sharee.bike-App/TINKLib/Repository/CopriCallsHttps.cs


using Serilog;
using System;
using System.IO;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using TINK.Model.Repository.Exception;
using TINK.Model.Repository.Request;
using TINK.Model.Repository.Response;
using TINK.Model.Logging;
using TINK.Repository.Response;

namespace TINK.Model.Repository
{
    /// <summary> Object which manages calls to copri. </summary>
    public class CopriCallsHttps : ICopriServer
    {
        /// <summary> Builds requests.</summary>
        private IRequestBuilder requestBuilder;

        /// <summary> Initializes a instance of the copri calls https object. </summary>
        /// <param name="p_oCopriHost">Host to connect to. </param>
        /// <param name="p_strMerchantId">Id of the merchant.</param>
        /// <param name="userAgent">Holds the name and version of the TINKApp.</param>
        /// <param name="sessionCookie">Session cookie if user is logged in, null otherwise.</param>
        public CopriCallsHttps(
            Uri p_oCopriHost,
            string p_strMerchantId,
            string userAgent,
            string sessionCookie = null)
        {
            m_oCopriHost = p_oCopriHost
                ?? throw new System.Exception($"Can not construct {GetType().ToString()}- object. Uri of copri host must not be null.");

            UserAgent = !string.IsNullOrEmpty(userAgent)
                ? userAgent
                : throw new System.Exception($"Can not construct {GetType().ToString()}- object. User agent must not be null or empty.");

            requestBuilder = string.IsNullOrEmpty(sessionCookie)
                ? new RequestBuilder(p_strMerchantId) as IRequestBuilder
                : new RequestBuilderLoggedIn(p_strMerchantId, sessionCookie);
        }

        /// <summary> Holds the URL for rest calls.</summary>
        private Uri m_oCopriHost;

        /// <summary> Spacifies name and version of app. </summary>
        private string UserAgent { get; }

        /// <summary> Returns true because value requested form copri server are returned. </summary>
        public bool IsConnected => true;

        /// <summary> Gets the merchant id.</summary>
        public string MerchantId => requestBuilder.MerchantId;

        /// <summary> Gets the session cookie if user is logged in, an empty string otherwise. </summary>
        public string SessionCookie => requestBuilder.SessionCookie;

        /// <summary> Logs user in. </summary>
        /// <param name="mailAddress">Mailaddress of user to log in.</param>
        /// <param name="password">Password to log in.</param>
        /// <param name="deviceId">Id specifying user and hardware.</param>
        /// <remarks>Response which holds auth cookie <see cref="ResponseBase.authcookie"/></remarks>
        public async Task<AuthorizationResponse> DoAuthorizationAsync(
            string mailAddress,
            string password,
            string deviceId)
        {
            return await DoAuthorizationAsync(
                m_oCopriHost.AbsoluteUri,
                requestBuilder.DoAuthorization(mailAddress, password, deviceId),
                () => requestBuilder.DoAuthorization(mailAddress, "********", deviceId),
                UserAgent);
        }

        /// <summary> Logs user out. </summary>
        /// <remarks>Response which holds auth cookie <see cref="ResponseBase.authcookie"/></remarks>
        public async Task<AuthorizationoutResponse> DoAuthoutAsync()
        {
            return await DoAuthoutAsync(m_oCopriHost.AbsoluteUri, requestBuilder.DoAuthout(), UserAgent);
        }

        /// <summary>Gets bikes available.</summary>
        /// <returns>Response holding list of bikes.</returns>
        public async Task<BikesAvailableResponse> GetBikesAvailableAsync()
        {
            return await GetBikesAvailableAsync(m_oCopriHost.AbsoluteUri, requestBuilder.GetBikesAvailable(), UserAgent);
        }

        /// <summary> Gets a list of bikes reserved/ booked by acctive user. </summary>
        /// <returns>Response holding list of bikes.</returns>
        public async Task<BikesReservedOccupiedResponse> GetBikesOccupiedAsync()
        {
            try
            {
                return await GetBikesOccupiedAsync(m_oCopriHost.AbsoluteUri, requestBuilder.GetBikesOccupied(), UserAgent);
            }
            catch (NotSupportedException)
            {
                // No user logged in.
                await Task.CompletedTask;
                return ResponseHelper.GetBikesOccupiedNone();
            }
        }

