Add request quota system

src/lib/quota/index.js

@@ -0,0 +1,33 @@
+const constants = require("../constants")
+const LimitByFrame = require("./LimitByFrame")
+const {getIdentifier} = require("./get_identifier")
+require("../testimports")(LimitByFrame, getIdentifier)
+
+const limiter = new LimitByFrame()
+
+function getIPFromReq(req) {
+	if (constants.quota.ip_mode === "header") {
+		return req.headers[constants.quota.ip_header]
+	} else { // constants.quota.ip_mode === "address"
+		return req.connection.remoteAddress
+	}
+}
+
+function remaining(req) {
+	if (!constants.quota.enabled) return Infinity // sure.
+
+	const ip = getIPFromReq(req)
+	const identifier = getIdentifier(ip)
+	return limiter.remaining(identifier)
+}
+
+function add(req, count) {
+	if (!constants.quota.enabled) return Infinity // why not.
+
+	const ip = getIPFromReq(req)
+	const identifier = getIdentifier(ip)
+	return limiter.add(identifier, count)
+}
+
+module.exports.remaining = remaining
+module.exports.add = add