Can anyone out there help me to understand
how to invoke the client method from server method using SignalR The server class resides in an CustomEvent handler in a different assembly.
I tried 3 different methods to invoke the method:
I named my hub as [HubName("notificationhub")]
Method1
Clients.addMessage(message);
This gives "Cannot perform runtime binding on a null reference"
Method 2
IHubContext context1 = GlobalHost.ConnectionManager.GetHubContext("notificationhub");
context1.Clients.addMessage('hello');
The client remained silent.
Method3
var hubConnection = new HubConnection("http://localhost:21120/");
var notification= hubConnection.CreateProxy("notificationhub");
hubConnection.Start().Wait();
notification.Invoke("Send", "Hello").Wait();
This method gives error : {"The remote server returned an error: (500) Internal Server Error."} To my surprise, i am able to invoke this method from a console application using the 3rd method.
what is the best solution for implementing this and what is the reason why i am not able to invoke the client method? Can anyone help me with this?
Regards
Vince
Here is how Im doing it, a bit a hack, but it works. It only works when calling hub from a controller, otherwise it wont work. Use UpdateHubFromController method.
public class UpdateFeedActivity : Hub
{
readonly IHubContext _hubContext ;
public UpdateFeedActivity()
{
_hubContext = _hubContext ?? GlobalHost.ConnectionManager.GetHubContext<UpdateFeedActivity>();
}
public void UpdateFeed(string groupname, string itemId, Enums.FeedActivityTypes activityType,
string userId="",
string actionResult1="",
string actionResult2="",
string actionResult3="")
{
Clients.Group(groupname).updateMessages(new FeedHubResponse
{
ItemId = itemId,
ActivityType = activityType.ToString(),
UserId = userId,
ActionResult1 = actionResult1,
ActionResult2 = actionResult2,
ActionResult3 = actionResult3
});
}
public void UpdateFeedFromController(string groupname, string itemId, Enums.FeedActivityTypes activityType,
string userId = "",
string actionResult1 = "",
string actionResult2 = "",
string actionResult3 = "")
{
_hubContext.Clients.Group(groupname).updateMessages(new FeedHubResponse
{
ItemId = itemId,
ActivityType = activityType.ToString(),
UserId = userId,
ActionResult1 = actionResult1,
ActionResult2 = actionResult2,
ActionResult3 = actionResult3
});
}
public void Join(string groupname)
{
Groups.Add(Context.ConnectionId, groupname);
}
}
public class FeedHubResponse
{
public string ItemId { get; set; }
public string UserId { get; set; }
public string ActionResult1 { get; set; }
public string ActionResult2 { get; set; }
public string ActionResult3 { get; set; }
public string ActivityType { get; set; }
public string Text { get; set; }
}
Related
I'm trying to make an endpoint to return a JSON response. I've tried narrowing it down to just the object and all I receive is {} or [{}] as a response. After debugging I confirmed that the object was being created correctly but when returning the response it was always blank. Below is simplified code but still has the same issue. Any ideas what I'm doing wrong?
[Route("{application}")]
[HttpGet]
public IActionResult Get(string application)
{
List<RequestedSetting> requestedSettings = new List<RequestedSetting>();
RequestedSetting rs = new RequestedSetting("foo", "bar");
requestedSettings.Add(rs);
return Json(requestedSettings);
}
public class RequestedSetting
{
public string Name;
public string Value;
public RequestedSetting(string name, string value)
{
Name = name;
Value = value;
}
}
I've also tried this:
[Route("{application}")]
[HttpGet]
public List<RequestedSetting> Get(string application)
{
List<RequestedSetting> requestedSettings = new List<RequestedSetting>();
RequestedSetting rs = new RequestedSetting("foo", "bar");
requestedSettings.Add(rs);
return requestedSettings;
}
Fields are not supported for serialisation in System.Text.Json. see the docs for more info.
Instead, change your class to use properties:
public class RequestedSetting
{
public string Name { get; set; }
public string Value { get; set; }
public RequestedSetting(string name, string value)
{
Name = name;
Value = value;
}
}
With this DTO:
public class QuestionDTO {
public Guid Id { get; set; }
public string Prompt { get; set; }
public List<Answer> Choices { get; set; }
public QuestionDTO() {
}
public QuestionDTO(Question question) {
this.Id = question.Id;
this.Prompt = question.Prompt;
this.Choices = question.Choices;
}
}
I was getting an error about Unable to Parse without a parameterless constructor. I have since fixed that, but now my objects are de-serialized empty:
using System.Text.Json;
var results = JsonSerializer.Deserialize<List<QuestionDTO>>(jsonString);
The jsonString contains 3 items with the correct data, and the deserialized list contains 3 items, but all the properties are empty.
