Develop Reference

Xamarin Forms Json Service Insert Data

I want to add a record to the json service in my application. How can I do this via Service Url. Here is my code.
CustomerModel customer = new CustomerModel();
customer.Name = entryCompanyName.Text;
customer.Title = entryCompanyTitle.Text;
customer.PhoneNumber = entryTelephone.Text;
customer.FaxNumber = entryFax.Text;
customer.Email = entryEmail.Text;
customer.CityId = 6444;
string json = JsonConvert.SerializeObject(customer);
string sContentType = "application/json";
string path = "service url";
HttpClient Client = new HttpClient();
var task = Client.PostAsync(path, new StringContent(json.ToString(), Encoding.UTF8, sContentType));
I'm trying M. Wiśnicki's solution, but I took this error
I did not get an error when I added System.net :( Where do i make mistakes?

This worked for me
public static async Task<string> PostEntityToApi<T>(string yourMethodUrl, T yourModel)
{
try
{
if (_httpClient == null)
{
_httpClient = new HttpClient { BaseAddress = new Uri(yourWebSiteUrl) };
}
var stringContentInput = new StringContent(JsonConvert.SerializeObject(dto), Encoding.UTF8, "application/json");
var response = await _httpClient.PostAsync(new Uri(yourWebSiteUrl. + apiUrl), stringContentInput);
if (!response.IsSuccessStatusCode)
{
throw new Exception(response.StatusCode.ToString());
}
var stringAsync = await response.Content.ReadAsStringAsync();
LoggingManager.Error("Received error response: " + stringAsync);
return stringAsync;
}
catch (Exception exception)
{
return null;
}
}

You can use WebRequest, this sample working for me, i use it in my app.
This is System.Net.WebRequest class, here you find doc.
public async Task<string> PostSample(object data, string uri)
{
// Create an HTTP web request using the URL:
var request = (HttpWebRequest) WebRequest.Create(new Uri(uri));
request.ContentType = "application/json";
request.Method = "POST";
var itemToSend = JsonConvert.SerializeObject(data);
using (var streamWriter = new StreamWriter(await request.GetRequestStreamAsync()))
{
streamWriter.Write(itemToSend);
streamWriter.Flush();
streamWriter.Dispose();
}
// Send the request to the server and wait for the response:
using (var response = await request.GetResponseAsync())
{
// Get a stream representation of the HTTP web response:
using (var stream = response.GetResponseStream())
{
var reader = new StreamReader(stream);
var message = JsonConvert.DeserializeObject<string>(reader.ReadToEnd());
return message;
}
}
}

Using HttpClient to GET

So, because HttpClient is "better," I need to convert WebClient to HttpClient, but it just doesn't work as expected. The following function uses WebClient and works like a charm.
private static void Authenticate()
{
Console.WriteLine("Authenticating . . .");
var clientId = ConfigurationManager.AppSettings["AuthNClientId"];
var uri = ConfigurationManager.AppSettings["AuthNUri"];
var userName = ConfigurationManager.AppSettings["AuthNUserName"];
var password = ConfigurationManager.AppSettings["AuthNPassword"];
var client = new WebClient();
string formData = $"client_id={clientId}&grant_type=password&username={userName}&password={password}";
client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
var response = client.UploadString($"{uri}", formData);
dynamic authResult = JsonConvert.DeserializeObject(response);
_accessToken = authResult.access_token;
if (_accessToken == null)
{
throw new ApplicationException("Unable to authenticate. Check your configuration file <appSettings>.");
}
Console.WriteLine("Authenticated.");
}
This code, on the other hand, returns a BadRequest response code.
static async Task<string> GetAuthenticationToken()
{
string token = string.Empty;
var clientId = ConfigurationManager.AppSettings["AuthNClientId"];
var uri = ConfigurationManager.AppSettings["AuthNUri"];
var userName = ConfigurationManager.AppSettings["AuthNUserName"];
var password = ConfigurationManager.AppSettings["AuthNPassword"];
client.BaseAddress = new Uri("https://myurl.com/oauth2/token");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Add("ContentType", "application/x-www-form-urlencoded");
var path = $"client_id={clientId}&grant_type=password&username={userName}&password={password}";
HttpResponseMessage response = await client.GetAsync($"https://myurl.com/oauth2/token?{path}");
if (response.IsSuccessStatusCode)
{
Console.WriteLine("success");
token = await response.Content.ReadAsStringAsync();
}
else { Console.WriteLine($"failure: {response.StatusCode}"); }
return token;
}
You can see that I've tried it a couple of ways, including setting the client BaseAddress as well as just try to pass the url into the GetAsync method.
Anyone see what I'm doing wrong here?

