We are developing using VS2010 and MVC4, deploying our web app on an IIS 7.5 on Windows7.
Our project has a long running process for which we want to display status and progress.
In order to accomplish this we have a small serializable class with properties that describe the current status. The long operation pseudo code goes like this:
int curentPercentComplete = 0;
EngineStatus status = new EngineStatus();
while (!done) {
status.PercentComplete = curentPercentComplete;
Session['status'] = status;
// do lengthy operation
curentPercentComplete = compute();
done = isJobFinished();
}
We also have an other controller action that tries to retrieve the current status from the session
which then encodes to json and returns it to the browser via an Ajax request.
Our problem is that we always seem to get the last saved data from the previous request, in other words the session object does not seem to update the Session['status'] field during the execution of the while block.
We have tried the session state mode both InProc and StateServer with exactly the same behavior.
Thanks in advance.
It turns out that the MVC framework performs a single update of the session data at the end of the request which means that only the last value is saved.
Since the "lengthy" operation is performed in a single request-response cycle, the idea of storing intermediate status information in the session is plain wrong.
Related
I have experience in Salesforce administration, but not in Salesforce development.
My task is to push a Order in Salesforce to an external REST API, if the order is in the custom status "Processing" and the Order Start Date (EffectiveDate) is in 10 days.
The order will be than processed in the down-stream system.
If the order was successfully pushed to the REST API the status should be changed to "Activated".
Can anybody give me some example code to get started?
There's very cool guide for picking right mechanism, I've been studying from this PDF for one of SF certifications: https://developer.salesforce.com/docs/atlas.en-us.integration_patterns_and_practices.meta/integration_patterns_and_practices/integ_pat_intro_overview.htm
A lot depends on whether the endpoint is accessible from Salesforce (if it isn't - you might have to pull data instead of pushing), what authentication it needs.
For push out of Salesforce you could use
Outbound Message - it'd be an XML document sent when (time-based in your case?) workflow fires, not REST but it's just clicks, no code. The downside is that it's just 1 object in message. So you can send Order header but no line items.
External Service would be code-free and you could build a flow with it.
You could always push data with Apex code (something like this). We'd split the solution into 2 bits.
The part that gets actual work done: At high level you'd write function that takes list of Order ids as parameter, queries them, calls req.setBody(JSON.serialize([SELECT Id, OrderNumber FROM Order WHERE Id IN :ids]));... If the API needs some special authentication - you'd look into "Named Credentials". Hard to say what you'll need without knowing more about your target.
And the part that would call this Apex when the time comes. Could be more code (a nightly scheduled job that makes these callouts 1 minute after midnight?) https://salesforce.stackexchange.com/questions/226403/how-to-schedule-an-apex-batch-with-callout
Could be a flow / process builder (again, you probably want time-based flows) that calls this piece of Apex. The "worker" code would have to "implement interface" (a fancy way of saying that the code promises there will be function "suchAndSuchName" that takes "suchAndSuch" parameters). Check Process.Plugin out.
For pulling data... well, target application could login to SF (SOAP, REST) and query the table of orders once a day. Lots of integration tools have Salesforce plugins, do you already use Azure Data Factory? Informatica? BizTalk? Mulesoft?
There's also something called "long polling" where client app subscribes to notifications and SF pushes info to them. You might have heard about CometD? In SF-speak read up about Platform Events, Streaming API, Change Data Capture (although that last one fires on change and sends only the changed fields, not great for pushing a complete order + line items). You can send platform events from flows too.
So... don't dive straight to coding the solution. Plan a bit, the maintenance will be easier. This is untested, written in Notepad, I don't have org with orders handy... But in theory you should be able to schedule it to run at 1 AM for example. Or from dev console you can trigger it with Database.executeBatch(new OrderSyncBatch(), 1);
public class OrderSyncBatch implements Database.Batchable, Database.AllowsCallouts {
public Database.QueryLocator start(Database.BatchableContext bc) {
Date cutoff = System.today().addDays(10);
return Database.getQueryLocator([SELECT Id, Name, Account.Name, GrandTotalAmount, OrderNumber, OrderReferenceNumber,
(SELECT Id, UnitPrice, Quantity, OrderId FROM OrderItems)
FROM Order
WHERE Status = 'Processing' AND EffectiveDate = :cutoff]);
}
public void execute(Database.BatchableContext bc, List<sObject> scope) {
Http h = new Http();
List<Order> toUpdate = new List<Order>();
// Assuming you want 1 order at a time, not a list of orders?
for (Order o : (List<Order>)scope) {
HttpRequest req = new HttpRequest();
HttpResponse res;
req.setEndpoint('https://example.com'); // your API endpoint here, or maybe something that starts with "callout:" if you'd be using Named Credentials
req.setMethod('POST');
req.setHeader('Content-Type', 'application/json');
req.setBody(JSON.serializePretty(o));
res = h.send(req);
if (res.getStatusCode() == 200) {
o.Status = 'Activated';
toUpdate.add(o);
}
else {
// Error handling? Maybe just debug it, maybe make a Task for the user or look into
// Database.RaisesPlatformEvents
System.debug(res);
}
}
update toUpdate;
}
public void finish(Database.BatchableContext bc) {}
public void execute(SchedulableContext sc){
Database.executeBatch(new OrderSyncBatch(), Limits.getLimitCallouts()); // there's limit of 10 callouts per single transaction
// and by default batches process 200 records at a time so we want smaller chunks
// https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_limits.htm
// You might want to tweak the parameter even down to 1 order at a time if processing takes a while at the other end.
