File

mod_pubsub_github/mod_pubsub_github.lua @ 5405:c7a5caad28ef

mod_http_oauth2: Enforce response type encoded in client_id The client promises to only use this response type, so we should hold them to that. This makes it fail earlier if the response type is disabled or the client is trying to use one that it promised not to use. Better than failing after login and consent.
author Kim Alvefur <zash@zash.se>
date Tue, 02 May 2023 16:31:25 +0200
parent 3531:3bece2db869c
line wrap: on
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module:depends("http");

local st = require "util.stanza";
local json = require "util.json";
local hashes = require "util.hashes";
local from_hex = require "util.hex".from;
local hmacs = {
	sha1 = hashes.hmac_sha1;
	sha256 = hashes.hmac_sha256;
	sha384 = hashes.hmac_sha384;
	sha512 = hashes.hmac_sha512;
};

local pubsub_service = module:depends("pubsub").service;

-- configuration
local default_node = module:get_option("github_node", "github");
local node_prefix = module:get_option_string("github_node_prefix", "github/");
local node_mapping = module:get_option_string("github_node_mapping");
local github_actor = module:get_option_string("github_actor") or true;
local github_secret = module:get_option("github_secret");

-- validation
assert(github_secret, "Please set 'github_secret'");

local error_mapping = {
	["forbidden"] = 403;
	["item-not-found"] = 404;
	["internal-server-error"] = 500;
	["conflict"] = 409;
};

local function verify_signature(secret, body, signature)
	if not signature then return false; end
	local algo, digest = signature:match("^([^=]+)=(%x+)");
	if not algo then return false; end
	local hmac = hmacs[algo];
	if not algo then return false; end
	return hmac(secret, body) == from_hex(digest);
end

function handle_POST(event)
	local request, response = event.request, event.response;

	if not verify_signature(github_secret, request.body, request.headers.x_hub_signature) then
		module:log("debug", "Signature validation failed");
		return 401;
	end

	local data = json.decode(request.body);
	if not data then
		response.status_code = 400;
		return "Invalid JSON. From you of all people...";
	end

	local node = default_node;
	if node_mapping then
		node = node_prefix .. data.repository[node_mapping];
	end

	local github_event = request.headers.x_github_event or data.object_kind;
	if not github_event and data.commits then
		github_event = "push"; -- curl?
	end
	module:log("debug", "Handling '%s' event: \n%s\n", github_event, tostring(request.body));

	if github_event == "push" then

		for _, commit in ipairs(data.commits) do
			local ok, err = pubsub_service:publish(node, github_actor, commit.id,
				st.stanza("item", { id = commit.id, xmlns = "http://jabber.org/protocol/pubsub" })
				:tag("entry", { xmlns = "http://www.w3.org/2005/Atom" })
					:tag("id"):text(commit.id):up()
					:tag("title"):text(commit.message:match("^[^\r\n]*")):up()
					:tag("summary"):text(("Commit to %s by %s: %s"):format(data.repository.name, commit.author.name, commit.message:match("^[^\r\n]*"))):up()
					:tag("content"):text(commit.message):up()
					:tag("link", { rel = "alternate", href = commit.url }):up()
					:tag("published"):text(commit.author.date):up()
					:tag("author")
						:tag("name"):text(commit.author.name):up()
						:tag("email"):text(commit.author.email):up()
						:up()
			);
			if not ok then
				return error_mapping[err] or 500;
			end
		end

	elseif github_event then
		module:log("debug", "Unsupported Github event %q", github_event);
		return 501;
	end

	response.status_code = 202;
	return "Thank you Github!";
end

module:provides("http", {
	route = {
		POST = handle_POST;
	};
});

if not node_mapping then
	function module.load()
		if not pubsub_service.nodes[default_node] then
			local ok, err = pubsub_service:create(default_node, true);
			if not ok then
				module:log("error", "Error creating node: %s", err);
			else
				module:log("debug", "Node %q created", default_node);
			end
		end
	end
end