UploadString is a POST method in the first example. In the second example a GET method is being done.
static async Task<string> GetAuthenticationTokenAsync() {
string token = string.Empty;
var clientId = ConfigurationManager.AppSettings["AuthNClientId"];
var uri = ConfigurationManager.AppSettings["AuthNUri"];
var userName = ConfigurationManager.AppSettings["AuthNUserName"];
var password = ConfigurationManager.AppSettings["AuthNPassword"];
var client = new HttpClient();
client.BaseAddress = new Uri(uri);
client.DefaultRequestHeaders.Accept.Clear();
var nameValueCollection = new Distionary<string, string>() {
{ "client_id", clientId },
{ "grant_type", "password" },
{ "username", userName },
{ "password", password },
};
var content = new FormUrlEncodedContent(nameValueCollection);
var response = await client.PostAsync("", content);
if (response.IsSuccessStatusCode) {
Console.WriteLine("success");
var json = await response.Content.ReadAsStringAsync();
dynamic authResult = JsonConvert.DeserializeObject(json);
token = authResult.access_token;
}
else { Console.WriteLine($"failure: {response.StatusCode}"); }
return token;
}

Paypal Rest Api With RestSharp not working in xamarin android

I have got error with RestSharp component when i am call Paypal Rest API.
I have the following code using Xamarin for Android.
public async Task<PayPalGetTokenResponse> GetAccessToken()
{
var restRequest = new RestRequest("/oauth2/token", Method.POST);
// Add headers
restRequest.AddHeader("Accept", "application/json");
restRequest.AddHeader("Accept-Language", "en_US");
// Make Authorization header
restClient.Authenticator = new HttpBasicAuthenticator(Config.ApiClientId, Config.ApiSecret);
// add data to send
restRequest.AddParameter("grant_type", "client_credentials");
var response = restClient.Execute<PayPalGetTokenResponse>(restRequest);
response.Data.DisplayError = CheckResponseStatus(response, HttpStatusCode.OK);
return response.Data;
}
But got error :"Error: SecureChannelFailure (The authentication or decryption has failed.)"
I have Also use ModernHttpClient but got same error
public async Task<PayPalGetTokenResponse> GetAccessToken()
{
string clientId = Config.ApiClientId;
string secret = Config.ApiSecret;
string oAuthCredentials = Convert.ToBase64String(Encoding.Default.GetBytes(clientId + ":" + secret));
string uriString = Config.ApiUrl+"/oauth2/token";
PayPalGetTokenResponse result;
HttpClient client = new HttpClient(new NativeMessageHandler());
var h_request = new HttpRequestMessage(HttpMethod.Post, uriString);
h_request.Headers.Authorization = new AuthenticationHeaderValue("Basic", oAuthCredentials);
h_request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
h_request.Headers.AcceptLanguage.Add(new StringWithQualityHeaderValue("en_US"));
h_request.Content = new StringContent("grant_type=client_credentials", UTF8Encoding.UTF8);
try
{
HttpResponseMessage response = await client.SendAsync(h_request);
//if call failed ErrorResponse created...simple class with response properties
if (!response.IsSuccessStatusCode)
{
var error = await response.Content.ReadAsStringAsync();
var errResp = JsonConvert.DeserializeObject<string>(error);
//throw new PayPalException { error_name = errResp.name, details = errResp.details, message = errResp.message };
}
var success = await response.Content.ReadAsStringAsync();
result = JsonConvert.DeserializeObject<PayPalGetTokenResponse>(success);
}
catch (Exception)
{
throw new HttpRequestException("Request to PayPal Service failed.");
}
return result;
}

Have you tried to force to modern day SSL protocol?
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
This works for me:
if (ServicePointManager.SecurityProtocol != SecurityProtocolType.Tls12)
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
var client = new RestClient(payPalURL) {
Encoding = Encoding.UTF8
};
var authRequest = new RestRequest("oauth2/token", Method.POST) {
RequestFormat = DataFormat.Json
};
client.Authenticator = new HttpBasicAuthenticator(clientId, secret);
authRequest.AddParameter("grant_type","client_credentials");
var authResponse = client.Execute(authRequest);

