What is the preferred way for handling web api endpoints for each controller?
For example, my MVC controller will be calling different endpoints.
These are the only ones for now, but it could change.
Also, I will be developing this locally and and deploying to development server.
http://localhost:42769/api/categories/1/products
http://localhost:42769/api/products/
public class ProductsController : Controller
{
HttpClient client;
string url = "http://localhost:42769/api/categories/1/products"; //api/categories/{categoryId}/products
public ProductsController()
{
client = new HttpClient();
client.BaseAddress = new Uri(url);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
// GET: Products
public async Task<ActionResult> ProductsByCategory()
{
HttpResponseMessage responseMessage = await client.GetAsync(url);
if (responseMessage.IsSuccessStatusCode)
{
var responseData = responseMessage.Content.ReadAsStringAsync().Result;
var products = JsonConvert.DeserializeObject<List<GetProductsByCategoryID>>(responseData);
return PartialView(products);
}
return View("Error");
}
}
Not sure I understand you question or problem, but I would create a wrapper class for the service and then have different methods for each resource that you need to call. Always think SOLID.
Example (written by hand)
public class Client
{
private Uri baseAddress;
public Client(Uri baseAddress)
{
this.baseAddress = baseAddress;
}
public IEnumerable<Products> GetProductsFromCategory(int categoryId)
{
return Get<IEnumerable<Product>>($"api/categories/{categoryId}/products");
}
public IEnumerable<Products> GetAllProducts()
{
return Get<IEnumerable<Product>>($"api/products");
}
private T Get<T>(string query)
{
using(var httpClient = new HttpClient())
{
httpClient.BaseAddress = baseAddress;
var response= httpClient.Get(query).Result;
return response.Content.ReadAsAsync<T>().Result;
}
}
}
Related
I am trying to build an API that receives a GET request from our website client, then makes a request to Eventbrite's API using out access token and returns the response to the web client.
I am trying to use HttpClient to make the request but it gives my Syste.NullReferenceException.
My code looks like:
public class CANWebsiteV3Controller : ApiController
{
private static readonly HttpClient client = new HttpClient();
private readonly HttpResponse _response;
private readonly HttpRequest _request;
public CANWebsiteV3Controller()
{
/*_response = HttpContext.Current.Response;
_request = HttpContext.Current.Request;*/
}
// GET api/<controller>/5
[Route("api2.0/CANWebsiteV3/GetEvents")]
[HttpGet]
public async void GetEvents()
{
string API_TOKEN = "XXXXXXXXXXXX";
string ORGANIZATION_ID = "YYYYYYYYYY";
string ENDPOINT = "https://www.eventbriteapi.com/v3/organizations/" + ORGANIZATION_ID + "/events/?time_filter=current_future";
try
{
client.DefaultRequestHeaders.Clear();
client.DefaultRequestHeaders.TryAddWithoutValidation("authorization", "Bearer XXXXXXXXXXXX");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var res = await client.GetAsync(ENDPOINT);
if (res.IsSuccessStatusCode)
{
string eventResponse = res.Content.ReadAsStringAsync().Result;
var events = JsonConvert.DeserializeObject(eventResponse);
events.WriteToReponse();
}
}
catch(Exception ex)
{
JsonResponse.NewResponse("Could not fetch events: "+ex.Message, false, ErrorType.Generic, HttpStatusCode.BadRequest);
}
}
}
I am trying to call my webapi locally. This is my postman url and it work great. http://localhost:8080/api/V1/Students
When calling from MVC application I get an exception 404 not found.
This is my student controller
var url = "/Students";
string test = ApiHelper.ApiClient.BaseAddress + url;
using (HttpResponseMessage response = await ApiHelper.ApiClient.GetAsync(url))
{
if (response.IsSuccessStatusCode)
{
listStudent = await response.Content.ReadAsAsync<List<StudentModel>>();
}
else
{
throw new Exception(response.ReasonPhrase);
}
}
Notice: test actually return the url "http://localhost:8080/api/V1/Students". Witch his good.
And this is my ApiHelper code.
public class ApiHelper
{
public static HttpClient ApiClient { get; set; }
public static void InitializeClient()
{
string ApiBaseUrl = ConfigurationManager.AppSettings["ApiUrl"];
ApiClient = new HttpClient();
ApiClient.BaseAddress = new Uri(ApiBaseUrl);
ApiClient.DefaultRequestHeaders.Accept.Clear();
ApiClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
}
When I debug it I found that on my response the Request URI
RequestUri {http://localhost:8080/Student}
This is where my api location is called
<appSettings>
<add key="ApiUrl" value="http://localhost:8080/api/V1" />
</appSettings>
What I am doing wrong in trying to call the local api?
api/v1 is a route prefix. Decorate your BaseAddress controller with this route prefix and tray again. Like so:
[RoutePrefix("api/V1")]
public class ProductController : Controller
{
The API I'm calling from my ASP.NET Web API app requires two tokens i.e. accessToken and userToken.
