interserve

Used as an alternative to large and deferred data transfer from clients and servers when dealing with large data that requires net.* splitting.
This initially was an experiment to see if we can use HTTP as a form of deferred networking, while not requiring any form of external communication outside the process.
Courtesy of Buildstruct for allowing me to reliably test this under their player-base.

This does not work on single-player/localhost, due to the fact HTTP is blocked from accessing localhost.
Do note that this does open ports & accepts HTTP requests, we recommend configuring this behind mitigation services such as Cloudflare.
You can find the binary here: https://github.com/eprosync/interstellar_gmod

Pros/Cons

This is just a simple list of pros/cons, there are alternatives that do not require interstellar such as gm_express, however it is to be note that in the future a similar API for this could be strictly made without using interstellar.

+ Deferred handling of incoming data, only aligned with source-engine's thread during lua execution.
+ Able to send large amounts of data greater than net 64 KB limit.
+ Endpoints are dynamically generated & unique per-player.
+ Server authoritive networking, requires server acknowledgement before serving.

- Susceptible to Denial of Service if not setup correctly.
- Not aligned with source-engine reliable data, may arrive later than sooner.
- Possible timeouts during window of receiving.
- Each server must have a unique extra port opened.

Configuration

• interserve_address [string] - Client's inverserve address or domain (format IP [no port] or domain)
• interserve_iport [number] - Server's interserve port (must be a valid port!)
• interserve_port [number] - Client's inverserve port (must be the same or targeting a proxy)
• interserve_ssl [boolean] - Client's inverserve SSL support
• interserve_trusted [boolean] - Client's inverserve trusted proxy support
• interserve_timeout [number] - Server's interserve timeout in seconds
• interserve_size [number] - Server's interserve max internal upload size

I recommend that on each server instance inside server.cfg you set the interserve_iport.
By default it targets 25500 which if you are using multiple instances will stop other server instances from attaching to the port if already in-use.

Functions

interserve:add(id: string)

• Adds a new interserve endpoint, cannot use interserve without registering an endpoint.
• Only available on server realms.

interserve:remove(id: string)

• Removes an existing interserve endpoint.
• Only available on server realms.

interserve:exists(id: string)

• Checks if an interserve endpoint has been registered.
• Only available on server realms.

interserve:receive(id: string, callback?: function)

• A callback for incoming data.
• callback: function(data: string, invoker?: Player)

interserve:send(id: string, data: string, invoker?: Player | Player[])

• For sending data to the server or client through interserve.
• invoker: the target player, only available on server realms.

interserve:broadcast(id: string, data: string)

• For sending data to all players on the server through interserve.
• Only available on server realms.

interserve:omit(id: string, data: string, ignore: Player | Player[])

• For sending data to players with an exclusion on the server through interserve.
• Only available on server realms.

interserve:failure(id: string, callback?: function)

• A callback for when failures are captured under interserve.
• callback: function(code: number, reason: string, headers?: {[index: string]: string})
• Only available on client realms.

interserve:interrupt(id: string, callback?: function)

• A callback for confirmations to uploads and downloads during threaded processing.
• Returning false in the callback will stop the process from continuing to receivers.
• callback: function(invoker: Player, req: iot.serve.request): boolean?
• Only available on server realms.

interserve:handshake(id: string, callback?: function)

• A callback for handshake confirmations to upload to the server
• Returning false in the callback will stop the upload process from continuing to interrupt.
• callback: function(invoker: Player, size: number): boolean?
• Only available on server realms.

Roadmap

• Add further endpoint obfuscation by using salt'ed MD5/SHA on startup.
• Built-in logger and profiler for endpoint monitoring.

Other additions to this depends on interstellar, and if I can implement it reliably.