C#•12mo ago

✅ Is it possible to lock method by id?

I don't know how to write correct question but I would try to describe my idea. Let's say I have this method: public async Task<Dto> Modify(string groupId) => .. Imagine there are 4 people inside 1 group and someone called Modify method. Modification was started, it takes 1 minute for example and someone from this group called Modify method again. I want to deny the second user to use Modify method because first user didn't get the response. How can I do it?

19 Replies

DaVinki•12mo ago

You can use the TryEnter method on a monitor. If it failed, another thread is already entered

SWEETPONYOP•12mo ago

Yes, I know about lock but actually I don't need it. Imagine we have 2 groups with people so lock can't help me

alex•12mo ago

if someone is already modifying, do you want the second caller to wait, or fail? you can have a lock for each group

SWEETPONYOP•12mo ago

named semaphore? by the way I think lock and async things are not good things idk

alex•12mo ago

i would use a ConcurrentDictionary<groupId, object> correct

SWEETPONYOP•12mo ago

hm didn't think about it maybe wait..

alex•12mo ago

the async method can change threads, which could lead to problems with the lock i dont know about that, youll have to do some research

DaVinki•12mo ago

Are you sure sharing something between multiple groups and locking only within those groups is the ideal scenario? What if you made an object for each group that they own? It might be an XY problem

Joschi•12mo ago

What about an AsyncLocal<bool> in the group object that keeps track of the state?

cap5lut•12mo ago

for lock behaviour, as in waiting til u acquire the lock, i usually use a SemaphoreSlim if i want to try to aquire a lock but otherwise fail, i usually use an int and Interlocked.Exchange() note that these ways of doing things arent safe for reentrant

Baturhan•12mo ago

Use redis for distrubted lock your keyword is "Distributed Locks"

alex•12mo ago

i dont think thats needed from a quick google, you should be fine with a SemaphoreSlim.WaitAsync

cap5lut•12mo ago

u could also choose to use dotNext.Threading, it comes with a bunch of async friendly locks AsyncExclusiveLock (https://dotnet.github.io/dotNext/features/threading/exclusive.html) is just one among many

SWEETPONYOP•12mo ago

it will be fun if we can do this: using @lock = lock;

alex•12mo ago

would be cool but its not a good idea to abuse Dispose like that

SWEETPONYOP•12mo ago

hehe

lock ("12")
{
    
}

namespace System.Threading
{
    public static class Monitor
    {
        public static void Enter(
            object obj, 
            ref bool taken)
        {
            Console.WriteLine("Hello, world!");
            taken = true;
        }

        public static void Exit(object obj)
        {
            Console.WriteLine("Bye, world!");
        }
    }
};

lock ("12")
{
    
}

namespace System.Threading
{
    public static class Monitor
    {
        public static void Enter(
            object obj, 
            ref bool taken)
        {
            Console.WriteLine("Hello, world!");
            taken = true;
        }

        public static void Exit(object obj)
        {
            Console.WriteLine("Bye, world!");
        }
    }
};

now Enter and Exit should implement AcquireAsync from AsyncExclusiveLock harold

cap5lut•12mo ago

using + IDisposable is quite often used for such stuff, especially u see often some kind of lease struct for some array which simply returns the array to the pool

alex•12mo ago

it makes sense for something that acquires and releases yeah

SWEETPONYOP•12mo ago

thanks for helping

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✅ Is it possible to lock method by id?