Asp.Net Core run once function

Question

When start Asp.Net Core I have to call the database through EntityFrameworkCore, I have to run it only once during user "Session"

Any suggests ?

Answer 1

I usually use IHostedService. There is a great article on this by Andrew Lock .

In essence, what you want to do is implement the IHostedService interface and put your DB code in the StartAsync method.

public class MigratorHostedService: IHostedService
{
    // We need to inject the IServiceProvider so we can create 
    // the scoped service, MyDbContext
    private readonly IServiceProvider _serviceProvider;
    public MigratorStartupFilter(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
    }

    public async Task StartAsync(CancellationToken cancellationToken)
    {
        // Create a new scope to retrieve scoped services
        using(var scope = _seviceProvider.CreateScope())
        {
            // Get the DbContext instance
            var myDbContext = scope.ServiceProvider.GetRequiredService<MyDbContext>();

            //Do the migration asynchronously
            await myDbContext.Database.MigrateAsync();
        }
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        // noop
        return Task.CompletedTask;
    }
}

This code was taken directly from the article mentioned and is only placed here to answer the question asked. All credit must go to Andrew Lock