How to Post Data to Specific Url Using Webclient in C#

How to post data to specific URL using WebClient in C#

I just found the solution and yea it was easier than I thought :)

so here is the solution:

string URI = "http://www.myurl.com/post.php";
string myParameters = "param1=value1¶m2=value2¶m3=value3";

using (WebClient wc = new WebClient())
{
    wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
    string HtmlResult = wc.UploadString(URI, myParameters);
}

it works like charm :)

Set a body for WebClient when making a Post Request

You can do with this simple code

Uri uri = new Uri("yourUri");
string data = "yourData";

WebClient client = new WebClient();
var result = client.UploadString(uri, data);

Remember that you can use UploadStringTaskAsync if you want to be async

Post Data To A Specific URL & Shows The Return Page

  public void PostProcessPayment(PostProcessPaymentRequest postProcessPaymentRequest)
    {

    string orderNo = postProcessPaymentRequest.Order.Id.ToString();
    string amount = postProcessPaymentRequest.Order.OrderTotal.ToString("0.00", CultureInfo.InvariantCulture);
    string merchantId = _NetConnectPaymentSettings.CustomerId;  
    string date = DateTime.Now.ToString("dd/MM/yyyy");
    string time = DateTime.Now.ToString("HH:mm:ss");
    string urlNetConnect = _NetConnectPaymentSettings.PaymentPage;


    string checksum = Generate_MerchantRequest_Check_Sum("7C12B6AECC51A3F3189799098AB1981", merchantId, orderNo, amount, date, time);

    var client = new HttpClient();

    var values = new List<KeyValuePair<string, string>>();
    values.Add(new KeyValuePair<string, string>("Merchant_ID", merchantId));
    values.Add(new KeyValuePair<string, string>("Order_NO", orderNo));
    values.Add(new KeyValuePair<string, string>("Order_Amount", amount));

    values.Add(new KeyValuePair<string, string>("Date", date));
    values.Add(new KeyValuePair<string, string>("Time", time));

    values.Add(new KeyValuePair<string, string>("CheckSum", checksum));
    values.Add(new KeyValuePair<string, string>("Transaction_Desc", "Shop From SM Motors"));


    var content = new FormUrlEncodedContent(values);



    //HttpResponseMessage response = client.PostAsync("http://www.smmotors.org", content).Result;

HttpResponseMessage response = client.PostAsync(urlNetConnect, content).Result;

    if (response.IsSuccessStatusCode)
    {
        var responseString = response.Content.ReadAsStringAsync();


        HttpContext.Current.Response.Write(responseString.Result);
        HttpContext.Current.ApplicationInstance.CompleteRequest();
        HttpContext.Current.Response.End();
        _webHelper.IsPostBeingDone = true;

    }
    else
    {
        throw new NopException();
    }


       return;
}

how to convert my Webclient to send Post request instead of Get request

Use UploadStringTaskAsync instead of DownloadStringTaskAsync.

   var url = currentURL+ "home/scanserver";
   wc.Headers.Add("Authorization", token);
   var json =wc.UploadStringTaskAsync(url, "FQDN=allscan");

NOTE that json is a Task<string> not a string. Are you sure that you want to use async behaviour?

How to post parameter to Azure Service URL using WebClient in C#

You'll be better off using HttpClient instead of WebClient . By looking at what the C++ code does it should be something like this in C# using HttpClient

    public void Test() {
        using (HttpClient client = new HttpClient()) {

        client.BaseAddress = new Uri("http://testservice.cloudapp.net");
        var response = client.PostAsync("api/test?value=1234", new StringContent(string.Empty)).Result;
        var statusCode = response.StatusCode;
        var errorText = response.ReasonPhrase;

        // response.EnsureSuccessStatusCode(); will throw an exception if status code does not indicate success

        var responseContentAsString = response.Content.ReadAsStringAsync().Result;
        var responseContentAsBYtes = response.Content.ReadAsByteArrayAsync().Result;
    }

}

Here is the async version of the code above

public async Task TestAsync() {
        using (HttpClient client = new HttpClient()) {

            client.BaseAddress = new Uri("http://testservice.cloudapp.net");
            var response = await client.PostAsync("api/test?value=1234", new StringContent(string.Empty));
            var statusCode = response.StatusCode;
            var errorText = response.ReasonPhrase;

            // response.EnsureSuccessStatusCode(); will throw an exception if status code does not indicate success

            var responseContentAsString = await response.Content.ReadAsStringAsync();
            var responseContentAsBYtes = await response.Content.ReadAsByteArrayAsync();
        }

    }

POSTing JSON to URL via WebClient in C#

You need a json serializer to parse your content, probably you already have it,
for your initial question on how to make a request, this might be an idea:

var baseAddress = "http://www.example.com/1.0/service/action";

var http = (HttpWebRequest)WebRequest.Create(new Uri(baseAddress));
http.Accept = "application/json";
http.ContentType = "application/json";
http.Method = "POST";

string parsedContent = <<PUT HERE YOUR JSON PARSED CONTENT>>;
ASCIIEncoding encoding = new ASCIIEncoding();
Byte[] bytes = encoding.GetBytes(parsedContent);

Stream newStream = http.GetRequestStream();
newStream.Write(bytes, 0, bytes.Length);
newStream.Close();

var response = http.GetResponse();

var stream = response.GetResponseStream();
var sr = new StreamReader(stream);
var content = sr.ReadToEnd();

hope it helps,

POST request using C# WebClient

As per the documentation (https://docs.microsoft.com/en-us/dotnet/api/system.net.webclient.uploadstring?view=net-5.0), UploadString sends a POST request by default.

So if you replace all your references to $_GET with $_POST in the PHP it should find the variables.

Alternatively you can specify the HTTP method when you call UploadString, e.g.

wc.UploadString(URI, "GET", myParameters)

Specific documentation for that method overload: https://docs.microsoft.com/en-us/dotnet/api/system.net.webclient.uploadstring?view=net-5.0#System_Net_WebClient_UploadString_System_String_System_String_System_String_

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P.S. your code is vulnerable to SQL injection attacks. You're using prepared statements, but that provides no protection unless you also use parameters with them. See How can I prevent SQL injection in PHP? for examples of how to create your queries safely in PHP.

Receive data from server using POST method and with a request body using WebClient in C#

Big Thanks to @Santiago Hernández. The issue was using wc.Headers.Add("Accept: application/json"); in the request header. Changing it to wc.Headers.Add("Content-Type: application/json"); returned a 200 Ok response. The code modification is as follows

using (var wc = new WebClient())
{
      wc.Headers.Add("Content-Type: application/json");
      wc.Headers.Add("User-Agent: xxxxxxx");
      wc.Headers.Add($"Authorization: Bearer {creds.APIKey.Trim()}");

      var jsonString = JsonConvert.SerializeObject(new UserRequestBody
      {
          group_id = userDetails.data.org_id
      });

      var response = wc.UploadString("https://api.xxxxx.yyy/v2/users", "POST", jsonString);
}

Accept tells the server the kind of response the client will accept and Content-type is about the payload/content of the current request or response. Do not use Content-type if the request doesn't have a payload/ body.

More information about this can be found here.

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