Implement a LuaSocket/LuaSec-based HTTP client

Note that LuaSec is actually optional, and will be loaded on-demand when the
first request using the https:// scheme is issued.

matrix/api.lua

@@ -34,7 +34,7 @@ local get_http_factory = function (http_factory)
       end
    end
    -- Try to import supplied HTTP client libraries, in order of preference.
-   local tries = http_factory and { http_factory } or { "chttp" }
+   local tries = http_factory and { http_factory } or { "chttp", "luasocket" }
    local errors = {}
    for i, http_factory in ipairs(tries) do
       local ok, factory = pcall(require, "matrix.factory." .. http_factory)

matrix/factory/luasocket.lua

@@ -0,0 +1,85 @@
+#! /usr/bin/env lua
+--
+-- luasocket.lua
+-- Copyright (C) 2016 Adrian Perez <aperez@igalia.com>
+--
+-- Distributed under terms of the MIT license.
+--
+
+local urlescape    = require "socket.url" .escape
+local stringsource = require "ltn12"      .source.string
+local tablesink    = require "ltn12"      .sink.table
+
+local request_https = function (...)
+   request_https = require "ssl.https" .request
+   return request_https(...)
+end
+
+local request_http = function (...)
+   request_http = require "socket.http" .request
+   return request_http(...)
+end
+
+local function make_request(t)
+   if t.url:sub(1, #"https://") == "https://" then
+      return request_https(t)
+   else
+      return request_http(t)
+   end
+end
+
+local function dict_to_query(d)
+   local r, i = {}, 0
+   for name, value in pairs(d) do
+      i = i + 1
+      r[i] = urlescape(name) .. "=" .. urlescape(value)
+   end
+   return table.concat(r, "&", 1, i)
+end
+
+local httpclient = {
+   quote   = require "socket.url" .escape,
+   unquote = require "socket.url" .unescape,
+}
+httpclient.__name  = "matrix.factory.luasocket"
+httpclient.__index = httpclient
+
+function httpclient:__tostring()
+   return self.__name
+end
+
+function httpclient:request(log, method, url, query_args, body, headers)
+   do
+      local qs = dict_to_query(query_args)
+      if #qs > 0 then
+         url = url .. "?" .. qs
+      end
+   end
+
+   log(">~> %s %s", method, url)
+   log(">>> %s", body)
+
+   local source
+   if body and #body > 0 then
+      headers["content-length"] = #body
+      source = stringsource(body)
+   end
+   local result = {}
+   local r, c, h = make_request {
+      url     = url,
+      method  = method,
+      headers = headers,
+      source  = source,
+      sink    = tablesink(result),
+   }
+   local response = table.concat(result)
+
+   log("<~< %d", c)
+   log("<<< %s", response)
+
+   return c, h, response
+end
+
+return function ()
+   return setmetatable({}, httpclient)
+end