Lua Script Performance Testing: Encapsulating HTTP/HTTPS GET and POST with JSON, FormData, and File Support

Performance testing is a crucial step in software development to ensure system stability and efficiency, and Lua, a lightweight scripting language, can be employed to write performance test scripts.

Lua is widely used in game development, embedded systems, and server‑side applications due to its fast execution and flexibility; using it for performance testing helps evaluate execution speed and resource consumption.

The following examples show how to encapsulate GET requests for both HTTP and HTTPS using the LuaSocket and LuaSec libraries.

local http = require("socket.http")
local https = require("ssl.https")
local ltn12 = require("ltn12")
local json = require("json")

-- HTTP GET
function httpGet(url)
  local response = {}
  local _, status = http.request{
    url = url,
    method = "GET",
    sink = ltn12.sink.table(response)
  }
  if status == 200 then
    return table.concat(response)
  else
    return nil
  end
end

-- HTTPS GET
function httpsGet(url)
  local response = {}
  local _, status = https.request{
    url = url,
    method = "GET",
    sink = ltn12.sink.table(response)
  }
  if status == 200 then
    return table.concat(response)
  else
    return nil
  end
end

-- Example usage
local result = httpGet("http://example.com")
print(result)
result = httpsGet("https://example.com")
print(result)

Similarly, POST requests can be wrapped for both HTTP and HTTPS, allowing custom headers and request bodies.

local http = require("socket.http")
local https = require("ssl.https")
local ltn12 = require("ltn12")
local json = require("json")
local mime = require("mime")

-- HTTP POST
function httpPost(url, data, contentType)
  local response = {}
  local requestBody = mime.b64(data)
  local _, status = http.request{
    url = url,
    method = "POST",
    headers = {
      ["Content-Type"] = contentType,
      ["Content-Length"] = #requestBody
    },
    source = ltn12.source.string(requestBody),
    sink = ltn12.sink.table(response)
  }
  if status == 200 then
    return table.concat(response)
  else
    return nil
  end
end

-- HTTPS POST
function httpsPost(url, data, contentType)
  local response = {}
  local requestBody = mime.b64(data)
  local _, status = https.request{
    url = url,
    method = "POST",
    headers = {
      ["Content-Type"] = contentType,
      ["Content-Length"] = #requestBody
    },
    source = ltn12.source.string(requestBody),
    sink = ltn12.sink.table(response)
  }
  if status == 200 then
    return table.concat(response)
  else
    return nil
  end
end

-- Example usage
local result = httpPost("http://example.com", "data", "application/json")
print(result)
result = httpsPost("https://example.com", "data", "application/json")
print(result)

The next example demonstrates how to handle JSON and multipart/form‑data payloads and how to read files for requests.

local http = require("socket.http")
local https = require("ssl.https")
local ltn12 = require("ltn12")
local json = require("json")
local mime = require("mime")

-- POST supporting JSON and FormData, with file upload
function httpPost(url, data, contentType)
  local response = {}
  local requestBody
  if contentType == "application/json" then
    requestBody = json.encode(data)
  elseif contentType == "multipart/form-data" then
    requestBody = mime.easymime(data)
  end
  local _, status = http.request{
    url = url,
    method = "POST",
    headers = {
      ["Content-Type"] = contentType,
      ["Content-Length"] = #requestBody
    },
    source = ltn12.source.string(requestBody),
    sink = ltn12.sink.table(response)
  }
  if status == 200 then
    return table.concat(response)
  else
    return nil
  end
end

-- Example: send JSON
local jsonData = { key = "value" }
local result = httpPost("http://example.com", jsonData, "application/json")
print(result)

-- Example: send FormData with file
local formData = {
  file = {
    data = "path/to/file",
    filename = "filename.txt",
    contentType = "text/plain"
  }
}
local result = httpPost("http://example.com", formData, "multipart/form-data")
print(result)

By using these reusable functions, you can flexibly simulate real‑world GET and POST requests over HTTP/HTTPS, handle different content types, and incorporate file uploads, enabling thorough performance evaluation of your Lua‑based services.