Authentication from C# HttpClient against Spring server JWT Tokens

I'm coding a Xamarin cross-platform mobile app. The server is a SpringMVC server which uses JWT Tokens to authenticate against each of the endpoints/webservices. So basically when I'm doing a request to a webservice for first time, before I need to hit a /authorize POST endpoint sending my email and password, the endpoint response will contain in the "Cookie" header an authenticaton token which comes as "AUTH_TOKEN={MD5-String}". Once I got the token I send the request to the endpoint, let's say /feed. But my problem is that I cannot figure out the way of setting the "Cookie" header in the C# HttpClient. I tried everything but the endpoing just keeps responding with the login screen html instead of the actual JSON response. I tried the same steps in Postman and other REST clients and It worked. So It means that I'm doing something wrong. Here's my code:
public class RestService : IRestService
{
HttpClient client;
HttpClientHandler handler;
CookieContainer cookies;
string authToken;
public List<Feed> FeedItems { get; private set; }
public RestService()
{
cookies = new CookieContainer();
handler = new HttpClientHandler();
handler.UseCookies = true; //Otherwise It'll not use the cookies container!!
handler.CookieContainer = cookies;
client = new HttpClient(handler);
client.MaxResponseContentBufferSize = 256000;
}
public async Task<List<Role>> GetFeedDataAsync()
{
//Request credentials
//Credentials validation
var credentials = new HalliganCredential()
{
email = Constants.Username,
password = Constants.Password
};
var jsonCredentials = JsonConvert.SerializeObject(credentials);
var jsonCredentialsContent = new StringContent(jsonCredentials, Encoding.UTF8, "application/json");
var authorizeUri = new Uri(Constants.AuthorizeEndpoint);
var authorizeResponse = await client.PostAsync(authorizeUri, jsonCredentialsContent);
if (authorizeResponse.IsSuccessStatusCode)
{
//If authentication went OK
IEnumerable<Cookie> responseCookies = cookies.GetCookies(authorizeUri).Cast<Cookie>();
foreach (Cookie cookie in responseCookies)
{
if (cookie.Name.Equals("AUTH-TOKEN"))
{
authToken = cookie.Value;
}
}
}
else
{
//Authentication failed throw error
throw new HttpRequestException("Authentication failed");
}
FeedItems = new List<Feed>();
//Making the GET request
var uri = new Uri(string.Format(Constants.FeedEnpoint, string.Empty));
try
{
cookies.Add(uri, new Cookie("Cookie", string.Format("AUTH_TOKEN={0}", authToken)));
client.DefaultRequestHeaders.Add("Cookie", string.Format("AUTH_TOKEN={0}", authToken));
handler.CookieContainer.Add(uri, new Cookie("Cookie", string.Format("AUTH_TOKEN={0}", authToken)));
var response = await client.GetAsync(uri);
response.EnsureSuccessStatusCode();
//Credentials validation
if (response.IsSuccessStatusCode)
{
var content = await response.Content.ReadAsStringAsync();
FeedItems = JsonConvert.DeserializeObject<List<Feed>>(content);
}
}
catch (Exception ex)
{
Debug.WriteLine(#"ERROR {0}", ex.Message);
}
return FeedItems;
}
}
When I reach the line var content = await response.Content.ReadAsStringAsync(); the response is an HTML string instead of the actual JSON response.
I tried with several other key values for the header, although "Cookie" is the one that worked on Postman.
I tried with "Set-Cookie", "set-cookie", "Set-Cookie", setting the header as "AUTH_TOKEN". I tried all this convinations in different places like adding them in the cookie CookieContainer, in the handler CookieContainer and in the client.DefaultRequestHeaders.
I tried setting on and off the handler.UseCookies = true; //Otherwise It'll not use the cookies container!! line.
Any help will be welcome!
UPDATE
I tried with one of the suggested solutions but didn't work I tried either with UseCookies in true and false.
//Making the GET request
var baseAddress = new Uri("http://app.******.io");
using (var handler = new HttpClientHandler { UseCookies = true })
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
{
var message = new HttpRequestMessage(HttpMethod.Get, "/api/v1/feed?api_key=sarasa");
message.Headers.Add("Cookie", string.Format("AUTH_TOKEN={0}", authToken));
message.Headers.Add("Cookie", string.Format("AUTH_TOKEN={0};", authToken));
message.Headers.Add("Set-Cookie", string.Format("AUTH_TOKEN={0}", authToken));
message.Headers.Add("AUTH_TOKEN", authToken);
var result = await client.SendAsync(message);
result.EnsureSuccessStatusCode();
if (result.IsSuccessStatusCode)
{
var content = await result.Content.ReadAsStringAsync();
FeedItems= JsonConvert.DeserializeObject<List<Feed>>(content);
}
}
return FeedItems;
UPDATE
I tried with the another solution, same results.
var baseAddress = new Uri("http://app.*****.io");
var cookieContainer = new CookieContainer();
using (var handler = new HttpClientHandler() { CookieContainer = cookieContainer })
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
{
cookieContainer.Add(baseAddress, new Cookie("Cookie", string.Format("AUTH_TOKEN={0}", authToken)));
cookieContainer.Add(baseAddress, new Cookie("Set-Cookie", string.Format("AUTH_TOKEN={0}", authToken)));
var result = client.GetAsync("/api/v1/roles?api_key=sarasa").Result;
result.EnsureSuccessStatusCode();
if (result.IsSuccessStatusCode)
{
var content = await result.Content.ReadAsStringAsync();
RolesItems = JsonConvert.DeserializeObject<List<Role>>(content);
}
}
Is there an alternative to HttpClient?

