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.NET Framework : HTTP clients


Curious Bot - December 1, 2018 - 0 comments

Reading GET response as string using System.Net.HttpWebRequest

string requestUri = "http://www.example.com";
string responseData;

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(parameters.Uri);
WebResponse response = request.GetResponse();

using (StreamReader responseReader = new StreamReader(response.GetResponseStream()))
{
responseData = responseReader.ReadToEnd();
}

Reading GET response as string using System.Net.WebClient

string requestUri = "http://www.example.com";
string responseData;

using (var client = new WebClient())
{
responseData = client.DownloadString(requestUri);
}

Reading GET response as string using System.Net.HttpClient

HttpClient is available through NuGet: Microsoft HTTP Client Libraries.

string requestUri = "http://www.example.com";
string responseData;

using (var client = new HttpClient())
{
using(var response = client.GetAsync(requestUri).Result)
{
response.EnsureSuccessStatusCode();
responseData = response.Content.ReadAsStringAsync().Result;
}
}

Sending a POST request with a string payload using System.Net.HttpWebRequest

string requestUri = "http://www.example.com";
string requestBodyString = "Request body string.";
string contentType = "text/plain";
string requestMethod = "POST";

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestUri)
{
Method = requestMethod,
ContentType = contentType,
};

byte[] bytes = Encoding.UTF8.GetBytes(requestBodyString);
Stream stream = request.GetRequestStream();
stream.Write(bytes, 0, bytes.Length);
stream.Close();

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

Sending a POST request with a string payload using System.Net.WebClient

string requestUri = "http://www.example.com";
string requestBodyString = "Request body string.";
string contentType = "text/plain";
string requestMethod = "POST";

byte[] responseBody;
byte[] requestBodyBytes = Encoding.UTF8.GetBytes(requestBodyString);

using (var client = new WebClient())
{
client.Headers[HttpRequestHeader.ContentType] = contentType;
responseBody = client.UploadData(requestUri, requestMethod, requestBodyBytes);
}

Sending a POST request with a string payload using System.Net.HttpClient

HttpClient is available through NuGet: Microsoft HTTP Client Libraries.

string requestUri = "http://www.example.com";
string requestBodyString = "Request body string.";
string contentType = "text/plain";
string requestMethod = "POST";

var request = new HttpRequestMessage
{
RequestUri = requestUri,
Method = requestMethod,
};

byte[] requestBodyBytes = Encoding.UTF8.GetBytes(requestBodyString);
request.Content = new ByteArrayContent(requestBodyBytes);

request.Content.Headers.ContentType = new MediaTypeHeaderValue(contentType);

HttpResponseMessage result = client.SendAsync(request).Result;
result.EnsureSuccessStatusCode();

Basic HTTP downloader using System.Net.Http.HttpClient

using System;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;

class HttpGet
{
private static async Task DownloadAsync(string fromUrl, string toFile)
{
using (var fileStream = File.OpenWrite(toFile))
{
using (var httpClient = new HttpClient())
{
Console.WriteLine("Connecting...");
using (var networkStream = await httpClient.GetStreamAsync(fromUrl))
{
Console.WriteLine("Downloading...");
await networkStream.CopyToAsync(fileStream);
await fileStream.FlushAsync();
}
}
}
}

static void Main(string[] args)
{
try
{
Run(args).Wait();
}
catch (Exception ex)
{
if (ex is AggregateException)
ex = ((AggregateException)ex).Flatten().InnerExceptions.First();

Console.WriteLine("--- Error: " +
(ex.InnerException?.Message ?? ex.Message));
}
}
static async Task Run(string[] args)
{
if (args.Length < 2)
{
Console.WriteLine("Basic HTTP downloader");
Console.WriteLine();
Console.WriteLine("Usage: httpget <url>[<:port>] <file>");
return;
}

await DownloadAsync(fromUrl: args[0], toFile: args[1]);

Console.WriteLine("Done!");
}
}

Remarks

The currently relevant HTTP/1.1 RFCs are:

There’s also the following informational RFCs:

And the experimental RFC:

Related protocols:

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