The following code is not working because it takes only the second token, not both. Looks like the second line is over-writing the first one.
How do I add multiple tokens to my request header?
_client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("APIAccessToken", "token1");
_client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("UserToken", "token2");
UPDATE:
Here's the way I set this up and it's not working. Basically, my API calls seem to go nowhere. I get no errors. Just no response.
First, I have the HttpClientAccessor that looks like this:
public static class HttpClientAccessor
{
private static Lazy<HttpClient> client = new Lazy<HttpClient>(() => new HttpClient());
public static HttpClient HttpClient
{
get
{
client.Value.BaseAddress = new Uri("https://api.someurl.com");
client.Value.DefaultRequestHeaders.Accept.Clear();
client.Value.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.Value.DefaultRequestHeaders.TryAddWithoutValidation("APIAccessToken", "token1");
client.Value.DefaultRequestHeaders.TryAddWithoutValidation("UserToken", "token2");
return client.Value;
}
}
}
I then have my ApiClient that will perform my API calls which looks like this:
public class MyApiClient
{
HttpClient _client;
public MyApiClient()
{
_client = HttpClientAccessor.HttpClient;
}
public async Task Get()
{
try
{
HttpResponseMessage response = await _client.GetAsync("/myendpoint"); // This is where it gets lost
var data = await response.Content.ReadAsStringAsync();
}
catch(Exception e)
{
var error = e.Message;
}
}
}
This is my controller action:
public class MyController : Controller
{
private readonly MyApiClient _client;
public MyController()
{
_client = new MyApiClient();
}
public IActionResult SomeAction()
{
_client.Get().Wait();
}
}
You are confusing the standard authorization header with custom headers
According to the linked documentation
Request Header
Add the generated tokens to the request headers "APIAccessToken" and "UserToken"
Example Request
APIAccessToken: zjhVgRIvcZItU8sCNjLn+0V56bJR8UOKOTDYeLTa43eQX9eynX90QntWtINDjLaRjAyOPgrWdrGK12xPaOdDZQ==
UserToken: 5sb8Wf94B0g3n4RGOqkBdPfX+wr2pmBTegIK73S3h7uL8EzU6cjsnJ0+B6vt5iqn0q+jkZgN+gMRU4Y5+2AaXw==
To get headers like above, add them to the client like below
_client.DefaultRequestHeaders.TryAddWithoutValidation("APIAccessToken", "token1");
_client.DefaultRequestHeaders.TryAddWithoutValidation("UserToken", "token2");
Based on shown update, the client is adding the headers every time the client is called. This should be in the value factory of the lazy client.
public static class HttpClientAccessor {
public static Func<HttpClient> ValueFactory = () => {
var client = new HttpClient();
client.BaseAddress = new Uri("https://someApiUrl");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.TryAddWithoutValidation("APIAccessToken", "token1");
client.DefaultRequestHeaders.TryAddWithoutValidation("UserToken", "token2");
return client;
};
private static Lazy<HttpClient> client = new Lazy<HttpClient>(ValueFactory);
public static HttpClient HttpClient {
get {
return client.Value;
}
}
}
The controller action also needs to be refactored to avoid deadlocks because of the mixing of async and blocking calls like .Wait() or .Result.
public class MyController : Controller {
private readonly MyApiClient _client;
public MyController() {
_client = new MyApiClient();
}
public async Task<IActionResult> SomeAction() {
await _client.Get();
//... code removed for brevity
}
}
I have MVC project with service like below:
namespace comp.Services
{
public class CompService
{
public HttpClient client = new HttpClient();
public CompService()
{
client.BaseAddress = new Uri("someapiurl");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
}
protected async Task<string> GetProductAsync(string path)
{
var resp = "nothing here";
HttpResponseMessage response = await client.GetAsync(path);
if (response.IsSuccessStatusCode)
{
resp = await response.Content.ReadAsStringAsync();
}
return resp;
}
public string GetProduct(string path)
{
return GetProductAsync(path).GetAwaiter().GetResult();
}
}
}
and actionResult to view:
namespace comp.Controllers
{
public class HomeController : Controller
{
public CompService compService;
public HomeController()
{
compService = new CompService();
}
public ActionResult About()
{
var timeServer = compService.GetProduct("/api/time");
ViewBag.timeServer = timeServer;
return View();
}
}
}
When in debuger I encounter this line:
HttpResponseMessage response = await client.GetAsync(path);
program exit from debuger and there is no respone in browser.
