I'm trying to develop an application where simultaneous users can interact and i need to have a persistent remote shared object with the list of users currently in session.
When a new user enter in the session he get the server's object with the list. That list was supose to have all the others users in session but is undefined.
I'm doing this first:
users_so = SharedObject.getRemote("users_so", nc.uri, true);
users_so.connect( nc );
users_so.addEventListener( SyncEvent.SYNC, usersSyncHandler );
then i set property to shared object
remoteUsers = new ArrayCollection();
remoteUsers.addItem(displayName);
users_so.setProperty("usersID", remoteUsers);
and finaly i put users in the list.
Thanks!
I would say, that you need to use sharedObject.setDirty("usersID");
SharedObject can't know, that you changed content of ArrayCollection, because the reference to it didn't change. You can use setDirty() to force synch.
Note: The SharedObject.setProperty()
method implements the setDirty()
method. In most cases, such as when
the value of a property is a primitive
type like String or Number, you would
use setProperty() instead of setDirty.
However, when the value of a property
is an object that contains its own
properties, use setDirty() to indicate
when a value within the object has
changed. In general, it is a good idea
to call setProperty() rather than
setDirty(), because setProperty()
updates a property value only when
that value has changed, whereas
setDirty() forces synchronization on
all subscribed clients.
I am using simple dynamic object for this. Client has read-only SharedObject and server decides when to add/remove client from this SharedObject.
m_so is SharedObject (remote), m_userList is Object (local)
if(m_so.data.userList != null) {
for (var key:String in m_so.data.userList) {
if(m_userList[key] == null) {
_addUser(m_so.data.userList[key]);
}
}
for(var clientId:String in m_userList) {
if(m_so.data.userList[clientId] == null) {
_removeUser(clientId);
}
}
}
application.onAppStart = function () {
userList = {};
so = SharedObject.get("roster", false);
so.setProperty("userList", userList);
}
application.onConnect = function (client /*Client*/, userId /*string*/) {
application.acceptConnection(client);
client.userId = userId;
userList[userId] = userId;
so.setProperty("userList", userList);
}
application.onDisconnect = function (client /*Client*/) {
var userId = client.userId;
delete userList[userId];
so.setProperty("userList", userList);
}
I found one solution that works better for me:
It consists in calling remote funcions on server and then broadcast to all clients. The clientes then apply the necessery changes making the solution a lot more stable.
Related
Based on the project tracker I have integrated a changelog into my app that relates my UserSettings model to a UserHistory model. The latter contains the fields FieldName, CreatedBy, CreatedDate, OldValue, NewValue.
The relation between both models works fine. Whenever a record is modified, I can see the changes in a changelog table. I now want add an "undo"-button to the table that allows the admin to undo a change he clicks on. I have therefore created a method that is handled by the widget that holds the changelog record:
function undoChangesToUserRecord(changelog) {
if (!isAdmin()) {
return;
}
var fieldName = changelog.datasource.item.FieldName;
var record = changelog.datasource.item.UserSettings;
record[fieldName] = changelog.datasource.item.OldValue;
}
In theory method goes the connection between UserHistory and UserSettings up to the field and rewrites its value. But when I click on the button, I get a "Failed due to circular reference" error. What am I doing wrong?
I was able to repro the issue with this bit of code:
google.script.run.ServerFunction(app.currentPage.descendants.SomeWidget);
It is kinda expected behavior, because all App Maker objects are pretty much complex and Apps Script RPC has some limitations.
App Maker way to implement it would look like this:
// Server side script
function undoChangesToUserRecord(key) {
if (!isAdmin()) {
return;
}
var history = app.models.UserHistory.getRecord(key);
if (history !== null) {
var fieldName = history.FieldName;
var settings = history.UserSettings;
settings[fieldName] = history.OldValue;
}
}
// Client side script
function onUndoClick(button) {
var history = widget.datasource.item;
google.script.run
.undoChangesToUserRecord(history._key);
}
I am using the following code to dynamically execute calls to a table method that may or may not be present.
However, it always returns Error executing code: myTableName table does not have method 'myUpdateMethod'.
Dicttable dictTable;
Common common;
ExecutePermission perm;
perm = new ExecutePermission();
dictTable= new DictTable(tableName2Id('myTableName'));
if (dictTable != null)
{
common = dictTable.makeRecord();
// Grants permission to execute the
// DictTable.callObject method. DictTable.callObject runs
// under code access security.
perm.assert();
dictTable.callObject('myUpdateMethod', common);
}
// Close the code access permission scope.
