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lua/pac3/core/shared/http.lua

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+--[[
+| This file was obtained through the combined efforts
+| of Madbluntz & Plymouth Antiquarian Society.
+|
+| Credits: lifestorm, Gregory Wayne Rossel JR.,
+| 	Maloy, DrPepper10 @ RIP, Atle!
+|
+| Visit for more: https://plymouth.thetwilightzone.ru/
+--]]
+
+
+local CL_LIMIT, CL_LIMIT_OVERRIDE, CL_NO_CLENGTH
+
+if CLIENT then
+	CL_LIMIT = CreateConVar("pac_webcontent_limit", "-1", {FCVAR_ARCHIVE}, "webcontent limit in kb, -1 = unlimited")
+	CL_NO_CLENGTH = CreateConVar("pac_webcontent_allow_no_content_length", "0", {FCVAR_ARCHIVE}, "allow downloads with no content length")
+	CL_LIMIT_OVERRIDE = CreateConVar("pac_webcontent_limit_force", "0", {FCVAR_ARCHIVE}, "Override serverside setting")
+end
+
+local SV_LIMIT = CreateConVar("sv_pac_webcontent_limit", "-1", CLIENT and {FCVAR_REPLICATED} or {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "webcontent limit in kb, -1 = unlimited")
+local SV_NO_CLENGTH = CreateConVar("sv_pac_webcontent_allow_no_content_length", "-1", CLIENT and {FCVAR_REPLICATED} or {FCVAR_ARCHIVE, FCVAR_REPLICATED}, "allow downloads with no content length")
+
+function pac.FixGMODUrl(url)
+	-- to avoid "invalid url" errors
+	-- gmod does not allow urls containing "10.", "172.16.", "192.168.", "127." or "://localhost"
+	-- we escape 10. and 127. can occur (mydomain.com/model10.zip) and assume the server supports
+	-- the escaped request
+	return url:Replace("10.", "%31%30%2e"):Replace("127.", "%31%32%37%2e")
+end
+
+local function http(method, url, headers, cb, failcb)
+
+	url = pac.FixGMODUrl(url)
+
+	return HTTP({
+		method = method,
+		url = url,
+		headers = headers,
+		success = function(code, data, headers)
+			if code < 400 then
+				cb(data, #data, headers)
+			else
+				local header = {}
+				for k,v in pairs(headers) do
+					table.insert(header, tostring(k) .. ": " .. tostring(v))
+				end
+
+				local err = "server returned code " .. code .. ":\n\n"
+				err = err .. "url: "..url.."\n"
+				err = err .. "================\n"
+
+				err = err .. "HEADER:\n"
+				err = err .. table.concat(header, "\n") .. "\n"
+
+				err = err .. "================\n"
+
+				err = err .. "BODY:\n"
+				err = err .. data .. "\n"
+
+				err = err .. "================\n"
+				failcb(err, code >= 400, code)
+			end
+		end,
+		failed = function(err)
+			if failcb then
+				failcb("_G.HTTP error: " .. err)
+			else
+				pac.Message("_G.HTTP error: " .. err)
+			end
+		end
+	})
+end
+
+function pac.FixUrl(url)
+	url = url:Trim()
+	url = url:gsub("[\"'<>\n\\]+", "")
+
+	if url:find("dropbox", 1, true) then
+		url = url:gsub([[^http%://dl%.dropboxusercontent%.com/]], [[https://dl.dropboxusercontent.com/]])
+		url = url:gsub([[^https?://dl.dropbox.com/]], [[https://www.dropbox.com/]])
+		url = url:gsub([[^https?://www.dropbox.com/s/(.+)%?dl%=[01]$]], [[https://dl.dropboxusercontent.com/s/%1]])
+		url = url:gsub([[^https?://www.dropbox.com/s/(.+)$]], [[https://dl.dropboxusercontent.com/s/%1]])
+		url = url:gsub([[^https?://www.dropbox.com/scl/(.+)$]], [[https://dl.dropboxusercontent.com/scl/%1]]) --Fix for new dropbox format.
