I have a url that contains valid xml, but unsure on how I could retrieve this with RestClient. I thought I could just download the string and then parse it like I allready to with WebClient.
Doing:
public static Task<String> GetLatestForecast(string url)
{
var client = new RestClient(url);
var request = new RestRequest();
return client.ExecuteTask<String>(request);
}
Makes VS cry about that 'string' must be a non-abstract type with a public parameterless constructor.
See executetask:
namespace RestSharp
{
public static class RestSharpEx
{
public static Task<T> ExecuteTask<T>(this RestClient client, RestRequest request)
where T : new()
{
var tcs = new TaskCompletionSource<T>(TaskCreationOptions.AttachedToParent);
client.ExecuteAsync<T>(request, (handle, response) =>
{
if (response.Data != null)
tcs.TrySetResult(response.Data);
else
tcs.TrySetException(response.ErrorException);
});
return tcs.Task;
}
}
}
Thanks to Claus Jørgensen btw for a awesome tutorial on Live Tiles!
I just want to download the string as I already have a parser waiting for it to parse it :-)
If all you want is a string, just use this approach instead:
namespace RestSharp
{
public static class RestSharpEx
{
public static Task<string> ExecuteTask(this RestClient client, RestRequest request)
{
var tcs = new TaskCompletionSource<string>(TaskCreationOptions.AttachedToParent);
client.ExecuteAsync(request, response =>
{
if (response.ErrorException != null)
tcs.TrySetException(response.ErrorException);
else
tcs.TrySetResult(response.Content);
});
return tcs.Task;
}
}
}
Related
I am dealing with a piece of code that looks like this:
public class Uploader : IUploader
{
public Uploader()
{
// assign member variables to dependency injected interface implementations
}
public async Task<string> Upload(string url, string data)
{
HttpResponseMessage result;
try
{
var handler = new HttpClientHandler();
var client = new HttpClient(handler);
result = await client.PostAsync(url, new FormUrlEncodedContent(data));
if (result.StatusCode != HttpStatusCode.OK)
{
return "Some Error Message";
}
else
{
return null; // Success!
}
}
catch (Exception ex)
{
// do some fancy stuff here
}
}
}
I am trying to unit test the Upload function. In particular, I need to mock the HttpClient. After reading the other answers on here and these two articles, I know that one of the better ways to solve this is to mock the HttpMessageHandler instead and pass that to HttpClient and have it return whatever I want.
So, I started along that path by first passing in HttpClient in the constructor as a dependency:
public class Uploader : IUploader
{
private readonly HttpClient m_httpClient; // made this a member variable
public Uploader(HttpClient httpClient) // dependency inject this
{
m_httpClient = httpClient;
}
public async Task<string> Upload(string url, string data)
{
HttpResponseMessage result;
try
{
var handler = new HttpClientHandler();
result = await m_httpClient.PostAsync(url, new FormUrlEncodedContent(data));
if (result.StatusCode != HttpStatusCode.OK)
{
return "Some Error Message";
}
else
{
return null; // Success!
}
}
catch (Exception ex)
{
// do some fancy stuff here
}
}
}
and adding: services.AddSingleton<HttpClient>(); to the ConfigureServices method of Startup.cs.
But now I face a slight issue where the original code specifically creates a HttpClientHandler to pass in. How then do I refactor that to take in a mockable handler?
I find the simplest way is to continue using HttpClient, but pass in a mocking HttpClientHandler such as https://github.com/richardszalay/mockhttp
Code sample from the link above:
var mockHttp = new MockHttpMessageHandler();
mockHttp.When("http://localhost/api/user/*")
.Respond("application/json", "{'name' : 'Test McGee'}");
// Inject the handler or client into your application code
var client = mockHttp.ToHttpClient();
var response = await client.GetAsync("http://localhost/api/user/1234");
var json = await response.Content.ReadAsStringAsync();
Console.Write(json); // {'name' : 'Test McGee'}
The Dependency Injection framework built into .NET Core ignores internal constructors, so it will call the parameter-less constructor in this scenario.
