How to follow redirects with curl -L in C#

To follow redirects in C# the way curl -L does, add -L to the command you pass to Curl.ExecuteAsync, or call .FollowRedirects() on CurlRequestBuilder. Like the curl CLI, CurlDotNet does not follow redirects unless you ask.

dotnet add package CurlDotNet

Without -L you get the redirect itself

using CurlDotNet;

var result = await Curl.ExecuteAsync("curl https://httpbin.org/redirect/2");

Console.WriteLine(result.StatusCode);             // 302
Console.WriteLine(result.GetHeader("Location"));  // /relative-redirect/1

That is useful when you want to inspect where a link points without fetching the target.

With -L

using CurlDotNet;

var result = await Curl.ExecuteAsync("curl -L https://httpbin.org/redirect/2");
Console.WriteLine(result.StatusCode);  // 200, after two hops

The fluent builder

using CurlDotNet.Core;

var result = await CurlRequestBuilder
    .Get("https://httpbin.org/redirect/3")
    .FollowRedirects()
    .WithMaxRedirects(5)
    .ExecuteAsync();

Console.WriteLine(result.StatusCode);

Limit the number of hops

--max-redirs N allows exactly N hops (-1 means unlimited; the default is 50). One more redirect after that throws CurlTooManyRedirectsException (curl error code 47):

using CurlDotNet;
using CurlDotNet.Exceptions;

try
{
    await Curl.ExecuteAsync("curl -L --max-redirs 1 https://httpbin.org/redirect/3");
}
catch (CurlTooManyRedirectsException ex)
{
    Console.WriteLine($"{ex.CurlErrorCode}: {ex.Message}");  // 47: Maximum (1) redirects followed: ...
}

Turn it on for many calls

using CurlDotNet;
using CurlDotNet.Core;

var settings = new CurlSettings().WithFollowRedirects(true);
var result = await Curl.ExecuteAsync("https://httpbin.org/redirect/1", settings);

Curl.DefaultFollowRedirects = true;  // every request in the process now follows redirects
var viaDefaults = await Curl.ExecuteAsync("https://httpbin.org/redirect/1");

Curl.DefaultFollowRedirects applies to every request, including plain Curl.ExecuteAsync(command) calls with no settings. LibCurl has WithFollowRedirects(maxRedirects) for an instance-wide default.

How redirects are handled

The shared HttpClient is created with AllowAutoRedirect = false. CurlDotNet’s own redirect handler follows each Location header, so curl’s rules apply instead of .NET’s defaults: