Develop Reference

Refactor HttpWebRequest to HttpClient?

How would I convert this to HttpClient? What I'm looking to do is submit a Tweet to the Twitter api and get the response as Json. The HttpWebRequest is working fine but I just want to port it to HttpClient. I made an attempt at it in the second code example, but it's not actually sending or receiving the response.
HttpWebRequest request = null;
WebResponse response = null;
string responseCode = String.Empty;
try
{
string postBody = "status=" + EncodingUtils.UrlEncode(status);
request = (HttpWebRequest)HttpWebRequest.Create(resource_url);
request.ServicePoint.Expect100Continue = true;
request.UseDefaultCredentials = true;
request.PreAuthenticate = true;
request.Credentials = CredentialCache.DefaultCredentials;
request.ServicePoint.ConnectionLimit = 1;
request.Headers.Add("Authorization", authHeader);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
using (Stream stream = request.GetRequestStream())
{
using (StreamWriter writer = new StreamWriter(stream))
{
writer.Write(postBody);
}
}
using (response = request.GetResponse())
{
response.ContentType = "application/json";
responseCode = ((HttpWebResponse)response).StatusCode.ToString();
}
}
catch (WebException ex)
{
if (ex.Status != WebExceptionStatus.NameResolutionFailure)
{
request.Abort();
request = null;
}
throw ex;
}
return responseCode;
This is what I've tried to get it work:
private async Task<string> MakeWebRequest1(string status, string resource_url, string authHeader)
{
HttpClientHandler clientHandler = new HttpClientHandler();
clientHandler.Credentials = CredentialCache.DefaultCredentials;
clientHandler.PreAuthenticate = true;
clientHandler.AllowAutoRedirect = true;
string responseCode = "";
string postBody = "status=" + EncodingUtils.UrlEncode(status);
var request = new HttpRequestMessage()
{
RequestUri = new Uri(resource_url),
Method = HttpMethod.Post,
};
request.Headers.Add("Authorization", authHeader);
// request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/x-www-form-urlencoded");
request.Content = new StringContent(postBody, Encoding.UTF8,"application/x-www-form-urlencoded");//CONTENT-TYPE header
using (HttpClient client = new HttpClient(clientHandler))
{
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
// Stream stuff = await client.GetStreamAsync(resource_url);
using (HttpResponseMessage response = await client.SendAsync(request))
{
response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
if(response.StatusCode == HttpStatusCode.OK)
{
responseCode = "OK";
}
}
}
clientHandler.Dispose();
return responseCode;
}
enter code here
I've tried to add another parameter to the request and it's always coming back as 401 unauthorized. I'm trying to create a Twitter thread. If I remove the in_reply_to_status_id then it's fine.
data = new Dictionary<string, string> {
["status"] = "#username + status,
["in_reply_to_status_id"] = "1167588690929115136"
};
The Twitter API describes it here https://developer.twitter.com/en/docs/tweets/post-and-engage/api-reference/post-statuses-update

Reference You're using HttpClient wrong to understand why a static client is being used.
static Lazy<HttpClient> client = new Lazy<HttpClient>(() => {
HttpClientHandler clientHandler = new HttpClientHandler {
Credentials = CredentialCache.DefaultCredentials,
PreAuthenticate = true,
AllowAutoRedirect = true
};
return new HttpClient(clientHandler);
});
private async Task<string> PostStatusRequestAsync(string status, string resource_url, string authHeader) {
using (var request = new HttpRequestMessage(HttpMethod.Post, resource_url)) {
request.Headers.TryAddWithoutValidation("Authorization", authHeader);
request.Headers.Accept.Clear();
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var data = new Dictionary<string, string> {
["status"] = status
};
request.Content = new FormUrlEncodedContent(data);
using (HttpResponseMessage response = await client.Value.SendAsync(request)) {
return response.StatusCode.ToString();
}
}
}
Note the use of the FormUrlEncodedContent for the request body, which will encode and concatenate the data as well as take care of the mime type header
...but it's not actually sending or receiving the response.
Ensure that the above is not invoked as a synchronous blocking call, like .Result, which could cause a deadlock.
For example, an async event handler can be used to make the async call
public async void onButtonClick(object sender, EventArgs args) {
//Non-blocking call
var tweetRequestCode = await PostStatusRequestAsync(TweetText, AuthUtils.GetResourceUrl(), AuthUtils.GetWebRequestHeader()));
//back on UI thread
//...
}
Reference Async/Await - Best Practices in Asynchronous Programming

