I'm building a profile page with update form. After submitting the form with new data and several page refreshes I see sometime new and sometimes old data. It depends on thread handling current request. One thread contains new data and another one old. NHibernate is configured using ThreadStaticSessionContext and NoCacheProvider. In Autofac UserStore, OwinContext.Authentication and UserManager are configured as InstancePerRequest.
I tried to change ThreadStaticSessionContext to CallSessionContext and it started working normally. So the question is: why it works(ThreadStaticSessionContext is preferable for multithread apps) and what negative effects can it bring?
Thanks!
ThreadStaticSessionContext is for long running processes such as windows services or windows apps. For web applications you want to be implementing Session Per Request. This is what the WebSessionContext is for.
I actually don't use any of the contexts and just wire it up myself. See my answer here for an example.
Related
When I am creating a new session (or try to access from an other computer) in Vaadin Flow I get this error:
Can't move a node from one state tree to another
From this link, I read something about UI and getUIId().
However, I don't understand how I should change my application in order to fix the error.
As Denis mentioned in the forum post you linked, wrong scope sounds like the most likely culprit. In other words, you are trying to use the exact same component instance in two different UIs, when both UIs should have their own instance. It's not possible to use the same instance in two places at the same time.
You can find the documentation for Vaadin Spring scopes here: https://vaadin.com/docs/latest/flow/integrations/spring/scopes
One possible cause of errors such as that is that if you're storing a Component in a static variable. You shouldn't do that - a Component instance can only belong to a single UI. A single UI in turn (in practice) means a single browser tab.
I have a VS 2013 Lightswitch HTML Client application to which I've added a button that makes a Web API REST post. This basically 'refreshes' the data in the table from the original upstream source. This is all working correctly, but the operation takes a few minutes, and I want to report status to the user as it runs.
Right now, I've tried attaching a simple Refresh when the post returns as follows:
$.post("/api/data/", "Refresh", function (response) {
screen.getData().then(function (newData) { screen.reQuery(); });
});
This doesn't actually seem to do a refresh (screen.reQuery is apparently the wrong call), but the better option would be to instead have the server show progress of this long-running application.
One thought I had would be to have the server call return data in the form of "percent done" in the response as it processes it, but I don't know if this would be delivered to the client piecemeal, nor the best way to display this to the user in Lightswitch.
I'm open to other third-party libraries that might help with this, but I'd like to stick with WebAPI for commanding instead of adding something like SignalR for now, if possible. Thanks!
In general this seems like not the best idea to run operations that takes minutes on the server.
A reasonable alternative is to create a single call, that will in turn create multiple Web Jobs (see Azure Web Jobs for more info). The Web Jobs will be broken to smaller individual tasks, and your html will query the web jobs rather than your Web API.
I am looking for a way to batch requests to the server. I found a post by Brad Wilson outlining how to make a batch handler using a message hanlder http://bradwilson.typepad.com/blog/2012/06/batching-handler-for-web-api.html#more but I wasn't able to get this working.
first I had compile errors because webapi did not understand "route-specific endpoint handler" like Brad's example used. there were also problems with the media type and/or formatter (can't remember which). My next attempt was to make a batch controller. so instead of a batch handler I had a batch controller. I almost has this working except when I used the MessageHandlerInvoker to call the individual commands I got exceptions about the additional handlers I have regsstered (1 for logging request/response and another to mimic user authentication).
At that point I stopped and reverted back to individual requests, not ideal, but it works.
My environment:
.net 4.0
VS 2010
mvc 4 front end (calls webapi)
webapi as a service tier
Has anyone else had any success with batched messages and webapi?
To be able to use per-route handlers you need ASP.NET Web API RTM which was only released yesterday (at the time when Brad wrote the article, it would only work with nightly MyGet feed builds or against Codeplex source).
You can get entire MVC4 RTM here or simply off Nuget.
