implement ratelimiting

.gitignore

@@ -1,5 +1,7 @@
 # view count
 .count.json
+# rate limited ips
+.ratelimit.json
 
 # ---> Node
 # Logs

conf.json

@@ -2,6 +2,7 @@
 	"port": 8001,
 	"path": "/viewcounter",
 	"site": "zvava.org",
-	"db": ".count.json",
+	"countDB": ".count.json",
+	"ratelimitDB": ".ratelimit.json",
 	"saveTimeout": 5000
 }

index.js

@@ -7,53 +7,52 @@ let config = readJson("conf.json", {
 	port: 8001,
 	path: "/viewcounter",
 	site: "zvava.org",
-	db: ".count.json",
+	countDB: ".count.json",
+	ratelimitDB: ".ratelimit.json",
 	saveTimeout: 5000,
 })
-// read existing view count
-let count = readJson(config.db)
+// read databases
+let count = readJson(config.countDB)
+let ratelimit = readJson(config.ratelimitDB)
 // store the save timeout
 let saveTimeout
 
 let server = new http.Server((request, response) => {
-	try {
-		if (request.url != config.path)
-			return close(response, 404)
+	if (request.url != config.path)
+		return close(response, 404)
 
-		switch (request.method) {
-			case "POST":
-				const chunks = []
-				request.on("data", chunk => chunks.push(chunk))
-				request.on("end", async () => {
-					let page = Buffer.concat(chunks).toString()
+	switch (request.method) {
+		case "POST":
+			const chunks = []
+			request.on("data", chunk => chunks.push(chunk))
+			request.on("end", async () => {
+				let page = Buffer.concat(chunks).toString()
 
-					// check if page is a valid url
-					if (/\/[a-zA-Z0-9_-]+.html/.test(page) && await validateUrl(page)) {
-						count[page] = count[page] ? count[page] + 1 : 1
-						saveCount()
-						close(response, 200, "counted page view", { views: count[page] })
-					} else {
-						close(response, 300, "invalid url provided")
-					}
-				})
-			break
+				// check if page is a valid url
+				if (/\/[a-zA-Z0-9_-]+.html/.test(page) && await validateUrl(page)) {
+					let message = incrementCount(request.socket.remoteAddress, page)
+						? "counted page view" : "you have seen this page today"
+					close(response, 200, { message, views: count[page] })
+				} else {
+					close(response, 300, "invalid url provided")
+				}
+			})
+		break
 
-			case "GET": close(response, 200, count); break
+		case "GET": close(response, 200, count); break
 
-			default: close(response, "invalid method " + request.method)
-		}
-	} catch (e) {
-		console.log(e)
+		default: close(response, "invalid method " + request.method)
 	}
 })
 
 server.listen(config.port)
 
 function saveCount() {
-	// if a timeout
-	saveTimeout && clearTimeout(saveTimeout)
+	clearTimeout(saveTimeout)
 	saveTimeout = setTimeout(() => {
-		fs.writeFile(config.db, JSON.stringify(count), (err) =>
+		fs.writeFile(config.countDB, JSON.stringify(count), (err) =>
+			err && console.error(err))
+		fs.writeFile(config.ratelimitDB, JSON.stringify(ratelimit), (err) =>
 			err && console.error(err))
 	}, config.saveTimeout)
 }
@@ -66,10 +65,10 @@ function readJson(file, defaultJson = {}) {
 }
 
 // helper function to close an incoming http request
-function close(res, code = 300, message = "", extraData = {}) {
+function close(res, code = 300, message = "") {
 	let data = typeof message == "string"
-		? { code, ...extraData, message: message || code.toString() }
-		: { code, ...extraData, ...message }
+		? { code, message: message || code.toString() }
+		: { code, ...message }
 	res.setHeader("Content-type", "application/json")
 	res.writeHead(code)
 	res.end(JSON.stringify(data))
@@ -98,3 +97,30 @@ function validateUrl(url) {
 		}
 	})
 }
+
+function incrementCount(ip, page) {
+	if (!ip) return false // in case client disconnected
+
+	// calculate date string
+	let d = new Date(); d = d.getMonth() + "-" + d.getDate()
+	// will increment count at end
+	let i = false
+
+	// create ratelimit profile for the ip if it doesn't exist already
+	if (!ratelimit[ip]) ratelimit[ip] = {}
+
+	i = !ratelimit[ip][page]
+		// if last visited date doesn't exist
+		? true
+		// else, check if last visited date was today
+		: ratelimit[ip][page] != d
+
+	if (i) {
+		// update last visited day
+		ratelimit[ip][page] = d
+		// increment page count if it exists, otherwise set page count to 1
+		count[page] = count[page] ? count[page] + 1 : 1
+		saveCount()
+		return true
+	}
+}