Redesign the protocol to use a capability system

 - The protocol now uses JSON instead of a quasi-binary format. While
   the former is more efficient to produce, the difference is pretty
   marginal. This helps simplify packet encoding/decoding.

 - All clients connect through the /connect endpoint, providing a
   session id (aka token) and list of capabilities.

 - Specific packets can only be sent to clients with a given capability.
   For instance, terminal packets are only sent to clients with the
   terminal:view capability, while file action packets are sent to both
   file:edit and file:host clients.

This is mostly intended to allow greater flexibility in the future, such
as a desktop-based file syncing program.

.luacheckrc

@@ -0,0 +1,92 @@
+local function mk_fields(fields)
+  local out = {}
+  for i = 1, #fields do out[fields[i]] = {} end
+  return { fields = out }
+end
+
+std = {
+  read_globals = {
+    fs = mk_fields { "makeDir", "complete", "copy", "isDir", "list", "getSize", "delete", "isReadOnly", "getFreeSpace", "find", "getDrive", "exists", "move", "combine", "getName", "getDir", "open" },
+    colours = mk_fields { "cyan", "purple", "brown", "lightGrey", "orange", "red", "magenta", "blue", "white", "grey", "rgb8", "pink", "test", "subtract", "black", "green", "combine", "yellow", "lime", "lightBlue" },
+    tostring = {},
+    _CC_DEFAULT_SETTINGS = {},
+    getfenv = {},
+    debug = mk_fields { "getupvalue", "debug", "getfenv", "getmetatable", "gethook", "setmetatable", "setfenv", "traceback", "getinfo", "setlocal", "setupvalue", "sethook", "getregistry", "getlocal" },
+    disk = mk_fields { "getID", "isPresent", "eject", "getMountPath", "stopAudio", "getLabel", "hasAudio", "playAudio", "getAudioTitle", "setLabel", "hasData" },
+    assert = {},
+    tonumber = {},
+    io = mk_fields { "lines", "write", "close", "flush", "open", "output", "read", "input", "type" },
+    redstone = mk_fields { "setAnalogOutput", "getBundledOutput", "getBundledInput", "setOutput", "setAnalogueOutput", "getInput", "getOutput", "setBundledOutput", "getAnalogueOutput", "testBundledInput", "getSides", "getAnalogInput", "getAnalogOutput", "getAnalogueInput" },
+    load = {},
+    http = mk_fields { "checkURLAsync", "websocketAsync", "checkURL", "request", "websocket", "post", "get" },
+    _G = {
+      read_only = false,
+      other_fields = true,
+    },
+    peripheral = mk_fields { "call", "isPresent", "getType", "getMethods", "wrap", "find", "getNames" },
+    vector = mk_fields { "new" },
+    term = mk_fields { "getCursorPos", "isColour", "getBackgroundColor", "getTextColour", "scroll", "redirect", "getPaletteColor", "setTextColor", "native", "setPaletteColour", "getTextColor", "clear", "write", "setPaletteColor", "setCursorPos", "getBackgroundColour", "isColor", "setTextColour", "blit", "current", "getSize", "getPaletteColour", "setCursorBlink", "setBackgroundColor", "setBackgroundColour", "clearLine" },
+    coroutine = mk_fields { "running", "yield", "status", "wrap", "create", "resume" },
+    textutils = mk_fields { "serialize", "unserialize", "empty_json_array", "serializeJSON", "urlEncode", "serialiseJSON", "complete", "serialise", "formatTime", "pagedTabulate", "slowWrite", "slowPrint", "pagedPrint", "tabulate", "unserialise" },
+    loadstring = {},
+    rednet = mk_fields { "CHANNEL_REPEAT", "isOpen", "unhost", "close", "send", "open", "host", "CHANNEL_BROADCAST", "broadcast", "run", "receive", "lookup" },
+    _HOST = {},
+    string = mk_fields { "sub", "find", "len", "gfind", "reverse", "rep", "match", "gmatch", "dump", "byte", "upper", "gsub", "format", "char", "lower" },
+    xpcall = {},
+    package = {
+      fields = {
+        preload = {},
+        config = {},
+        loaders = {},
+        loaded = {
+          read_only = false,
+          other_fields = true,
+        },
+        path = {},
+      },
+    },
+    parallel = mk_fields { "waitForAll", "waitForAny" },
+    print = {},
+    unpack = {},
+    __inext = {},
+    printError = {},
+    require = {},
+    _ENV = {
+      read_only = false,
+      other_fields = true,
+    },
+    write = {},
+    next = {},
+    ipairs = {},
+    rawequal = {},
+    getmetatable = {},
+    sleep = {},
+    loadfile = {},
+    settings = mk_fields { "clear", "unset", "set", "getNames", "save", "load", "get" },
+    rawset = {},
+    dofile = {},
+    bit32 = mk_fields { "band", "rshift", "bor", "bnot", "bxor", "arshift", "btest", "lrotate", "lshift", "replace", "rrotate", "extract" },
+    pairs = {},
+    rs = mk_fields { "setAnalogOutput", "getBundledOutput", "getBundledInput", "setOutput", "setAnalogueOutput", "getInput", "getOutput", "setBundledOutput", "getAnalogueOutput", "testBundledInput", "getSides", "getAnalogInput", "getAnalogOutput", "getAnalogueInput" },
+    help = mk_fields { "path", "topics", "completeTopic", "setPath", "lookup" },
+    window = mk_fields { "create" },
+    math = mk_fields { "log", "ceil", "atan", "acos", "ldexp", "rad", "pow", "asin", "pi", "deg", "tan", "cos", "tanh", "random", "abs", "frexp", "log10", "floor", "sinh", "max", "sqrt", "modf", "huge", "min", "mod", "fmod", "randomseed", "atan2", "exp", "sin", "cosh" },
+    _VERSION = {},
+    pcall = {},
+    keys = mk_fields { "a", "c", "b", "e", "pageUp", "g", "f", "i", "h", "k", "j", "space", "l", "o", "n", "q", "f1", "s", "insert", "u", "t", "eight", "numPadEnter", "six", "x", "numPad6", "z", "backslash", "rightBracket", "f9", "yen", "left", "numPadSubtract", "noconvert", "grave", "rightCtrl", "numPad2", "rightAlt", "delete", "f4", "home", "leftAlt", "numPad8", "getName", "numLock", "f8", "r", "pageDown", "y", "numPadEquals", "at", "pause", "w", "f11", "slash", "f5", "rightShift", "period", "multiply", "numPad0", "nine", "f13", "capsLock", "two", "leftBracket", "minus", "scollLock", "colon", "f14", "v", "equals", "three", "up", "d", "convert", "f7", "apostrophe", "f15", "f10", "stop", "f2", "numPad3", "comma", "numPad1", "numPadAdd", "tab", "f3", "numPad4", "kana", "four", "right", "numPadDecimal", "numPad7", "leftShift", "backspace", "numPad9", "end", "one", "kanji", "cimcumflex", "m", "semiColon", "underscore", "zero", "p", "return", "ax", "seven", "f6", "enter", "numPadDivide", "numPad5", "f12", "leftCtrl", "down", "five", "numPadComma" },
+    gps = mk_fields { "CHANNEL_GPS", "locate" },
+    bit = mk_fields { "band", "blogic_rshift", "bxor", "bor", "bnot", "blshift", "brshift" },
+    select = {},
+    paintutils = mk_fields { "drawPixel", "drawLine", "loadImage", "drawImage", "drawFilledBox", "parseImage", "drawBox" },
+    os = mk_fields { "sleep", "unloadAPI", "getComputerID", "startTimer", "queueEvent", "cancelTimer", "time", "clock", "setAlarm", "computerID", "reboot", "getComputerLabel", "setComputerLabel", "run", "pullEventRaw", "cancelAlarm", "computerLabel", "version", "shutdown", "loadAPI", "pullEvent", "epoch", "day" },
+    rawget = {},
+    table = mk_fields { "pack", "insert", "getn", "foreachi", "maxn", "foreach", "sort", "unpack", "concat", "remove" },
+    read = {},
+    colors = mk_fields { "cyan", "purple", "brown", "orange", "red", "magenta", "lime", "white", "blue", "rgb8", "lightGray", "pink", "test", "subtract", "black", "green", "combine", "yellow", "lightBlue", "gray" },
+    setfenv = {},
+    setmetatable = {},
+    type = {},
+    error = {},
+    shell = mk_fields { "exit", "path", "setDir", "clearAlias", "programs", "dir", "getCompletionInfo", "resolveProgram", "setPath", "getRunningProgram", "setCompletionFunction", "history", "run", "complete", "completeProgram", "resolve", "setAlias", "aliases" },
+  }
+}