public sealed class Uploader : IUploader
{
private readonly HttpClient m_httpClient;
public Uploader() : this(new HttpClientHandler())
{
}
internal Uploader(HttpClientHandler handler)
{
m_httpClient = new HttpClient(handler);
}
// regular methods
}
In your unit tests, you can use the constructor accepting the HttpClientHandler:
[Fact]
public async Task ShouldDoSomethingAsync()
{
var mockHttp = new MockHttpMessageHandler();
mockHttp.When("http://myserver.com/upload")
.Respond("application/json", "{'status' : 'Success'}");
var uploader = new Uploader(mockHttp);
var result = await uploader.UploadAsync();
Assert.Equal("Success", result.Status);
}
Normally I'm not a big fan of having an internal constructor to facilitate testing, however, I find this more obvious and self-contained than registering a shared HttpClient.
HttpClientFactory might be another good option, but I haven't played around with that too much, so I'll just give info on what I've found useful myself.
One way would be to abstract your HTTP functionality into a service i.e. HttpService which implements an interface of IHttpService:
IHttpService
public interface IHttpService
{
Task<HttpResponseMessage> Post(Uri url, string payload, Dictionary<string, string> headers = null);
}
HttpService
public class HttpService : IHttpService
{
private static HttpClient _httpClient;
private const string MimeTypeApplicationJson = "application/json";
public HttpService()
{
_httpClient = new HttpClient();
}
private static async Task<HttpResponseMessage> HttpSendAsync(HttpMethod method, Uri url, string payload,
Dictionary<string, string> headers = null)
{
var request = new HttpRequestMessage(method, url);
request.Headers.Add("Accept", MimeTypeApplicationJson);
if (headers != null)
{
foreach (var header in headers)
{
request.Headers.Add(header.Key, header.Value);
}
}
if (!string.IsNullOrWhiteSpace(payload))
request.Content = new StringContent(payload, Encoding.UTF8, MimeTypeApplicationJson);
return await _httpClient.SendAsync(request);
}
public async Task<HttpResponseMessage> Post(Uri url, string payload, Dictionary<string, string> headers = null)
{
return await HttpSendAsync(HttpMethod.Post, url, payload, headers);
}
}
Add to your services:
services.AddSingleton<IHttpService, HttpService>();
In your class you would then inject IHttpService as a dependency:
public class Uploader : IUploader
{
private readonly IHttpService _httpService; // made this a member variable
public Uploader(IHttpService httpService) // dependency inject this
{
_httpService = httpService;
}
public async Task<string> Upload(string url, string data)
{
HttpResponseMessage result;
try
{
result = await _httpService.PostAsync(new Uri(url), data);
if (result.StatusCode != HttpStatusCode.OK)
{
return "Some Error Message";
}
else
{
return null; // Success!
}
}
catch (Exception ex)
{
// do some fancy stuff here
}
}
}
You could then use Moq to mock HttpService in your unit test:
[TestClass]
public class UploaderTests
{
private Mock<IHttpService> _mockHttpService = new Mock<IHttpService>();
[TestMethod]
public async Task WhenStatusCodeIsNot200Ok_ThenErrorMessageReturned()
{
// arrange
var uploader = new Uploader(_mockHttpService.Object);
var url = "someurl.co.uk";
var data = "data";
// need to setup your mock to return the response you want to test
_mockHttpService
.Setup(s => s.PostAsync(url, data))
.ReturnsAsync(new HttpResponseMessage(HttpStatusCode.InternalServerError));
// act
var result = await uploader.Upload(new Uri(url), data);
// assert
Assert.AreEqual("Some Error Message", result);
}
[TestMethod]
public async Task WhenStatusCodeIs200Ok_ThenNullReturned()
{
// arrange
var uploader = new Uploader(_mockHttpService.Object);
var url = "someurl.co.uk";
var data = "data";
// need to setup your mock to return the response you want to test
_mockHttpService
.Setup(s => s.PostAsync(new Uri(url), data))
.ReturnsAsync(new HttpResponseMessage(HttpStatusCode.OK));
// act
var result = await uploader.Upload(url, data);
// assert
Assert.AreEqual(null, result);
}
}
I'm trying to pass a query string into a BaseAddress but it doesn't recognize the quotation mark "?".