CodeAccessPermission::revertAssert();
These objects are in different models, but just for kicks I tried making a reference between the two models to see if it made a difference. It did not fix the issue.
Thanks
Changed the method being called from static to non-static.
Started working, then found the callStatic() equivalent.
Here is the code I ended up using for the non-static method, which has no params.
Dicttable dictTable;
Common common;
ExecutePermission perm;
perm = new ExecutePermission();
dictTable= new DictTable(tableName2Id('MyTableName'));
if (dictTable != null)
{
common = dictTable.makeRecord();
// Grants permissions
perm.assert();
if (dictTable.doesMethodExist('myMethodName'))
{
dictTable.callObject('myMethodName', common);
}
}
// Close the code access permission scope.
CodeAccessPermission::revertAssert();
When creating a user, entries are required in multiple tables. I am trying to create a transaction that creates a new entry into one table and then pass the new entityid into the parent table and so on. The error I am getting is
The transaction manager has disabled its support for remote/network
transactions. (Exception from HRESULT: 0x8004D024)
I believe this is caused by creating multiple connections within a single TransactionScope, but I am unsure on what the best/most efficient way of doing this is.
[OperationBehavior(TransactionScopeRequired = true)]
public int CreateUser(CreateUserData createData)
{
// Create a new family group and get the ID
var familyGroupId = createData.FamilyGroupId ?? CreateFamilyGroup();
// Create the APUser and get the Id
var apUserId = CreateAPUser(createData.UserId, familyGroupId);
// Create the institution user and get the Id
var institutionUserId = CreateInsUser(apUserId, createData.AlternateId, createData.InstitutionId);
// Create the investigator group user and return the Id
return AddUserToGroup(createData.InvestigatorGroupId, institutionUserId);
}
This is an example of one of the function calls, all the other ones follow the same format
public int CreateFamilyGroup(string familyGroupName)
{
var familyRepo = _FamilyRepo ?? new FamilyGroupRepository();
var familyGroup = new FamilyGroup() {CreationDate = DateTime.Now};
return familyRepo.AddFamilyGroup(familyGroup);
}
And the repository call for this is as follows
public int AddFamilyGroup(FamilyGroup familyGroup)
{
using (var context = new GameDbContext())
{
var newGroup = context.FamilyGroups.Add(familyGroup);
context.SaveChanges();
return newGroup.FamilyGroupId;
}
}
I believe this is caused by creating multiple connections within a single TransactionScope
Yes, that is the problem. It does not really matter how you avoid that as long you avoid it. A common thing to do is to have one connection and one EF context per WCF request. You need to find a way to pass that EF context along.
The method AddFamilyGroup illustrates a common anti-pattern with EF: You are using EF as a CRUD facility. It's supposed to me more like a live object graph connected to the database. The entire WCF request should share the same EF context. If you move in that direction the problem goes away.
We are rying to use WF with multiple tracking participants which essentially listen to different queries - one for activity states, one for custom tracknig records which are a subclass of CustomTrackingRecord.
The problem is that we can use both TrackingParticipants indivisually, but not together - we never get our subclass from CustomTrackingRecord but A CustomTrackingRecord.
If I put bopth queries into one TrackingParticipant and then handle everythign in one, both work perfectly (which indicates teh error is not where we throw them).
The code in question for the combined one is:
public WorkflowServiceTrackingParticipant ()
{
this.TrackingProfile = new TrackingProfile()
{
ActivityDefinitionId = "*",
ImplementationVisibility = ImplementationVisibility.All,
Name = "WorkflowServiceTrackingProfile",
Queries = {
new CustomTrackingQuery() { Name = "*", ActivityName = "*" },
new ActivityStateQuery() {
States = {
ActivityStates.Canceled,
ActivityStates.Closed,
ActivityStates.Executing,
ActivityStates.Faulted
}
},
}
};
}
When using two TrackingParticipants we have two TrackingProfile (with different names) that each have one of the queries.
in the track method, when using both separate, the lines:
protected override void Track(TrackingRecord record, TimeSpan timeout)
{
Console.WriteLine("*** ActivityTracking: " + record.GetType());
if (record is ActivityBasedTrackingRecord)
{
System.Diagnostics.Debugger.Break();
}
never result in the debugger hitting, when using only the one to track our CustomTrackingRecord subclass (ActivityBasedTrackingRecord) then it works.
Anyone else knows about this? For now we have combined both TrackingParticipants into one, but this has the bad side effect that we can not dynamically expand the logging possibilities, which we would love to. Is this a known issue with WWF somewhere?
Version used: 4.0 Sp1 Feature Update 1.
I guess I encounterad the exact same problem.
