Synchronization issue? in Anglesharp with async calls

Question

I'm trying to write a routine that iterates through a set of accounts, and for each, creates a BrowsingContext in Anglesharp and logs in to a website. Here's my code.

public async Task Initialise(Account account)
    {

            this.Account = account;
            log.Debug("Starting InitialiseAsync for AccountId {0}", this.Account.Id);
            _config = Configuration.Default.WithDefaultLoader().WithDefaultCookies();
            var browsingContext = AngleSharp.BrowsingContext.New(_config);


            //Call to load the login page
            await browsingContext.OpenAsync(_myUrl) 
                     .ConfigureAwait(continueOnCapturedContext: false);;

            //Call to log in
            log.Debug("Calling SubmitAsync for AccountId {0}, and Url {1}", Account.Id, _myUrl);
            var task = await browsingContext.Active.QuerySelector("form").SubmitAsync(new

            {
                username = Account.User,
                pass = Account.Password
            }).ConfigureAwait(continueOnCapturedContext: false);


            log.Debug("Completed InitialiseAsync AccountId {0}, and Url {1}", Account.Id, _myUrl);

            return task;

    }


   [Test]
    public void TestBed()
    {
        var _data = new DataController();
        var accounts = _data.GetAccounts();


        async Task DoStuffWithItem(Account account)
        {
            var ass = new PlaygroundSession();
            await ass.Initialise(account);
        }

        var tasks = accounts.Select(a => DoStuffWithItem(a)).ToList();

         await Task.WhenAll(tasks);


    }

If I only have one account to process, this works and quickly. If I use 2 accounts, then it works, but the SubmitAsync for the 1st account takes 45 seconds to complete. If I use 3 accounts what always happens is as follows:

   1st account calls OpenSync
   2nd account calls OpenSync
   3rd account calls OpenSync
   2nd account calls SubmitAsync
   1st account calls SubmitAsync
   3rd account calls SubmitAsync
   2nd account completes

And then i get

System.Net.WebException: The request was aborted: The request was canceled.
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)

That's for Account 1

After the error Account 3 logs completion. I've verified that for 1 and 3 the login was a success.

user_4579452 · Answer

Author of the Anglesharp Framework suggested I try the Anglesharp.IO library's HttpRequester instead.

Changing

_config = Configuration.Default.WithDefaultLoader().WithDefaultCookies();
var browsingContext = AngleSharp.BrowsingContext.New(_config);

to

var client = new HttpClient();
var requester = new HttpClientRequester(client);
_config = Configuration.Default.WithRequester(requester)
                    .WithDefaultLoader().WithDefaultCookies();
var browsingContext = BrowsingContext.New(_config);

fixes the issue.

Synchronization issue? in Anglesharp with async calls

1 Answers