File

plugins/mod_http_errors.lua @ 11665:148075532021

net.server_epoll: Prevent stack overflow of opportunistic writes net.http.files serving a big enough file on a fast enough connection with opportunistic_writes enabled could trigger a stack overflow through repeatedly serving more data that immediately gets sent, draining the buffer and triggering more data to be sent. This also blocked the server on a single task until completion or an error. This change prevents nested opportunistic writes, which should prevent the stack overflow, at the cost of reduced download speed, but this is unlikely to be noticeable outside of Gbit networks. Speed at the cost of blocking other processing is not worth it, especially with the risk of stack overflow.
author Kim Alvefur <zash@zash.se>
date Sun, 11 Jul 2021 09:39:21 +0200
parent 11664:d83f8f44caea
child 11820:0375ef78ed64
line wrap: on
line source

module:set_global();

local server = require "net.http.server";
local codes = require "net.http.codes";
local xml_escape = require "util.stanza".xml_escape;
local render = require "util.interpolation".new("%b{}", xml_escape);

local show_private = module:get_option_boolean("http_errors_detailed", false);
local always_serve = module:get_option_boolean("http_errors_always_show", true);
local default_message = { module:get_option_string("http_errors_default_message", "That's all I know.") };
local default_messages = {
	[400] = { "What kind of request do you call that??" };
	[403] = { "You're not allowed to do that." };
	[404] = { "Whatever you were looking for is not here. %";
		"Where did you put it?", "It's behind you.", "Keep looking." };
	[500] = { "% Check your error log for more info.";
		"Gremlins.", "It broke.", "Don't look at me." };
	["/"] = {
		"A study in simplicity.";
		"Better catch it!";
		"Don't just stand there, go after it!";
		"Well, say something, before it runs too far!";
		"Welcome to the world of XMPP!";
		"You can do anything in XMPP!"; -- "The only limit is XML.";
		"You can do anything with Prosody!"; -- the only limit is memory?
	};
};

local messages = setmetatable(module:get_option("http_errors_messages", {}), { __index = default_messages });

local html = [[
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>{title}</title>
<style>
body{margin-top:14%;text-align:center;background-color:#f8f8f8;font-family:sans-serif}
h1{font-size:xx-large}
p{font-size:x-large}
p.warning>span{font-size:large;background-color:yellow}
p.extra{font-size:large;font-family:courier}
@media(prefers-color-scheme:dark){
body{background-color:#161616;color:#eee}
p.warning>span{background-color:inherit;color:yellow}
}
</style>
</head>
<body>
<h1>{icon?{icon_raw!?}} {title}</h1>
<p>{message}</p>
{warning&<p class="warning"><span>&#9888; {warning?} &#9888;</span></p>}
{extra&<p class="extra">{extra?}</p>}
</body>
</html>
]];

local function get_page(code, extra)
	local message = messages[code];
	if always_serve or message then
		message = message or default_message;
		return render(html, {
			title = rawget(codes, code) or ("Code "..tostring(code));
			message = message[1]:gsub("%%", function ()
				return message[math.random(2, math.max(#message,2))];
			end);
			extra = extra;
		});
	end
end

-- Main error page handler
module:hook_object_event(server, "http-error", function (event)
	if event.response then
		event.response.headers.content_type = "text/html; charset=utf-8";
	end
	return get_page(event.code, (show_private and event.private_message) or event.message or (event.error and event.error.text));
end);

-- Way to use the template for other things so to give a consistent appearance
module:hook("http-message", function (event)
	if event.response then
		event.response.headers.content_type = "text/html; charset=utf-8";
	end
	return render(html, event);
end);

local icon = [[
<svg xmlns="http://www.w3.org/2000/svg" height="0.7em" viewBox="0 0 480 480" width="0.7em">
<rect fill="#6197df" height="220" rx="60" ry="60" width="220" x="10" y="10"></rect>
<rect fill="#f29b00" height="220" rx="60" ry="60" width="220" x="10" y="240"></rect>
<rect fill="#f29b00" height="220" rx="60" ry="60" width="220" x="240" y="10"></rect>
<rect fill="#6197df" height="220" rx="60" ry="60" width="220" x="240" y="240"></rect>
</svg>
]];

-- Something nicer shown instead of 404 at the root path, if nothing else handles this path
module:hook_object_event(server, "http-error", function (event)
	local request, response = event.request, event.response;
	if request and response and request.path == "/" and response.status_code == 404 then
		response.status_code = 200;
		response.headers.content_type = "text/html; charset=utf-8";
		local message = messages["/"];
		return render(html, {
				icon_raw = icon,
				title = "Prosody is running!";
				message = message[math.random(#message)];
			});
	end
end, 1);