Web API PUT,DELETE, POST methods via URI - asp.net

Question

I am very new to the whole consept of API's. So far, I managed to build a web api that has GET,POST,PUT and DELETE methods.
Now, from an ASP.NET project, I try to finally use my web api.
Here's what I do for GET method:
string info = new WebClient() { }.DownloadString("https://mywebapisite.com/item/" + id);
Item item = JsonConvert.DeserializeObject<Item>(info);
This functions all fine. As you can see, all the GET method needs is an id.
However, for the POST method, I have no clue what to do.
I can create a new Item instance, but don't know what to do with it.
By the way, I also used ASP.NET to make my web.api.
There is a built-in feature in ASP.NET 5 called Swagger. It can perform all the tasks very succesfully. Is there like a code-behind for what Swagger does.
PS: I know that this question must be very common and basic. If you could refer me to another question in stackoverflow or simply tell me what to search on google I would appreciate it. (As you may guess, I don't even know what to search for)

Answer 1

pseudo code to consume post request in C#
var requestObj = GetDummyDataTable();
using (var client = new HttpClient())
{
// Setting Base address.
client.BaseAddress = new Uri("https://localhost:8080/");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = new HttpResponseMessage();
// HTTP POST
response = await client.PostAsJsonAsync("api/product", requestObj).ConfigureAwait(false);
if (response.IsSuccessStatusCode)
{
// Reading Response.
string result = response.Content.ReadAsStringAsync().Result;
var responseObj = JsonConvert.DeserializeObject<DataTable>(result);
}
}

Answer 2

You can refer the following code to call the API using HttpClient:
////using System.Net.Http.Headers;
////using System.Text;
using (var client = new HttpClient())
{
var requesturi = "https://localhost:7110/api/ToDo/relativeAddress";
var item = new TestUserViewModel()
{
Name = "John Doe",
Age = 33
};
////using System.Text.Json; // use JsonSerializer.Serialize method to convert the object to Json string.
StringContent content = new StringContent(JsonSerializer.Serialize(item), Encoding.UTF8, "application/json");
//HTTP POST
var postTask = client.PostAsync(requesturi, content);
postTask.Wait();
var result = postTask.Result;
if (result.IsSuccessStatusCode)
{
var Content = await postTask.Result.Content.ReadAsStringAsync();
return RedirectToAction("Privacy");
}
}
The API method like this:
[Route("api/[controller]")]
[ApiController]
public class TodoController : ControllerBase
{
[HttpPost]
[Route("relativeAddress")]
public string GetAddress([FromBody] TestUserViewModel testUser)
{
return "Address A";
}
And the result like this:
You can also refer this link to set the Content-Type.

Answer 3

You seem a little bit lost, and I get it. Api learning path is kinda weird, I recommend you watch a tutorial (My favorite https://www.youtube.com/playlist?list=PLLWMQd6PeGY0bEMxObA6dtYXuJOGfxSPx)
But if you need code asap, you could refer the following code.
Ps: The others answers are really good!
using System.Net.Http;
using System.Net.Http.Headers;
public class ApiHelper
{
public HttpClient ApiClient { get; set; }
public void InitializeClient()
{
ApiClient = new HttpClient();
ApiClient.BaseAddress = new Uri("https://mywebapisite.com/");
ApiClient.DefaultRequestHeaders.Accept.Clear();
ApiClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
public async Task PostSomething(FormUrlEncodedContent data)
{
using (HttpResponseMessage response = await ApiClient.PostAsync("/item",data)
{
var result = await response.Content.ReadAsAsync<string>();
}
}
}