The quotation breaks the URI
First I create my BaseAddress
httpClient.BaseAddress = new Uri($"https://api.openweathermap.org/data/2.5/weather?appid={Key}/");
Then I call the GetAsync method, trying to add another parameter
using (var response = await ApiHelper.httpClient.GetAsync("&q=mexico"))....
This is the URI the code is calling
https://api.openweathermap.org/data/2.5/&q=mexico
I'd be tempted to use a DelegatingHandler if you need to apply an API key to every single request:
private class KeyHandler : DelegatingHandler
{
private readonly string _escapedKey;
public KeyHandler(string key) : this(new HttpClientHandler(), key)
{
}
public KeyHandler(HttpMessageHandler innerHandler, string key) : base(innerHandler)
{
// escape the key since it might contain invalid characters
_escapedKey = Uri.EscapeDataString(key);
}
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
// we'll use the UriBuilder to parse and modify the url
var uriBuilder = new UriBuilder(request.RequestUri);
// when the query string is empty, we simply want to set the appid query parameter
if (string.IsNullOrEmpty(uriBuilder.Query))
{
uriBuilder.Query = $"appid={_escapedKey}";
}
// otherwise we want to append it
else
{
uriBuilder.Query = $"{uriBuilder.Query}&appid={_escapedKey}";
}
// replace the uri in the request object
request.RequestUri = uriBuilder.Uri;
// make the request as normal
return base.SendAsync(request, cancellationToken);
}
}
Usage:
httpClient = new HttpClient(new KeyHandler(Key));
httpClient.BaseAddress = new Uri($"https://api.openweathermap.org/data/2.5/weather");
// since the logic of adding/appending the appid is done based on what's in
// the query string, you can simply write `?q=mexico` here, instead of `&q=mexico`
using (var response = await ApiHelper.httpClient.GetAsync("?q=mexico"))
** Note: If you're using ASP.NET Core, you should call services.AddHttpClient() and then use IHttpHandlerFactory to generate the inner handler for KeyHandler.
This is how I work around it:
Http client impl:
namespace StocksApi2.httpClients
{
public interface IAlphavantageClient
{
Task<string> GetSymboleDetailes(string queryToAppend);
}
public class AlphavantageClient : IAlphavantageClient
{
private readonly HttpClient _client;
public AlphavantageClient(HttpClient httpClient)
{
httpClient.BaseAddress = new Uri("https://www.alphavantage.co/query?apikey=<REPLACE WITH YOUR TOKEN>&");
httpClient.DefaultRequestHeaders.Add("Accept", "application/json; charset=utf-8");
httpClient.DefaultRequestHeaders.Add("User-Agent", "HttpClientFactory-Sample");
_client = httpClient;
}
public async Task<string> GetSymboleDetailes(string queryToAppend)
{
_client.BaseAddress = new Uri(_client.BaseAddress + queryToAppend);
return await _client.GetStringAsync("");
}
}
}
Controller:
namespace StocksApi2.Controllers
{
[ApiController]
[Route("api/[controller]")]
public class SymbolDetailsController : ControllerBase
{
private readonly IAlphavantageClient _client;
public SymbolDetailsController(IAlphavantageClient client)
{
_client = client;
}
[HttpGet]
public async Task<ActionResult> Get([FromQuery]string function = "TIME_SERIES_INTRADAY",
[FromQuery]string symbol = "MSFT", [FromQuery]string interval = "5min")
{
try {
string query = $"function={function}&symbol={symbol}&interval={interval}";
string result = await _client.GetSymboleDetailes(query);
return Ok(result);
}catch(Exception e)
{
return NotFound("Error: " + e);
}
}
}
}
And in Startup.cs inside ConfigureServices:
services.AddHttpClient();
services.AddHttpClient<IAlphavantageClient, AlphavantageClient>();
The client and a generic method for the API requests are created here:
public class Client : IDisposable
{
private HttpClient _client;
private void CreateClient()
{
_client = new HttpClient();
_client.DefaultRequestHeaders.Accept.Clear();
_client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
_client.DefaultRequestHeaders.Add("KEY", token);
}
public void Dispose() => _client?.Dispose();
public enum Method { GET, POST, PUT, DELETE }
public HttpResponseMessage Request(string url, Method method, object data, HttpContent request)
{
if (data != null)
request = new StringContent(Serialize(data), Encoding.UTF8, "application/json");
