I'm using a WCF data Service to access a MSSQL database. If the client requests data (e.g. from the table "Projects") i build my cache like this:
var collection = new ObservableCollection<Project>();
foreach (var project in this.Entities.Project)
{
collection.Add(project);
}
return collection;
If I want to refresh the list I just call
collection.Clear();
and call the above method again. If I edit a project and refresh the list as described above it works fine, but if i change the data on one client instance and refresh the list on another one the service doesn't load the changed project.
How can I force the DataService to re- load a whole entity (e.g. "Projects") even if from the service's point of view nothing has changed?
Possible solution:
public partial class Entities
{
public void RefreshProject(Project pr)
{
this.Detach(pr);
pr = this.Project.Where(p => p.Id == pr.Id).Single();
}
}
Usage:
entities.RefreshProject(project);
Related
I have implemented Specflow to reuse some steps across features as in this example -Specflow,Selenium-Share data between different Step definitions or classes .Since, in our project, we are integrating multiple features & reusing them. What is the best way to share browser session across features if its triggered in between steps as per the above approach?
My Scenario:
Once an application created, I need to launch new session, login different User-set different services and approve it.
But after logging in fails with below error on Step definition 4 in reused Whenstep of Given(Set the service to (.*)). That particular step is from different feature, hence the new session needs to be used in those steps. The LaunchURl method below is just launching the website with url, no new session created - This works fine
OpenQA.Selenium.WebDriverException : Unexpected error. System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it "IP here"
[Given(#"A New Application is added")]
public void GivenANewApplicationIsAdded()
{
Given("UK_The Service is set");
Given("User Navigated to New Application screen");
When("User fills up form as in data row 1");
Then("new SID generated");
}
[Given(#"New Browser Launched")]
public void GivenNewBrowserLaunched()
{
SeleniumContext sl = new SeleniumContext();
this.seleniumContext = sl;
}
[Given(#"Login is successful with ""(.*)"" and ""(.*)""")]
public void GivenLoginIsSuccessfulWithAnd(string userName, string password)
{
SuperTests spr = new SuperTests();
_driver = spr.LaunchURL(seleniumContext.WebDriver);
//seleniumContext.WebDriver = _driver;
LoginPage lg = new LoginPage(_driver);
lg.LoginProcess(userName, password);
}
[Given(#"Set the service to ""(.*)""")]
public void GivenSetTheServiceTo(string serviceId)
{
When("Select a Service from the option "+serviceId);
Then("The Services is changed to the one selected " + serviceId);
}
In other feature
[When(#"Select a Service from the option (.*)")]
public void WhenSelectAServiceFromTheOptionTestTeam(string p0)
{
HomePage mst = new HomePage(seleniumContext.WebDriver);
mst.SetServiceId(p0);
}
The 2 work around what we figured was
Create a new instance of binding class to call the methods or steps as shown below
[Given(#"Set the service to ""(.*)""")]
public void GivenSetTheServiceTo(string serviceId)
{
var serIdSteps = new UK_SetServiceIDSteps(seleniumContext);
serIdSteps.WhenUK_SelectAServiceFromTheOptionTest(serviceId);
serIdSteps.ThenUK_TheServicesIsChangedToTheOneSelected(serviceId);
}
or
tried this which worked as well- basically calling a new method to create a new session. for this I need not create any new instance for Binding class. Called the Step directly.
[Given(#"New Browser Launched")]
public void GivenNewBrowserLaunched()
{
SuperTests spr = new SuperTests();
_driver = spr.LaunchURL("Firefox");
seleniumContext.WebDriver = _driver;
}
public void GivenSetTheServiceTo(string serviceId)
{
When("UK_Select a Service from the option "+serviceId);
Then("UK_The Services is changed to the one selected " + serviceId);
}
Not sure, which is correct way of doing it? Trying to figure it out from Reusable steps point?The latter one is not advised as we need to change the type of browser to launch at multiple place.
I'm trying to implement pagination using App Engine's RPC and GWT (it's an app engine connected project).
How can I pass both the query results and the web-safe cursor object to the GWT client from the RPC?
I've seen examples using a servlet but I want to know how to do it without a servelt.
I've considered caching the cursor on the server using memcache but I'm not sure if that's appropriate or what should be used as the key (session identifier I would assume, but I'm not sure how those are handled on App Engine).
Links to example projects would be fantastic, I've been unable to find any.
OK, so the best way to do this is to store the cursor as a string on the client.