src/codes.ts

@@ -11,4 +11,5 @@ export const enum WebsocketCodes {
   GoingAway = 1001,
   UnsupportedData = 1003,
   PolicyViolation = 1008,
+  TryAgainLater = 1013,
 }

src/host/_make.lua

@@ -8,7 +8,7 @@ local function has_content(line)
         not (line:match("^%s*%-%-[^%[]") or line:match("^%s*%-%-$"))
 end
 
-for _, dep in pairs { "argparse", "framebuffer", "encode" } do
+for _, dep in pairs { "argparse", "framebuffer", "encode", "json" } do
     out:write(("package.preload[%q] = function(...)\n"):format(dep))
 
     for line in io.lines(dep .. ".lua") do

src/host/argparse.lua

@@ -120,10 +120,14 @@ function parser:parse(...)
 end
 
 local function get_usage(arg)
-  if arg.argument then return arg.mvar
-  elseif arg.value then return arg.names[1] .. "=" .. arg.mvar
-  else return arg.names[1]
+  local name
+  if arg.argument then name = arg.mvar
+  elseif arg.value then name = arg.names[1] .. "=" .. arg.mvar
+  else name = arg.names[1]
   end
+
+  if #arg.names > 1 then name = name .. "," .. table.concat(arg.names, ",", 2) end
+  return name
 end
 
 local function create(prefix)
@@ -144,7 +148,7 @@ local function create(prefix)
       print("USAGE")
       local max = 0
       for i = 1, #parser.list do max = math.max(max, #get_usage(parser.list[i])) end
-      local format = "%" .. (max +1 ) .. "s %s"
+      local format = " %-" .. max .. "s %s"
 
       for i = 1, #parser.list do
         local arg = parser.list[i]
@@ -158,4 +162,8 @@ local function create(prefix)
   return parser
 end
 