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;
}
}
}

Async HttpWebRequest call using C#

I have the following code:
//ids are a list of strings
foreach (string id in ids)
{
string serviceurl = "https://xxx.xx.xxx/internal/v2/idsearch?id=" + id;
List<string> lst = new List<string>();
var task = WebUtil.MakeAsyncRequest("GET", serviceurl, "application/json");
string val = task.Result;
if (val != "")
lst.Add(val);
}
public static Task<string> MakeAsyncRequest(string method,string url, string contentType)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.ContentType = contentType;
request.Method = method;
request.Timeout = 20000;
request.Proxy = null;
string clientId = ConfigManager.GetClientId;
string clientSecret = ConfigManager.GetClientSecret;
request.Headers.Add(HttpRequestHeader.Authorization, ConfigManager.GetServiceKey);
request.Headers.Add("client_id", clientId);
request.Headers.Add("client_secret", clientSecret);
Task<WebResponse> task = Task.Factory.FromAsync(
request.BeginGetResponse,
asyncResult => request.EndGetResponse(asyncResult),
(object)null);
return task.ContinueWith(t => ReadStreamFromResponse(t.Result));
}
private static string ReadStreamFromResponse(WebResponse response)
{
using (Stream responseStream = response.GetResponseStream())
using (StreamReader sr = new StreamReader(responseStream))
{
//Need to return this response
string strContent = sr.ReadToEnd();
return strContent;
}
}
It all works fine but i am just not sure if i am implementing the async process properly as it seems like it is doing it synchronously. I would really appreciate anyone who could help me identify what i am doing wrong...thanks!
EDIT:
Here is how i solved it....
var taskList = new List<Task<string>>();
foreach (string id in ids)
{
string serviceurl = "https://xxx.xx.xxx/internal/v2/idsearch?id=" + id;
taskList.Add(WebUtil.MakeAsyncRequest(serviceurl, "application/json"));
}
try
{
string[] val = await Task.WhenAll(taskList.ToArray());
}
catch (Exception)
{
throw;
}
public static async Task<string> MakeAsyncRequest(string url, string contentType)
{
using (HttpClient client = new HttpClient())
{
var requestMessage = new HttpRequestMessage()
{
RequestUri = new Uri(url),
Method = HttpMethod.Get,
};
// Add our custom headers
requestMessage.Headers.Add("client_id", ConfigManager.GetClientId);
requestMessage.Headers.Add("client_secret", ConfigManager.GetClientSecret);
requestMessage.Headers.Authorization = new AuthenticationHeaderValue(ConfigManager.GetServiceKey);
requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(contentType));
HttpResponseMessage response = await client.SendAsync(requestMessage);
var result = await response.Content.ReadAsStringAsync();
string res = result.ToString();
return res;
}
}

ReadToEnd is synchronous, yes. There are async equivalents.
Also note, that DNS resolution is synchronous here. This is a bug that is persistently not being fixed.
Probably, the best fix is to use HttpClient which makes downloading a string asynchronously a one-liner.

I suppose the best way for making an async request is HttpClient.
You can write something like this:
var client = new HttpClient();
var request = new HttpRequestMessage()
{
RequestUri = new Uri("xxxxxx"),
Method = HttpMethod.Get,
};
request.Headers.Accept.Add(new ....);
var response = await client.SendAsync(request);
//read a result from the repsonse

Set Timeout of 10 seconds to HttpWebRequest in WP8.1

I need to set a timeout of 10 seconds to all the Http web request in Wp8.1 app. I dont find a Timeout instead a ContinueTimeout property in the HttpWebRequest class.
A Quick search gave be few alternatives. Using a CancellationToken being one and the other one is using Task. Will some one give me pointers as to how to modify my current code.
This is how I'm creating a request
string uri = MyClass.HTTP_URI + "user/server-timestamps";
var request = (HttpWebRequest)WebRequest.Create(uri);
request.Method = MyClass.HTTP_GET;
request.Accept = "application/json";
request.Headers[HTTP_AUTHENTICATION_TOKEN] = "token"
request.Headers[API_KEY] = API_KEY_VALUE;
This is how I'm sending the request
try
{
WebResponse responseObject = await Task<WebResponse>.Factory.FromAsync(request.BeginGetResponse, request.EndGetResponse, request);
HttpWebResponse response = (HttpWebResponse)responseObject;
statusCode = (int)response.StatusCode;
if (statusCode == 200)
{
var responseStream = responseObject.GetResponseStream();
var sr = new StreamReader(responseStream);
received = await sr.ReadToEndAsync();
//Do stuff
}
}

You can use HttpClient class and CancellationTokenSource. Just modify it.
try
{
CancellationTokenSource cts = new CancellationTokenSource(2000);
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Accept.Add(new Windows.Web.Http.Headers.HttpMediaTypeWithQualityHeaderValue(""));
HttpRequestMessage msg = new HttpRequestMessage(new HttpMethod("POST"), new Uri("Url"));
HttpResponseMessage response = await client.SendRequestAsync(msg).AsTask(cts.Token);
}
catch(TaskCanceledException ex)
{
}

