Web API and OData V4 Queries, Functions and Attribute Routing Part 2

This post continues on from Getting started with Web API and OData V4.

Part 1 Getting started with Web API and OData V4 Part 1.
Part 2 Web API and OData V4 Queries, Functions and Attribute Routing Part 2
Part 3 Web API and OData V4 CRUD and Actions Part 3
Part 4 Web API OData V4 Using enum with Functions and Entities Part 4
Part 5 Web API OData V4 Using Unity IoC, SQLite with EF6 and OData Model Aliasing Part 5
Part 6 Web API OData V4 Using Contained Models Part 6
Part 7 Web API OData V4 Using a Singleton Part 7
Part 8 Web API OData V4 Using an OData T4 generated client Part 8
Part 9 Web API OData V4 Caching Part 9
Part 10 Web API OData V4 Batching Part 10
Part 11 Web API OData V4 Keys, Composite Keys and Functions Part 11

Breaking changes:
Web API 2.2 OData V4 no longer supports DateTime! DateTimeOffset is supported instead of this. $inlinecount has also been replaced with $count.

Code: https://github.com/damienbod/WebAPIODataV4

Queries
With Web API OData V4, it is possible to create complex queries which can use functions etc to page, fill data tables or filter your data as required. In this post, some of the basic or standard queries are demonstrated.

Example of $expand

http://localhost:51902/odata/Person?$expand=EmailAddress
http://localhost:51902/odata/Person(7)?$expand=EmailAddress
http://localhost:51902/odata/Person?$expand=PersonPhone
http://localhost:51902/odata/Person(7)?$expand=PersonPhone($expand=PhoneNumberType)

Example of $skip, $top

http://localhost:51902/odata/Person?$top=7&$skip=0
http://localhost:51902/odata/Person?$top=7&$skip=7

Example of $orderby

http://localhost:51902/odata/ContactType?$orderby=Name
http://localhost:51902/odata/Person?$orderby=LastName
http://localhost:51902/odata/Person?$orderby=LastName&$top=7&$skip=7

Example of $select

http://localhost:51902/odata/Person?$select=FirstName,MiddleName,LastName

Example of $filter

For this to work, the filter option has to be activated:

[EnableQuery(PageSize = 20, AllowedQueryOptions= AllowedQueryOptions.Filter  )]
public IHttpActionResult Get()
{  
  return Ok(_db.Person.AsQueryable());
}

http://localhost:51902/odata/Person?$filter=FirstName eq 'Ken'

http://localhost:51902/odata/Person?$filter=EmailAddress/any(q: q/EmailAddress1 eq 'kevin0@adventure-works.com')

http://localhost:51902/odata/Person?$expand=EmailAddress&$filter=EmailAddress/any(q: q/EmailAddress1 eq 'kevin0@adventure-works.com')

http://localhost:51902/odata/PersonPhone?$filter=startswith(PhoneNumber,'6')

or urlencoded

http://localhost:51902/odata/Person?$filter=FirstName%20eq%20%27Ken%27

http://localhost:51902/odata/Person?$filter=EmailAddress/any%28q:%20q/EmailAddress1%20eq%20%27kevin0@adventure-works.com%27%29

http://localhost:51902/odata/Person?$expand=EmailAddress&$filter=EmailAddress/any%28q:%20q/EmailAddress1%20eq%20%27kevin0@adventure-works.com%27%29

http://localhost:51902/odata/PersonPhone?$filter=startswith%28PhoneNumber%20,%20%276%27%29

The cast function is also supported with $filter

http://localhost:51902/odata/PersonPhone?$filter=startswith(PhoneNumber, cast('42', Edm.String))

http://localhost:51902/odata/PersonPhone?$filter=startswith%28PhoneNumber%20,%20cast%2842,%20%27Edm.String%27%29%29

Example of $count

This replaces $inlinecount from V3.

Count also needs to be enabled.