The new json library is case sensitive by default. You can change this by providing a settings option. Here is a sample:
private JsonSerializerOptions _options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true }
private async Task SampleRequest()
{
var result = await HttpClient.GetStreamAsync(QueryHelpers.AddQueryString(queryString, queryParams));
_expenses = await JsonSerializer.DeserializeAsync<List<Common.Dtos.Expenses.Models.Querys.ExpensesItem>>(result, _options);
}
I have a web API application. I'm supposed to do a post to an endpoint. When l tried my API controller in postman, l get the error message "
Requested resource does not support HTTP 'POST'
I'm new to Web API so any help and suggestions are welcomed.
This is my model class:
namespace Products.Models
{
public class Prouct
{
public string ProductID { get; set; }
public string ProductName { get; set; }
public string ProductPrice { get; set; }
public string VoucherID { get; set; }
}
}
Here is my controller class
[RoutePrefix("api/products")]
public class ProductsController : ApiController
{
static HttpClient client = new HttpClient();
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
public string Get(int id)
{
return "value";
}
[Route("products")]
public async Task PostAsync(string ProductID, string ProductName, string ProductPrice,
string VoucherID)
{
Products p = new Products();
p.ProductID = ProductID;
p.ProductName = ProductName;
p.ProductPrice = ProductPrice;
p.VoucherID = VoucherID;
var client = new HttpClient { BaseAddress = new
Uri("http://localhost:51613/") };
var response = await
client.PostAsJsonAsync("api/products",
p);
if (response.IsSuccessStatusCode)
{
}
public void Put(int id, [FromBody]string value)
{
}
public void Delete(int id)
{
}
You need to specify HttpPost on PostAsync method. by default, it is [HttpGet].
[HttpPost]
[Route("products")]
public async Task PostAsync(string ProductID, string ProductName, string ProductPrice, string VoucherID)
{
// implementation
}
Looks like you're stuck in a loop. Why does the PostAsync method call itself after having been invoked? This will result in an endless request loop.
var client = new HttpClient { BaseAddress = new Uri("http://localhost:51613/") };
This is not related to the fact that the [HttpPost] attribute is required however.
Please observe that you are supposed to use [FromBody] . Also inside Postman (image attached) you have to choose "Raw" data with the product json with type as JSON(application.json).
[HttpPost]
[Route("products")]
public async Task PostAsync([FromBody] Products p)
{
var client = new HttpClient
{
BaseAddress = new
Uri("http://localhost:51613/")
};
var response = await
client.PostAsJsonAsync("api/products",
p);
if (response.IsSuccessStatusCode)
{
}
}
I'm looking for a reliable solution to log details of requests and responses made to and from our controllers. However, some of the data passing through contains sensitive information that should not be written to a log.
In the controller, the inbound request is bound to a single model from the request body, and as the request is answered, a single model is passed to the Ok() result like this (very simplified):
[HttpGet]
[Route("Some/Route")]
public IHttpActionResult SomeController([FromBody] RequestType requestObj)
{
ResponseType responseObj = GetResponse(requestObj)
return this.Ok(responseObj);
}
Now my goal is to somehow log the contents of the request and response object at the beginning and end of the controller, respectively. What I would like to do is bind the models first, then log out their attributes. An example of the RequestType is something like:
public class RequestType
{
public string SomeAttribute { get; set; }
public string AnotherAttribute { get; set; }
public string Password{ get; set; }
}
And the log would look something like:
[date-time] Request to SomeController:
SomeAttribute: "value_from_request"
AnotherAttribute: "another_value"
Password: "supersecret123"
Now clearly we don't want the password to be logged. So I would like to create a custom data annotation that would not log certain fields. Its use would look like this (updated RequestType):
public class RequestType
{
public string SomeAttribute { get; set; }
public string AnotherAttribute { get; set; }
[SensitiveData]
public string Password{ get; set; }
}
Where would I start with this? I'm not incredibly familliar with .NET, but know that there are many sort of magic classes that can be subclassed to override some of their functionality. Is there any such class that can help here? Even better, is there any way to do this during the model binding? So we could catch errors that occur during model binding as well?
We should be able to achieve what you're looking for with an ActionFilterAttribute.
