OwinRequest extensions for getting query string, form body, and header parameters as Dictionary<string,string>

OwinRequestExtensions.cs

    /// <summary>
    /// Owin Request extensions.
    /// <see href="https://gist.github.com/randyburden/42bc688780564ed01107"> Original Gist </see>
    /// </summary>
    public static class OwinRequestExtensions
    {
        /// <summary>
        /// Gets the combined request parameters from the form body, query string, and request headers.
        /// </summary>
        /// <param name="request">Owin request.</param>
        /// <returns>Dictionary of combined form body, query string, and request headers.</returns>
        public static Dictionary<string, string> GetRequestParameters(this IOwinRequest request)
        {
            List<Dictionary<string, string>> dictionaries = new List<Dictionary<string, string>>();
            dictionaries.Add(request.GetBodyParameters());
            dictionaries.Add(request.GetQueryParameters());
            dictionaries.Add(request.GetHeaderParameters());
            
            /// <see href="http://stackoverflow.com/a/294145/3582770"> Merge dictionaries, duplicate keys are forbidden </see>
            var allParameters = dictionaries.SelectMany(dict => dict)
                         .ToDictionary(pair => pair.Key, pair => pair.Value);

            return allParameters;
        }

        /// <summary>
        /// Gets the query string request parameters.
        /// </summary>
        /// <param name="request">Owin Request.</param>
        /// <returns>Dictionary of query string parameters.</returns>
        public static Dictionary<string, string> GetQueryParameters(this IOwinRequest request)
        {
            var dictionary = new Dictionary<string, string>(StringComparer.CurrentCultureIgnoreCase);

            foreach (var pair in request.Query)
            {
                var value = GetJoinedValue(pair.Value);

                dictionary.Add(pair.Key, value);
            }

            return dictionary;
        }

        /// <summary>
        /// Gets the form body request parameters.
        /// </summary>
        /// <param name="request">Owin Request.</param>
        /// <returns>Dictionary of form body parameters.</returns>
        public static Dictionary<string, string> GetBodyParameters(this IOwinRequest request)
        {
            var dictionary = new Dictionary<string, string>(StringComparer.CurrentCultureIgnoreCase);

            var formCollectionTask = request.ReadFormAsync();

            formCollectionTask.Wait();

            foreach (var pair in formCollectionTask.Result)
            {
                var value = GetJoinedValue(pair.Value);

                dictionary.Add(pair.Key, value);
            }

            return dictionary;
        }

        /// <summary>
        /// Gets the header request parameters.
        /// </summary>
        /// <param name="request">Owin Request.</param>
        /// <returns>Dictionary of header parameters.</returns>
        public static Dictionary<string, string> GetHeaderParameters(this IOwinRequest request)
        {
            var dictionary = new Dictionary<string, string>(StringComparer.CurrentCultureIgnoreCase);

            foreach (var pair in request.Headers)
            {
                var value = GetJoinedValue(pair.Value);

                dictionary.Add(pair.Key, value);
            }

            return dictionary;
        }

        private static string GetJoinedValue(string[] value)
        {
            if (value != null)
                return string.Join(",", value);

            return null;
        }
    }