如何将 HttpContext 传递给新线程 c#

Question

I need to invoke my process and forget about it. I have a method which is able to invoke my process and return "Accepted" without waiting. The problem is that I cannot access HttpContext inside the new thread (inside action). I would like to forward HttpContext from the main thread to the new one however it doesn't work.

private async Task<string> InvokeAsyncProcess(bool wait, Func<Task<Statistics>> action, string name)
{
    var oldHttpContext = System.Web.HttpContext.Current;
    if (wait)
    {
        Statistics stats = await action.Invoke();
        return JsonConvert.SerializeObject(stats);
    }
    else
    {
        Thread job = new Thread(async f =>
        {
            try
            {
                System.Web.HttpContext.Current = oldHttpContext;

                await LogService.LogAsync(LogCategory.Info, name, "Started in the background", null, null);
                Statistics stats = await action.Invoke();
                await LogService.LogAsync(LogCategory.Info, name, string.Format("Finished, returned data: {0}", JsonConvert.SerializeObject(stats)), null, null);
            }
            catch (Exception e)
            {
                await LogService.LogAsync(LogCategory.Error, name, "Error...", e, null);
            }
        });

        job.Start(); 
        Response.StatusCode = (int)HttpStatusCode.Accepted;
        return "Accepted";  // Accepted = 202
    }
}

Answer 1

You can pass parameters to a new thread with ParameterizedThreadStart

var job = new Thread(async input =>
{
    HttpContext httpContext = (HttpContext)input;

});

job.Start(HttpContext.Current)

Although I don't recommend passing HttpContext to a new thread. It's a good idea since HttpContext is not thread safe. Also after you return "Accepted"; the current request will finish and it will dispose HttpContext . So you might get some disposed objects in the new thread.