To do this you have to create a wrapper class that is transportable so you can pass back it to the client via RequestFactory that can hold the results list and the cursor string. To do that you create a normal POJO and then a proxy for it.
here's what the code looks like for the POJO:
public class OrganizationResultsWrapper {
public List<Organization> list;
public String webSafeCursorString;
public List<Organization> getList() {
return list;
}
public void setList(List<Organization> list) {
this.list = list;
}
public String getWebSafeCursorString() {
return this.webSafeCursorString;
}
public void setWebSafeCursorString(String webSafeCursorString) {
this.webSafeCursorString = webSafeCursorString;
}
}
for the proxy:
#ProxyFor(OrganizationResultsWrapper.class)
public interface OrganizationResultsWrapperProxy extends ValueProxy{
List<OrganizationProxy> getList();
void setList(List<OrganizationProxy> list);
String getWebSafeCursorString();
void setWebSafeCursorString(String webSafeCursorString);
}
set up your service and requestFactory to use the POJO and proxy respectively
// service class method
#ServiceMethod
public OrganizationResultsWrapper getOrganizations(String webSafeCursorString) {
return dao.getOrganizations(webSafeCursorString);
}
// request factory method
Request<OrganizationResultsWrapperProxy> getOrganizations(String webSafeCursorString);
Then make sure and run the RPC wizard so that your validation process runs otherwise you'll get a request context error on the server.
Here's the implementation in my data access class:
public OrganizationResultsWrapper getOrganizations(String webSafeCursorString) {
List<Organization> list = new ArrayList<Organization>();
OrganizationResultsWrapper resultsWrapper = new OrganizationResultsWrapper();
Query<Organization> query = ofy().load().type(Organization.class).limit(50);
if (webSafeCursorString != null) {
query = query.startAt(Cursor.fromWebSafeString(webSafeCursorString));
}
QueryResultIterator<Organization> iterator = query.iterator();
while (iterator.hasNext()) {
list.add(iterator.next());
}
resultsWrapper.setList(list);
resultsWrapper.setWebSafeCursorString(iterator.getCursor().toWebSafeString());
return resultsWrapper;
}
a second option would be to save the webSafeCursorString in the memcache, as you already mentioned.
my idea looks like this:
the client sends always request like this "getMyObjects(Object... myParams, int maxResults, String clientPaginationString)". the clientPaginationString is uniquely created like shown below
server receives request and looks into the memcache if there is a webSafeCursorString for the key clientPaginationString
if the server finds nothing, he creates the query and save the webSafeCursorString into memcache with the clientPaginationString as the key. -> returns the results
if the server finds the webSafeCursorString he restarts the query with it and returns the results
the problems are how to clean the memcache and how to find a unique clientPaginationString:
a unique clientPaginationString should be the current UserId + the params of the current query + timestemp. this should work just fine!
i really can't think of a easy way how to clean the memcache, however i think we do not have to clean it at all.
we could store all the webSafeCursorStrings and timestemps+params+userid in a WebSafeCursor-Class that contains a map and store all this in the memcache... and clean this Class ones in a while (timestamp older then...).
one improvement i can think of is to save the webSafeCursorString in the memcache with a key that is created on the server (userSessionId + servicename + servicemethodname + params). however, important is that the client sends an information if he is interested in a new query (memcache is overriden) or wants the next pagination results (gets webSafeCursorString from memcache). a reload of the page should work. a second tap in the browser would be a problem i think...
what would you say?
I use Entity Framework 4 and Self Tracking Entities. The schema is like:
Patient -> Examinations -> LeftPictures
-> RightPictures
So there is TrackableCollection of these two relationships Patient 1 - * ....Pictures.
Now when loading the customers Form and browsing the details I dont need to load these
data images, only when another form is loaded for Examination details!
I am using a class library as a Data Repository to get data from the database (SQL Server) and this code:
public List<Patient> GetAllPatients()
{
try
{
using (OptoEntities db = new OptoEntities())
{
List<Patient> list = db.Patients
.Include("Addresses")
.Include("PhoneNumbers")
.Include("Examinations").ToList();
list.ForEach(p =>
{
p.ChangeTracker.ChangeTrackingEnabled = true;
if (!p.Addresses.IsNull() &&
p.Addresses.Count > 0)
p.Addresses.ForEach(a => a.ChangeTracker.ChangeTrackingEnabled = true);
if (!p.PhoneNumbers.IsNull() &&
p.PhoneNumbers.Count > 0)
p.PhoneNumbers.ForEach(a => a.ChangeTracker.ChangeTrackingEnabled = true);
if (!p.Examinations.IsNull() &&
p.Examinations.Count > 0)
p.Examinations.ForEach(e =>
{
e.ChangeTracker.ChangeTrackingEnabled = true;
});
});
return list;
}
}
catch (Exception ex)
{
return new List<Patient>();
}
}
Now I need when calling the Examination details form to go and get all the Images for the Examination relationship (LeftEyePictures, RightEyePictures). I guess that is called Lazy Loading and I dont understood how to make it happen while I'm closing the Entities connection immidiately and I would like to stay like this.