You can create an extension method than accepts CancellationToken and use it like this:
var request = (HttpWebRequest)WebRequest.Create(uri);
// ...
try
{
using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10)))
{
await request.GetResponseAsyncCancelable(cts.Token);
}
}
catch (OperationCanceledException)
{
// handle cancellation, if desired
}
// ...
public static class HttpWebRequestExt
{
public static async Task<HttpWebResponse> GetResponseAsyncCancelable(
this HttpWebRequest #this,
CancellationToken token)
{
using (token.Register(() => request.Abort(), useSynchronizationContext: false))
{
try
{
// BTW: any reason why not use request.GetResponseAsync,
// rather than FromAsync? It's there in WP 8.1:
// var response = await request.GetResponseAsync();
var response = (HttpWebResponse)await Task<WebResponse>.Factory.FromAsync(request.BeginGetResponse, request.EndGetResponse, request);
token.ThrowIfCancellationRequested();
return response;
}
catch (WebException ex)
{
// WebException caused by cancellation?
if (!token.IsCancellationRequested)
throw; // no, just re-throw
// yes, wrap it with OperationCanceledException
throw new OperationCanceledException(ex.Message, ex, token);
}
}
}
}
BTW, is there any reason you're not using GetResponseAsync, which is there in WP 8.1? See the code comments inline.

Converting ordinary Http Post web request with Async and Await

How I can convert my traditional HttpWebRequest "POST" call with Async / Await pattern, Here with this I am attaching my current code, Any one please help me to convert this code using Async / Await pattern for windows phone 8.
public void GetEnvironmentVariables(Action<Credentials> getResultCallback, Action<Exception> getErrorCallback)
{
CredentialsCallback = getResultCallback;
ErrorCallback = getErrorCallback;
var uri = new Uri(BaseUri);
var request = (HttpWebRequest)WebRequest.Create(uri);
request.Method = "POST";
request.ContentType = "application/json";
var jsonObject = new JObject
{
new JProperty("apiKey",_api),
new JProperty("affiliateId",_affid),
};
var serializedResult = JsonConvert.SerializeObject(jsonObject);
byte[] requestBody = Encoding.UTF8.GetBytes(serializedResult);
request.BeginGetRequestStream(GetRequestStreamCallback, new object[] { request, requestBody });
}
private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
var request = (HttpWebRequest)((object[])asynchronousResult.AsyncState)[0];
using (var postStream = request.EndGetRequestStream(asynchronousResult))
{
var byteArray = (byte[])((object[])asynchronousResult.AsyncState)[1];
// Write to the request stream.
postStream.Write(byteArray, 0, byteArray.Length);
}
request.BeginGetResponse(GetResponseCallback, request);
}
private void GetResponseCallback(IAsyncResult asynchronousResult)
{
var request = (HttpWebRequest)asynchronousResult.AsyncState;
try
{
var response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
if (response != null)
{
var reader = new StreamReader(response.GetResponseStream());
string responseString = reader.ReadToEnd();
Credentails = JsonConvert.DeserializeObject<Credentials>(responseString);
if (Credentails != null && string.IsNullOrEmpty(Credentails.Err))
CredentialsCallback(Credentails);
else
{
if (Credentails != null)
ErrorCallback(new Exception(string.Format("Error Code : {0}", StorageCredentails.Err)));
}
}
}
catch (WebException we)
{
var reader = new StreamReader(we.Response.GetResponseStream());
string responseString = reader.ReadToEnd();
Debug.WriteLine(responseString);
ErrorCallback(we);
}
}

