Multiple OData entity GET methods - entity-framework

Question

I've used OData with entity framework to create a simple web service. Everything works fine. I just need to know how to add additional GET commands such as "GetByCategory" or "GetByDate". These will use different SQL views to return complex filtered results.
** WebApiConfig.cs *
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Web.Http;
using Microsoft.Owin.Security.OAuth;
using Newtonsoft.Json.Serialization;
using System.Web.Http.OData.Builder;
using System.Web.Http.OData.Extensions;
using NRHSData.Models;
namespace NRHSData
{
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
// Web API configuration and services
// Configure Web API to use only bearer token authentication.
config.SuppressDefaultHostAuthentication();
config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));
config.AddODataQueryFilter();
// Web API routes
config.MapHttpAttributeRoutes();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
ODataConventionModelBuilder builder = new ODataConventionModelBuilder();
builder.Namespace = "NRHSData";
builder.EntitySet<employee>("employees");
builder.EntitySet<vw_employee_listing>("vw_employee_listings");
builder.EntitySet<physician>("physicians");
builder.EntitySet<vw_physician_listing>("vw_physician_listings");
builder.EntitySet<employeedepartment>("employeedepartments");
builder.EntitySet<vw_employeedepartment_listing>("vw_employeedepartment_listings");
builder.EntitySet<news>("news");
builder.EntitySet<vw_news_listing>("vw_news_listings");
builder.EntitySet<vw_news_current>("vw_news_current");
config.Routes.MapODataServiceRoute("odata", "odata", builder.GetEdmModel());
}
}
}
** newsController.cs *
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web.Http;
using System.Web.Http.ModelBinding;
using System.Web.Http.OData;
using System.Web.Http.OData.Routing;
using NRHSData.Models;
namespace NRHSData.Controllers
{
[Authorize]
public class newsController : ODataController
{
private ENTDATAEntities db = new ENTDATAEntities();
// GET: odata/news
[EnableQuery]
public IQueryable<vw_news_listing> Getnews()
{
return db.vw_news_listings;
}
// GET: odata/news(5)
[EnableQuery]
public SingleResult<vw_news_listing> Getnews([FromODataUri] int key)
{
return SingleResult.Create(db.vw_news_listings.Where(news => news.newsid == key));
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
private bool newsExists(int key)
{
return db.news.Count(e => e.newsid == key) > 0;
}
// PUT: odata/news(5)
public async Task<IHttpActionResult> Put([FromODataUri] int key, Delta<news> patch)
{
Validate(patch.GetEntity());
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
news news = await db.news.FindAsync(key);
if (news == null)
{
return NotFound();
}
patch.Put(news);
try
{
await db.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!newsExists(key))
{
return NotFound();
}
else
{
throw;
}
}
return Updated(news);
}
// POST: odata/news
public async Task<IHttpActionResult> Post(news news)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
db.news.Add(news);
await db.SaveChangesAsync();
return Created(news);
}
// PATCH: odata/news(5)
[AcceptVerbs("PATCH", "MERGE")]
public async Task<IHttpActionResult> Patch([FromODataUri] int key, Delta<news> patch)
{
Validate(patch.GetEntity());
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
news news = await db.news.FindAsync(key);
if (news == null)
{
return NotFound();
}
patch.Patch(news);
try
{
await db.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!newsExists(key))
{
return NotFound();
}
else
{
throw;
}
}
return Updated(news);
}
// DELETE: odata/news(5)
public async Task<IHttpActionResult> Delete([FromODataUri] int key)
{
news news = await db.news.FindAsync(key);
if (news == null)
{
return NotFound();
}
db.news.Remove(news);
await db.SaveChangesAsync();
return StatusCode(HttpStatusCode.NoContent);
}
}
}

Answer 1

I assume you are trying to address such requests:
~/News/GetByDate()
There are 2 options:
Using OData Actions. Add an action named GetByDate and issue the Request through 'POST ~/News/GetByDate()' But it does NOT align with the protocol. An Action should have some side effect. So the second option comes.
Using OData Functions, which must not have side effect. To implement this, you need to upgrade to the new bits: System.Web.OData.dll. here is a sample about functions: https://aspnet.codeplex.com/SourceControl/latest#Samples/WebApi/OData/v4/ODataFunctionSample/ .