This uses Netty's global traffic shaping handlers to limit the rate at
which packets can be sent and received. If the bandwidth limit is hit,
we'll start dropping packets, which will mean remote servers send
traffic to us at a much slower pace.
This isn't perfect, as there is only a global limit, and not a
per-computer one. As a result, its possible for one computer to use
all/most bandwidth, and thus slow down other computers.
This would be something to improve on in the future. However, I've spent
a lot of time reading the netty source code and docs, and the
implementation for that is significantly more complex, and one I'm not
comfortable working on right now.
For the time being, this satisfies the issues in #33 and hopefully
alleviates server owner's concerns about the http API. Remaining
problems can either be solved by moderation (with help of the
//computercraft track` command) or future updates.
Closes#33
The HTTP filtering system becomes even more complex! Though in this
case, it's pretty minimal, and definitely worth doing.
For instance, the following rule will allow connecting to localhost on
port :8080.
[[http.rules]]
host = "127.0.0.1"
port = 8080
action = "allow"
# Other rules as before.
Closes#540
timetout, max_upload, max_download and max_websocket_message may now be
configured on a domain-by-domain basis. This uses the same system that
we use for the block/allow-list from before:
Example:
[[http.rules]]
host = "*"
action = "allow"
max_upload = 4194304
max_download = 16777216
timeout = 30000
When creating a peripheral or custom Lua object, one must implement two
methods:
- getMethodNames(): String[] - Returns the name of the methods
- callMethod(int, ...): Object[] - Invokes the method using an index in
the above array.
This has a couple of problems:
- It's somewhat unwieldy to use - you need to keep track of array
indices, which leads to ugly code.
- Functions which yield (for instance, those which run on the main
thread) are blocking. This means we need to spawn new threads for
each CC-side yield.
We replace this system with a few changes:
- @LuaFunction annotation: One may annotate a public instance method
with this annotation. This then exposes a peripheral/lua object
method.
Furthermore, this method can accept and return a variety of types,
which often makes functions cleaner (e.g. can return an int rather
than an Object[], and specify and int argument rather than
Object[]).
- MethodResult: Instead of returning an Object[] and having blocking
yields, functions return a MethodResult. This either contains an
immediate return, or an instruction to yield with some continuation
to resume with.
MethodResult is then interpreted by the Lua runtime (i.e. Cobalt),
rather than our weird bodgey hacks before. This means we no longer
spawn new threads when yielding within CC.
- Methods accept IArguments instead of a raw Object array. This has a
few benefits:
- Consistent argument handling - people no longer need to use
ArgumentHelper (as it doesn't exist!), or even be aware of its
existence - you're rather forced into using it.
- More efficient code in some cases. We provide a Cobalt-specific
implementation of IArguments, which avoids the boxing/unboxing when
handling numbers and binary strings.
This replaces the allow/block lists with a series of rules. Each rule
takes the form
[[http.rules]]
host = "127.0.0.0/8"
action = "block"
This is pretty much the same as the previous config style, in that hosts
may be domains, wildcards or in CIDR notation. However, they may also be
mixed, so you could allow a specific IP, and then block all others.
OK, so let's get this out of the way, there's some actual changes mixed
in here too. I'm really sorry:
- Turtles can now not be renamed with unnamed item tags (previously it
would clear the name, this seemed a little unideal).
- commands.getBlock(s)Data will also include NBT.
Now, onto the horror story which is these inspection changes:
- Make a lot of methods static
- Typo fixes
- Make utility classes final + private constructor
- Lots of reformatting (ifs -> ternary, invert control flow, etc...)
- ???
- Profit!
I'm so going to regret this - can pretty much guarantee this is going to
break something.
- Convert terminals from a polling-based system to a more event-driven
one: they now accept an onChanged callback, which marks the parent as
dirty.
- Schedule ticks when monitors are marked as dirty.
- Add several missing @Overrides. This has nothing to do with the rest
of the changes, but I'm bad at good git practice.
- We now error if there are too many websockets, instead of queuing
them up. As these have a more explicit "lifetime", it could be
confusing if http.websocket just blocks indefinitely.
- Fix a CCME when cleaning up resources.
- Move all HTTP tasks to a unified "MonitoredResource" model. This
provides a uniform way of tracking object's lifetimes and disposing
of them when complete.
- Rewrite HTTP requests to use Netty instead of standard Java. This
offers several advantages:
- We have access to more HTTP verbs (mostly PATCH).
- We can now do http -> https redirects.
- We no longer need to spawn in a new thread for each HTTP request.
While we do need to run some tasks off-thread in order to resolve
IPs, it's generally a much shorter task, and so is less likely to
inflate the thread pool.
- Introduce several limits for the http API:
- There's a limit on how many HTTP requests and websockets may exist
at the same time. If the limit is reached, additional ones will be
queued up until pending requests have finished.
- HTTP requests may upload a maximum of 4Mib and download a maximum
of 16Mib (configurable).
- .getResponseCode now returns the status text, as well as the status
code.
Jonathan Coates