I use BindingSource components through the application.
What is the best method to get the desired results?
Thank you.
Self tracking entities don't support lazy loading. Moreover lazy loading works only when entities are attached to live context. You don't need to close / dispose context immediately. In case of WinForms application context usually lives for longer time (you can follow one context per form or one context per presenter approach).
WinForms application is scenario for normal attached entities where all these features like lazy loading or change tracking work out of the box. STEs are supposed to be used in distributed systems where you need to serialize entity and pass it to another application (via web service call).
I use the following RIA Services call to register and return a Project entity.
// On Server; inside RIA Domain Service
[Invoke]
public Project CreateNewProject(String a_strKioskNumber)
{
Decimal dProjectID = ObjectContext.RegisterProjectNumber(a_strKioskNumber)
.FirstOrDefault() ?? -1m;
// Tried this but it returned zero (0)
//int nChanged = ObjectContext.SaveChanges();
var project = (from qProject in ObjectContext.Projects.Include("ProjectItems")
where qProject.ID == dProjectID
select qProject)
.FirstOrDefault();
if (project == null)
return null;
return project;
}
As you can see, it calls a stored procedure that returns a project ID. It uses this ID to look up the Project entity itself and return it. When the Project entity is returned to the client it is detached. I attach it to the DomainContext and modify it.
// At Client
_activeProject = a_invokeOperation.Value; // <-- Detached
_context.Projects.Attach(_activeProject); // <-- Unmodified
if (_activeProject != null)
{
_activeProject.AuthenticationType = "strong"; // <-- Modified
_activeProject.OwnerID = customer.ID;
_projectItems.Do(pi => _activeProject.ProjectItems.Add(pi));
_activeProject.Status = "calculationrequired";
}
At this point it has an entity state of Modified. When I submit changes it gives me an exception regarding a UNIQUE KEY violation as if it is trying to insert it rather than update it.
// At Client
_context.SubmitChanges(OnProjectSaved, a_callback);
I'm using the same DomainContext instance for all operations. Why should this not work?
What's going wrong? This is rather frustrating.
Edits:
I tried this (as suggested by Jeff):
[Invoke]
public void SaveProject(Project a_project)
{
var project = (from qProject in ObjectContext.Projects
where qProject.ID == a_project.ID
select qProject)
.FirstOrDefault();
project.SubmitDate = a_project.SubmitDate;
project.PurchaseDate = a_project.PurchaseDate;
project.MachineDate = a_project.MachineDate;
project.Status = a_project.Status;
project.AuthenticationType = a_project.AuthenticationType;
project.OwnerID = a_project.OwnerID;
project.ProjectName = a_project.ProjectName;
project.OwnerEmail = a_project.OwnerEmail;
project.PricePerPart = a_project.PricePerPart;
project.SheetQuantity = a_project.SheetQuantity;
project.EdgeLength = a_project.EdgeLength;
project.Price = a_project.Price;
project.ShipToStoreID = a_project.ShipToStoreID;
project.MachiningTime = a_project.MachiningTime;
int nChangedItems = ObjectContext.SaveChanges();
}
It did absolutely nothing. It didn't save the project.
What happens if you add a SaveProject method on the server side and send the object back to the server for saving?
I've not done EF with RIA Services, but I've always sent my objects back to the server for saving. I'm assuming that SubmitChanges call you are making wires up everything properly for you for sending it back to the server, but perhaps it is doing something wrong and handling it manually will fix it.
I dont have the source at the moment but I have seen it recommended that you use a new context for each operation in Silverlight. I ran into a similar problem today and it was because I was using a Service level context that was remembering previous values that I didnt want, I changed to creating a new context for each service call and the behavior became what I expected.
public void SaveResponses(ICollection<Responses> items, Action<SubmitOperation> callback)
{
try
{
SurveysDomainContext _context = new SurveysDomainContext();
foreach (Responses item in items)
{
_context.Responses.Add(item);
}
_context.SubmitChanges(callback, null);
}
catch (Exception)
{
throw;
}
}
As for the notion that one can't use a singleton global DomainContext, this is actually debatable. In my project I use a singleton DomainContext with no issues. In other projects, we have created a new DomainContext for different modules in the app where the entities are reused. There are definitely pros and cons. See:
Strategies for Handling Your DomainContext (external blog)
It seems that the problem is that when you attach your project to the DomainContext it checks the _context.Projects entityset and isn't finding an entity with that primary key, and then assumes that the newly attached entity doesn't exist serverside yet and that submitting changes should insert it. A possible workaround might be to explicitly load the newly created Project into the DomainContext. It would ensure that it sets the correct state on the entity--that is, that the project already exists on the server and that that it's an update instance, rather than an insert instance.