switch (method)
{
case Method.POST: return _client.PostAsync(url, request).Result;
case Method.PUT: return _client.PutAsync(url, request).Result;
case Method.DELETE: return _client.DeleteAsync(url).Result;
default: return _client.GetAsync(url).Result;
}
}
public Task<HttpResponseMessage> RequestAsync(string url, Method method, object data, HttpContent request)
{
if (data != null)
request = new StringContent(Serialize(data), Encoding.UTF8, "application/json");
switch (method)
{
case Method.GET: return _client.GetAsync(url);
case Method.POST: return _client.PostAsync(url, request);
case Method.PUT: return _client.PutAsync(url, request);
case Method.DELETE: return _client.DeleteAsync(url);
default: return _client.GetAsync(url);
}
}
public string Post(string url, object data) =>
Request(url, Method.POST, data, null).Content.ReadAsStringAsync().Result;
public Task<HttpResponseMessage> PostAsync(string url, object data) =>
RequestAsync(url, Method.POST, data, null);
//UTILS
private static string Serialize(object data) =>
data == null
? string.Empty
: JsonConvert.SerializeObject(data, new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore });
}
I'm trying to call these methods to specific classes, to simplify the usage of it for the customer. For example, to create a new checkout for a transaction in a credit card:
public class Checkout : SDK
{
private static Client client;
public Checkout() => client = new Client();
public static async Task Credit(object data) =>
await client.PostAsync(url, data);
}
The request needs to be mounted based on a few models, that can have this structure and I'm trying to generate it in a simple way, like this:
public async Task Test()
{
var transaction = new Transaction
{
PaymentMethod = new PaymentMethod { Code = "1" },
Application = "Test",
Vendor = "Name",
Customer = new Customer
{
//Customer details...
},
Products = new List<TransactionProduct>
{
//Products...
}
};
var teste = Checkout.Credit(transaction);
Console.WriteLine(teste);
}
And all I get as return is:
System.Threading.Tasks.Task`1[System.Threading.Tasks.VoidTaskResult]
Id = 1, Status = WaitingForActivation, Method = "{null}", Result = "{Not yet computed}"
I've tried to add await for the Checkout.Credit call, but I get:
CS0815 Test C# Cannot assign void to an implicitly-typed variable
Unit testing this with a simple HttpClient requests works like a charm, but I'm not being able to identify the problem on my project structure, so any help will be very much appreciated.
Task is the return type for an async method that does not have a return value.
Or, to put it another way, async wraps T values into Task<T> (or void returns into Task), and await unwraps those values. Since Credit returns Task, the type of the expression Checkout.Credit(transaction) is Task, and the type of the expression await Checkout.Credit(transaction) is void. And you cannot assign void to var teste; that's what the compiler error is saying.
To fix this, give your async method return types. In particular:
public static async Task<HttpResponseMessage> Credit(object data) =>
await client.PostAsync(url, data);
On a side note, this is quite strange:
public string Post(string url, object data) => ...;
public Task<HttpResponseMessage> PostAsync(string url, object data) => ...;
Usually, if you have a Method and a MethodAsync where Method has some return type TResult, then MethodAsync will have the return type Task<TResult>, not Task<SomeCompletelyDifferentType>. A more natural API would be something like this:
public async Task<HttpResponseMessage> PostAsync(string url, object data)
{
var result = await Request(url, Method.POST, data, null);
return await result.Content.ReadAsStringAsync();
}
I want to try and refactor this method a bit better while I am having some difficulty in understand the async I have a web api2 project which I use my data access layer to share to a phone app. I am not sure if I have the syntax correct I am using a xamrian shared library here in a xamrian forms app.
I will have various methods link get clients which will have the end point API/clients but obv their return type would be different.
