Passing DateTimeOffset as WebAPI query string

Question

I\'ve got a WebAPI action that looks like so:

[Route(\"api/values/{id}\")]
public async Task Delete(string id, DateTimeOffset date         


        

Answer 1

Create a custom type converter as follows:

public class DateTimeOffsetConverter : TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        if (sourceType == typeof(string))
            return true;

        return base.CanConvertFrom(context, sourceType);
    }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(DateTimeOffset))
            return true;

        return base.CanConvertTo(context, destinationType);
    }

    public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
    {
        var s = value as string;

        if (s != null)
        {
            if (s.EndsWith("Z", StringComparison.OrdinalIgnoreCase))
            {
                s = s.Substring(0, s.Length - 1) + "+0000";
            }

            DateTimeOffset result;
            if (DateTimeOffset.TryParseExact(s, "yyyyMMdd'T'HHmmss.FFFFFFFzzz", CultureInfo.InvariantCulture, DateTimeStyles.None, out result))
            {
                return result;
            }
        }

        return base.ConvertFrom(context, culture, value);
    }

In your startup sequence, such as WebApiConfig.Register, add this type converter dynamically to the DateTimeOffset struct:

TypeDescriptor.AddAttributes(typeof(DateTimeOffset),
                             new TypeConverterAttribute(typeof(DateTimeOffsetConverter)));

You can now just pass DateTimeOffset values in the compact form of ISO8601, which omits hyphens and colons that interfere with the URL:

api/values/20171231T012345-0530
api/values/20171231T012345+0000
api/values/20171231T012345Z

Note that if you have fractional seconds, you may need to include a trailing slash in the url.

api/values/20171231T012345.1234567-0530/

You could also put it in the querystring if you like:

api/values?foo=20171231T012345-0530