So I am working on writing an extension class for my project using HttpClient since I am moving over from HttpWebRequest.
When doing the POST request, how do I send a normal string as a parameter? No json or anything just a simple string.
And this is what it looks like so far.
static class HttpClientExtension
{
static HttpClient client = new HttpClient();
public static string GetHttpResponse(string URL)
{
string fail = "Fail";
client.BaseAddress = new Uri(URL);
HttpResponseMessage Response = client.GetAsync(URL).GetAwaiter().GetResult();
if (Response.IsSuccessStatusCode)
return Response.Content.ReadAsStringAsync().GetAwaiter().GetResult();
else
return fail;
}
public static string PostRequest(string URI, string PostParams)
{
client.PostAsync(URI, new StringContent(PostParams));
HttpResponseMessage response = client.GetAsync(URI).GetAwaiter().GetResult();
string content = response.Content.ReadAsStringAsync().GetAwaiter().GetResult();
return content;
}
}
If you look at this like
client.PostAsync(URI, new StringContent(PostParams));
You can see that I just tried creating new StringContent and passing a string into it and the response returned 404 page not found. How do I properly use Post.Async(); do I send a string or byte array? Because with HttpWebRequest you would do it like this
public static void SetPost(this HttpWebRequest request, string postdata)
{
request.Method = "POST";
byte[] bytes = Encoding.UTF8.GetBytes(postdata);
using (Stream requestStream = request.GetRequestStream())
requestStream.Write(bytes, 0, bytes.Length);
}
You need prepare object and then you will serialize the object using Newtonsoft.Json . After that you will prepare byte content from the buffer. We are using api url api/auth/login and it is not full api url as we used dependency injection and configure base address in startup, see the second code.
public async void Login(string username, string password)
{
LoginDTO login = new LoginDTO();
login.Email = username;
login.Password = password;
var myContent = JsonConvert.SerializeObject(login);
var buffer = System.Text.Encoding.UTF8.GetBytes(myContent);
var byteContent = new ByteArrayContent(buffer);
byteContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
var response = await httpClient.PostAsync("api/auth/login", byteContent);
var contents = await response.Content.ReadAsStringAsync();
}
services.AddHttpClient<IAuthService, AuthService>(client =>
{
client.BaseAddress = new Uri("https://localhost:44354/");
});
.NET 5 Solution
In .NET 5, There is new class JsonContent and you can implement this easily
LoginDTO login = new LoginDTO();
login.Email = username;
login.Password = password;
JsonContent content = JsonContent.Create(login);
var url = "http://...";
HttpResponseMessage response = await httpClient.PostAsync(url, content);
In the PostRequest
the following is done..
client.PostAsync(URI, new StringContent(PostParams));
HttpResponseMessage response = client.GetAsync(URI).GetAwaiter().GetResult();
Which does not capture the response of the POST.
Refactor to
public static string PostRequest(string URI, string PostParams) {
var response = client.PostAsync(URI, new StringContent(PostParams)).GetAwaiter().GetResult();
var content = response.Content.ReadAsStringAsync().GetAwaiter().GetResult();
return content;
}
HttpClient
is primarily meant to be used async so consider refactoring to
public static async Task<string> PostRequestAsync(string URI, string PostParams) {
var response = await client.PostAsync(URI, new StringContent(PostParams));
var content = await response.Content.ReadAsStringAsync();
return content;
}
I have worked the following (using the package Ngonzalez.ImageProcessorCore).
Query (ASP.NET Core 2 Controller):
async Task<byte[]> CreateImage(IFormFile file)
{
using (var memoryStream = new MemoryStream())
{
await file.CopyToAsync(memoryStream);
var image = new Image(memoryStream);
var height = image.Height < 150 ? image.Height : 150;
image.Resize((int)(image.Width * height / image.Height), height).Save(memoryStream);
return memoryStream.ToArray();
}
}
[HttpPost, ValidateAntiForgeryToken]
public async Task<IActionResult> ImageAdd(ImageAddVm vm)
{
byte[] image = null;
if (vm.File != null && vm.File.Length > 0)
image = await CreateImage(vm.File);
if (image != null)
{
var json = JsonConvert.SerializeObject(new { vm.ObjectId, image });
var content = new StringContent(json, Encoding.UTF8, "application/json");
var client= new HttpClient();
await client.PostAsync($"{ApiUrl}/SaveImage", content);
}
return RedirectToAction("ReturnAction");
}
Api (ASP.NET Core 2 Controller):
public class ObjectImage
{
public int ObjectId { get; set; }
public byte[] Image { get; set; }
}
[HttpPost("SaveImage")]
public void SaveImage([FromBody]object content)
{
var obj = JsonConvert.DeserializeObject<ObjectImage>(content.ToString());
_db.Images.Find(obj.ObjectId).Image = obj.Image;
_db.SaveChanges();
}
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