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OData Wonderland

Nothing is easy with OData at first.

This ODashit is killing me softly.

At this point I managed to survive in OData wonderland, successfully create working OData function with 3 parameter that return collection of Route entity

http://localhost:20999/CS/odata/Route/f.SearchRoute(DepartureAirportID='KNO',DestinationAirportID='UPG',AirlineID=123)

I Wonder how the hell I expand the navigation property to client ?

Actually it's quite simple, as usual we need to have attribute <HttpGet> and <EnableQuery> then the expand will work

But, remember we are in OData wonderland so odd things happen

       <HttpGet>        <EnableQuery(MaxExpansionDepth:=3)>        Function SearchRoute(departureAirportID As String, destinationAirportID As String, <FromODataUri> airlineID As Integer) As IEnumerable(Of Route)            Dim a = _uowa.RepositoryAsync(Of Route).Query(Function(q) q.RouteItem.DepartureAirport.IATA = departureAirportID And q.RouteItem.DestinationAirport.IATA = destinationAirportID And (q.RouteItem.AirlineID = airlineID Or airlineID = 0)) _                        .Include(Function(o) o.RouteItem) _                        .Include(Function(r) r.RouteItem.DepartureAirport) _                        .Include(Function(s) s.RouteItem.DestinationAirport) _                        .Include(Function(p) p.SubRoute) _                        .Select() '.AsQueryable()            Return a        End Function

When I add the bold include line, the expand functionality failed with 

"Cannot compare elements of type 'System.Collections.Generic.ICollection`1[[CS.Data.Models.Route, CS.Data, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]'. Only primitive types, enumeration types and entity types are supported."

This is the query that cause the error

http://localhost:20999/CS/odata/Route/f.SearchRoute(DepartureAirportID='KNO',DestinationAirportID='UPG',AirlineID=123)?$expand=RouteItem,SubRoute

And this is the query that solve the error

http://localhost:20999/CS/odata/Route/f.SearchRoute(DepartureAirportID='KNO',DestinationAirportID='UPG',AirlineID=123)?$expand=RouteItem,SubRoute&$top=100

What ? by just adding "&$top=100" what the heck that top statement relate to the error ??!!

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OData Wonderbug

OData problem again. The more I use OData the more I "OShit problem again !". OFrustating !!!

So now I need a function bound in entity named Route. So I create this legit code

In ODataConfig

       Dim fSearchRoute = builder.EntityType(Of Route).Collection.Function("SearchRoute")        fSearchRoute.ReturnsCollectionFromEntitySet(Of Route)("Route")        fSearchRoute.Parameter(Of String)("DepartureAirportID")        fSearchRoute.Parameter(Of String)("DestinationAirportID")        fSearchRoute.Parameter(Of Integer)("AirlineID")

In ApiController

       <HttpGet>        <EnableQuery>        <ODataRoute("SearchRoute(DepartureAirportID={departureAirportID},DestinationAirportID={destinationAirportID},AirlineID={airlineID})")>        Function SearchRoute( <FromODataUri> departureAirportID As String, <FromODataUri> destinationAirportID As String, <FromODataUri> airlineID As Integer) As IQueryable(Of Route)            Dim a = _uowa.RepositoryAsync(Of Route).Query(Function(q) q.RouteItem.DepartureAirport.IATA = departureAirportID And q.RouteItem.DestinationAirport.IATA = destinationAirportID).Include(Function(r) r.RouteItem.DepartureAirport).Include(Function(s) s.RouteItem.DestinationAirport).Select().AsQueryable            Return a        End Function

Call In Browser

http://localhost:20999/CS/odata/Route/Default.SearchRoute(DepartureAirportID='KNO',DestinationAirportID='UPG',AirlineID=123)($expand=RouteItem)

So, whats the problem ? See bold parameter above ? It return nothing !

How do I get it work ? When that <FromODataUri> attribute is removed from declaration, It works !!

Function SearchRoute( departureAirportID As String, destinationAirportID As String, <FromODataUri> airlineID As Integer) As IQueryable(Of Route) 

Odd enough, the airlineID has no problem whether using <FromODataUri> attribute or not

What is the explaination of this behaviour, OData !!!!???

[xuperxonix]

OData Wonderror

Gosh, waste about 4 hours to get this simple problem done !

The problem was to get this web API /odata/Staff('0001') to return data instead of 404.

After stumbled so many resource that lead to routing convention problem,  nothing worked !

I then suspect the problem not caused by something wrong in routing convention but because of I use ViewModel instead exposing my Entity.

A look into my ODataConventionModelBuilder I found an entity that directly exposed without ViewModel. Query against  this entity in OData with key return a valid data. This prove my suspicion.

With this new clue I then googled : "odataconventionmodelbuilder entityset aliasing"

and voila it directly brought me to this SO : How do I map an OData query against a DTO to an EF entity? with a promising answer !

The Solution

Change code from builder.EntitySet(Of StaffView)("Staff") To builder.ModelAliasingEnabled = True builder.EntitySet(Of StaffView)("Staff").EntityType.Name = "Staff"

Imagine 4 hours just to find this solution.

Well that the cost of learning things by yourself without a mentor.

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I'll keep this as a reference

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I'm Back

Ah.. long time no post. Just remember this blog recently. 

So at this point I already conquered SPA. A project is almost done.

Going to host a Web API and considering the security aspect of it.

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Single Page Apps with AngularJS Routing and Templating

Been playing with SPA the whole day. So after reviewing a ton I choose to go Angular as my presentation framework because it do support a bunch of things like : data binding, routing, animate, and UI. Also, more and more dev community joining Angular's trend.

