From 1863be5cb24cfe8158903344035d26cb7ae120c5 Mon Sep 17 00:00:00 2001
From: Kampfkarren <boynedmaster@gmail.com>
Date: Tue, 22 Jan 2019 08:18:51 -0800
Subject: [PATCH 1/2] Unique GUID shim - Closes #153

---
 lib/instances/HttpService.lua      | 27 +++++++++++++++++++++++----
 lib/instances/HttpService_spec.lua | 23 +++++++++++++++++++++++
 2 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/lib/instances/HttpService.lua b/lib/instances/HttpService.lua
index 93e3004..a5ef19c 100644
--- a/lib/instances/HttpService.lua
+++ b/lib/instances/HttpService.lua
@@ -4,6 +4,15 @@ local json = import("../json")
 
 local HttpService = BaseInstance:extend("HttpService")
 
+local guidCounter = 0
+
+local GUID_DASH_POINTS = {
+	[8] = true,
+	[12] = true,
+	[16] = true,
+	[20] = true,
+}
+
 function HttpService.prototype:JSONEncode(input)
 	return json.encode(input)
 end
@@ -18,15 +27,25 @@ function HttpService.prototype:GenerateGUID(wrapInCurlyBraces)
 		error(("Unable to cast %s to bool"):format(argType), 2)
 	end
 
+	local zeroPadded = ("%032x"):format(guidCounter)
+	local guid = ""
+	for index = 1, 32 do
+		guid = guid .. zeroPadded:sub(index, index)
+		if GUID_DASH_POINTS[index] then
+			guid = guid .. "-"
+		end
+	end
+	guidCounter = guidCounter + 1
+
 	--[[
 		`GenerateGUID` allows any value type for `wrapInCurlyBraces`, but it
 		only omits the curly braces when `wrapInCurlyBraces` is set to `false`
 	]]
-	if wrapInCurlyBraces == false then
-		return "04AEBFEA-87FC-480F-A98B-E5E221007A90"
-	else
-		return "{04AEBFEA-87FC-480F-A98B-E5E221007A90}"
+	if wrapInCurlyBraces ~= false then
+		guid = "{" .. guid .. "}"
 	end
+
+	return guid
 end
 
 return HttpService
\ No newline at end of file
diff --git a/lib/instances/HttpService_spec.lua b/lib/instances/HttpService_spec.lua
index ca45d3a..4c66d0f 100644
--- a/lib/instances/HttpService_spec.lua
+++ b/lib/instances/HttpService_spec.lua
@@ -20,6 +20,29 @@ describe("instances.HttpService", function()
 	end)
 
 	describe("GenerateGUID", function()
+		it("should have proper length guids", function()
+			local instance = HttpService:new()
+			local guid = instance:GenerateGUID(false)
+
+			assert.equal(36, #guid)
+		end)
+
+		it("should give unique guids", function()
+			local instance = HttpService:new()
+			local guids = {}
+
+			for _ = 1, 100 do
+				guids[instance:GenerateGUID()] = true
+			end
+
+			local guidsGenerated = 0
+			for _ in pairs(guids) do
+				guidsGenerated = guidsGenerated + 1
+			end
+
+			assert.equal(100, guidsGenerated)
+		end)
+
 		it("should omit curly braces when wrapInCurlyBraces is false", function()
 			local instance = HttpService:new()
 			local guid = instance:GenerateGUID(false)

From 4b2e90f8b49a6851e9b65da88038679008ef2352 Mon Sep 17 00:00:00 2001
From: Kampfkarren <boynedmaster@gmail.com>
Date: Tue, 22 Jan 2019 11:59:53 -0800
Subject: [PATCH 2/2] Real GUIDs

---
 lib/instances/HttpService.lua | 63 ++++++++++++++++++++++++++---------
 1 file changed, 47 insertions(+), 16 deletions(-)

diff --git a/lib/instances/HttpService.lua b/lib/instances/HttpService.lua
index a5ef19c..8b5e660 100644
--- a/lib/instances/HttpService.lua
+++ b/lib/instances/HttpService.lua
@@ -4,14 +4,29 @@ local json = import("../json")
 
 local HttpService = BaseInstance:extend("HttpService")
 
-local guidCounter = 0
+-- Credit to https://stackoverflow.com/a/32389020
+local AND, OR = 1, 4
 
-local GUID_DASH_POINTS = {
-	[8] = true,
-	[12] = true,
-	[16] = true,
-	[20] = true,
-}
+local function bit(a, b, oper)
+	local r, m, s = 0, 2^52
+	repeat
+		s, a, b = a + b + m, a % m, b % m
+		r, m = r + m * oper % (s - a - b), m / 2
+	until m < 1
+	return r
+end
+
+local function band(a, b)
+	return bit(a, b, AND)
+end
+
+local function bor(a, b)
+	return bit(a, b, OR)
+end
+
+local function tohex(number)
+	return ("%02x"):format(number)
+end
 
 function HttpService.prototype:JSONEncode(input)
 	return json.encode(input)
@@ -27,15 +42,31 @@ function HttpService.prototype:GenerateGUID(wrapInCurlyBraces)
 		error(("Unable to cast %s to bool"):format(argType), 2)
 	end
 
-	local zeroPadded = ("%032x"):format(guidCounter)
-	local guid = ""
-	for index = 1, 32 do
-		guid = guid .. zeroPadded:sub(index, index)
-		if GUID_DASH_POINTS[index] then
-			guid = guid .. "-"
-		end
-	end
-	guidCounter = guidCounter + 1
+	local random = math.random
+
+	local guid =
+		("%s%s%s%s-%s%s-%s%s-%s%s-%s%s%s%s%s%s"):format(
+			tohex(random(0, 255), 2),
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+
+			tohex(bor(band(random(0, 255), 0x0F), 0x40)),
+			tohex(random(0, 255)),
+
+			tohex(bor(band(random(0, 255), 0x3F), 0x80)),
+			tohex(random(0, 255)),
+
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+			tohex(random(0, 255)),
+			tohex(random(0, 255))
+		)
 
 	--[[
 		`GenerateGUID` allows any value type for `wrapInCurlyBraces`, but it