It makes more sense to put the address first then have the large
structure to send as the second argument to sendTo. The opposite order
was originally chosen to be similar to that of sendto in BSD sockets.
Reverse the direction of the API for sending messages from
messageDefinition.send(link, { content });
to
link.send(new MessageClass(content));
and convert all message definitions to use the JSON serialisable class
pattern and explicit registration of message handlers, along with a
end-to-end based routing of messages instead of link to link.
The experience I gained from the existing way messages were defined and
sent over links was that it was difficult to understand for people
unfamiliar with the system. The automatic registration of message
handlers ment that code was being called as if by magic from nowhere
with no easy way to discover it. The manual forwarding and rules for
what can be sent where and how obscured its working.
The use of pure JSON as both input and output from message handlers made
it tedious to work with. Data had to be manually converted between the
program representation and the over the wire format, which made handler
code unplesant to write. Particularly because the over the wire format
used snake_case while the program code uses camelCase for variables.
The idea behind the decision to do it this way was to make it more clear
which data came from the wire and which from the program, and while this
worked it didn't make message handlers any nicer to write.
The direction of the API and magic registration of message handlers also
meant that a future migration to TypeScript would be troublesome. While
it may be possible to implement, the degree of TypeScript magic required
would go starkly against the principle of keep it simple stupid.
By refactoring to using the JSON serialisable class pattern most of
these issues go away. There is no longer a need to distinguish the on
wire format of messages with the program representation because the only
place that deals with the wire format of messages are the toJSON and
fromJSON methods on the classes themselves. Message handlers will work
with proper instances of classes instead of raw data, something that
makes them easier to write, and trivial to type with TypeScript.
End-to-end routing also simplifies sending messages that need to do
mulitple hops to reach the destination. And removes the need for having
all messages be specified in plugin's info module, as they can be routed
without having to be parsed completely.
The explicit registration of message handlers is something that I
thought would be tedious boilerplate code that could be automated away.
But experience now shows it to be the opposite. Allthough dull
repetition, the purpose it serves is to link together the code in a way
that humans can easily find. With explicit registration searching the
name of the message handler in the editor will show the registration that
ties it together with the type of message it handles and the kind of
registration. With implicit registration searching the name of the
message handler turns up only the handler with no clue as to what calls
it.
The role of a slave as a host for Factorio servers is not well reflected
in its name and has caused confusion among users. Rename slave to host
to better reflect its role as a host of Factorio servers.
The role of the master server as the party controlling every part of the
cluster is not well reflected in its name and has caused confusion among
users on several occasions. Rename master to controller to better
reflects its role.
Add authentication plugin that does a simple challenge response protocol
to verify that the player trying to log in is who they claim to be. The
process goes as follows:
1. A player code is generated for a player that wants to log in and is
displayed in-game.
2. The player code is input into the web interface and the master
generates a verification code as a challenge back along with a token.
3. The player inputs the verification code in-game and is logged in to
the web interface in doing so.
To do the actual login the web interface polls a verify endpoint every 2
seconds until the code has either been verified or expired. The
challenge comes from being unable to control the verification code and
having to input it as a player logging into one of the servers in order
to login.
Some additional steps are taken in order to increase the difficulty for
an attacker to subvert the challenge:
- The login process must be started from in-game.
- Generated codes are only valid for a limited timespan which is
configurable and 2 minutes by default.
- The verification code comes with a token that only works with one
player code and verification code combo and must be provided to pass
validation.
Hornwitser