Tracy without session - concept of using files as a storage [WIP]

[forrest79]

• new feature
• issue Tracy always starts a session #356
• BC break: no

We have a project, where session is started only for logged users. It's a little bit tricky, that Tracy in devel mode always starts session. This could possible hide some bug on devel environment, that is, in better scenario catch with tests, in worse scenario on production :-)

This is just concept, how to let developer choose between session as storage (default and works the same way as now) or file storage. In configuration, you can enable it with setting directory for data files:

tracy:
	fileStorage: %tempDir%

If this concept will be approved, I can prepare PR for actual Tracy version.

[dg]

Thanks a lot for PR.

I need to understand why you're doing this. From my point of view:

• sessions is a storage on a disk whose identifier is transferred in a cookie.
• your FileStorage is a storage on a disk whose identifier is transferred in a cookie

I simply don't understand why to reimplement session by own class.

I used to do something like that a long time ago e1e204c#diff-20100846c73ff8ebc44f72ccbbf13c22, but now I don't remember why :-) and there was issue about it #154

[forrest79]

I tried to show our reasons in description, maybe not enough clear :-) Imagine web, that in some cases use PHP session (in our case for logged users and some other minor use cases...) but for most requests (~80%), you're not starting session and web needs to cover both variants - session could be running or not. And when you're on your local development machine with Tracy, PHP session is always running, so you can't simply simulate environment without session and is very easy to create a bug. With this PR, you can choose to use "Tracy session" and PHP session is working in the same way as on production web.

By default, PHP session is still used, so with this, I think, that you can cover #154. This is just for those, who don't wat to start PHP session because of Tracy.

[dg]

Ok I get it.

[forrest79]

I think, that maybe there is no need to have FileStorage in Tracy repository, just ability to use your own storage could be also suitable.

[ikeblaster]

@dg I have probably found another reason to implement this.

TLDR: Session handlers (e.g. memcached) can have size limits. Some tracy info easily becomes too big and this can even lead to session destruction.

---

It's actually quite common situation - when you have request with redirect, then the panel is saved into session. Together with memcached as a session handler it can easily lead to hitting the session size limit. In our case the result is completely deleted session (without any error message visible) and user being redirected to a login page. This was really weird at first and I wonder how nobody has ever met that before (or at least google doesn't return to me anything similar).

On production it's obviously not a problem, there is no tracy, we have this on our dev site. So far I have just switched to files session handler, but I would rather see better solution. It's desirable to have dev environment as close as possible to production site. I was also thinking about custom session handler, which would split the session between files (just $_SESSION['_tracy']['redirect']) and memcached (the rest).

Or am I overlooking something?

[forrest79]

Hi, I just want to ask, if you have though about this? We're using our fork with this update several months without any problem and right now, we're finishing update to Nette 3, so we will use this also with Tracy 2.7. Thanks for some info.

[dg]

I'm going to put it in version 2.8 or the next one.

[forrest79]

Great to hear that, thanks 👍