tbf/RestClient/BaseClient.cs

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

namespace RestClient
{
    public class BaseClient
    {
        private string _baseUrl;

        public string ErrorMessage { get; set; }

        private AuthenticationHeaderValue _authValue;

        public BaseClient(string baseUrl)
        {
            this._baseUrl = baseUrl;
        }

        public void SetToken(string token)
        {
            _authValue = new AuthenticationHeaderValue("Bearer", token);
        }

        protected Uri GetUrl(string relativeUrl)
        {
            try
            {
                return new Uri(_baseUrl + relativeUrl);
            }
            catch (Exception)
            {
                Trace.TraceError("Invalid url " + relativeUrl);
                return null;
            }
        }

        protected async Task<TResult> GetResultAsync<TResult>(string relativeUrl)
        {
            ErrorMessage = String.Empty;
            Uri url = null;
            try
            {
                url = new Uri(_baseUrl + relativeUrl);
            }
            catch (Exception)
            {
                Trace.TraceError("Invalid url " + relativeUrl);
                return default(TResult);
            }
            using (var client = GetClient())
            {
                try
                {
                    var result = await client.GetAsync(url).ConfigureAwait(false);
                    var parsedResult = await result.Content.ReadAsStringAsync().ConfigureAwait(false);
                    if (result.IsSuccessStatusCode)
                    {
                        return JsonConvert.DeserializeObject<TResult>(parsedResult);
                    }
                    if (result.StatusCode == System.Net.HttpStatusCode.NotFound)
                    {
                        //Create not an error message, because communication is okay, only the meter is not available in database.
                        return default(TResult);
                    }
                    try
                    {
                        string Messages = await result.Content.ReadAsStringAsync();
                        var errors = JsonConvert.DeserializeObject<Dictionary<string, object>>(Messages);
                        string ServiceError = String.Empty;
                        if (errors != null)
                        {
                            ServiceError = errors["Message"].ToString();
                        }
                        ErrorMessage = string.Format("Error message: {0}", ServiceError);
                    }
                    catch
                    {
                        result.EnsureSuccessStatusCode();
                    }
                    return default(TResult);
                }
                catch (Exception ex)
                {
                    string Message = ex.Message;
                    if (ex.InnerException != null)
                    {
                        Message += ". " + ex.InnerException.Message;
                    }
                    Trace.TraceError(Message);
                    ErrorMessage = Message;
                    return default(TResult);
                }
            }
        }

        /// <summary>
        /// Post method.
        /// </summary>
        /// <typeparam name="TResult"></typeparam>
        /// <param name="relativeUrl"></param>
        /// <param name="Position"></param>
        /// /// <param name="withBaseUrl"></param>
        /// <returns>The new resource</returns>
        protected async Task<string> PostWithReturnDataAsync<TResult>(string relativeUrl, bool withBaseUrl, TResult Position)
        {
            string data = string.Empty;
            ErrorMessage = String.Empty;
            Uri url = null;
            try
            {
                if (withBaseUrl)
                {
                    url = new Uri(_baseUrl + relativeUrl);
                }
                else
                {
                    url = new Uri(relativeUrl);
                }
            }
            catch (Exception ex)
            {
                Trace.TraceError("Invalid url " + url);
                ErrorMessage = ex.Message;
                return data;
            }
            using (var client = GetClient())
            {
                try
                {
                    string json = JsonConvert.SerializeObject(Position);
                    HttpContent content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
                    HttpResponseMessage response = await client.PostAsync(url.ToString(), content).ConfigureAwait(false);
                    if (response.IsSuccessStatusCode)
                    {
                        data = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
                        return data;
                    }
                    else
                    {
                        if (response.StatusCode == HttpStatusCode.NotFound)
                        {
                            ErrorMessage = String.Format("Status code: {0}. Url: {1}", response.StatusCode, url);
                        }
                        else
                        {
                            string errorMessageService = string.Empty;
                            string message = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
                            if (string.IsNullOrEmpty(message))
                            {
                                errorMessageService = response.ReasonPhrase;
                            }
                            else
                            {
                                try
                                {
                                    var errors = JsonConvert.DeserializeObject<Dictionary<string, object>>(message);
                                    errorMessageService = errors["Message"].ToString();
                                }
                                catch (Exception)
                                {
                                    errorMessageService = message;
                                }
                            }
                            ErrorMessage = String.Format("Status code: {0}. Error message: {1}", response.StatusCode, errorMessageService);
                        }
                        return data;
                    }
                }
                catch (Exception ex)
                {
                    Trace.TraceError(ex.Message);
                    ErrorMessage = ex.Message;
                    return data;
                }
            }
        }

        protected HttpClient GetClient()
        {
            HttpClientHandler handler = new HttpClientHandler();
            handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };
            HttpClient client = new HttpClient(handler);
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            client.DefaultRequestHeaders.Authorization = _authValue;
            return client;
        }
    }
}