added afterLogout trigger

[mtrezza]

Analogous to the existing beforeLogin trigger, this afterLogout trigger can be used to perform certain clean-up actions upon user logout.

The afterLogout trigger contains the _Session object that was deleted. Usually, a session object contains a pointer to a _User object with which the session is associated. With that, actions can be taken for the specific user that logged out.

Caveat:
The afterLogout is only triggered when a session object was deleted upon logout. If a user logs out but there is not session object to be deleted, the afterLogout trigger is not called. This is by design, because without a session object to determine who logged out, the afterLogout trigger does not seem useful.

[mtrezza]

Notes:

• tests included
• afterLogout is a trigger on the _Session class, so the trigger validation had to be changed. Before, any trigger on the _Session class was forbidden, now only the afterLogout trigger is allowed for the _Session class.

[codecov]

Codecov Report

Merging #6217 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #6217      +/-   ##
==========================================
- Coverage   93.82%   93.81%   -0.02%     
==========================================
  Files         167      167              
  Lines       11293    11302       +9     
==========================================
+ Hits        10596    10603       +7     
- Misses        697      699       +2

Impacted Files	Coverage Δ
src/Routers/UsersRouter.js	94.26% <100%> (+0.07%)	⬆️
src/cloud-code/Parse.Cloud.js	97.95% <100%> (+0.28%)	⬆️
src/triggers.js	94.09% <100%> (+0.02%)	⬆️
src/Adapters/Storage/Mongo/MongoStorageAdapter.js	92.27% <0%> (-0.71%)	⬇️
...dapters/Storage/Postgres/PostgresStorageAdapter.js	97.01% <0%> (-0.09%)	⬇️
src/RestWrite.js	93.75% <0%> (+0.16%)	⬆️
src/Routers/PushRouter.js	96.55% <0%> (+3.44%)	⬆️

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[dplewis]

I have a few comments.

[dplewis]

The afterLogout trigger contains the _Session object that was deleted.

Is this true?

[mtrezza]

@dplewis Yes, the session object is deleted from the DB and returned here. If there was any session object to delete.

See this._runAfterLogoutTrigger(req, records.results[0]);.

[dplewis]

Oh i see from the tests. Would I get the user?

[mtrezza]

@dplewis Yes, you can get the user, if there was a user associated with the session.

[dplewis]

LGTM

[mtrezza]

@dplewis I just noticed that in the tests I do not get the user from the session. The session object only looks like this:
ParseSession { _objCount: 5, className: '_Session', id: 'IigxK0tazS' }.

There seem to be fields missing, do you know why?
I assume the tests only mock the session object?

I do however get the whole session object incl. the user in a development environment setup.

[dplewis]

It is an object that extends ParseObject. I assume you can do req.object.get(“user”) and fetch the user. Can you add it to the tests.

[mtrezza]

Oh you are right, that works. I just didn't see it in the console log. I will add this to the tests.

[acinader]

super nice @mtrezza

[mtrezza]

Thanks all for the fast review 🚀

[vince1995]

Sorry for pulling up this old thread but is there a reason fornow only the afterLogout trigger is allowed for the _Session class? Why not all the other triggers?