[EnableQuery(PageSize = 20, AllowedQueryOptions= AllowedQueryOptions.Count)]
public IHttpActionResult Get()
{  
  return Ok(_db.Person.AsQueryable());
}

http://localhost:51902/odata/Person?$count=true

This returns the total count of possible records. The odata.count for this example is shown below.

Example of $metadata

http://localhost:51902/odata/Person?$format=application/json;odata.metadata=full

ODATA V4 Attribute Routing

The PersonController uses OData attribute routing. This is similar to Web API attribute routing. You can add an ODataRoutePrefix attribute to the controller or ODataRoute attributes to the different actions. As with Web API attribute routing, various parameters can be added to the URL.

[ODataRoutePrefix("Person")]
public class PersonController : ODataController
{
  readonly DomainModel _db = new DomainModel();

  [ODataRoute]
  [EnableQuery(PageSize = 20, AllowedQueryOptions= AllowedQueryOptions.All  )]
  public IHttpActionResult Get()
  {  
    return Ok(_db.Person.AsQueryable());
  }

  [ODataRoute("({key})")]
  [EnableQuery(PageSize = 20, AllowedQueryOptions = AllowedQueryOptions.All)]
  public IHttpActionResult Get([FromODataUri] int key)
  {
    return Ok(_db.Person.Find(key));
  }

OData Attribute Routing can be activated in the Web API config method.

 config.MapODataServiceRoute("odata", "odata", model: GetModel()); 

OData V4 Functions

OData V4 Functions allows for specific or complex selects to be called with a simple function call.
The Web API config needs to be updated from the last post. It is possible to define a function for the whole service, for a collection of specific entities or for an entity itself. In this example, the function is defined for a collection of Person entities.

The Function is defined as follows:

FunctionConfiguration myFirstFunction = persons
  .EntityType
  .Collection
  .Function("MyFirstFunction");
myFirstFunction.ReturnsCollectionFromEntitySet<Person>("Person");

Now that the function is defined, it needs to be added to the Person Controller:

[EnableQuery(PageSize = 20, AllowedQueryOptions = AllowedQueryOptions.All)]
[ODataRoute("Default.MyFirstFunction")]
[HttpGet]
public IHttpActionResult MyFirstFunction()
{
 return Ok(_db.Person.Where(t => t.FirstName.StartsWith("K")));
}

This can then be tested in fiddler:
http://localhost:51902/odata/Person/Default.MyFirstFunction()

Note:
The functions or actions require a namespace in the Web API implementation of OData V4. If none is defined for the OData model builder in the configuration, a “Default” namespace is used. This is different to the old WCF Data services which supported V3.

Links:

http://blogs.msdn.com/b/webdev/archive/2014/03/13/getting-started-with-asp-net-web-api-2-2-for-odata-v4-0.aspx

http://msdn.microsoft.com/en-us/library/ff478141.aspx

http://www.odata.org/documentation/odata-version-2-0/uri-conventions/

SAMPLES: https://aspnet.codeplex.com/SourceControl/latest#Samples/WebApi/OData/v4/

https://aspnetwebstack.codeplex.com/SourceControl/latest

http://aspnetwebstack.codeplex.com/

http://www.asp.net/web-api/overview/releases/whats-new-in-aspnet-web-api-22

http://www.asp.net/web-api/overview/odata-support-in-aspnet-web-api/odata-routing-conventions

http://stackoverflow.com/questions/18233059/apicontroller-vs-odatacontroller-when-exposing-dtos

http://meyerweb.com/eric/tools/dencoder/

http://techbrij.com/jquery-datatables-asp-net-web-api-odata-service

http://www.asp.net/web-api/overview/odata-support-in-aspnet-web-api/supporting-odata-query-options

http://www.dotnetcurry.com/showarticle.aspx?ID=1008

http://msdn.microsoft.com/en-us/library/gg312156.aspx

[.NETWorld] Getting started with OData v4 in ASP.NET Web API

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