Capture Requests Attribute
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public sealed class CaptureRequestsAttribute : ActionFilterAttribute // *IMPORTANT* This is in the System.Web.Http.Filters namespace, not System.Web.Mvc
{
public override void OnActionExecuting(HttpActionContext actionContext)
{
var messages = actionContext.ActionArguments.Select(arg => GetLogMessage(arg.Value));
var logMessage = $"[{DateTime.Now}] Request to " +
$"{actionContext.ControllerContext.Controller}]:\n{string.Join("\n", messages)}";
WriteToLog(logMessage);
base.OnActionExecuting(actionContext);
}
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
var result = actionExecutedContext.Response.Content as ObjectContent;
var message = GetLogMessage(result?.Value);
var logMessage = $"[{DateTime.Now}] Response from " +
$"{actionExecutedContext.ActionContext.ControllerContext.Controller}:\n{message}";
WriteToLog(logMessage);
base.OnActionExecuted(actionExecutedContext);
}
private static void WriteToLog(string message)
{
// todo: write you logging stuff here
}
private static string GetLogMessage(object objectToLog)
{
if (objectToLog == null)
{
return string.Empty;
}
var type = objectToLog.GetType();
var properties = type.GetProperties();
if (properties.Length == 0)
{
return $"{type}: {objectToLog}";
}
else
{
var nonSensitiveProperties = type
.GetProperties()
.Where(IsNotSensitiveData)
.Select(property => $"{property.Name}: {property.GetValue(objectToLog)}");
return string.Join("\n", nonSensitiveProperties);
}
}
private static bool IsNotSensitiveData(PropertyInfo property) =>
property.GetCustomAttributes<SensitiveDataAttribute>().Count() == 0;
}
Sensitive Data Attribute
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public sealed class SensitiveDataAttribute : Attribute
{
}
Then, you can just add it to your WebApi controller (or a specific method in it):
[CaptureRequests]
public class ValuesController : ApiController
{
// .. methods
}
And finally your models can just add the SensitiveDataAttribute:
public class TestModel
{
public string Username { get; set; }
[SensitiveData]
public string Password { get; set; }
}
This does not make use of DataAnnotations,however, One way that comes to mind would be to use the serialization. If your payload is within a reasonable size you could serialize and deserialize your RequestType class when reading and writing to/from a log. This would require a custom serialization format or making use of the default, xml.
[Seriliazeble()]
public class RequestType
{
public string SomeAttribute { get; set; }
public string AnotherAttribute { get; set; }
[NonSerialized()]
public string Password{ get; set; }
}
Using the above attribute will omit Password from serialization. Then you copuld proceed to Logger.Log(MySerializer.Serialize(MyRequest)); and your sensitive data will be omitted.
This link describes the approach in detail.
For xml serialization, simply use the XmlSerializer class.
public class MySerializationService
{
public string SerializeObject(object item)
{
XmlSerializer serializer = new XmlSerializer(item.GetType());
System.IO.MemoryStream aMemStr = new System.IO.MemoryStream();
System.Xml.XmlTextWriter writer = new System.Xml.XmlTextWriter(aMemStr, null);
serializer.Serialize(writer, item);
string strXml = System.Text.Encoding.UTF8.GetString(aMemStr.ToArray());
return strXml;
}
public object DeSerializeObject(Type objectType, string objectString)
{
object obj = null;
XmlSerializer xs = new XmlSerializer(objectType);
obj = xs.Deserialize(new StringReader(objectString));
return obj;
}
}
Then using the above or similar methods you can read and write in a custom format.
Write :
string logData=new MySerializationService().SerializeObject(myRequest);
Read :
RequestType loggedRequest= (RequestType)new MySerializationService().DeSerializeObject(new RequestType().GetType(), logData);
I am Beginner at Asp.net so can anyone plz help me to show the data provided in the below shown JSON Api in Asp.net Step by Step.It be of great help if this is answered.
http://fantasy.premierleague.com/web/api/elements/180/
A good way to use Json in C# is with Json.NET
JSON.NET - Official site will help you work with it.
Example to use it
public class User {
public User(string json) {
JObject jObject = JObject.Parse(json);
JToken jUser = jObject["user"];
name = (string) jUser["name"];
teamname = (string) jUser["teamname"];
email = (string) jUser["email"];
players = jUser["players"].ToArray();
}
public string name { get; set; }
public string teamname { get; set; }
public string email { get; set; }
public Array players { get; set; }
}
// Use
private void Run() {
string json = #"{""user"":{""name"":""asdf"",
""teamname"":""b"",""email"":""c"",""players"":[""1"",""2""]}}";
User user = new User(json);
Console.WriteLine("Name : " + user.name);
Console.WriteLine("Teamname : " + user.teamname);
Console.WriteLine("Email : " + user.email);
Console.WriteLine("Players:");
foreach (var player in user.players)
Console.WriteLine(player);
}