-return create
+local function is_help(cmd)
+  return cmd == "help" or cmd == "--help" or cmd == "-h" or cmd == "-?"
+end
+
+return { create = create, is_help = is_help }

src/host/encode.lua

@@ -4,7 +4,7 @@
 -- a limit of how much impact any of it actually makes. Kinda pointless though
 -- as this does 5Mb/s on my machine.
 local function fletcher_32(str)
-  local s1, s2, len, byte = 0, 0, #str, string.byte
+  local s1, s2, byte = 0, 0, string.byte
 
   if #str % 2 ~= 0 then str = str .. "\0" end
   for i = 1, #str, 2 do

src/host/framebuffer.lua

@@ -1,5 +1,7 @@
 --- Just another frame buffer, but this one is serialisable!
 
+local stringify = require("json").stringify
+
 local colour_lookup = {}
 for i = 0, 16 do
   colour_lookup[string.format("%x", i)] = 2 ^ i
@@ -32,6 +34,7 @@ local function buffer(original)
   local text_colour = {}
   local back_colour = {}
   local palette = {}
+  local palette_24 = {}
 
   local cursor_x, cursor_y = 1, 1
 
@@ -50,6 +53,7 @@ local function buffer(original)
     for i = 0, 15 do
       local c = 2 ^ i
       palette[c] = { original.getPaletteColour( c ) }
+      palette_24[c] = colours.rgb8(original.getPaletteColour( c ))
     end
   end
 
@@ -116,7 +120,7 @@ local function buffer(original)
     local preStart = math.min(1, preStop)
     local postStart = cursor_x + #writeText
     local postStop = sizeX
-    local sub, rep = string.sub, string.rep
+    local sub = string.sub
 
     text[cursor_y] = sub(lineText, preStart, preStop)..writeText..sub(lineText, postStart, postStop)
     text_colour[cursor_y] = sub(lineColor, preStart, preStop)..writeFore..sub(lineColor, postStart, postStop)
@@ -230,12 +234,14 @@ local function buffer(original)
       if not palcol then error("Invalid colour (got " .. tostring(colour) .. ")", 2) end
       if type(r) == "number" and g == nil and b == nil then
           palcol[1], palcol[2], palcol[3] = colours.rgb8(r)
+          palette_24[colour] = r
       else
           if type(r) ~= "number" then error("bad argument #2 (expected number, got " .. type(r) .. ")", 2) end
           if type(g) ~= "number" then error("bad argument #3 (expected number, got " .. type(g) .. ")", 2) end
           if type(b) ~= "number" then error("bad argument #4 (expected number, got " .. type(b ) .. ")", 2 ) end
 
           palcol[1], palcol[2], palcol[3] = r, g, b
+          palette_24[colour] = colours.rgb8(r, g, b)
       end
 
       dirty = true
@@ -254,30 +260,25 @@ local function buffer(original)
   function redirect.is_dirty() return dirty end
   function redirect.clear_dirty() dirty = false end
 
-  local function char(x)
-    if x <= 0 then return "00"
-    elseif x >= 255 then return "ff"
-    else return ("%02x"):format(x) end
-  end
-
   function redirect.serialise()
-    local palettes = {}
-    for i = 0, 15 do
-      local c = palette[2^i]
-      palettes[i * 3 + 1] = char(math.floor(c[1] * 255))
-      palettes[i * 3 + 2] = char(math.floor(c[2] * 255))
-      palettes[i * 3 + 3] = char(math.floor(c[3] * 255))
-    end
+    return stringify {
+      packet = 0x10,
 
-    return char(sizeX) .. char(sizeY) .. char(cursor_x) .. char(cursor_y)
-        .. (cursor_blink and "1" or "0") .. cur_text_colour .. cur_back_colour
-        .. table.concat(palettes)
-        .. table.concat(text)
-        .. table.concat(text_colour)
-        .. table.concat(back_colour)
+      width = sizeX, height = sizeY,
+      cursorX = cursor_x, cursorY = cursor_y, cursorB = cursor_blink,
+      curFore = cur_text_colour, curBack = cur_back_colour,
+
+      palette = palette_24,
+      text = text, fore = text_colour, back = back_colour
+    }
   end
 
+  -- Ensure we're in sync with the parent terminal
+  redirect.setCursorPos(1, 1)
+  redirect.setBackgroundColor(colours.black)
+  redirect.setTextColor(colours.white)
   redirect.clear()
+
   return redirect
 end