        /// <summary> Get list of stations. </summary>
        /// <returns>List of files.</returns>
        public async Task<StationsAllResponse> GetStationsAsync()
        {
            return await GetStationsAsync(m_oCopriHost.AbsoluteUri, requestBuilder.GetStations(), UserAgent);
        }

        /// <summary> Get authentication keys. </summary>
        /// <param name="bikeId">Id of the bike to get keys for.</param>
        /// <returns>Response holding authentication keys.</returns>
        public async Task<ReservationBookingResponse> GetAuthKeys(int bikeId)
            => await GetAuthKeysAsync(m_oCopriHost.AbsoluteUri, requestBuilder.CalculateAuthKeys(bikeId), UserAgent);


        /// <summary> Gets booking request response.</summary>
        /// <param name="bikeId">Id of the bike to book.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Booking response.</returns>
        public async Task<ReservationBookingResponse> DoReserveAsync(
            int bikeId,
            Uri operatorUri)
        {
            return await DoReserveAsync(
                operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri, 
                requestBuilder.DoReserve(bikeId), 
                UserAgent);
        }

        /// <summary> Gets canel booking request response.</summary>
        /// <param name="bikeId">Id of the bike to book.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Response on cancel booking request.</returns>
        public async Task<ReservationCancelReturnResponse> DoCancelReservationAsync(
            int bikeId,
            Uri operatorUri)
        {
            return await DoCancelReservationAsync(
                operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri, 
                requestBuilder.DoCancelReservation(bikeId), 
                UserAgent);
        }

        /// <summary> Get authentication keys. </summary>
        /// <param name="bikeId">Id of the bike to get keys for.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Response holding authentication keys.</returns>
        public async Task<ReservationBookingResponse> CalculateAuthKeysAsync(
            int bikeId,
            Uri operatorUri)
            => await GetAuthKeysAsync(
                operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri, 
                requestBuilder.CalculateAuthKeys(bikeId), 
                UserAgent);

        /// <summary> Updates lock state for a booked bike. </summary>
        /// <param name="bikeId">Id of the bike to update locking state for.</param>
        /// <param name="location">Geolocation of lock.</param>
        /// <param name="state">New locking state.</param>
        /// <param name="batteryPercentage">Holds the filling level percentage of the battery.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Response on updating locking state.</returns>
        public async Task<ReservationBookingResponse> UpdateLockingStateAsync(
            int bikeId,
            LocationDto location,
            lock_state state,
            double batteryLevel,
            Uri operatorUri)
        {
            return await DoUpdateLockingStateAsync(
                operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri, 
                requestBuilder.UpateLockingState(bikeId, location, state, batteryLevel), 
                UserAgent);
        }

        /// <summary> Gets booking request request. </summary>
        /// <param name="bikeId">Id of the bike to book.</param>
        /// <param name="guid">Used to publish GUID from app to copri. Used for initial setup of bike in copri.</param>
        /// <param name="batteryPercentage">Holds the filling level percentage of the battery.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Requst on booking request.</returns>
        public async Task<ReservationBookingResponse> DoBookAsync(
            int bikeId, 
            Guid guid, 
            double batteryPercentage,
            Uri operatorUri)
        {
            return await DoBookAsync(
                operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri, 
                requestBuilder.DoBook(bikeId, guid, batteryPercentage), 
                UserAgent);
        }

        /// <summary> Returns a bike. </summary>
        /// <param name="bikeId">Id of the bike to return.</param>
        /// <param name="location">Geolocation of lock.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Response on returning request.</returns>
        public async Task<ReservationCancelReturnResponse> DoReturn(
            int bikeId, 
            LocationDto location,
            Uri operatorUri)
        {
            return await DoReturn(
                operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri, 
                requestBuilder.DoReturn(bikeId, location), 
                UserAgent);
        }

        /// <summary> Submits feedback to copri server. </summary>
        /// <param name="isBikeBroken">True if bike is broken.</param>
        /// <param name="message">General purpose message or error description.</param>
        /// <param name="operatorUri">Holds the uri of the operator or null, in case of single operator setup.</param>
        /// <returns>Response on submitting feedback request.</returns>
        public async Task<SubmitFeedbackResponse> DoSubmitFeedback(
            string message,
            bool isBikeBroken,
            Uri operatorUri) => 
                await DoSubmitFeedback(
                    operatorUri?.AbsoluteUri ?? m_oCopriHost.AbsoluteUri,
                    requestBuilder.DoSubmitFeedback(message, isBikeBroken),
                    UserAgent);

