dotenv.lua

-- Define a dotenv object
local dotenv = {}

-- Define a function to read a file and return its contents as a string
local function readFile(filename)
  -- Open the file in read mode
  local file = io.open(filename, 'r')
  -- Check if the file exists
  if not file then
    -- Return nil and an error message
    return nil, 'File not found: ' .. filename
  end
  -- Read the whole file content
  local content = file:read('*a')
  -- Close the file
  file:close()
  -- Return the content
  return content
end

-- Define a function to parse a .env file and return a table of key-value pairs
local function parseEnv(content)
  -- Create an empty table to store the pairs
  local pairs = {}
  -- Loop through each line in the content
  for line in content:gmatch('[^\r\n]+') do
    -- Trim any leading or trailing whitespace from the line
    line = line:match('^%s*(.-)%s*$')
    -- Ignore empty lines or lines starting with #
    if line ~= '' and line:sub(1, 1) ~= '#' then
      -- Split the line by the first = sign
      local key, value = line:match('([^=]+)=(.*)')
      -- Trim any leading or trailing whitespace from the key and value
      key = key:match('^%s*(.-)%s*$')
      value = value:match('^%s*(.-)%s*$')
      -- Check if the value is surrounded by double quotes
      if value:sub(1, 1) == '"' and value:sub(-1, -1) == '"' then
        -- Remove the quotes and unescape any escaped characters
        value = value:sub(2, -2):gsub('\\"', '"')
      end
      -- Check if the value is surrounded by single quotes
      if value:sub(1, 1) == "'" and value:sub(-1, -1) == "'" then
        -- Remove the quotes
        value = value:sub(2, -2)
      end
      -- Store the key-value pair in the table
      pairs[key] = value
    end
  end
  -- Return the table
  return pairs
end

-- Define a function to load the environment variables from a .env file into the _G table
function dotenv:load(filename)
  -- Use .env as the default filename if not provided
  filename = filename or '.env'
  -- Read the file content
  local content, err = readFile(filename)
  -- Check if there was an error
  if not content then
    -- Return nil and the error message
    return nil, err
  end
  -- Parse the file content
  local pairs = parseEnv(content)
  -- Loop through the pairs
  for key, value in pairs(pairs) do
    -- Check if the key is not already in the _G table
    if not _G[key] then
      -- Set the key-value pair in the _G table
      _G[key] = value
    end
  end
  -- Return true
  return true
end

-- Return the dotenv object
return dotenv