From d1c02019db9a6fb2ab053091c9a4a32dc00b8b50 Mon Sep 17 00:00:00 2001
From: Tom Smeding <tom@tomsmeding.com>
Date: Mon, 22 Aug 2022 15:28:10 +0200
Subject: Initial

---
 server.js | 180 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 180 insertions(+)
 create mode 100755 server.js

(limited to 'server.js')

diff --git a/server.js b/server.js
new file mode 100755
index 0000000..21d9094
--- /dev/null
+++ b/server.js
@@ -0,0 +1,180 @@
+#!/usr/bin/env node
+const express = require("express");
+const http = require("http");
+const socketio = require("socket.io");
+const fs = require("fs");
+
+const [DBFILE, PORT] = (() => {
+  if (process.argv.length == 3) {
+    return [process.argv[2], 8000];
+  } else if (process.argv.length == 4) {
+    return [process.argv[2], +process.argv[3]];
+  } else {
+    console.log("Usage: ./server.js <dbfile.txt> [port]");
+    process.exit(1);
+  }
+})();
+
+const app = express();
+const httpServer = http.Server(app);
+const io = socketio(httpServer);
+
+const STATIC = __dirname + "/static";
+
+
+// ------------------------------
+//           "database"
+// ------------------------------
+
+class Database {
+  #filename;
+  #list;
+  #lastbackup;
+
+  constructor(filename) {
+    this.#filename = filename;
+    this.#list = JSON.parse(fs.readFileSync(this.#filename));
+    this.#lastbackup = new Date();
+  }
+
+  add_new(string) {
+    for (let i = 0; i < this.#list.length; i++) {
+      if (this.#list[i][1] == string) {
+        return "already existed";
+      }
+    }
+
+    this.#list.push([0, string]);
+    this.#sort();
+    this.#persist();
+
+    return null;
+  }
+
+  set_votes(string, votes) {
+    for (let i = 0; i < this.#list.length; i++) {
+      if (this.#list[i][1] == string) {
+        this.#list[i][0] = votes;
+        this.#sort();
+        this.#persist();
+        return null;
+      }
+    }
+
+    return `'${string}' does not exist`;
+  }
+
+  remove(string) {
+    for (let i = 0; i < this.#list.length; i++) {
+      if (this.#list[i][1] == string) {
+        this.#list.splice(i, 1);
+        this.#persist();
+        return null;
+      }
+    }
+
+    return "does not exist";
+  }
+
+  get() {
+    return this.#list;
+  }
+
+  #sort() {
+    this.#list.sort((a, b) => {
+      if (a[0] != b[0]) return b[0] - a[0];
+      if (a[1] < b[1]) return -1;
+      if (a[1] > b[1]) return 1;
+      return 0;
+    });
+  }
+
+  #persist() {
+    fs.writeFile(this.#filename, JSON.stringify(this.#list), err => {
+      if (err != null) {
+        console.error("Error writing to file:", err);
+        console.log(JSON.stringify(this.#list));
+      }
+    });
+
+    const now = new Date();
+    if (now - this.#lastbackup > 60 * 1000) {
+      const dotidx = this.#filename.lastIndexOf(".");
+      const bakfname =
+        dotidx == -1
+          ? this.#filename + now.getTime()
+          : this.#filename.slice(0, dotidx) + "." + now.getTime() + this.#filename.slice(dotidx);
+      fs.writeFile(bakfname, JSON.stringify(this.#list), err => {
+        if (err != null) {
+          console.error("Error copying to backup file:", err);
+        } else {
+          console.log(`Copied to ${bakfname}`);
+        }
+      });
+
+      this.#lastbackup = now;
+    }
+  }
+};
+
+const database = new Database(DBFILE);
+
+
+// ------------------------------
+//         Express routes
+// ------------------------------
+
+app.use(express.static(STATIC));
+
+app.get("/", (req, res) => {
+    res.sendFile(STATIC + "/index.html");
+});
+
+
+// ------------------------------
+//       socket.io bindings
+// ------------------------------
+
+let next_socket_id = 1;
+let num_connected = 0;
+
+io.on("connection", socket => {
+  const socket_id = next_socket_id++;
+  if (++num_connected >= 2) {
+    socket.emit("alert", `You're user number ${num_connected}, multi-user settings will mess up!`);
+  }
+  console.log(`new socket connection id=${socket_id} (nc=${num_connected})`);
+
+  socket.on("disconnect", () => {
+    num_connected--;
+    console.log(`disconnect id=${socket_id} (nc=${num_connected})`);
+  });
+
+  socket.on("new", string => {
+    const res = database.add_new(string);
+    if (res != null) socket.emit("error", res);
+  });
+
+  socket.on("set_votes", (string, votes) => {
+    const res = database.set_votes(string, votes);
+    if (res != null) socket.emit("error", res);
+  });
+
+  socket.on("delete", string =>{
+    const res = database.remove(string);
+    if (res != null) socket.emit("error", res);
+  });
+
+  socket.emit("init", database.get());
+});
+
+
+// ------------------------------
+//             setup
+// ------------------------------
+
+const server = httpServer.listen(PORT, () => {
+	const host = server.address().address;
+	const port = server.address().port;
+	console.log("Server listening at http://" + host + ":" + port);
+});
-- 
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