How to set large string inside HttpContent when using HttpClient?

Question

So, I created a HttpClient and am posting data using HttpClient.PostAsync().

I set the HttpContent using

HttpCo

Answer 1

This code works for me, basically you send post data "application/x-www-form-urlencoded" within string content over http client, hope this can help anyone with the same problem like me

void sendDocument()
    {
        string url = "www.mysite.com/page.php";
        StringBuilder postData = new StringBuilder();
        postData.Append(String.Format("{0}={1}&", HttpUtility.HtmlEncode("prop"), HttpUtility.HtmlEncode("value")));
        postData.Append(String.Format("{0}={1}", HttpUtility.HtmlEncode("prop2"), HttpUtility.HtmlEncode("value2")));
        StringContent myStringContent = new StringContent(postData.ToString(), Encoding.UTF8, "application/x-www-form-urlencoded");
        HttpClient client = new HttpClient();
        HttpResponseMessage message = client.PostAsync(url, myStringContent).GetAwaiter().GetResult();
        string responseContent = message.Content.ReadAsStringAsync().GetAwaiter().GetResult();
    }

Answer 2

I figured it out with the help of my friend. What you would want to do is avoid using FormUrlEncodedContent(), because it has restrictions on the size of the uri. Instead, you can do the following :

    var jsonString = JsonConvert.SerializeObject(post_parameters);
    var content = new StringContent(jsonString, Encoding.UTF8, "application/json");

Here, we don't need to use HttpContent to post to the server, StringContent gets the job done !

Answer 3

FormUrlEncodedContent internally uses Uri.EscapeDataString : from reflection, I can see that this method has constants limiting the size of request length.

A possible solution is to create a new implementation of FormUrlEncodedContent by using System.Net.WebUtility.UrlEncode (.net 4.5) to bypass this limitation.

public class MyFormUrlEncodedContent : ByteArrayContent
{
    public MyFormUrlEncodedContent(IEnumerable<KeyValuePair<string, string>> nameValueCollection)
        : base(MyFormUrlEncodedContent.GetContentByteArray(nameValueCollection))
    {
        base.Headers.ContentType = new MediaTypeHeaderValue("application/x-www-form-urlencoded");
    }
    private static byte[] GetContentByteArray(IEnumerable<KeyValuePair<string, string>> nameValueCollection)
    {
        if (nameValueCollection == null)
        {
            throw new ArgumentNullException("nameValueCollection");
        }
        StringBuilder stringBuilder = new StringBuilder();
        foreach (KeyValuePair<string, string> current in nameValueCollection)
        {
            if (stringBuilder.Length > 0)
            {
                stringBuilder.Append('&');
            }

            stringBuilder.Append(MyFormUrlEncodedContent.Encode(current.Key));
            stringBuilder.Append('=');
            stringBuilder.Append(MyFormUrlEncodedContent.Encode(current.Value));
        }
        return Encoding.Default.GetBytes(stringBuilder.ToString());
    }
    private static string Encode(string data)
    {
        if (string.IsNullOrEmpty(data))
        {
            return string.Empty;
        }
        return System.Net.WebUtility.UrlEncode(data).Replace("%20", "+");
    }
}

To send large content, it's better to use StreamContent.