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Exercise: Fastest Server Matchmaking

Find the fastest responding game server using asynchronous task combinators.

Problem statement

In multiplayer gaming, a client must often ping multiple regional matchmaking servers simultaneously to determine which one offers the lowest latency. You need to implement a utility that simulates pinging three servers and automatically selects the one that responds first, allowing the player to connect without waiting for the slower servers.

Task requirements

  • Start the simulated ping process for three regions: “US-East”, “Europe”, and “Asia”.

  • Determine which server responds first.

  • Extract and return the name of the winning server from the utility class.

Constraints

  • You must use Task.WhenAny inside the Matchmaker class to race the three tasks against each other.

  • You must await the winning task to extract its string result.

  • Do not block the thread using .Result or .Wait().

Good luck trying the exercise! If you’re unsure how to proceed, check the “Solution” tab above.

Get hints

  • Pass the three tasks into Task.WhenAny separated by commas inside FindFastestServerAsync.

  • Task.WhenAny returns a Task<Task<string>>. The first await gives you the winning Task<string>.

  • You need a second await to get the actual string value from the winning task, which you then return.

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Quiz Yourself: Multithreading in .NET
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Home
Courses
Learn C# Fundamentals

Exercise: Fastest Server Matchmaking

Find the fastest responding game server using asynchronous task combinators.

Problem statement

In multiplayer gaming, a client must often ping multiple regional matchmaking servers simultaneously to determine which one offers the lowest latency. You need to implement a utility that simulates pinging three servers and automatically selects the one that responds first, allowing the player to connect without waiting for the slower servers.

Task requirements

  • Start the simulated ping process for three regions: “US-East”, “Europe”, and “Asia”.

  • Determine which server responds first.

  • Extract and return the name of the winning server from the utility class.

Constraints

  • You must use Task.WhenAny inside the Matchmaker class to race the three tasks against each other.

  • You must await the winning task to extract its string result.

  • Do not block the thread using .Result or .Wait().

Good luck trying the exercise! If you’re unsure how to proceed, check the “Solution” tab above.

Get hints

  • Pass the three tasks into Task.WhenAny separated by commas inside FindFastestServerAsync.

  • Task.WhenAny returns a Task<Task<string>>. The first await gives you the winning Task<string>.

  • You need a second await to get the actual string value from the winning task, which you then return.

Similar Problems
Task Combinators and Cancellation
Advanced Data Parallelism
Async Best Practices and Exceptions
Quiz Yourself: Multithreading in .NET
Exercise: Thread-Safe Voucher Redemption
Exercise: Shipping API Timeout Fallback
Creating Threads
Parameterized Methods
Synchronizing Threads
Lock and Monitor
C# 14.0
using System.Threading.Tasks;
namespace Multiplayer;
public class Matchmaker
{
    public async Task<string> FindFastestServerAsync()
    {
        Task<string> usTask = PingServerAsync("US-East", 700);
        Task<string> euTask = PingServerAsync("Europe", 500);
        Task<string> asiaTask = PingServerAsync("Asia", 550);
        // TODO: Use Task.WhenAny to wait for the fastest server to respond
        // TODO: Await the winner to get the server name
        // TODO: Return the winning server name
        
        return string.Empty; 
    }
    private async Task<string> PingServerAsync(string region, int delayInMilliseconds)
    {
        await Task.Delay(delayInMilliseconds);
        return region;
    }
}