I found a really nice action filter that converts a comma-separated parameter to a generic type list: http://stevescodingblog.co.uk/fun-with-action-filters/
I would like to use it but it will not work for an ApiController, it completely ignore it. Can someone help convert this for Web API use?
[AttributeUsage(AttributeTargets.Method)]
public class SplitStringAttribute : ActionFilterAttribute
{
public string Parameter { get; set; }
public string Delimiter { get; set; }
public SplitStringAttribute()
{
Delimiter = ",";
}
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (filterContext.ActionParameters.ContainsKey(this.Parameter))
{
string value = null;
var request = filterContext.RequestContext.HttpContext.Request;
if (filterContext.RouteData.Values.ContainsKey(this.Parameter)
&& filterContext.RouteData.Values[this.Parameter] is string)
{
value = (string)filterContext.RouteData.Values[this.Parameter];
}
else if (request[this.Parameter] is string)
{
value = request[this.Parameter] as string;
}
var listArgType = GetParameterEnumerableType(filterContext);
if (listArgType != null && !string.IsNullOrWhiteSpace(value))
{
string[] values = value.Split(Delimiter.ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
var listType = typeof(List<>).MakeGenericType(listArgType);
dynamic list = Activator.CreateInstance(listType);
foreach (var item in values)
{
try
{
dynamic convertedValue = TypeDescriptor.GetConverter(listArgType).ConvertFromInvariantString(item);
list.Add(convertedValue);
}
catch (Exception ex)
{
throw new ApplicationException(string.Format("Could not convert split string value to '{0}'", listArgType.FullName), ex);
}
}
filterContext.ActionParameters[this.Parameter] = list;
}
}
base.OnActionExecuting(filterContext);
}
private Type GetParameterEnumerableType(ActionExecutingContext filterContext)
{
var param = filterContext.ActionParameters[this.Parameter];
var paramType = param.GetType();
var interfaceType = paramType.GetInterface(typeof(IEnumerable<>).FullName);
Type listArgType = null;
if (interfaceType != null)
{
var genericParams = interfaceType.GetGenericArguments();
if (genericParams.Length == 1)
{
listArgType = genericParams[0];
}
}
return listArgType;
}
}
What namespace are you using for ActionFilterAttribute
? For Web API you need to be using System.Web.Http.Filters
namespace and not System.Web.Mvc
.
EDIT
Here's a rough conversion, not fully tested.
SplitStringAttribute
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Net.Http;
using System.Web.Http.Controllers;
using System.Web.Http.Filters;
namespace StackOverflowSplitStringAttribute.Infrastructure.Attributes
{
[AttributeUsage(AttributeTargets.Method)]
public class SplitStringAttribute : ActionFilterAttribute
{
public string Parameter { get; set; }
public string Delimiter { get; set; }
public SplitStringAttribute()
{
Delimiter = ",";
}
public override void OnActionExecuting(HttpActionContext filterContext)
{
if (filterContext.ActionArguments.ContainsKey(Parameter))
{
var qs = filterContext.Request.RequestUri.ParseQueryString();
if (qs.HasKeys())
{
var value = qs[Parameter];
var listArgType = GetParameterEnumerableType(filterContext);
if (listArgType != null && !string.IsNullOrWhiteSpace(value))
{
string[] values = value.Split(Delimiter.ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
var listType = typeof(List<>).MakeGenericType(listArgType);
dynamic list = Activator.CreateInstance(listType);
foreach (var item in values)
{
try
{
dynamic convertedValue = TypeDescriptor.GetConverter(listArgType).ConvertFromInvariantString(item);
list.Add(convertedValue);
}
catch (Exception ex)
{
throw new ApplicationException(string.Format("Could not convert split string value to '{0}'", listArgType.FullName), ex);
}
}
filterContext.ActionArguments[Parameter] = list;
}
}
}
base.OnActionExecuting(filterContext);
}
private Type GetParameterEnumerableType(HttpActionContext filterContext)
{
var param = filterContext.ActionArguments[Parameter];
var paramType = param.GetType();
var interfaceType = paramType.GetInterface(typeof(IEnumerable<>).FullName);
Type listArgType = null;
if (interfaceType != null)
{
var genericParams = interfaceType.GetGenericArguments();
if (genericParams.Length == 1)
{
listArgType = genericParams[0];
}
}
return listArgType;
}
}
}
CsvController
using System.Web.Http;
using System.Collections.Generic;
using StackOverflowSplitStringAttribute.Infrastructure.Attributes;
namespace StackOverflowSplitStringAttribute.Controllers
{
public class CsvController : ApiController
{
// GET /api/values
[SplitString(Parameter = "data")]
public IEnumerable<string> Get(IEnumerable<string> data)
{
return data;
}
}
}
Example request
http://localhost:52595/api/csv?data=this,is,a,test,joe