The same code written in console application works.
In VS output is message that response is succes:
Application Insights Telemetry (unconfigured): {"name":"Microsoft.ApplicationInsights.Dev.RemoteDependency","time":"2018-02-18T13:48:31","tags":{"ai.internal.sdkVersion":"rddf:2.2.0-738","ai.internal.nodeName":"DESKTOP-xxxxx","ai.cloud.roleInstance":"DESKTOP-xxxxx"},"data":{"baseType":"RemoteDependencyData","baseData":{"ver":2,"name":"/api/v1/time","id":"xxxxx=","data":"https://api.xxx.com/api/v1/time","duration":"00:00:01.3150000","resultCode":"200","success":true,"type":"Http","target":"xxx","properties":{"DeveloperMode":"true"}}}}
In browser console output:
[14:51:33 GMT+0100 (Central European Standard Time)] Browser Link: Failed to send message to browser link server:
Error: SignalR: Connection must be started before data can be sent. Call .start() before .send()
Thanks for help.
You should really keep the code async all the way through in stead of trying to mix synchronous and asynchronous code
namespace comp.Services {
public class CompService {
static HttpClient client = new HttpClient();
static CompService() {
client.BaseAddress = new Uri("someapiurl");
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
}
public async Task<string> GetProductAsync(string path) {
var resp = string.Empty;
using(var response = await client.GetAsync(path)) {
if (response.IsSuccessStatusCode) {
resp = await response.Content.ReadAsStringAsync();
}
}
return resp;
}
}
}
The controller action should also be made async
namespace comp.Controllers {
public class HomeController : Controller {
private CompService compService;
public HomeController() {
compService = new CompService();
}
public async Task<ActionResult> About() {
var timeServer = await compService.GetProductAsync("api/time");
ViewBag.timeServer = timeServer;
return View();
}
}
}
That said, the service should also be abstracted
public interface ICompService {
Task<string> GetProductAsync(string path)
}
public class CompService : ICompService {
//...code removed for brevity
}
and injected into the controller instead of creating it manually.
public class HomeController : Controller {
private ICompService compService;
public HomeController(ICompService compService) {
this.compService = compService;
}
public async Task<ActionResult> About() {
var timeServer = await compService.GetProductAsync("api/time");
ViewBag.timeServer = timeServer;
return View();
}
}
Reference Async/Await - Best Practices in Asynchronous Programming
What you've got is a deadlock. Unlike console apps, ASP.Net applications run in a Synchronization Context. That context is captured when you block with GetResult(). Then, in GetProductAsync, you await on the context that is blocked. It cannot resume until GetResult is done which cannot resolve until the await is done.
#NKosi 's answer should resolve the problem, there is no reason for you to have any synchronous code.
For demonstration only
You can hack your code to work by explicitly allowing your await to run on a different context. You should not do this in production, it is not a fix. It can fail if someone maintaining the CompService is not careful.
To await against a different context change this:
var timeServer = await compService.GetProductAsync("api/time");
To this:
var timeServer = await compService.GetProductAsync("api/time").ConfigureAwait(false);
I mention this only to help you understand what is happening in your code. Don't "fix" it this way and move on.
I have webapi and her method:
[HttpPost, HttpGet]
[ActionName("GetData")]
public MyData GetData([FromUri] MyData data)
{
return datamanager.get(data);
}
How do I invoke this method? I.e. how do I send data parameter through query part of URL?
To invoke get method which takes no parameters I use following code:
public static async Task<myClassl> GetData()
{
HttpClient client = new HttpClient();
client.BaseAddress = new Uri("http://sasa.com");
HttpResponseMessage response = await client.GetAsync("api/GetData");
myClassl data = await response.Content.ReadAsAsync<myClassl>();
return data ;
}
Thanks.
Try the following solution:
HttpClient client = new HttpClient();
string baseApiAddress = ConfigurationManager.AppSettings["baseApiAddress"];
client.BaseAddress = new Uri(baseApiAddress);
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response=client.GetAsync("/api/GetData",data, new JsonMediaTypeFormatter()).Result;
if (response.IsSuccessStatusCode)
{
var mydata = response.Content.ReadAsAsync<MyData>().Result;
}
else
{
Debug.WriteLine(response.ReasonPhrase);
}