        /// <summary> Logs user in. </summary>
        /// <param name="copriHost">Host to connect to. </param>
        /// <param name="command">Command to log user in.</param>
        /// <remarks>Response which holds auth cookie <see cref="ResponseBase.authcookie"/></remarks>
        public static async Task<AuthorizationResponse> DoAuthorizationAsync(
            string copriHost,
            string command,
            Func<string> displayCommand,
            string userAgent = null)
        {
#if !WINDOWS_UWP
            /// Extract session cookie from response.
            string l_oResponseText = string.Empty;
            try
            {
                l_oResponseText = await PostAsync(
                    copriHost,
                    command,
                    userAgent,
                    displayCommand); // Do not include password into exception output when an error occurres.
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Login fehlgeschlagen aufgrund eines Netzwerkfehlers.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Login fehlgeschlagen aufgrund eines Netzwerkfehlers.", l_oException);
                }

                throw;
            }

            return JsonConvert.DeserializeObject<ResponseContainer<AuthorizationResponse>>(l_oResponseText)?.tinkjson;
#else
            return null;
#endif
        }

        /// <summary> Logs user out. </summary>
        /// <param name="copriHost">Host to connect to. </param>
        /// <param name="command">Command to log user out.</param>
        public static async Task<AuthorizationoutResponse> DoAuthoutAsync(
            string p_strCopriHost,
            string p_oCommand,
            string userAgent = null)
        {
#if !WINDOWS_UWP
            string l_oLogoutResponse;
            try
            {
                l_oLogoutResponse = await PostAsync(p_strCopriHost, p_oCommand, userAgent);
            }

            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Login fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Login fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                throw;
            }

            /// Extract session cookie from response.
            return JsonConvert.DeserializeObject<ResponseContainer<AuthorizationoutResponse>>(l_oLogoutResponse)?.tinkjson;
#else
            return null;
#endif
        }

        /// <summary>
        /// Get list of stations from file.
        /// </summary>
        /// <param name="p_strCopriHost">URL of the copri host to connect to.</param>
        /// <param name="p_oCommand">Command to get stations.</param>
        /// <returns>List of files.</returns>
        public static async Task<StationsAllResponse> GetStationsAsync(
        string p_strCopriHost,
        string p_oCommand,
        string userAgent = null)
        {
#if !WINDOWS_UWP
            string l_oStationsAllResponse;
            try
            {
                l_oStationsAllResponse = await PostAsync(p_strCopriHost, p_oCommand, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Abfage der verfügbaren Räder fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Abfage der verfügbaren Räder fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<StationsAllResponse>>(l_oStationsAllResponse)?.tinkjson;
#else
            return null;
#endif
        }

        /// <summary> Gets a list of bikes from Copri. </summary>
        /// <param name="p_strCopriHost">URL of the copri host to connect to.</param>
        /// <param name="p_oCommand">Command to get bikes.</param>
        /// <returns>Response holding list of bikes.</returns>
        public static async Task<BikesAvailableResponse> GetBikesAvailableAsync(
            string p_strCopriHost,
            string l_oCommand,
            string userAgent = null)
        {
#if !WINDOWS_UWP           
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(p_strCopriHost, l_oCommand, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Abfage der verfügbaren Räder fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Abfage der verfügbaren Räder fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return CopriCallsStatic.DeserializeBikesAvailableResponse(l_oBikesAvaialbeResponse);
#else
            return null;
#endif
        }

        /// <summary> Gets a list of bikes reserved/ booked by acctive user from Copri.</summary>
        /// <param name="p_strCopriHost">URL of the copri host to connect to.</param>
        /// <param name="p_oCommand">Command to post.</param>
        /// <returns>Response holding list of bikes.</returns>
        public static async Task<BikesReservedOccupiedResponse> GetBikesOccupiedAsync(
            string p_strCopriHost,
            string p_oCommand,
            string userAgent = null)
        {
#if !WINDOWS_UWP            
            string l_oBikesOccupiedResponse;
            try
            {
                l_oBikesOccupiedResponse = await PostAsync(p_strCopriHost, p_oCommand, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Abfage der reservierten/ gebuchten Räder fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Abfage der reservierten/ gebuchten Räder fehlgeschlagen wegen Netzwerkfehler.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return CopriCallsStatic.DeserializeBikesOccupiedResponse(l_oBikesOccupiedResponse);
#else
            return null;
#endif
        }