I finally could set the Cookie header parameter, but I change HttpClient by HttpWebRequest
Getting the Cookies
//Credentials validation
var credentials = new CompanyCredential()
{
Email = Constants.Username,
Password = Constants.Password
};
var jsonCredentials = JsonConvert.SerializeObject(credentials);
var request = (HttpWebRequest) WebRequest.Create(new Uri(baseAddress, Constants.AuthorizeEndpoint));
request.ContentType = "application/json";
request.Method = "POST";
var requestStream = request.GetRequestStreamAsync().Result;
var streamWriter = new StreamWriter(requestStream);
streamWriter.Write(jsonCredentials);
streamWriter.Flush();
try
{
HttpWebResponse response = (HttpWebResponse) request.GetResponseAsync().Result;
if (response.StatusCode.Equals(HttpStatusCode.OK))
{
authToken = response.Headers["Set-Cookie"];
tokenExpireDate = DateTime.ParseExact(response.Headers["Expires"], "yyyy-MM-dd HH:mm:ss,fff",
System.Globalization.CultureInfo.InvariantCulture);
}
else
{
//Authentication failed throw error
throw new HttpRequestException("Authentication failed");
}
} catch (Exception e)
{
Debug.WriteLine(string.Format("Warning: {0}", e.Message));
}
Setting the Cookies
var request = (HttpWebRequest)WebRequest.Create(new Uri(baseAddress, endpoint));
SetHeaders(request);
if (string.IsNullOrEmpty(authToken))
{
throw new AuthTokenNullException();
}
request.Headers["Cookie"] = authToken;
request.Method = "GET";
HttpWebResponse response = request.GetResponseAsync().Result as HttpWebResponse;
if (!response.StatusCode.Equals(HttpStatusCode.OK))
{
throw new HttpRequestException(string.Format("Warning expected response as 200 and got {0}", Convert.ToString(response.StatusCode)));
}
var reader = new StreamReader(response.GetResponseStream());
string stringResponse = reader.ReadToEnd();
return JsonConvert.DeserializeObject<T>(stringResponse);

Using a token to search on Twitter with OAuth2

Before Twitter switched to OAuth2, I was using the following query:
string atomTweetSearchURL = string.Format("http://search.twitter.com/search.atom?q={0}", searchText);
This no longer works, so now I'm trying to switch to OAuth2. I manage to successfully retrieve a token, but once I've got this, I seem to be unable to actually perform the search. Here's the latest incarnation of what I've tried:
var searchUrl = string.Format("https://api.twitter.com/1.1/search/tweets.json?q={0}&access_token={1}&token_type={2}", srchStr, twitAuthResponse.access_token, twitAuthResponse.token_type);
WebRequest srchRequest = WebRequest.Create(searchUrl);
using (var response2 = await srchRequest.GetResponseAsync())
{
Stream stream = response2.GetResponseStream();
using (StreamReader sr = new StreamReader(stream))
{
string jsonResponse = await sr.ReadToEndAsync();
}
}
This gives me a 400 - bad request.
I've also tried building the request like this:
System.Net.Http.HttpClient srchRequest = new System.Net.Http.HttpClient();
string authHdr = string.Format(srchHeaderFormat, twitAuthResponse.token_type, twitAuthResponse.access_token);
srchRequest.DefaultRequestHeaders.Add("Authorization", authHdr);
There's a massive quantity of articles out there detailing how to do this, but none of them seem to work correctly with WinRT. Can anyone point me in the right direction?
EDIT
Here's my code to get the token:
var oAuthConsumerKey = key;
var oAuthConsumerSecret = secret;
var oAuthUri = new Uri("https://api.twitter.com/oauth2/token");
var authHeaderFormat = "Basic {0}";
var authHeader = string.Format(authHeaderFormat,
Convert.ToBase64String(Encoding.UTF8.GetBytes(Uri.EscapeDataString(oAuthConsumerKey)
+ ":" +
Uri.EscapeDataString((oAuthConsumerSecret)))
));
var req = new HttpClient();
req.DefaultRequestHeaders.Add("Authorization", authHeader);
HttpRequestMessage msg = new HttpRequestMessage(new HttpMethod("POST"), oAuthUri);
msg.Content = new HttpStringContent("grant_type=client_credentials");
msg.Content.Headers.ContentType = new Windows.Web.Http.Headers.HttpMediaTypeHeaderValue("application/x-www-form-urlencoded");
HttpResponseMessage response = await req.SendRequestAsync(msg);
TwitAuthenticateResponse twitAuthResponse;
using (response)
{
string objectText = await response.Content.ReadAsStringAsync();
twitAuthResponse = JSonSerialiserHelper.Deserialize<TwitAuthenticateResponse>(objectText);
}