Im pretty new to struts2 and Ajax ,Actually i have a drop down menu in JSP lets say first.jsp, When user select a choice from dropdown menu,I am calling a function of Action class lets say Method1.In this method i am fetching some value from DB(lets say:a,b,c) and one value from java memory lets say d.Then I am forwarding to second.jsp and display all the parameters(a,b,c and d) in tabular format.
Now problem is that the parameter d is dynamic ,this is updating by some other application and if its change then I have to show it on JSP wihout any action.
One solution is I use in second.jsp , so after interval of 10 second again Mehod1 will call and it will fetch value(a,b,c) from db and updated value of d from java memory. and disply it to second.jsp.But in this case i am unnecessary retrieving value from db while my purpose is just to get value d from memory.This is working but this is causing my application to slower.
Can any body suggetst some other solution? or can i do it using ajax and how?
Any other advice? any help is appreciated.try to be more clear, i'm in lack of ideas in this problem, even it sounds like a classic :I have spend hours trying to play around with this but have got nowhere
Okay... What you're asking is a little fuzzy so let me rephrase:
You have a user (USER1) who opens a web page and sees some data.
You have a second user (USER2) (who may be an application) who is able set a value from time to time.
When USER2 updates that value you want USER1 to see it change in their open browser window?
If this is the case you need to understand basic ajax. For that get these demo applications working:
This example uses dojo and perhaps the S2 ajax tag lib I don't remember I prefer not to use ajax tags (as they are deprecated and prefer jquery for ajax):
http://struts.apache.org/2.x/docs/struts-2-spring-2-jpa-ajax.html
This example here shows a very similar application but using jquery, no tag library, upgraded to Spring 3, it still needs polish:
http://www.kenmcwilliams.com/Downloads/
Now that you know how to get data via ajax, look at the request with firebug. You'll see that the request is just like a typical function call, the browser keeps waiting for the data to come back.
What you do is simply not return from the action until new data is provided. This is called long polling see: http://en.wikipedia.org/wiki/Comet_%28programming%29#Ajax_with_long_polling
If you have not written a simple chat program, using just terminal windows I recommend you do so. Two windows per client (client-send, client-receive windows) and you'll need a server program. I remember hacking one together in a few hours using _Thinking In Java 2nd Edition (Later books took out the networking section if I remember correctly). Anyways between understanding client server interaction and long polling will let you get things working. It would be fun to extend the simple terminal based chat application to a S2 ajax chat application. Would make an awesome tutorial! PS: This is just an application of the producer/consumer problem (If you understand that then I guess you don't need to do the fun exercise).
The interfaces would look very pretty if the server was managed by spring. I know there must be nice servers already written but I am not familiar with any, but would love to hear of one.
I'm looking at using Subsonic with a multi-tenant ASP.net web application. There are multiple DB's (one per client/instance). The user logs in with a domain suffix to their username (e.g. user#tenant1, user#tenant2).
The custom membership provider will then determine which database a user is using, and authenticate against it. All user-initiated calls in the webapp will be wrapped in a SharedDbConnectionScope call, however I have a question regarding caching subsonic items.
Basically each instance will have a few records that rarely change (search options/configurations). I would like to read these in the Application_Start event, and cache them into the ApplicationState.
In the Application_Start event, it would loop over each client database, use a SharedDbConnectionScope to connect to each DB, and create these cached records (e.g. Application('tenant1_search_obj') = subsonic_object
When a user loads the search page, it would then check what domain a user is in, and then retreive that search option from the cache.
Is this feasible? I'm just concerned that if I cache an object, when I retrieve it from the application cache it won't know what connection its using, and might possibly pull in the wrong data.
I'd like to avoid putting this in the session object if possible.
it's possible, but probably not a good idea since it doesn't scale at all - you're going to pop a new connection for every single client whether they show up or not.
Maybe your best bet is to "lazy load" the setting - first hit on the search page loads the config into the cache or Application settings and there it stays.
Other than that - to answer your question it is possible. If you're using SubSonic 3, just create a new provider on the fly using ProviderFactory.GetProvider(connectionString, "System.Data.SqlClient") and then execute your stuff against it.
For SubSonic 2 - SharedConnectionScope is what you want.