curl Too Many Redirects in C# (-L and –max-redirs)

curl redirect errors in C# come in two forms: a 301/302 response that is returned unfollowed because -L was not given, and CurlTooManyRedirectsException when the chain exceeds --max-redirs. CurlDotNet follows the same rules as command-line curl, and this page shows how to enable redirects, cap them, and handle the exception.

Redirects Are Not Followed by Default

Without -L, a redirect is just a response with a 3xx status and a Location header:

using CurlDotNet;

var result = await Curl.ExecuteAsync("curl https://httpbin.org/redirect/1");

Console.WriteLine(result.StatusCode);              // 302
Console.WriteLine(result.IsSuccess);               // False (only 2xx counts)
Console.WriteLine(result.GetHeader("Location"));   // /get

Following Redirects

-L / –location

var result = await Curl.ExecuteAsync("curl -L https://httpbin.org/redirect/3");
Console.WriteLine(result.StatusCode);   // 200, after three hops

Builder: FollowRedirects()

using CurlDotNet.Core;

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

Process-Wide Default

Curl.DefaultFollowRedirects = true;   // every command now behaves as if -L were given

var result = await Curl.ExecuteAsync("curl https://httpbin.org/redirect/1");

CurlSettings

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

Limiting Redirects

The default limit is 50 hops, matching curl. --max-redirs N allows exactly N redirects (-1 means unlimited); when the server sends one more, CurlTooManyRedirectsException (exit code 47) is thrown with RedirectCount set and curl’s message “Maximum (N) redirects followed”:

using CurlDotNet.Exceptions;

try
{
    var result = await Curl.ExecuteAsync("curl -L --max-redirs 2 https://httpbin.org/redirect/5");
}
catch (CurlTooManyRedirectsException ex)
{
    Console.WriteLine($"Gave up after {ex.RedirectCount} redirects");   // 2
    Console.WriteLine(ex.CurlErrorCode);                                // 47
}

Builder equivalent: .FollowRedirects().WithMaxRedirects(2).

Watching the Chain

-w '%{url_effective}' appends the final URL to the body, and -v writes each hop’s request and response header block to the start of result.Body:

var result = await Curl.ExecuteAsync("curl -L -w '%{url_effective}' https://httpbin.org/redirect/3");
Console.WriteLine(result.Body);   // ... body of the final page, then https://httpbin.org/get

-iL includes every hop’s response headers in the body as well, as curl does.

Other Redirect Exceptions

Exception CurlErrorCode Thrown when
CurlUnsupportedProtocolException 1 With -L, the Location header points at a scheme other than http/https (for example ftp:// or file:///etc/passwd); curl refuses to switch protocols. Fetch that URL explicitly if you trust it, or drop -L to see the redirect itself
CurlMalformedUrlException 3 The Location header is not a valid URL
CurlRedirectException 47 Reserved: exists in CurlDotNet.Exceptions but nothing throws it; catch CurlTooManyRedirectsException

Method and Credentials on Redirect

CurlDotNet follows curl’s rules, which explain many “works in the browser, fails with -L” reports:

Common Causes of Redirect Loops

Choosing a Limit