Multithreaded treated as single thread

[openbullet]

Hello,
first of all I'd like to thank you for your amazing library!

I want to solve multiple challenges at the same time in a multithreaded way.

In this snippet I will execute a get request in parallel for the same website 5 times, using the standard HttpClient without the solver:

Stopwatch sw = new Stopwatch();
var jobs = 5;
var target = new Uri("http://example.com");

var tasks = Enumerable.Range(1, jobs).Select(async n =>
{
    using (var handler = new HttpClientHandler())
    {
        using (var client = new HttpClient(handler))
        {
            await client.GetAsync(target);
            Console.WriteLine($"[{sw.Elapsed.TotalSeconds} s] [Job {n}] Completed");
        }
    }
});

sw.Start();
Console.WriteLine($"Started {jobs} jobs");
Task.WhenAll(tasks).Wait();
sw.Stop();

The output will look like this:

[0,481979 s] [Job 4] SUCCESS
[0,4822557 s] [Job 5] SUCCESS
[0,4830797 s] [Job 1] SUCCESS
[0,5180153 s] [Job 2] SUCCESS
[0,5286887 s] [Job 3] SUCCESS

So the jobs are completed correctly in no specific order and in around the same time, which is exactly what I want.

Now if I introduce the CloudflareSolver inside those tasks, I will write something like this

Stopwatch sw = new Stopwatch();
var jobs = 5;
var target = new Uri("http://example.com");

var tasks = Enumerable.Range(1, jobs).Select(async n =>
{
    using (var handler = new HttpClientHandler())
    {
        using (var client = new HttpClient(handler))
        {
            var cf = new CloudflareSolver() { MaxTries = 3, ClearanceDelay = 3000 };
            var result = await cf.Solve(client, handler, target);
            Console.WriteLine($"[{sw.Elapsed.TotalSeconds} s] [Job {n}] Completed");
        }
    }
});

sw.Start();
Console.WriteLine($"Started {jobs} jobs");
Task.WhenAll(tasks).Wait();
sw.Stop();

which for any website (both protected by cloudflare and not) gives this result (in the cloudflare case since it takes more time the timestamps are like 3s, 6s, 9s etc)

[0,6562882 s] [Job 1] SUCCESS
[0,8766025 s] [Job 2] SUCCESS
[1,1023446 s] [Job 3] SUCCESS
[1,3321279 s] [Job 4] SUCCESS
[1,5533806 s] [Job 5] SUCCESS

This is clearly a synchronous execution where only one solver is able to run at the same time even if I have multiple separate instances of the solvers.

Why do you think this happens?

Thank you for your help,
Ruri

P.S. the same happens even if I give it the ClearanceHandler directly.

[openbullet]

In case you are wondering why I need to do this, instead of just solving the challenge once and then using the cookies for my multiple requests, it's because I want to use a different proxy for each of the 5 http clients, so I need to solve 5 different challenges since one challenge is valid only for a certain IP, as I'm sure you're already aware.

[openbullet]

Hi, I fixed this issue by removing the SemaphoreLocker in CloudflareDetector.cs and removing the static keyword from the one in CloudflareSolver.cs
Do you want me to make a pull request or would you prefer to keep the lock? It does break multithread use so it's up to you.