Add HTTP::Cookie#destroy

[a-alhusaini]

Reasoning

I tried to use cookies.delete("...") today and it didn't cause the cookie to expire from the browser. It sent it again on the next request.

This method sets the cookie value to an empty string and seets the expiry date to 5 minutes ago. Browsers automatically delete expired cookies.

My aim is to provide a convenience to anyone who happens to need to use HTTP::Cookie

[ysbaddaden]

Since the intent is to expire the cookie, then #expire would be a better name than #destroy.

I'd also put an expiration date far further than 5 minutes ago (clocks can get unsynced) and use a fixed date, like the UNIX timestamp (1970-01-01 00:00:00 UTC).

[a-alhusaini]

@ysbaddaden Hey julian! This little function is a convenience for destroying cookies (which usually means setting their expiry to some date in the past and setting their value to blank)

I just thought others might want a convenient function to destroy cookies.

Although as you pointed out, it is superflous. I just PR'd it to promote developer happiness :3

[straight-shoota]

It would be much appreciated to follow the guidelines for feature discussions and open an issue for a new proposal first, to keep the general discussion independent of a PR with a concrete implementation.
Since this is relatively trivial, I suppose we can continue the discussion here. But next time, please open an issue first please.

[straight-shoota]

Actually, setting Expires to a date in the past does not fully ensure the cookie to expire. Max-Age takes precedence. If Max-Age is set, the value of Expires doesn't matter.

So I think the functionality should be implemented as self.max_age = Time::Span.zero.
We could also consider self.expires = Time::UNIX_EPOCH on top, just for good measure, but that should not really be necessary.

[a-alhusaini]

Sorry about the typo. I can't run the test suite locally so I'm relying on the CI.

[Sija]

Suggested change

	# tell the browser to delete the cookie.
	# Set its value to an empty string
	# and set its expiration time to the past
	# Browsers delete cookies that have expired.
	def destroy
	self.value = ""
	self.expires = Time::UNIX_EPOCH
	self.max_age = Time::Span.zero
	end
	# Tells the browser to expire the cookie by setting its
	# max age time to zero and its expiration time to the past.
	def expire
	self.expires = Time::UNIX_EPOCH
	self.max_age = Time::Span.zero
	end

[a-alhusaini]

Could you elaborate on why you suggest that we remove setting the value to a blank string?

[Sija]

Sure, my reasoning was twofold:

1. expire method name IMO implies only cookie expiration, not emptying its value
2. Spec doesn't mention (or I've not seen it does) clearing out the value as the requirement for a cookie expiration

[a-alhusaini]

I believe destroy will better represent what the function does. And there are many methods with a name similar to #expire I think calling it #destroy would be more clear.

[straight-shoota]

Clearing the value is not a requirement for expiration. But I think it makes a lot of sense not to send the value you want gone to the client again.

[straight-shoota]

IMO the name #destroy makes sense. Expiration is just the mechanism used to signal to the client to forget this cookie.

[Sija]

I still do think that's a bit unexpected to clear the value in here. Just sayin'