+		return url
+	end
+
+	if url:find("drive.google.com", 1, true) and not url:find("export=download", 1, true) then
+		local id =
+			url:match("https://drive.google.com/file/d/(.-)/") or
+			url:match("https://drive.google.com/file/d/(.-)$") or
+			url:match("https://drive.google.com/open%?id=(.-)$")
+
+		if id then
+			return "https://drive.google.com/uc?export=download&id=" .. id
+		end
+		return url
+	end
+
+	if url:find("gitlab.com", 1, true) then
+		return url:gsub("^(https?://.-/.-/.-/)blob", "%1raw")
+	end
+
+	url = url:gsub([[^http%://onedrive%.live%.com/redir?]],[[https://onedrive.live.com/download?]])
+	url = url:gsub("pastebin.com/([a-zA-Z0-9]*)$", "pastebin.com/raw.php?i=%1")
+	url = url:gsub("github.com/([a-zA-Z0-9_]+)/([a-zA-Z0-9_]+)/blob/", "github.com/%1/%2/raw/")
+
+	return url
+end
+
+function pac.getContentLength(url, cb, failcb)
+	return http("HEAD", url, {["Accept-Encoding"] = "none"}, function(_, _, headers)
+		local length
+
+		-- server have rights to send headers in any case
+		for key, value in pairs(headers) do
+			if string.lower(key) == "content-length" then
+				length = tonumber(value)
+
+				if not length or math.floor(length) ~= length then
+					return failcb(string.format("malformed server reply with header content-length (got %q, expected valid integer number)", value), true)
+				end
+
+				break
+			end
+		end
+
+		if length then return cb(length) end
+
+		return pac.contentLengthFallback(url, cb, failcb)
+	end, function(err, over400, code)
+		if code == 405 then
+			return pac.contentLengthFallback(url, cb, failcb)
+		end
+
+		return failcb(err, over400)
+	end )
+end
+
+-- Performs a GET but requests 0 bytes
+-- We can then read the response headers to determine the content size.
+-- This allows Google Drive and other hosts to work with PAC even with content-length limits set
+-- (They typically block HEAD requests)
+function pac.contentLengthFallback(url, cb, failcb)
+	local function fail()
+		return failcb("unable to determine content length", true)
+	end
+
+	return http("GET", url, {["Range"] = "bytes=0-0"}, function(data, data_length, headers)
+		-- e.g. "bytes 0-0/11784402"
+		local contentRange = headers["Content-Range"]
+		if not contentRange then return fail() end
+
+		local spl = string.Split(contentRange, "/")
+		local contentLength = spl[2]
+
+		if contentLength then return cb(tonumber(contentLength)) end
+
+		return fail()
+	end )
+end
+
+function pac.HTTPGet(url, cb, failcb)
+	if not url or url:len() < 4 then
+		failcb("url length is less than 4 (" .. tostring(url) .. ")", true)
+		return
+	end
+
+	url = pac.FixUrl(url)
+
+	local limit = SV_LIMIT:GetInt()
+
+	if CLIENT and (CL_LIMIT_OVERRIDE:GetBool() or limit == -1) then
+		limit = CL_LIMIT:GetInt()
+	end
+
+	if limit == -1 then
+		return http("GET", url, nil, cb, failcb)
+	end
+
+	return pac.getContentLength(url, function(length)
+		if length then
+			if length <= (limit * 1024) then
+				http("GET", url, nil, cb, failcb)
+			else
+				failcb("download is too big (" .. string.NiceSize(length) .. ")", true)
+			end
+		else
+			local allow_no_contentlength = SV_NO_CLENGTH:GetInt()
+
+			if CLIENT and (CL_LIMIT_OVERRIDE:GetBool() or allow_no_contentlength < 0) then
+				allow_no_contentlength = CL_NO_CLENGTH:GetInt()
+			end
+
+			if allow_no_contentlength > 0 then
+				http("GET", url, nil, cb, failcb)
+			else
+				failcb("unknown file size when allow_no_contentlength is " .. allow_no_contentlength, true)
+			end
+		end
+	end, failcb)
+end