C# – Read POST Request body in Web API 2

asp.net-web-api2c

Just for learning purpose, I am logging all http requests to my Web API 2 application using a handler.

enum LogType {Information = 1, Warning = 2, Error = 3 }
public class LogHandler: DelegatingHandler
{
    async protected override Task SendAsync(HttpRequestMessage httpRequest, CancellationToken cancellationToken)
    {
        Trace.WriteLine(httpRequest.ToString(), LogType.Information.ToString());
        var response = await base.SendAsync(httpRequest, cancellationToken);
        return response;
    }
}

This just prints the Request Headers as follows:

Information: Method: POST, RequestUri: 'http://localhost:49964/school/title?number=1&name=swanand pangam', Version: 1.1, Content: System.Web.Http.WebHost.HttpControllerHandler+LazyStreamContent, Headers:
{
  Cache-Control: no-cache
  Connection: keep-alive
  Accept: text/csv
  Accept-Encoding: gzip
  Accept-Encoding: deflate
  Host: localhost:49964
  User-Agent: PostmanRuntime/7.1.1
  Postman-Token: 074c3aab-3427-4368-be25-439cbabe0654
  Content-Length: 31
  Content-Type: text/plain
}

But I am also sending a json object in POST body which is not printed. I want to print both the Headers as well as body. Also I can't find anything in the 'HttpRequestMessage' object while debugging.

Best Answer

You should read the content as below

    // log request body
    string requestBody = await httpRequest.Content.ReadAsStringAsync();
    Trace.WriteLine(requestBody);

This will log the request body.

Method A: HttpClient (Preferred)

Available in: .NET Framework 4.5+, .NET Standard 1.1+, .NET Core 1.0+ .

It is currently the preferred approach, and is asynchronous and high performance. Use the built-in version in most cases, but for very old platforms there is a NuGet package.

using System.Net.Http;

Setup

It is recommended to instantiate one HttpClient for your application's lifetime and share it unless you have a specific reason not to.

private static readonly HttpClient client = new HttpClient();

See HttpClientFactory for a dependency injection solution.

POST

var values = new Dictionary<string, string>
{
    { "thing1", "hello" },
    { "thing2", "world" }
};

var content = new FormUrlEncodedContent(values);

var response = await client.PostAsync("http://www.example.com/recepticle.aspx", content);

var responseString = await response.Content.ReadAsStringAsync();

GET

var responseString = await client.GetStringAsync("http://www.example.com/recepticle.aspx");

Method B: Third-Party Libraries

RestSharp

POST

 var client = new RestClient("http://example.com");
 // client.Authenticator = new HttpBasicAuthenticator(username, password);
 var request = new RestRequest("resource/{id}");
 request.AddParameter("thing1", "Hello");
 request.AddParameter("thing2", "world");
 request.AddHeader("header", "value");
 request.AddFile("file", path);
 var response = client.Post(request);
 var content = response.Content; // Raw content as string
 var response2 = client.Post<Person>(request);
 var name = response2.Data.Name;

Flurl.Http

It is a newer library sporting a fluent API, testing helpers, uses HttpClient under the hood, and is portable. It is available via NuGet.

    using Flurl.Http;

POST

var responseString = await "http://www.example.com/recepticle.aspx"
    .PostUrlEncodedAsync(new { thing1 = "hello", thing2 = "world" })
    .ReceiveString();

GET

var responseString = await "http://www.example.com/recepticle.aspx"
    .GetStringAsync();

Method C: HttpWebRequest (not recommended for new work)

Available in: .NET Framework 1.1+, .NET Standard 2.0+, .NET Core 1.0+. In .NET Core, it is mostly for compatibility -- it wraps HttpClient, is less performant, and won't get new features.

using System.Net;
using System.Text;  // For class Encoding
using System.IO;    // For StreamReader

POST

var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");

var postData = "thing1=" + Uri.EscapeDataString("hello");
    postData += "&thing2=" + Uri.EscapeDataString("world");
var data = Encoding.ASCII.GetBytes(postData);

request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = data.Length;

using (var stream = request.GetRequestStream())
{
    stream.Write(data, 0, data.Length);
}

var response = (HttpWebResponse)request.GetResponse();

var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

GET

var request = (HttpWebRequest)WebRequest.Create("http://www.example.com/recepticle.aspx");

var response = (HttpWebResponse)request.GetResponse();

var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();

Method D: WebClient (Not recommended for new work)

This is a wrapper around HttpWebRequest. Compare with HttpClient.

Available in: .NET Framework 1.1+, NET Standard 2.0+, .NET Core 2.0+

using System.Net;
using System.Collections.Specialized;

POST

using (var client = new WebClient())
{
    var values = new NameValueCollection();
    values["thing1"] = "hello";
    values["thing2"] = "world";

    var response = client.UploadValues("http://www.example.com/recepticle.aspx", values);

    var responseString = Encoding.Default.GetString(response);
}

GET

using (var client = new WebClient())
{
    var responseString = client.DownloadString("http://www.example.com/recepticle.aspx");
}

Best Answer

Related Solutions

C# – How to make an HTTP POST web request

Method A: HttpClient (Preferred)

Setup

Method B: Third-Party Libraries

Method C: HttpWebRequest (not recommended for new work)

Method D: WebClient (Not recommended for new work)

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