        /// <summary> Get auth keys from COPRI. </summary>
        /// <param name="copriHost">Host to connect to. </param>
        /// <param name="command">Command to log user in.</param>
        /// <returns>Response on booking request.</returns>
        public static async Task<ReservationBookingResponse> GetAuthKeysAsync(
            string p_strCopriHost,
            string p_oCommand,
            string userAgent = null)
        {
#if !WINDOWS_UWP
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(p_strCopriHost, p_oCommand, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Schlosssuche wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Schlosssuche wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<ReservationBookingResponse>>(l_oBikesAvaialbeResponse)?.tinkjson;
#else
            return null;
#endif
        }
        /// <summary> Gets booking request response. </summary>
        /// <param name="copriHost">Host to connect to. </param>
        /// <param name="command">Command to log user in.</param>
        /// <returns>Response on booking request.</returns>
        public static async Task<ReservationBookingResponse> DoReserveAsync(
            string p_strCopriHost,
            string p_oCommand,
            string userAgent = null)
        {
#if !WINDOWS_UWP
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(p_strCopriHost, p_oCommand, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Reservierung des Fahrrads wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Reservierung des Fahrrads wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<ReservationBookingResponse>>(l_oBikesAvaialbeResponse)?.tinkjson;
#else
            return null;
#endif
        }

        /// <summary> Gets canel booking request response.</summary>
        /// <param name="copriHost">Host to connect to. </param>
        /// <param name="command">Command to log user in.</param>
        /// <returns>Response on cancel booking request.</returns>
        public static async Task<ReservationCancelReturnResponse> DoCancelReservationAsync(
            string copriHost,
            string command,
            string userAgent = null)
        {
#if !WINDOWS_UWP            
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(copriHost, command, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Reservierung des Fahrrads aufgrund eines Netzwerkfehlers fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Reservierung des Fahrrads aufgrund eines Netzwerkfehlers fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<ReservationCancelReturnResponse>>(l_oBikesAvaialbeResponse)?.tinkjson;
#else
            return null;
#endif
        }

        public static async Task<ReservationBookingResponse> DoUpdateLockingStateAsync(
            string copriHost,
            string command,
            string agent = null)
        {
#if !WINDOWS_UWP
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(copriHost, command, agent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Aktualisierung des Schlossstatuses wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Aktualisierung des Schlossstatuses wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<ReservationBookingResponse>>(l_oBikesAvaialbeResponse)?.tinkjson;
#else
            return null;
#endif
        }

        public static async Task<ReservationBookingResponse> DoBookAsync(
            string copriHost,
            string command,
            string agent = null)
        {
#if !WINDOWS_UWP
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(copriHost, command, agent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Buchung des Fahrrads wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Buchung des Fahrrads wegen Netzwerkfehler fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<ReservationBookingResponse>>(l_oBikesAvaialbeResponse)?.tinkjson;
#else
            return null;
#endif
        }

        public static async Task<ReservationCancelReturnResponse> DoReturn(
            string copriHost,
            string command,
            string userAgent = null)
        {
#if !WINDOWS_UWP            
            string l_oBikesAvaialbeResponse;
            try
            {
                l_oBikesAvaialbeResponse = await PostAsync(copriHost, command, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Rückgabe des Fahrrads aufgrund eines Netzwerkfehlers fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Rückgabe des Fahrrads aufgrund eines Netzwerkfehlers fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<ReservationCancelReturnResponse>>(l_oBikesAvaialbeResponse)?.tinkjson;
#else
            return null;
#endif
        }

        public async Task<SubmitFeedbackResponse> DoSubmitFeedback(
            string copriHost,
            string command,
            string userAgent = null)
        {
#if !WINDOWS_UWP            
            string userFeedbackResponse;
            try
            {
                userFeedbackResponse = await PostAsync(copriHost, command, userAgent);
            }
            catch (System.Exception l_oException)
            {
                if (l_oException.GetIsConnectFailureException())
                {
                    throw new WebConnectFailureException("Senden der Rückmeldung aufgrund eines Netzwerkfehlers fehlgeschlagen.", l_oException);
                }

                if (l_oException.GetIsForbiddenException())
                {
                    throw new WebForbiddenException("Senden der Rückmeldung aufgrund eines Netzwerkfehlers fehlgeschlagen.", l_oException);
                }

                throw;
            }

            // Extract bikes from response.
            return JsonConvert.DeserializeObject<ResponseContainer<SubmitFeedbackResponse>>(userFeedbackResponse)?.tinkjson;
#else
            return null;
#endif
        }

