This function is an synchronous wrapper around PerformHttpRequest which will await the data internally, preventing the need for callbacks. It's available on server build 9515 and newer
PerformHttpRequestAwait(string url, string method = 'GET', string data = '', table headers = {}, table options = { followLocation = true })
local errorCode, resultData, resultHeaders, errorData = PerformHttpRequestAwait("http://some-cool-url.here/some-important-document.txt")
print("Error Code: " .. errorCode)
print("Result Data: " .. resultData)
print("Result Headers: " .. resultHeaders)
print("Error Data: " .. errorData)