In #34709 we updated the guide, but `actioncable/README.md` is still
outdated. Instead of fixing content in the file. I suggest
not duplicate the info that is already in the guide and instead remove
the info from the file and just add a message:
"You can read more about Action Cable in the
[Action Cable Overview](https://edgeguides.rubyonrails.org/action_cable_overview.html) guide."
The same approach is being used for Action Mailbox and Action Text,
see #34812 and #34878.
In some examples and guides we are recommending to use code like:
```ruby
verified_user = User.find_by(id: cookies.signed[:user_id])
```
My suggestion is to use instead:
```ruby
verified_user = User.find_by(id: cookies.encrypted[:user_id])
```
which invites users to prefer the "newer" encrypted cookies over the
"legacy" signed cookies.
WebSocket always defers the decision to the server, because it didn't
have to deal with legacy compatibility... but the same-origin policy is
still a reasonable default.
Origin checks do not protect against a directly connecting attacker --
they can lie about their host, but can also lie about their origin.
Origin checks protect against a connection from 3rd-party controlled
script in a context where a victim browser's cookies will be passed
along. And if an attacker has breached that protection, they've already
compromised the HTTP session, so treating the WebSocket connection in
the same way seems reasonable.
In case this logic proves incorrect (or anyone just wants to be more
paranoid), we retain a config option to disable it.
When the `allow_same_origin_as_host` is set to `true`, the request
forgery protection permits `HTTP_ORIGIN` values starting with the
corresponding `proto://` prefix followed by `HTTP_HOST`. This way
it is not required to specify the list of allowed URLs.
- Remove "Configuration", "Running the server", "Dependencies" and "Deployment"
sections from the Action Cable README as they are already duplicated in the
Action Cable overview guide.
This PR checks all active Action Cable documentation for typos and other
fixes. It aims to make sure that when Rails 5 is released, that the
Action Cable docs are up to snuff with the other documentation included
with Rails.
[ci skip]
zzak