        /// <summary> http get- request.</summary>
        /// <param name="Url">Ulr to get info from.</param>
        /// <returns>response from server</returns>
        public static async Task<string> Get(string Url)
        {
            string result = string.Empty;
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(Url);
            myRequest.Method = "GET";
            using (var myResponse = await myRequest.GetResponseAsync())
            {
                using (var sr = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8))
                {
                    result = sr.ReadToEnd();
                }
            }

            return result;
        }

        /// <summary> http- post request.</summary>
        /// <param name="p_strCommand">Command to send.</param>
        /// <param name="p_oDisplayCommand">Command to display/ log used for error handling.</param>
        /// <param name="uRL">Address of server to communicate with.</param>
        /// <returns>Response as text.</returns>
        /// <changelog> An unused member PostAsyncHttpClient using HttpClient for posting was removed 2020-04-02.</changelog>
        private static async Task<string> PostAsync(
            string uRL,
            string p_strCommand,
            string userAgent = null,
            Func<string> p_oDisplayCommand = null)
        {
            if (string.IsNullOrEmpty(p_strCommand))
            {
                Log.ForContext<CopriCallsHttps>().Fatal("Can not post command. Command must not be null or empty.");

                throw new ArgumentException("Can not post command. Command must not be null or empty.");
            }

            if (string.IsNullOrEmpty(uRL))
            {
                Log.ForContext<CopriCallsHttps>().Fatal("Can not post command. Host must not be null or empty.");

                throw new ArgumentException("Can not post command. Host must not be null or empty.");
            }

            // Get display version of command to used for display/ logging (password should never be included in output)
            Func<string> displayCommandFunc = p_oDisplayCommand ?? delegate () { return p_strCommand; };

            try
            {
#if !WINDOWS_UWP
                var l_strHost = uRL;

                // Returns a http request.
                var l_oRequest = WebRequest.CreateHttp(l_strHost);

                l_oRequest.Method = "POST";
                l_oRequest.ContentType = "application/x-www-form-urlencoded";
                l_oRequest.UserAgent = userAgent;

                // Workaround for issue https://bugzilla.xamarin.com/show_bug.cgi?id=57705  
                // If not KeepAlive is set to true Stream.Write leads arbitrarily to an object disposed exception.
                l_oRequest.KeepAlive = true;

                byte[] l_oPostData = Encoding.UTF8.GetBytes(p_strCommand);

                l_oRequest.ContentLength = l_oPostData.Length;

                // Get the request stream.
                using (Stream l_oDataStream = await l_oRequest.GetRequestStreamAsync())
                {
                    // Write the data to the request stream.
                    await l_oDataStream.WriteAsync(l_oPostData, 0, l_oPostData.Length);
                }

                // Get the response.
                var l_oResponse = await l_oRequest.GetResponseAsync() as HttpWebResponse;

                if (l_oResponse == null)
                {
                    throw new System.Exception(string.Format("Reserve request failed. Response form from server was not of expected type."));
                }

                if (l_oResponse.StatusCode != HttpStatusCode.OK)
                {
                    throw new CommunicationException(string.Format(
                        "Posting request {0} failed. Expected status code is {1} but was {2}.",
                        displayCommandFunc(),
                        HttpStatusCode.OK,
                        l_oResponse.StatusCode));
                }

                string response = string.Empty;

                // Get the request stream.
                using (Stream l_oDataStream = l_oResponse.GetResponseStream())
                using (StreamReader l_oReader = new StreamReader(l_oDataStream))
                {
                    // Read the content.
                    response = l_oReader.ReadToEnd();

                    // Display the content.
                    Console.WriteLine(response);

                    // Clean up the streams.
                    l_oResponse.Close();
                }

                Log.ForContext<CopriCallsHttps>().Verbose("Post command {DisplayCommand} to host {URL} received {ResponseText:j}.", displayCommandFunc(), uRL, response);

                return response;
#else
                return null;
#endif
            }
            catch (System.Exception l_oException)
            {
                Log.ForContext<CopriCallsHttps>().InformationOrError("Posting command {DisplayCommand} to host {URL} failed. {Exception}.", displayCommandFunc(), uRL, l_oException);
                throw;
            }
        }
    }
}