polyfill luncheon

http_button/luncheon/headers.lua

@@ -0,0 +1,209 @@
+---@class Headers
+---
+---A map of the key value pairs from the header portion
+---of an HTTP request or response. The fields listed below
+---are some common headers but the list is not exhaustive.
+---
+---When each header is serialized, it is added as a property with
+---lower_snake_case. For example, `X-Forwarded-For` becomes `x_forwarded_for`.
+---
+---Typically each header's value will be a string, however if there are multiple entries
+---for any header, it will be a table of strings.
+---
+---@field private _inner table A table containing the deserialized header key/value pairs
+---@field private _last_key string The last key deserialized, for multiline headers
+local Headers = {}
+
+Headers.__index = Headers
+
+local function _append(t, key, value)
+  value = tostring(value)
+  if not t[key] then
+    t[key] = value
+  elseif type(t[key]) == "string" then
+    t[key] = { t[key], value }
+  else
+    table.insert(t[key], value)
+  end
+end
+
+---Serialize a key value pair w/o the trailing new line
+---
+--- If the provided value is a `string[]`, it will be joined with `\r\n` into one
+--- string, though no trailing new line will be provided
+---@param key string
+---@param value string|string[]
+---@return string
+function Headers.serialize_header(key, value)
+  if type(value) == "table" then
+    local serialized = {}
+    for _, v in ipairs(value) do
+      table.insert(serialized, Headers.serialize_header(key, v))
+    end
+    return table.concat(serialized, "\r\n")
+  end
+  -- special case for MD5
+  key = string.gsub(key, "md5", "mD5")
+  -- special case for ETag
+  key = string.gsub(key, "etag", "ETag")
+  if #key < 3 then
+    return string.format("%s: %s", key:upper(), value)
+  end
+  -- special case for WWW-*
+  key = string.gsub(key, "www", "WWW")
+  local replaced = key:sub(1, 1):upper() .. string.gsub(key:sub(2), "_(%l)", function(c)
+    return "-" .. c:upper()
+  end)
+  return string.format("%s: %s", replaced, value)
+end
+
+---Serialize the whole set of headers separating them with a '\\r\\n'
+---@return string
+function Headers:serialize()
+  local ret = ""
+  for header in self:iter() do
+    ret = ret .. header .. "\r\n"
+  end
+  return ret
+end
+
+function Headers:_handle_single_line(line)
+  if string.match(line, "^%s+") ~= nil then
+    if not self._last_key then
+      return nil, "Header continuation with no key"
+    end
+    local existing = self:get_one(self._last_key)
+    self._inner[self._last_key] = string.format("%s %s", existing, string.sub(line, 2))
+    return 1
+  end
+  for raw_key, value in string.gmatch(line, '([^%c()<>@,;:\\"/%[%]?={} \t]+): (.+);?') do
+    self:append(raw_key, value)
+  end
+  return 1
+end
+
+---Append a chunk of headers to this map
+---@param text string
+---@return integer|nil success 1 if successful
+---@return nil|string err if ret1 is `nil` an error message
+function Headers:append_chunk(text)
+  if type(text) ~= "string" then
+    return nil, "invalid header, expected string found " .. type(text)
+  end
+  for chunk in string.gmatch(text, "([^\r\n]+)") do
+    local s, err = self:_handle_single_line(chunk)
+    if not s then
+      return nil, err
+    end
+  end
+  return 1
+end
+
+---Constructor for a Headers instance with the provided text
+---@param text string
+---@return Headers|nil
+---@return nil|string
+function Headers.from_chunk(text)
+  local headers = Headers.new()
+  local s, err = headers:append_chunk(text)
+  if not s then
+    return nil, err
+  end
+  return headers
+end
+
+---Bare constructor
+---@return Headers
+function Headers.new()
+  local ret = {
+    _inner = {},
+    last_key = nil,
+  }
+  setmetatable(ret, Headers)
+  return ret
+end
+
+---Convert a standard header key to the normalized
+---lua identifer used by this collection
+---@param key string
+---@return string
+function Headers.normalize_key(key)
+  local lower = string.lower(key)
+  local normalized = string.gsub(lower, "-", "_")
+  return normalized
+end
+
+---Insert a single key value pair to the collection will duplicate existing keys
+---@param key string
+---@param value string
+---@return Headers
+function Headers:append(key, value)
+  key = Headers.normalize_key(key)
+  _append(self._inner, key, value)
+  self._last_key = key
+  return self
+end
+
+---Insert a single key value pair to the collection will not duplicate keys
+---@param key string
+---@param value string
+---@return Headers
+function Headers:replace(key, value)
+  key = Headers.normalize_key(key)
+  self._inner[key] = value
+  self._last_key = key
+  return self
+end
+
+---Get a header from the map of headers
+---
+---This will first normalize the provided key. For example
+---'Content-Type' will be normalized to `content_type`.
+---If more than one value is provided for that header, the
+---last value will be provided
+---@param key string
+---@return string
+function Headers:get_one(key)
+  local k = Headers.normalize_key(key or "")
+  local value = self._inner[k]
+  if type(value) == "table" then
+    return value[#value]
+  else
+    return value
+  end
+end
+
+---Get a header from the map of headers as a list of strings.
+---In the event that a header's key is duplicated, the value
+---is stored internally as a list of values. This method is
+---useful for getting that list.
+---
+---
+---This will first normalize the provided key. For example
+---'Content-Type' will be normalized to `content_type`.
+---@param key string
+---@return string[]
+function Headers:get_all(key)
+  local k = Headers.normalize_key(key or "")
+  local values = self._inner[k]
+  if type(values) == "string" then
+    return { values }
+  end
+  return values
+end
+
+---Return a lua iterator over the key/value pairs in this header map
+---@return function():string|nil
+function Headers:iter()
+  local last = nil
+  return function()
+    local k, v = next(self._inner, last)
+    last = k
+    if not k then
+      return
+    end
+    return Headers.serialize_header(k, v)
+  end
+end
+
+return Headers

http_button/luncheon/init.lua

@@ -0,0 +1,11 @@
+local Headers = require "luncheon.headers"
+local Request = require "luncheon.request"
+local Response = require "luncheon.response"
+local utils = require "luncheon.utils"
+
+return {
+  Headers = Headers,
+  Request = Request,
+  Response = Response,
+  utils = utils,
+}