Starting from ASP.NET side I've come across with these video :

Building a Single Page Application with ASP.NET and AngularJS

Single Page Applications with Microsoft ASP.NET

The later one spit more knowledge. It introduce me with some SPA template. It makes me sure that I can still use MVC or Web API at the server side. It also provide nice resource about SPA at : http://www.johnpapa.net/spa/

After all, I'm not really satisfied with this video because it use Durandal and Knockout which I don't prefer. So I keep looking for how to do SPA with Angular.

other question arise :

How am I supposed to arrange my project structure ?

Visual Studio do provide SPA template but I still don't clear what to do next. So I'm looking for downloadable SPA template. Fortunately, when I stumble across NuGet I found one interesting package : HotTowel.Angular.Breeze.

I wonder if JohnPapa really provide HotTowel with angular as in previous video he only mention HotTowel with Durandal. So I just test it and it turns out to be true. From here I got more concrete example of how my project structure should be. 

So the answer is, it is exactly the same with SPA template provided by Visual Studio just adding another folder name "App" to contain all the client side SPA files (View, ViewModel, Controller, Directive, Route, etc). You may group it by view or controller.

Update : This is a more complete answer.

The next question Is :

How do I extend the example with my own pages.

At this point I don't really understand how to Inject page in main page. I need to understand about SPA routing. So I come across this article that explain it in simple manner.

Until here, I'll proceed to conquer SPA :)

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Ok, this is worth to note since it is going to be hard to troubleshoot if one encounter this problem.

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MapInheritedProperties

Since the problem with SQL server I have been wondering what is the best strategy to sync database between client and server.

One option is to add TimeStamp attribute and using logical delete so I can sync deleted data too. But I am reluctant to use logical delete because it will affect my data query in every entity to exclude logical deleted data.

If I don't want to use logical delete, My sync service must be able to recognized deleted data. That is also problematic. Then I'm back to option one, logical delete.

Fortunately, I'm using a generic repository. So I can easily alter physical delete to logical delete in repository to affect all entity. Also in repository, I alter the query to exclude logical deleted data.

Also fortunately I'm using EntityBase class so I can easily add property to all my entity.

Found out that char is not map to database by EF. To workaround this I can use Data Annotation or EntityTypeConfiguration and pass it to modelbuilder.

Data Annotations

[StringLength( 36 )] [Column( TypeName = "char" )] public string UserIdentifier{ get; set; }

Fluent API

class UserProfileConfiguration:EntityTypeConfiguration<UserProfile> { public UserProfileConfiguration() { this.Property(p => p.UserIdentifier) .HasMaxLength(36) .IsFixedLength() .IsUnicode(false); } }

protected override void OnModelCreating(DbModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); modelBuilder.Configurations.Add(new UserProfileConfiguration()); }

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Another trap

Today another strange behavior of the coding world. 

Well I have setup Database Initializer with EF. I'm using DropCreateDatabaseIfModelChanges to Seed my database. What strange is that though I update my model class with new property the Seed method never triggered. 

Google only give me article related to migration but I don't think that's the cause because when I run add-migrations there was no migration code created.

So, look back at my model class I saw a different.

public class Stock : EntityBase { [ScaffoldColumn (false)] public int ID { get; set; } public string Name { get; set; }

[UIHint("GridForeignKey")] public int CategoryID { get; set; }

[UIHint("GridForeignKey")] public int SubCategoryID { get; set; }

[UIHint("Integer")] public int LastQty { get; set; }

[UIHint("DescriptionText")] public string Description { get; set; }

public bool IsActive { get; set; }

[ScaffoldColumn(false)] public DateTime TimeStamp = DateTime.Now;

//Navigation Property [ForeignKey("CategoryID")] public Category Category { get; set; } [ForeignKey("SubCategoryID")] public SubCategory SubCategory { get; set; }

public string TestProperty;

}

The problem is that property TestProperty is not declared with {get; set}. EF seem to ignore property without {get; set;}.

After I put {get; set;}, EF kick in the seed method and and kendo form scafolding also work too.

Still don't know why this behavior occurs.

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God damned SQL Server

This almost drive me nuts !

God damned SQL Express cannot attach my mdf file!

What I want is only to rename default database name created by Visual Studio from aspnet-WebApplication2-20140601123335.mdf to IdentityContext.mdf. I already change the logical filename via SSMS and successfully attached it.

But when it being attach when my web application runs, it just failed : 

Database aspnet-WebApplication2-20140601123335.mdf' already exists. Choose a different database name. Cannot attach the file IdentityCotext.mdf' as database 'IdentityContext'.

I'm sure I have cleared all occurrence of aspnet-WebApplication2-20140601123335 but that god damned SQL keep recognizing it. From where ?

Frustrated, I restart my computer as my last hope that it will be resolved.

Irritating !! unacceptable !! the problem persists. How the hell ?!

~~~

OK, now, after I banged my head to wall and got some enlightenment. The problem is related to User Instance=true in my connection string. This caused my database attached to invisible instance. So in that invisible instance, I don't know how, aspnet-WebApplication2-20140601123335.mdf is STUCK there. 

How the hell I get it remove if I cannot connect to that invisible instance ?

here is the answer.

Then after successfully connected to that instance I drop that god damned database and it works now !

There it goes, wasted my precious 3 hours for this silly rename problem, grrrr

( ` ')=333#

[xuperxonix]

OK, this is nice reference :)

So I need to alter my database at client and server to record timestamp. Ugh this gonna take some times.

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Tumblr

I don't really satisfied with tumblr since it cannot format part of my writings to code.

Need to google a way out.

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JSON flavoured web api

Gotta log how I set my web api to return JSON instead of xml 

in WebApiConfig.register put a formatter config as below :

config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new System.Net.Http.Headers.MediaTypeHeaderValue("text/html"));