How would one make the below work well with a list view say.
How would I consume the below method as well , what is general practise to then store the jobs locally in sql lite.
public string BaseUrl { get; set; }
public string EndPoint { get; set; }
Lets go out to the web service and grab the job list.
public async List<Job> GetJSON()
{
List<Job> rootObject = new List<Job>();
try
{
var client = new System.Net.Http.HttpClient();
var response = await client.GetAsync("http://myinternaliis/api/job");
string json = await response.Content.ReadAsStringAsync();
if (json != "")
{
rootObject = JsonConvert.DeserializeObject< List<Job>>(json);
}
}
catch (InvalidCastException e)
{
throw e;
}
return await rootObject;
}
Thanks for help in improving my understanding.
I guess you are looking for something like:
public async Task<T> GetJson<T>(string url)
{
using (var client = new System.Net.Http.HttpClient())
{
var response = await client.GetAsync(url);
var json = await response.Content.ReadAsStringAsync();
return (T)JsonConvert.DeserializeObject<T>(json);
}
}
Usually I have:
IApi - defines all the API methods
IHttpService - defines methods like Get, Post and etc.
IJsonConverter - defines methods like serialize and deserialize.
Here is an example:
public interface IJsonConverter
{
T Deserialize<T>(string json);
string Serialize<T>(T data);
}
public class JsonConveter : IJsonConverter
{
public T Deserialize<T>(string json) => JsonConvert.DeserializeObject<T>(json);
public string Serialize<T>(T data) => JsonConvert.Serialize(data);
}
public interface IHttpService
{
Task<T> Get<T>(string url);
}
public class HttpService : IHttpService
{
readonly IJsonConverter jsonConverter;
public HttpService(IJsonConverter jsonConverter)
{
this.jsonConverter = jsonConverter;
}
public async Task<T> Get<T>(string url)
{
using (var client = new System.Net.Http.HttpClient())
{
var response = await client.GetAsync(url);
var json = await response.Content.ReadAsStringAsync();
return jsonConverter.Deserialize<T>(json);
}
}
}
public interface IApi
{
Task<List<Job>> GetJobs();
}
public class Api : IApi
{
readonly string url = "http://myinternaliis/api/";
readonly IHttpService httpService;
public Api(IHttpService httpService)
{
this.httpService = httpService;
}
public Task<List<Job>> GetJobs() => httpService.Get<List<Job>>($"{url}job");
}
I think I might be retarded or I'm asking too much out of C# but I can't get this to work.
What essentially I'm trying to do is to wrap an API-client with some logging functions and a method to request a new token from the API-server.
controller:
public class TestController : ApiController
{
[HttpGet]
[Route("api/model/get/{id}"]
public IHttpActionResult GetModel<Model>(int id)
{
var result = Service.DoHttp<Model>(ServiceClass.GetModel, id);
}
}
service:
public static class ServiceClass
{
private static readonly HttpClient client = new HttpClient() { BaseAddress = new Uri(Globals.ExternalApiPath) };
private static string TokenHeader = "";
public async static Task<HttpResponseMessage> GetModel(int id)
{
var response = client.GetAsync($"/api/get/{id}");
return await response;
}
public static T DoHttp<T>(Func<int, HttpResponseMessage> funk, int id)
{
try
{
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", TokenHeader);
var result = funk(id);
if (result.IsSuccessStatusCode)
{
return result.Content.ReadAsAsync<T>().Result;
}
else
{
throw new Exception(String.Format($"Unknown error! Unable to contact remote API! AccessToken: {TokenHeader} Status code: {result.StatusCode}"));
}
}
catch (Exception e)
{
// log ex
throw e;
}
}
}
But my Service.DoHttp(Service.GetModel, id); complains about it being the wrong return type.
What am I doing wrong or have I misunderstood the whole concept?
EDIT: Compiler complains about 'Task ServiceClass.GetModel(int)' has the wrong return type
Change the DoHttp method to the following.
public static T DoHttp<T>(Func<int, Task<HttpResponseMessage>> funk, int id)
As the GetModel method returns a Task you need to use a task as the return type of the Func too.