Custom DateTime Model Binding in ASP.NET Web API

Custom DateTime Model Binding in ASP.NET Web API.md

This gist shows how to write a custom DateTime model binder in ASP.NET Web API.

Looking for ASP.NET Core? https://gist.github.com/vickramravichandran/f06d63bfb50f27e6549978b7538d214c

Related: http://www.vickram.me/custom-datetime-model-binding-in-asp-net-web-api

DateTimeParameterAttribute.cs

public class DateTimeParameterAttribute : ParameterBindingAttribute
{
    public string DateFormat { get; set; }

    public bool ReadFromQueryString { get; set; }


    public override HttpParameterBinding GetBinding(
        HttpParameterDescriptor parameter)
    {
        if (parameter.ParameterType == typeof(DateTime?))
        {
            var binding = new DateTimeParameterBinding(parameter);

            binding.DateFormat = DateFormat;
            binding.ReadFromQueryString = ReadFromQueryString;

            return binding;
        }

        return parameter.BindAsError("Expected type DateTime?");
    }
}

DateTimeParameterBinding.cs

public class DateTimeParameterBinding : HttpParameterBinding
{
    public string DateFormat { get; set; }

    public bool ReadFromQueryString { get; set; }


    public DateTimeParameterBinding(HttpParameterDescriptor descriptor)
        : base(descriptor) { }

    public override Task ExecuteBindingAsync(
        ModelMetadataProvider metadataProvider,
        HttpActionContext actionContext,
        CancellationToken cancellationToken)
    {
        string dateToParse = null;
        string paramName = this.Descriptor.ParameterName;

        if (ReadFromQueryString)
        {
            // reading from query string
            var nameVal = actionContext.Request.GetQueryNameValuePairs();
            dateToParse = nameVal.Where(q => q.Key.EqualsEx(paramName))
                                 .FirstOrDefault().Value;
        }
        else
        {
            // reading from route
            var routeData = actionContext.Request.GetRouteData();
            object dateObj = null;
            if (routeData.Values.TryGetValue(paramName, out dateObj))
            {
                dateToParse = Convert.ToString(dateObj);
            }
        }

        DateTime? dateTime = null;
        if (!string.IsNullOrEmpty(dateToParse))
        {
            if (string.IsNullOrEmpty(DateFormat))
            {
                dateTime = ParseDateTime(dateToParse);
            }
            else
            {
                dateTime = ParseDateTime(dateToParse, new string[] { DateFormat });
            }
        }

        SetValue(actionContext, dateTime);

        return Task.FromResult<object>(null);
    }        

    public DateTime? ParseDateTime(
        string dateToParse,
        string[] formats = null,
        IFormatProvider provider = null,
        DateTimeStyles styles = DateTimeStyles.AssumeLocal)
    {
        string[] CUSTOM_DATE_FORMATS = new string[] 
            { 
                "yyyyMMddTHHmmssZ",
                "yyyyMMddTHHmmZ",
                "yyyyMMddTHHmmss",
                "yyyyMMddTHHmm",
                "yyyyMMddHHmmss",
                "yyyyMMddHHmm",
                "yyyyMMdd",
                "yyyy-MM-ddTHH-mm-ss",
                "yyyy-MM-dd-HH-mm-ss",
                "yyyy-MM-dd-HH-mm",
                "yyyy-MM-dd",
                "MM-dd-yyyy"
            };

        if (formats == null)
        {
            formats = CUSTOM_DATE_FORMATS;
        }

        DateTime validDate;

        foreach (var format in formats)
        {
            if (format.EndsWith("Z"))
            {
                if (DateTime.TryParseExact(dateToParse, format,
                         provider,
                         DateTimeStyles.AssumeUniversal,
                         out validDate))
                {
                    return validDate;
                }
            }

            if (DateTime.TryParseExact(dateToParse, format,
                     provider, styles, out validDate))
            {
                return validDate;
            }
        }

        return null;
    }
}

MainController.cs

[RoutePrefix("api")]
public class MainController : ApiController  
{
    [Route("EchoDate/{date}")]
    [HttpGet]
    public DateTime? EchoDate(
        [DateTimeParameter]
        DateTime? date)
    {
        return date;
    }

    [Route("EchoCustomDate/{date}")]
    [HttpGet]
    public DateTime? EchoCustomDateFormat(
        [DateTimeParameter(DateFormat = "dd_MM_yyyy")]
        DateTime? date)
    {
        return date;
    }
}

WebApiConfig.cs

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // add the rule to the collection
        config.ParameterBindingRules
              .Add(typeof(DateTime?), 
                   des => new DateTimeParameterBinding(des));
    }
}