The TL;DR is that this commit enforces the use of correct IDs, introduces a
BrowserContext, and adds some CDP tests.
These are the ids we need to be aware of when talking about CDP:
- id
- browserContextId
- targetId
- sessionId
- loaderId
- frameId
The `id` is the only one that _should_ originate from the driver. It's attached
to most messages and it's how we maintain a request -> response flow: when
the server responds to a specific message, it echo's back the id from the
requested message. (As opposed to out-of-band events sent from the server which
won't have an `id`). When I say "id" from this point forward, I mean every id
except for this req->res id.
Every other id is created by the browser.
Prior to this commit, we didn't really check incoming ids from the driver. If
the driver said "attachToTarget" and included a targetId, we just assumed that
this was the current targetId. This was aided by the fact that we only used
hard-coded IDS. If _we_ only "create" a frameId of "FRAME-1", then it's tempting
to think the driver will only ever send a frameId of "FRAME-1".
The issue with this approach is that _if_ the browser and driver fall out of sync
and there's only ever 1 browserContextId, 1 sessionId and 1 frameId, it's not
impossible to imagine cases where we behave on the thing.
Imagine this flow:
- Driver asks for a new BrowserContext
- Browser says OK, your browserContextId is 1
- Driver, for whatever reason, says close browserContextId 2
- Browser says, OK, but it doesn't check the id and just closes the only
BrowserContext it knows about (which is 1)
By both re-using the same hard-coded ids, and not verifying that the ids sent
from the client correspond to the correct ids, any issues are going to be hard
to debug.
Currently LOADER_ID and FRAEM_ID are still hard-coded. Baby steps.
CDP is now an struct which contains its own state a browser and a session.
When a client connection is made and successfully upgrades, the client creates
the CDP instance. There is now a cleaner separation betwen Server, Client and
CDP.
Removed a number of allocations, especially when writing results/events from
CDP to the client. Improved input message parsing. Tried to remove some usage
of undefined.
