Why use HttpClient for Synchronous Connection
I'd re-iterate Donny V. answer and Josh's
"The only reason I wouldn't use the async version is if I were trying to support an older version of .NET that does not already have built in async support."
(and upvote if I had the reputation.)
I can't remember the last time if ever, I was grateful of the fact HttpWebRequest threw exceptions for status codes >= 400. To get around these issues you need to catch the exceptions immediately, and map them to some non-exception response mechanisms in your code...boring, tedious and error prone in itself. Whether it be communicating with a database, or implementing a bespoke web proxy, its 'nearly' always desirable that the Http driver just tell your application code what was returned, and leave it up to you to decide how to behave.
Hence HttpClient is preferable.
For anyone coming across this now, .NET 5.0 has added a synchronous Send
method to HttpClient
. https://github.com/dotnet/runtime/pull/34948
The merits as to why where discussed at length here: https://github.com/dotnet/runtime/issues/32125
You can therefore use this instead of SendAsync
. For example
public string GetValue()
{
var client = new HttpClient();
var webRequest = new HttpRequestMessage(HttpMethod.Post, "http://your-api.com")
{
Content = new StringContent("{ 'some': 'value' }", Encoding.UTF8, "application/json")
};
var response = client.Send(webRequest);
using var reader = new StreamReader(response.Content.ReadAsStream());
return reader.ReadToEnd();
}
This code is just a simplified example - it's not production ready.
but what i am doing is purely synchronous
You could use HttpClient
for synchronous requests just fine:
using (var client = new HttpClient())
{
var response = client.GetAsync("http://google.com").Result;
if (response.IsSuccessStatusCode)
{
var responseContent = response.Content;
// by calling .Result you are synchronously reading the result
string responseString = responseContent.ReadAsStringAsync().Result;
Console.WriteLine(responseString);
}
}
As far as why you should use HttpClient
over WebRequest
is concerned, well, HttpClient
is the new kid on the block and could contain improvements over the old client.
public static class AsyncHelper
{
private static readonly TaskFactory _taskFactory = new
TaskFactory(CancellationToken.None,
TaskCreationOptions.None,
TaskContinuationOptions.None,
TaskScheduler.Default);
public static TResult RunSync<TResult>(Func<Task<TResult>> func)
=> _taskFactory
.StartNew(func)
.Unwrap()
.GetAwaiter()
.GetResult();
public static void RunSync(Func<Task> func)
=> _taskFactory
.StartNew(func)
.Unwrap()
.GetAwaiter()
.GetResult();
}
Then
AsyncHelper.RunSync(() => DoAsyncStuff());
if you use that class pass your async method as parameter you can call the async methods from sync methods in a safe way.
it's explained here : https://cpratt.co/async-tips-tricks/