Lua Environment

Planetary Processing's server-side Lua environment runs using LuaJIT, this means it is effectively the same as Lua 5.1 but with some tweaks and significantly improved performance.

Please note that some of Lua and LuaJIT's libraries are not available within the PP environment. The following libaries are not available: os, io, jit, table, package and coroutine.

The math library remains, as do various libraries added by PP. Additionally, require, dofile and similar will still work for loading Lua files from within your game repository.

Runtime metatables and metamethods are not currently supported.

Additionally, we have incorporated an open source JSON encoding/decoding library, documentation here: https://github.com/rxi/json.lua

Tables

On our backend, we implement tables in a slightly different way to the normal Lua virtual machine. Tables used as a standard dictionary are similar to regular Lua, however, non-serialisable objects (i.e. functions, etc.) are not guaranteed to be persisted.

Array-style tables (e.g. {1, 2, 3}) are handled differently and as such we have provided a library for manipulating them that provides some of the functionality in Lua's table library.

The library works by taking an array-style table, manipulating it, and returning the result. This is distinct from Lua's built in tables, as the modifications are not made in place.

We provide three functions: api.table.Append(table, item), api.table.Remove(table, index) and api.table.Join(table, table).

x = {1, 2, 3}
print(x) -- prints [1, 2, 3]
x = api.table.Append(x, 4) -- append 4
print(x) -- prints [1, 2, 3, 4]
x = api.table.Remove(x, 1) -- remove the first item
print(x) -- prints [2, 3, 4]
x = api.table.Join(x, {5, 6, 7}) -- join the two tables
print(x) -- prints [2, 3, 4, 5, 6, 7]

Note that Append can be used with multiple item parameters like so:

x = {1, 2, 3}
print(x) -- prints [1, 2, 3, 4]
x = api.table.Append(x, 5, 6) -- add both 5 and 6 to the end of the table
print(x) -- prints [1, 2, 3, 4, 5, 6]

Note that modifying tables in-place by index is still supported as normal, and length operations will work as normal. However, you cannot index outside of the current length of the table.

x = {1, 2, 3}
print(x) -- prints [1, 2, 3]
x[1] = 0 -- modify the first element
print(x) -- prints [0, 2, 3]
print(#x) -- prints 3, the length of the table
x[#x+1] = 42 -- this will fail, instead you should use api.table.Append

Utils

We provide utilities through the api.util section of the API.

The Unix timestamps used in time functions will provide the amount of time elapsed since: 00:00:00 1st January 1970. Since this is a large integer, it will display in logs using scientific e notation. For example 1.741084186e+09 will be printed for a functional value of 1741083281 seconds.

api.util.Time() -- returns the unix timestamp in seconds
api.util.TimeMillis() -- returns the unix timestamp in milliseconds

HTTP Requests

Premium Only

[This feature is still in Open Beta and may have some bugs. Please direct any feedback to the Planetary Processing Team on Discord]

We provide a simple HTTP API through the api.http section of the API. This API is for making HTTP Requests from within your game. For external requests to your game please use our HTTP REST API.

These requests are rate limited to a maximum of 5 HTTP calls per update tick. The API is as follows:

api.http.Get(url, headers)
api.http.Post(url, headers, body)
api.http.Put(url, headers, body)
api.http.Delete(url, headers)

Where the url and body are strings and the headers are a table of the form:

{["header_name"]=value}

Every HTTP API endpoint returns the status code and the body of the response, as a string. Currently this process is sequential and blocking, so the code will not progress until there is a return.

An example of an HTTP Get request is below:

local code, body = api.http.Get("https://www.ismycomputeronfire.com/", {})
if code == 200 then
  print(body)
else
  print("something wrong, http code:", code)
end

API

The global environment API is shown below, these functions are accessed by interfacing with the api.table, api.util, and api.httpobjects from any server-side script.

Table

These functions are accessed by interfacing with the api.tableobject.

Method	Parameters	Returns	Description
Append	table: table item: Any	table modified	Adds the item to the end of the table.
Remove	table: table index: integer	table modified	Removes an item from the table at the selected index.
Join	table: table table: table	table modified	Combine one table with another, to form a single table.

---

Utils

These functions are accessed by interfacing with the api.utilobject.

Method	Parameters	Return Value	Description
Time	None	int	Returns the number of seconds elapsed since a fixed point in history (Unix epoch)
TimeMillis	None	int	Returns the number of milliseconds elapsed since a fixed point in history (Unix epoch)

---

HTTP Requests

These functions are accessed by interfacing with the api.http object.

Method	Parameters	Return Value	Description
Get	url: string headers: table	code: int body: string	Sends a GET request to an HTTP endpoint.
Post	url: string headers: table body: string	code: int body: string	Sends a POST request to an HTTP endpoint.
Put	url: string headers: table body: string	code: int body: string	Sends a PUT request to an HTTP endpoint.
Delete	url: string headers: table	code: int body: string	Sends a DELETE request to an HTTP endpoint.