This problem occurs due to the restrictions of the extension mechanism. There can be only one instance per extension type per workflow instance (according to Microsoft's documentation). Interesting enough though, one can add multiple instances of the same type to one workflow's extensions which - in case of TrackingParticipant derivates - causes weird behavior, because only one of their tracking profiles is used for all participants of the respective type, but all their overrides of the Track method are getting invoked.
There is a (imho) ugly workaround to this: derive a new participant class from TrackingParticipant for each task (task1, task2, logging ...)
Regards,
Jacob
I think that this problem isn't caused by extension mechanism, since DerivedParticipant 1 and DerivedParticipant 2 are not the same type(WF internals just use polymorphism on the base class).
I was running on the same issue, my Derived1 was tracking records that weren't described in its profile.
Derived1.TrackingProfile.Name was "Foo" and Derived2.TrackingProfile.Name was null
I changed the name from null to "Bar" and it worked as expected.
Here is a WF internal reference code, describing how is the Profile selected
// System.Activities.Tracking.RuntimeTrackingProfile.RuntimeTrackingProfileCache
public RuntimeTrackingProfile GetRuntimeTrackingProfile(TrackingProfile profile, Activity rootElement)
{
RuntimeTrackingProfile runtimeTrackingProfile = null;
HybridCollection<RuntimeTrackingProfile> hybridCollection = null;
lock (this.cache)
{
if (!this.cache.TryGetValue(rootElement, out hybridCollection))
{
runtimeTrackingProfile = new RuntimeTrackingProfile(profile, rootElement);
hybridCollection = new HybridCollection<RuntimeTrackingProfile>();
hybridCollection.Add(runtimeTrackingProfile);
this.cache.Add(rootElement, hybridCollection);
}
else
{
ReadOnlyCollection<RuntimeTrackingProfile> readOnlyCollection = hybridCollection.AsReadOnly();
foreach (RuntimeTrackingProfile current in readOnlyCollection)
{
if (string.CompareOrdinal(profile.Name, current.associatedProfile.Name) == 0 && string.CompareOrdinal(profile.ActivityDefinitionId, current.associatedProfile.ActivityDefinitionId) == 0)
{
runtimeTrackingProfile = current;
break;
}
}
if (runtimeTrackingProfile == null)
{
runtimeTrackingProfile = new RuntimeTrackingProfile(profile, rootElement);
hybridCollection.Add(runtimeTrackingProfile);
}
}
}
return runtimeTrackingProfile;
}
I have an ASP.NET application that caches some business objects. When a new object is saved, I call remove on the key to clear the objects. The new list should be lazy loaded the next time a user requests the data.
Except there is a problem with different views of the cache in different clients.
Two users are browsing the site
A new object is saved by user 1 and the cache is removed
User 1 sees the up to date view of the data
User 2 is also using the site but does not for some reason see the new cached data after user 1 has saved a new object - they continue to see the old list
This is a shortened version of the code:
public static JobCollection JobList
{
get
{
if (HttpRuntime.Cache["JobList"] == null)
{
GetAndCacheJobList();
}
return (JobCollection)HttpRuntime.Cache["JobList"];
}
}
private static void GetAndCacheJobList()
{
using (DataContext context = new DataContext(ConnectionUtil.ConnectionString))
{
var query = from j in context.JobEntities
select j;
JobCollection c = new JobCollection();
foreach (JobEntity i in query)
{
Job newJob = new Job();
....
c.Add(newJob);
}
HttpRuntime.Cache.Insert("JobList", c, null, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.Default, null);
}
}
public static void SaveJob(Job job, IDbConnection connection)
{
using (DataContext context = new DataContext(connection))
{
JobEntity ent = new JobEntity();
...
context.JobEntities.InsertOnSubmit(ent);
context.SubmitChanges();
HttpRuntime.Cache.Remove("JobList");
}
}
Does anyone have any ideas why this might be happening?
Edit: I am using Linq2SQL to retreive the objects, though I am disposing of the context.
I would ask you to make sure you do not have multiple production servers for load balancing purpose. In that case you will have to user some external dependency architecture for invalidating/removing the cache items.
That's because you don't synchronize cache operations. You should lock on writing your List to the cache (possibly even get the list inside the lock) and on removing it from the cache also. Otherwise, even if reading and writing are synchronized, there's nothing to prevent storing the old List right after your call to Remove. Let me know if you need some code example.
I would also check, if you haven't already, that the old data they're seeing hasn't been somehow cached in ViewState.
You have to make sure that User 2 sent a new request. Maybe the content it saws is from it's browser's cache, not the cache from your server