ok, thanks to RainerAtSpirit for pointing me in the right direction to find this. I looked at John Papa's jumpstarter examples and he has a datacontext that does this under the primeData function.
So using the syntax he used there I was able to get it to work correctly like this:
getAthleteAndEfforts: function (athleteId, athleteQueryCompleted, effortsQueryCompleted) {
return Q.all([
datacontext.getAthlete(athleteId, athleteQueryCompleted),
datacontext.getAthleteEfforts(athleteId, effortsQueryCompleted)]);
}
I had seen the Q.all in the Q documentation but wasn't sure how to use it, but this example helped. I tested this and it works both in debug and release modes.
Not sure why the first version is working at all, but you'd return a promise when datacontext is making async calls.
function activate() {
return datacontext.getAthlete(loadAthlete);
}
or
function activate() {
return datacontext.getAthlete(loadAthlete).then( return datacontext.getOtherData(loadOtherData));
}
Check #John Papa's jumpstarter for more examples: https://github.com/johnpapa/PluralsightSpaJumpStartFinal/search?q=activate
How are you supposed to conditionally display menu items based on roles in the Bootstrap Sample project? I was thinking of doing the following
Implement INavigatonRouteFilter - really just implementing the shouldRemove(Route navigationRoutes) method - by getting the default controller/action for the route and seeing if the user is authorized
Call NavigationRoutes.Filters.Add(myAuthorizationFilter) after configuring the NavigationRoutes in App_Start
There are two problems I see with this approach:
I don't actually know how to do the first step unless I add in a bunch of conditional statements to check for Controller's name explicitly
This seems like it could make NavigationRoutes.Filters very hard to deal with once there are a lot of filters or a desire for more modularity later on
I don't know that I've explained the problem clearly enough, but basically I want to use what is provided in the Bootstrap sample to implement authorization-based navigation menu display if at all possible. Using INavigationRouteFilter just seemed like the most natural way to do so.
For those looking for an answer or at least a quick fix.
Here's what I've come up with after 5 minutes and I most certainly haven't though about any side effects this may have.
routes.MapNavigationRoute<HomeController>("Index", c => c.Index())
.FilterRoute(() => !WebSecurity.IsAuthenticated);
You can either do all your filtering in your call to FilterRoute() or you can add more extension methods to save you some characters.
I'm thinking of .RequireRole("Adiministrators"); that calls WebSecurity.RequireRoles() in turn (or HttpContext.Current.User.IsInRole()) etc.
public static NavigationRouteBuilder FilterRoute(this NavigationRouteBuilder builder, Func<bool> func)
{
var currentRoute = builder._parent;
NavigationRoutes.Filters.Add(new BootstrapAuthorizationFilter(builder, x =>
{
if (x == currentRoute)
return func();
else
return false;
}));
return builder;
}
and BootstrapAuthorizationFilter is just a class implementing INavigationRouteFilter that calls func() in its ShouldRemove() method
public class BootstrapAuthorizationFilter : INavigationRouteFilter
{
private NavigationRouteBuilder builder;
private Func<NamedRoute, bool> func;
public BootstrapAuthorizationFilter(NavigationRouteBuilder builder, Func<NamedRoute, bool> func)
{
this.builder = builder;
this.func = func;
}
public bool ShouldRemove(Route navigationRoutes)
{
if (navigationRoutes is NamedRoute)
return func(navigationRoutes as NamedRoute);
return false;
}
}
Clearly nothing fancy and I'm not sure if I'd use it in production.
But I think is simple enough and works (for the cases I tested).
Having said that, I hope the new routing functionality is going to be released soon :)