With the 1.1 API you don't pass the access token as part of the url, you need to include it as the Authorization header as "Bearer access_token" so you were almost there!
EDIT
To do this in the Windows.Web.Http namespace the following works:
private static async Task SearchTweets(AuthenticationResponse twitAuthResponse)
{
string srchStr = "tweet";
var client = new HttpClient();
var searchUrl = string.Format("https://api.twitter.com/1.1/search/tweets.json?q={0}", srchStr);
var uri = new Uri(searchUrl);
client.DefaultRequestHeaders.Authorization = new HttpCredentialsHeaderValue("Bearer", twitAuthResponse.AccessToken);
var response2 = await client.GetAsync(uri);
string content = await response2.Content.ReadAsStringAsync();
}
Or with System.Net.Http use the following:
This code will run the search for srchStr using the access token you already acquired as you showed in the first example:
var client = new HttpClient();
var searchUrl = string.Format("https://api.twitter.com/1.1/search/tweets.json?q={0}", srchStr);
var uri = new Uri(searchUrl);
client.DefaultRequestHeaders.Add("Authorization", string.Format("Bearer {0}", twitAuthResponse.access_token));
HttpResponseMessage response = await client.GetAsync(uri);
Task<string> content = response.Content.ReadAsStringAsync();
EDIT
This is a strange one, I tested your code and you're right it does throw an exception when attempting to add the Auth header, however the code I had used for grabbing the Access Token is almost identical but uses the System.Net.Http methods rather than the Windows.Web.Http ones that you use and it works, so I'll provide my code here, maybe this is a bug in the framework, or someone else can provide some more insight! This also uses the JSON.NET library which can be found on NuGet.
private static async Task SearchTweets(AuthenticationResponse twitAuthResponse)
{
string srchStr = "tweet";
var client = new HttpClient();
var searchUrl = string.Format("https://api.twitter.com/1.1/search/tweets.json?q={0}", srchStr);
var uri = new Uri(searchUrl);
client.DefaultRequestHeaders.Add("Authorization", string.Format("Bearer {0}", twitAuthResponse.AccessToken));
HttpResponseMessage response2 = await client.GetAsync(uri);
string content = await response2.Content.ReadAsStringAsync();
}
private async void GetAuthenticationToken()
{
var client = new HttpClient();
var uri = new Uri("https://api.twitter.com/oauth2/token");
var encodedConsumerKey = WebUtility.UrlEncode(TwitterConsumerKey);
var encodedConsumerSecret = WebUtility.UrlEncode(TwitterConsumerSecret);
var combinedKeys = String.Format("{0}:{1}", encodedConsumerKey, encodedConsumerSecret);
var utfBytes = System.Text.Encoding.UTF8.GetBytes(combinedKeys);
var encodedString = Convert.ToBase64String(utfBytes);
client.DefaultRequestHeaders.Add("Authorization", string.Format("Basic {0}", encodedString));
var data = new List<KeyValuePair<string, string>>
{
new KeyValuePair<string, string>("grant_type", "client_credentials")
};
var postData = new FormUrlEncodedContent(data);
var response = await client.PostAsync(uri, postData);
AuthenticationResponse authenticationResponse;
using (response)
{
if (response.StatusCode != System.Net.HttpStatusCode.OK)
throw new Exception("Did not work!");
var content = await response.Content.ReadAsStringAsync();
authenticationResponse = JsonConvert.DeserializeObject<AuthenticationResponse>(content);
if (authenticationResponse.TokenType != "bearer")
throw new Exception("wrong result type");
}
await SearchTweets(authenticationResponse);
}
}
class AuthenticationResponse
{
[JsonProperty("token_type")]
public string TokenType { get; set; }
[JsonProperty("access_token")]
public string AccessToken { get; set; }
}