Umbraco-CMS/src/Umbraco.Web/HttpRequestExtensions.cs

using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using Umbraco.Core;

namespace Umbraco.Web
{
    /// <summary>
    /// Extension methods for the HttpRequest and HttpRequestBase objects
    /// </summary>
    public static class HttpRequestExtensions
    {
        /// <summary>
        /// Extracts the value from the query string and cleans it to prevent xss attacks.
        /// </summary>
        /// <param name="request"></param>
        /// <param name="key"></param>
        /// <param name="valueIfNotFound"></param>
        /// <returns></returns>
        public static string CleanForXss(this HttpRequest request, string key, string valueIfNotFound = "")
        {
            var item = request.GetItemAsString(key, valueIfNotFound);
            return item.CleanForXss();
        }

        /// <summary>
        /// Safely get a request item as string, if the item does not exist, an empty string is returned.
        /// </summary>
        /// <param name="request"></param>
        /// <param name="key"></param>
        /// <param name="valueIfNotFound">The value to return if the key is not found in the collection</param>
        /// <returns></returns>
        public static string GetItemAsString(this HttpRequest request, string key, string valueIfNotFound = "")
        {
            return new HttpRequestWrapper(request).GetItemAsString(key, valueIfNotFound);
        }

        /// <summary>
        /// Safely get a request item as string, if the item does not exist, an empty string is returned.
        /// </summary>
        /// <param name="request"></param>
        /// <param name="key"></param>
        /// <param name="valueIfNotFound">The value to return if the key is not found in the collection</param>
        /// <returns></returns>
        public static string GetItemAsString(this HttpRequestBase request, string key, string valueIfNotFound = "")
        {
            var val = request[key];
            return !val.IsNullOrWhiteSpace() ? val : valueIfNotFound;
        }

        /// <summary>
        /// Safely get the item from the query string and convert it to type 'T', otherwise will return default(T).
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="request"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static T GetItemAs<T>(this HttpRequestBase request, string key)
        {
            var val = request[key];
            var whitespaceCheck = !val.IsNullOrWhiteSpace() ? val : string.Empty;
            if (whitespaceCheck.IsNullOrWhiteSpace())
                return (T) typeof (T).GetDefaultValue();
            var attempt = val.TryConvertTo<T>();
            if (attempt.Success)
                return attempt.Result;
            return (T)typeof(T).GetDefaultValue();
        }

        /// <summary>
        /// Safely get the item from the query string and convert it to type 'T', otherwise will return default(T).
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="request"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static T GetItemAs<T>(this HttpRequest request, string key)
        {
            return new HttpRequestWrapper(request).GetItemAs<T>(key);
        }

    }
}