}
}
In my Laravel application I used Auth::user() in multiple places. I am just worried that Laravel might be doing some queries on each call of Auth::user()
Kindly advice
No the user model is cached. Let's take a look at Illuminate\Auth\Guard#user:
public function user()
{
if ($this->loggedOut) return;
// If we have already retrieved the user for the current request we can just
// return it back immediately. We do not want to pull the user data every
// request into the method because that would tremendously slow an app.
if ( ! is_null($this->user))
{
return $this->user;
}
As the comment says, after retrieving the user for the first time, it will be stored in $this->user and just returned back on the second call.
For same Request, If you run Auth::user() multiple time, it will only run 1 query and not multiple time.
But , if you go and call for another request with Auth::user() , it will go and run 1 query again.
This cannot be cached for all request after first request has been made due to security point of view.
So, It runs 1 query per request irrespective of number of time you are calling.
I see use of some session here to avoid run multiple query, so you can try these code : http://laravel.usercv.com/post/16/using-session-against-authuser-in-laravel-4-and-5-cache-authuser
Thanks
I am developing a game using TCP. The clients send and listen the server using TCP. When the server receives a request, then it consults the database (SQL Server Express / Entity Framework) and sends a response back to client.
I'm trying to make a MMORPG, so I need to know all the players locations frequently, so I used a System.Timer to ask the server the location of the players around me.
The problem:
If I configure the timer to trigger for every 500ms a method that asks the server the currently players location, then I can open 2 instances of the client app, but it's laggy. If I configure to trigger for every 50ms, then when I open the second instance, the SQL Server throws this exception often:
"The connection was not closed. The connection's current state is open."
I mean, what the hell? I know I am requesting A LOT of things to the database in a short period, but how do real games deals with this?
Here is one code that throws the error when SQL Server seems to be overloaded (second line of the method):
private List<CharacterDTO> ListAround()
{
List<Character> characters = new List<Character>();
characters = ObjectSet.Character.AsNoTracking().Where(x => x.IsOnline).ToList();
return GetDto(characters);
}
Your real problem is ObjectSet is not Thread Safe. You should be creating a new database context inside ListAround and disposing it when you are done with it, not re-using the same context over and over again.
private List<CharacterDTO> ListAround()
{
List<Character> characters = new List<Character>();
using(var ObjectSet = new TheNameOfYourDataContextType())
{
characters = ObjectSet.Character.AsNoTracking().Where(x => x.IsOnline).ToList();
return GetDto(characters);
}
}
I resolved the problem changing the strategy. Now I don't update the players positions in real time to the database. Instead, I created a list (RAM memory) in the server, so I manage only this list. Eventually I will update the information to the database.
I have a Grid, a Store and Model for its data and AJAX proxy for the Store that is pointing to my self-written PHP back-end. The PHP backend writes to log each time it is called.
The system works OK for Read, Update and Delete calls. However now I need to add new field to Store, which I do in such a way:
(here, some new data were generated...)
var newEntry=Ext.ModelManager.create({
id:id,
title: title,
url: '/php/'+fname,
minithumb: '/php/'+small,
thumb:'/php/'+thumb
}, 'MyApp.model.fileListModel');
var store=Ext.getCmp('currGallery').getStore();
store.add(newEntry);
store.sync();
I have the new line appearing in the Grid.
But with or withour sync() call, I have no calls going to my PHP back end. It however reads one more time. Store has parameter autoSync :true and does great updating data automatically when I edit existing line in the Grid.
What am I missing?
Try not to set id when creating new record.
In fact I was missing a
newEntry.phantom = true;
flag. After I set it before adding to store, Store and its Proxy started to send data to server.
Maybe ID solution also works, dunno.
I have problem to call WCF RIA service again to refresh data at client side. Here is my case:
At server side, a domain service is something like:
public IQueryable<Person> GetPersonByID(int id)
{
var result = this.ObjectContext.Persons.
Where(e => e.PersonID == id);
return result; // check point 1
}
At client side, I make a call in the following way (this is call by a button I called "refresh" button):
this._amsService.Context.Load<Person>(
this._amsService.Context.GetPersonByIDQuery(this.Person.ID),
LoadBehavior.RefreshCurrent,
result =>
{
this.Person = result.Entities.FirstOrDefault(); //check point 2
this.RaisePropertyChanged("Person");
}, null);
Here is what I'm trying:
Suppose I have a person in DB with data say personID=1, Age = 16.
Then run the app, I get the data in the right way.
then go to database, update data with SQL to change Age = 20.
Then back to app and click the "refresh" button to make a new call, but the age is not updated to 20, it is still 16.
I run the app in debug mode, and check the data:
At check point 1, I check data in result, it is fine, Age = 20.
At check point 2, I check data in result.Entities, the data has not been refreshed, it's still Age = 16.
I have tried LoadBehavior.MergeIntoCurrent,LoadBehavior.RefreshCurrent, but no success.
So I need to refresh the SL app host page to reload the whole SL app, then I can see the new data. This is not acceptable to end users.
I don't understand why. I also try to use fiddler to catch the data when click on refresh button, the data did get the latest Age = 20.
How to resolve this problem?
First of all, is you entity in edit mode? if you entity is in Edit mode, RIA will keep your changes , and only update the original values when you load the entity again.
You can check IsEditing property of your Person entity to find out. and try to check the OriginalValue of your entity. var original = Person.GetOriginal()