Since Windows Phone 8 doesn't seem to offer the TAP methods you need such as GetRequestStreamAsync the first thing to do is write a little wrapper to provide them for yourself:
public static class WebRequestAsyncExtensions
{
public static Task<Stream> GetRequestStreamAsync(this WebRequest request)
{
return Task.Factory.FromAsync<Stream>(
request.BeginGetRequestStream, request.EndGetRequestStream, null);
}
public static Task<WebResponse> GetResponseAsync(this WebRequest request)
{
return Task.Factory.FromAsync<WebResponse>(
request.BeginGetResponse, request.EndGetResponse, null);
}
}
Note the use of Task.Factory.FromAsync - this is the preferred way to get an await-friendly wrapper around an APM-based async API such as those offered by WebRequest. This is far more efficient than using Task.Factory.StartNew as suggested by someone else, because that would spin up a new thread, whereas this won't need to.
With this in place, you can now write your code in the same way you would on platforms where these TAP-style methods are available (e.g. Windows 8 store apps, desktop apps, etc.):
public async Task GetEnvironmentVariablesAsync(Action<Credentials> getResultCallback, Action<Exception> getErrorCallback)
{
CredentialsCallback = getResultCallback;
ErrorCallback = getErrorCallback;
var uri = new Uri(BaseUri);
var request = (HttpWebRequest) WebRequest.Create(uri);
request.Method = "POST";
request.ContentType = "application/json";
var jsonObject = new JObject
{
new JProperty("apiKey",_api),
new JProperty("affiliateId",_affid),
};
var serializedResult = JsonConvert.SerializeObject(jsonObject);
byte[] requestBody = Encoding.UTF8.GetBytes(serializedResult);
// ASYNC: using awaitable wrapper to get request stream
using (var postStream = await request.GetRequestStreamAsync())
{
// Write to the request stream.
// ASYNC: writing to the POST stream can be slow
await postStream.WriteAsync(requestBody, 0, requestBody.Length);
}
try
{
// ASYNC: using awaitable wrapper to get response
var response = (HttpWebResponse) await request.GetResponseAsync();
if (response != null)
{
var reader = new StreamReader(response.GetResponseStream());
// ASYNC: using StreamReader's async method to read to end, in case
// the stream i slarge.
string responseString = await reader.ReadToEndAsync();
Credentails = JsonConvert.DeserializeObject<Credentials>(responseString);
if (Credentails != null && string.IsNullOrEmpty(Credentails.Err))
CredentialsCallback(Credentails);
else
{
if (Credentails != null)
ErrorCallback(new Exception(string.Format("Error Code : {0}", StorageCredentails.Err)));
}
}
}
catch (WebException we)
{
var reader = new StreamReader(we.Response.GetResponseStream());
string responseString = reader.ReadToEnd();
Debug.WriteLine(responseString);
ErrorCallback(we);
}
}
Note the four lines with // ASYNC: comments - these show where I've made changes. I've collapsed your method down to one, because that's a) possible once you're using async and await and b) much easier than trying to pass things from one method to the next using state arguments.
Notice that the second and fourth of these actually makes async some things you were previously doing synchronously: writing data into the request stream, and reading data out of the response stream. For a small request this probably doesn't matter, but if large amounts of data are being transferred, a synchronous call to Write or ReadToEnd may block. Fortunately, although Windows Phone 8 appears to be missing the TAP methods on WebRequest, it does offer them on Stream and StreamReader so this works without needing to write any extension methods.

I'm new to the community, so here goes my first post. In this case, you can return anytype using a generic Task. This has worked well for me in the past.
Server Side
public class MyController : ApiController
{
public Task<string> PostAsync()
{
return Task.Factory.StartNew(() =>
{
return "populate me with any type and data, but change the type in the response signature.";
});
}
}
Client Side
public class HomeController : Controller
{
public Task<ViewResult> Index()
{
return Task.Factory.StartNew(() =>
{
var model = "use a provider, get some data, or something";
return View(model);
});
}
}

This should do the job:
public async void GetEnvironmentVariables(Action<Credentials> getResultCallback, Action<Exception> getErrorCallback) {
CredentialsCallback = getResultCallback;
ErrorCallback = getErrorCallback;
var uri = new Uri(BaseUri);
var request = (HttpWebRequest)WebRequest.Create(uri);
request.Method = "POST";
request.ContentType = "application/json";
var jsonObject = new JObject {
new JProperty("apiKey", _api),
new JProperty("affiliateId", _affid),
};
var serializedResult = JsonConvert.SerializeObject(jsonObject);
var requestBody = Encoding.UTF8.GetBytes(serializedResult);
var requestStream = request.GetRequestStream();
requestStream.Write(requestBody, 0, requestBody.Length);
await GetResponse(request);
}
private async Task GetResponse(WebRequest request) {
Stream resStream = null;
try {
var response = await request.GetResponseAsync();
if (response == null) {
return;
}
resStream = response.GetResponseStream();
if (resStream == null) {
return;
}
var reader = new StreamReader(resStream);
var responseString = await reader.ReadToEndAsync();
Credentails = JsonConvert.DeserializeObject<Credentials>(responseString);
if (Credentails != null && string.IsNullOrEmpty(Credentails.Err)) {
CredentialsCallback(Credentails);
}
else {
if (Credentails != null) {
ErrorCallback(new Exception(string.Format("Error Code : {0}", StorageCredentails.Err)));
}
}
}
catch (WebException we) {
if (resStream != null) {
var reader = new StreamReader(resStream);
var responseString = reader.ReadToEnd();
Debug.WriteLine(responseString);
}
ErrorCallback(we);
}
}