Code Samples

Astronauts in Space

This code sample uses HttpService’s GetAsync to make a request to Open Notify, a web service that provides data from NASA. The request is made to an endpoint that provides information on how many astronauts are currently in space. The response is provided in JSON format, so it is parsed using JSONDecode. Finally, the response data is then processed and printed to the Output.

Test this script by pasting the source code into a Script (HttpService cannot be used by LocalScripts). Also, be sure to enable HTTP Requests in your Game Settings (Home > Game Settings).

local HttpService = game:GetService("HttpService")

local URL_ASTROS = "http://api.open-notify.org/astros.json"

-- Make the request to our endpoint URL
local response = HttpService:GetAsync(URL_ASTROS)

-- Parse the JSON response
local data = HttpService:JSONDecode(response)

-- Information in the data table is dependent on the response JSON
if data.message == "success" then
	print("There are currently " .. data.number .. " astronauts in space:")
	for i, person in pairs(data.people) do
		print(i .. ": " .. person.name .. " is on " .. person.craft)
	end
end

Where is the International Space Station?

This code sample uses HttpService’s GetAsync to make a request to an endpoint at Open Notify, a website that provides information from NASA. The endpoint provides information on the current location of the International Space Station. This example uses a defensive coding technique that you should use when making web requests. It wraps the call to GetAsync and JSONDecode in pcall, which protects our script from raising an error if either of these fail. Then, it checks the raw response for all proper data before using it. All of this is put inside a function that returns true or false depending of the request’s success.

Whenever you’re working with web requests, you should prepare for anything to go wrong. Perhaps your web endpoint changes or goes down - you don’t want your game scripts raising errors and breaking your game. You want to handle both success and failure gracefully - have a plan in case your data is not available. Use pcall and make plenty of validity checks (if statements) on your data to make sure you’re getting exactly what you expect.

local HttpService = game:GetService("HttpService")

-- Where is the International Space Station right now?
local URL_ISS = "http://api.open-notify.org/iss-now.json"

local function printISS()
	local response
	local data
	-- Use pcall in case something goes wrong
	pcall(function ()
		response = HttpService:GetAsync(URL_ISS)
		data = HttpService:JSONDecode(response)
	end)
	-- Did our request fail or our JSON fail to parse?
	if not data then return false end
	
	-- Fully check our data for validity. This is dependent on what endpoint you're 
	-- to which you're sending your requests. For this example, this endpoint is 
	-- described here:  http://open-notify.org/Open-Notify-API/ISS-Location-Now/
	if data.message == "success" and data.iss_position then
		if data.iss_position.latitude and data.iss_position.longitude then
			print("The International Space Station is currently at:")
			print(data.iss_position.latitude .. ", " .. data.iss_position.longitude)
			return true
		end
	end
	return false
end

if printISS() then
	print("Success")
else
	print("Something went wrong")
end

New Pastebin Post

Pastebin.com is a website that allows users to paste text (usually source code) for others to view publicly. This code sample uses HttpService PostAsync and the pastebin web API to automatically create a new public paste on the website. Since pastebin’s API is designed to take data in as a URL encoded string, the code uses a for-loop to turn the dataFields table into a URL encoded string, such as hello=world&foo=bar. This is used as the HTTP POST data.

Test this code by first going to pastebin.com/api#1 and getting an API key (you’ll need a pastebin account to do this). Then, paste your unique developer API key into the field api_dev_key in the code sample’s dataFields table. Fill in any other information about the post you want to make, then run this code in a Script (not a LocalScript). If all goes well, you’ll get a URL to your new paste in the Output window (or some error string from pastebin).

local HttpService = game:GetService("HttpService")

local URL_PASTEBIN_NEW_PASTE = "https://pastebin.com/api/api_post.php"
local dataFields = {
	-- Pastebin API developer key from
	-- https://pastebin.com/api#1
	["api_dev_key"] = "FILL THIS WITH YOUR API DEVELOPER KEY";    
	
	["api_option"] = "paste";                                -- keep as "paste"
	["api_paste_name"] = "HttpService:PostAsync";            -- paste name
	["api_paste_code"] = "Hello, world";                     -- paste content
	["api_paste_format"] = "text";                            -- paste format
	["api_paste_expire_date"] = "10M";                       -- expire date        
	["api_paste_private"] = "0";                             -- 0=public, 1=unlisted, 2=private
	["api_user_key"] = "";                                   -- user key, if blank post as guest
}

-- The pastebin API uses a URL encoded string for post data
-- Other APIs might use JSON, XML or some other format
local data = ""
for k, v in pairs(dataFields) do
	data = data .. ("&%s=%s"):format(
		HttpService:UrlEncode(k),
		HttpService:UrlEncode(v)
	)
end
data = data:sub(2) -- Remove the first &

-- Here's the data we're sending
print(data)

-- Make the request
local response = HttpService:PostAsync(URL_PASTEBIN_NEW_PASTE, data, Enum.HttpContentType.ApplicationUrlEncoded, false)
-- The response will be the URL to the new paste (or an error string if something was wrong)
print(response)