Added cookie accessor/iterator to CookieContainer

[shravan2x]

Background and Motivation

There's currently no way to access all cookies in a CookieContainer instance without known their domain names. CookieContainer also does not expose a list of domains it holds cookies for. I propose adding a GetAllCookies() method for this. It seems I'm not the only one with a use-case for it https://stackoverflow.com/questions/15983166/how-can-i-get-all-cookies-of-a-cookiecontainer

Latest API proposal

Based on discussion below - #44094 (comment)

public class CookieContainer
{
  // Existing API:
  public CookieCollection GetCookies(Uri uri);

  // Proposed API:
  public CookieCollection GetAllCookies();
}

Original API proposal

 public IEnumerable<Cookie> GetAllCookies();

or

class CookieContainer : IEnumerable<Cookie>

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[KalleOlaviNiemitalo]

CookieContainer tries to be thread-safe, although I don't see that in the documentation. If other threads add or remove cookies while you enumerate them, does that invalidate the enumerator?

[shravan2x]

CookieContainer tries to be thread-safe, although I don't see that in the documentation. If other threads add or remove cookies while you enumerate them, does that invalidate the enumerator?

It could invalidate it and throw an exception on the next iteration, or it could iterate an older "snapshot" similar to how ConcurrentDictionary works. Either would make sense to me though the latter would be preferred.

The only bad version would be one that doesn't make any guarantees and just silently corrupts itself to miss entries or return duplicate ones.

[geoffkizer]

Seems like just implementing IEnumerable<Cookie> is the cleanest approach here, unless there's some problem with that.

[geoffkizer]

Actually, we already did this. See dotnet/corefx#30080. I knew it sounded familiar.

[shravan2x]

@geoffkizer That's weird, I just made a new project using .NET 5.0 and I still can't get it to work:

Maybe it was changed after? I don't see it in master either https://github.com/dotnet/runtime/blob/master/src/libraries/System.Net.Primitives/src/System/Net/CookieContainer.cs#L94

[geoffkizer]

Sorry, the linked issue is about CookieCollection, not CookieContainer.

[shravan2x]

Ah that makes sense. Agree that implementing IEnumerable<Cookie> is the cleanest approach.