C#•2y ago

✅ [SOLVED] Need help with converting async method to a 'normal' method

I tried a few solutions to be able to call an async method from my Main method but those have failed, here is the link: https://stackoverflow.com/questions/9343594/how-to-call-asynchronous-method-from-synchronous-method-in-c Here is my code:

public static class FileEncryptor
        {
            private const int AesKeySize = 256;
            private const int AesBlockSize = 128;
            public const int KeySizeInBytes = AesKeySize / 8;

            /// <summary>
            /// Encrypts a file using a 32 character key.
            /// </summary>
            public static Task EncryptAsync(string inputFilePath, string outputFilePath, string key, CancellationToken token = default)
            {
                if (string.IsNullOrWhiteSpace(key))
                {
                    //if key is empty do jack
                }

                byte[] keyBytes = Encoding.UTF8.GetBytes(key);
                return EncryptAsync(inputFilePath, outputFilePath, keyBytes, token);
            }
            public static async Task EncryptAsync(string inputFilePath, string outputFilePath, byte[] keyBytes, CancellationToken token = default)
            {
                if (!File.Exists(inputFilePath))
                {
                }
                if (keyBytes.Length != KeySizeInBytes)
                { 
                }
                using var aes = Aes.Create();
                aes.BlockSize = AesBlockSize;
                aes.KeySize = AesKeySize;
                aes.Key = keyBytes;

                await using FileStream outFileStream = new(outputFilePath, FileMode.Create);

                // Write initialization vector to beginning of file
                await outFileStream.WriteAsync(aes.IV.AsMemory(0, aes.IV.Length), token);

                ICryptoTransform encryptor = aes.CreateEncryptor();
                await using CryptoStream cryptoStream = new(
                    outFileStream,
                    encryptor,
                    CryptoStreamMode.Write);

                await using var inputFileStream = new FileStream(inputFilePath, FileMode.Open);

                await inputFileStream.CopyToAsync(cryptoStream, token);
            }
        }

public static class FileEncryptor
        {
            private const int AesKeySize = 256;
            private const int AesBlockSize = 128;
            public const int KeySizeInBytes = AesKeySize / 8;

            /// <summary>
            /// Encrypts a file using a 32 character key.
            /// </summary>
            public static Task EncryptAsync(string inputFilePath, string outputFilePath, string key, CancellationToken token = default)
            {
                if (string.IsNullOrWhiteSpace(key))
                {
                    //if key is empty do jack
                }

                byte[] keyBytes = Encoding.UTF8.GetBytes(key);
                return EncryptAsync(inputFilePath, outputFilePath, keyBytes, token);
            }
            public static async Task EncryptAsync(string inputFilePath, string outputFilePath, byte[] keyBytes, CancellationToken token = default)
            {
                if (!File.Exists(inputFilePath))
                {
                }
                if (keyBytes.Length != KeySizeInBytes)
                { 
                }
                using var aes = Aes.Create();
                aes.BlockSize = AesBlockSize;
                aes.KeySize = AesKeySize;
                aes.Key = keyBytes;

                await using FileStream outFileStream = new(outputFilePath, FileMode.Create);

                // Write initialization vector to beginning of file
                await outFileStream.WriteAsync(aes.IV.AsMemory(0, aes.IV.Length), token);

                ICryptoTransform encryptor = aes.CreateEncryptor();
                await using CryptoStream cryptoStream = new(
                    outFileStream,
                    encryptor,
                    CryptoStreamMode.Write);

                await using var inputFileStream = new FileStream(inputFilePath, FileMode.Open);

                await inputFileStream.CopyToAsync(cryptoStream, token);
            }
        }

So how do I go about converting this to something that I can easily call like a normal function from Main?

23 Replies

cap5lut•2y ago

why not just make ur Main async?

JakenVeina•2y ago

was about to say that's also kinda the opposite of what the title says

cap5lut•2y ago

public class Program
{
  public static void Main()
  {
    Console.WriteLine("Hello ...");
    Thread.Sleep(1000);
    Console.WriteLine("... World!");
  }
}

public class Program
{
  public static void Main()
  {
    Console.WriteLine("Hello ...");
    Thread.Sleep(1000);
    Console.WriteLine("... World!");
  }
}

and

public class Program
{
  public static async Task Main()
  {
    Console.WriteLine("Hello ...");
    await Task.Delay(1000);
    Console.WriteLine("... World!");
  }
}

public class Program
{
  public static async Task Main()
  {
    Console.WriteLine("Hello ...");
    await Task.Delay(1000);
    Console.WriteLine("... World!");
  }
}

are both valid entry points and do more or the same

c0nstantOP•2y ago

I wouldn't know why would I go async, I am too used to the old ways of coding something that works, speed is not really a concern here but I would like to hear how would you do that?

JakenVeina•2y ago

So how do I go about converting this to something that I can easily call like a normal function from Main

You don't, you have async work to do, so your method must be async. Also, the method is ALREADY a "normal" function that can easily be called from Main()

cap5lut•2y ago

async doesnt mean that its faster, its just async ;p

JakenVeina•2y ago

you missed async on Main

cap5lut•2y ago

noticed and fixed ;p thx for pointing out 🙂

c0nstantOP•2y ago

thanks for the advise, I will see what I can do after the changes

JakenVeina•2y ago

on the rare occasion that you DO need to call an async method from a non-async method, and wait for its completion, you do

var result = MyMethodAsync().GetAwaiter().GetResult();

var result = MyMethodAsync().GetAwaiter().GetResult();

avoid doing this unless you have no other option

c0nstantOP•2y ago

Somehow, it actually worked this time. So the last time I was trying to run it, my IDE had automatically added async as part of my main method, something like static async Main(string[] args) Now I rebuilt it and can finally run it I don't know how to explain this :/ but it worked thanks 🙂

JakenVeina•2y ago

async methods must return Task 99.99% of the time

c0nstantOP•2y ago

by returning task do you mean something like await Task.Delay(1000);?

JakenVeina•2y ago

no, I mean defining the method's return type to be Task or Task<T>

c0nstantOP•2y ago

Got it

cap5lut•2y ago

the Main method can come in a lot of variants static int Main(string[] args) static int Main() static void Main(string[] args) static void Main() and the same for async, instead of void it would be Task and instead of int it would be Task<int> (and it can be either just static or static async)

JakenVeina•2y ago

uhh, why'd you list each version twice?

cap5lut•2y ago

oh fixed 😂

c0nstantOP•2y ago

I am getting familiar, thanks for sharing

cap5lut•2y ago

lets mention top-level statements for completion as well:

Console.WriteLine("Hello World");

Console.WriteLine("Hello World");

can also be a complete "main method" (the compiler automatically builds a Program class with the Main method then)

JakenVeina•2y ago

lets mention top-level statements for completion as well:

could we, instead, not? 😆

cap5lut•2y ago

too late 😒 $close

MODiX•2y ago

Use the /close command to mark a forum thread as answered

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✅ [SOLVED] Need help with converting async method to a 'normal' method