So maybe something like:
//after your Project has already been created serverside with the invoke
_context.Load(_context.SomeQueryThatLoadsYourNewlyCreatedProject(), LoadBehavior.RefreshCurrent, (LoadOperation lo) => {
Project project = lo.Entities.FirstOrDefault(); //is attached and has correct state
if (project != null)
{
project.AuthenticationType = "strong";
project.OwnerID = customer.ID;
project.Do(pi => _activeProject.ProjectItems.Add(pi));
project.Status = "calculationrequired";
_context.SubmitChanges(); //hopefully will trigger an update, rather than an insert
}
});
I’m facing an issue with NHibernate performance and can you please suggest me some optimizations? Below mentioned is a small summary of my application architecture
I have a windows service which is listening to a messaging bus. On receiving a message the service creates an object out of which a property is the received xml snippet and saves the message to the DB (uses NH). There is a WPF UI with a readonly connection to the DB, and on refresh of the UI it displays the objects on the screen.
While the UI does a refresh, it retrieves the xml and deserializes it , from which the object’s properties are derived and binded to the screen.
For example assume an xml XXX is received by the service, it deserializes the xml , creates the book object and save it to the DB and a property/column is SCHEMA which contains the xml snippet.
The UI while refreshed searches all book objects by ID and creates the book objects out of the xml which is being saved (yes, the xml is the constructor param).
Now my issue is that the refresh takes more than 2 minutes to display say 50 book objects. I analyzed it using the NHibernate profiler, and found that the time spend within the DB is negligible, however time spent to create the entities is proportionally huge(10ms:1990 ms).I guess it’s due to the fairly huge size of xml snippet and it’s deserialization.
My question is, how can I improve the performance. I dispose sessions after every refresh and is not lazy loading (please note that the time spend in DB is negligible). On every refresh it’s possible that all objects are updated by some downstream systems or maybe one of them are updated.Can I implement some sort of caching mechanism in this case?
Thanks in advance for any suggestions.
Regards,
-Mike
The entire list of 50 books could be saved in a singleton class meant for caching. Like a cache manager. You could also use say an enterprise library cache but I would suggest an in memory cache. If a book gets added you could update the cache. The cache would have the entire xml so no deserialisation would happen. Also you could update the db in an ansynchronous thread and reduce the time.
Here is the pseudo code
On the service, whenever I receive a message
public void OnMessage(string message)
{
//deserializes the message
DeserializedObject schema = deserializationFactory.Deserialize(message);
var book = new Book(schema,message);
// saves the book using a new session
repository.Save(book);
}
The book object:
public class Book
{
public DeserializedObject Schema{get;set;}
private string xml;
public string Xml{get{return xml;}}
public Book(DeserializedObject schema,string xml):this(schema)
{
this.xml = xml;
}
public Book(DeserializedObject schema):this()
{
this.Schema = schema;
}
public virtual XmlDocument XmlSchema
{
get
{
var doc = new XmlDocument();
if (Schema!= null)
{
var serializer = new XmlSerializer(typeof(DeserializedObject));
var stream = new MemoryStream();
serializer.Serialize(stream, Schema);
stream.Position = 0;
doc.Load(stream);
}
return doc;
}
}
public virtual string SerializedSchema
{
get { return XmlSchema.OuterXml; }
set
{
if (value != null)
Schema = value.Deserialize< DeserializedObject >();
}
}
public string Author
{
get{return Schema.Author;}
}
}
Now the Mapping for Book(uses FNH)
public class BookMap:ClassMap<Book>
{
LazyLoad();
Table("Books");
IdGenerator.Instance.GenerateId(this, "book_id_seq", book => book.Id);
Map(book=> book.SerializedSchema, "SERIALIZED_SCHEMA")
.CustomSqlType("Clob")
.CustomType("StringClob");
}
On UI:
public void OnRefresh()
{
//In reality the call to DB runs on a background worker and the records are binded to the grid after a context switch.
//GetByCriteria creates a new session every time a refresh happens.
datagrid.DataContext = repository.GetByCriteria(ICriterion allBooksforToday);
}
The important thing to note here is Book type is shared between the service and the UI. However, only service can do a write to the DB, wherin the UI can update the trade object (basically the xml) and sends it over the messaging bus (again the xml). The service once receiving it updates the DB.
The xml size will be approximately 20 KB, so that would mean that if I'm loading say 50 books I'll be loading close to an MB of data.
Thanks,-Mike