C# : How To send '&' ,''+' Passing Special Character In Content body With HttpWebRequest of Type "application/x-www-form-urlencoded"

I've created a simple API in ASP.NET Core using C#. Now, I want to call that API which has an endpoint that takes a long string containing the description, which can also have special characters, using the application/x-www-form-urlencoded POST method. Let's discuss how we can do that in ASP.NET Core.

Considering that our content-type is "application/x-www-form-urlencoded", we must ensure that the POST body is properly encoded, especially if it contains special characters like '&' or  '+', which have a special meaning in a form.

We can achieve this by passing our string through HttpUtility.UrlEncode before writing it to the request stream, this function will encode special characters in a way that is safe for passing in a URL.

    using System;
    using System.IO;
    using System.Net;
    using System.Text;
    using System.Web;

    public class HttpWebRequestExample
    {
        public void SendRequest()
        {
            // Create the request object
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.quickpickdeal.com/api/Employee/GetAllEmployee");

            // Set the request method
            request.Method = "POST";

            // Set the content type
            request.ContentType = "application/x-www-form-urlencoded";

            // Create the data to be sent in the content body
            string postData = "name=" + HttpUtility.UrlEncode("value1") + "&phonenumber=" + HttpUtility.UrlEncode("value2") + "&data_with_ampersand=" + HttpUtility.UrlEncode("value&with&ampersand");

            // Convert the string to a byte array
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            // Set the content length
            request.ContentLength = byteArray.Length;

            // Get the request stream and write the data to it
            using (Stream dataStream = request.GetRequestStream())
            {
                dataStream.Write(byteArray, 0, byteArray.Length);
            }

            // Get the response from the server
            using (WebResponse response = request.GetResponse())
            {
                // Process the response
                // Your code here...
            }
        }
    }
    

Above code ensures that our POST body is properly encoded, making it safe for transmission in a URL and preventing any issues with special characters like '&', '+' or any special character.

Sending Passing Special Character in Content Body with C# HttpWebRequest

When using HttpWebRequest in C# to send data of type "application/x-www-form-urlencoded", we may encounter difficulties in sending the Special character in the content body,  this is because the  Special character like '&' character is a reserved character in URL encoding, and if not properly encoded, it can be misinterpreted as a separator between key-value pairs.

To properly send the '&' character in the content body, we need to URL encode it before adding it to the request. 

    using System;
    using System.IO;
    using System.Net;
    using System.Text;

    public class HttpWebRequestExample
    {
        public void SendRequest()
        {
            // Create the request object
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.quickpickdeal.com/);

            // Set the request method
            request.Method = "POST";

            // Set the content type
            request.ContentType = "application/x-www-form-urlencoded";

            // Create the data to be sent in the content body
            string postData = "id=value1&name=value2&data_with_ampersand=" + Uri.EscapeDataString("ashok&with&ampersand");

            // Convert the string to a byte array
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            // Set the content length
            request.ContentLength = byteArray.Length;

            // Get the request stream and write the data to it
            using (Stream dataStream = request.GetRequestStream())
            {
                dataStream.Write(byteArray, 0, byteArray.Length);
            }

            // Get the response from the server
            using (WebResponse response = request.GetResponse())
            {
               
            }
        }
    }
    

In above code snippet, we properly encode the '&' character in the content body using Uri.EscapeDataString() method. This ensures that the '&' character is treated as part of the value and not as a separator between key-value pairs.With this approach, we can successfully send the '&' character in the content body of a HttpWebRequest with type "application/x-www-form-urlencoded".

Considering that our content-type is "application/x-www-form-urlencoded", we must ensure that the POST body is properly encoded, especially if it contains special characters like '&' which have a special meaning in a form.

This function allows you to post form data to a specified API endpoint and deserialize the response content into the specified TResult type.

PM > Install-Package Microsoft.AspNet.WebApi.Client

public static async Task<TResult> PostFormData<TResult>(string apiUrl, IEnumerable<KeyValuePair<string, string>> formData)
{
    using (var client = new HttpClient())
    {
        using (var content = new FormUrlEncodedContent(formData))
        {
            content.Headers.Clear();
            content.Headers.Add("Content-Type", "application/x-www-form-urlencoded");

            HttpResponseMessage response = await client.PostAsync(apiUrl, content);

            return await response.Content.ReadAsAsync<TResult>();
        }
    }
}