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import express from "express"; |
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const CACHE_LIFETIME = 30 * 1000; // 30 seconds in milliseconds |
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/** |
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* Manages client and bike connections with caching. |
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*/ |
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const clientManager = { |
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/** @type {Array<express.Response>} */ |
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clients: [], |
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/** |
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* @type {Object<string, {data: any, res: express.Response | null, timestamp: number | null}>} |
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*/ |
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cachedBikeData: {}, |
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/** |
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* Adds a new client to the clients array. |
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* @param {express.Response} client - The client to add. |
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*/ |
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addClient(client) { |
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this.clients.push(client); |
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}, |
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/** |
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* Removes a client from the clients array. |
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* @param {express.Response} client - The client to remove. |
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*/ |
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removeClient(client) { |
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this.clients = this.clients.filter(c => c !== client); |
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}, |
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/** |
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* Initializes a new bike entry in the cache. |
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* @param {Number} bikeId - The bike ID. |
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* @param {express.Response} res - The bike connection response to add. |
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*/ |
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addBike(bikeId, res) { |
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this.cachedBikeData[bikeId] = { |
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res: res, |
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data: null, |
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timestamp: null |
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}; |
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}, |
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/** |
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* Removes a bike's res key (and value) from the cache object |
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* @param {Number} bikeId - Id of the bike for which to set res to null |
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*/ |
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removeBike(bikeId) { |
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this.cachedBikeData[bikeId].res = null |
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}, |
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/** |
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* Updates bike data in the cache and writes to database if necessary. |
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* @param {Number} bikeId - The bike ID. |
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* @param {any} dbData - Data to update database with. |
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* @param {any} cachedData - Data to cache. |
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* @param {Function} updateBike - Function to write data to the database. |
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*/ |
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async updateBikeData(bikeId, cachedData, dbData, updateBike) { |
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const cacheEntry = this.cachedBikeData[bikeId]; |
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// Kolla om det finns en timestamp eller om cachen har gått ut |
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const isCacheExpired = !cacheEntry.timestamp || (Date.now() - cacheEntry.timestamp > CACHE_LIFETIME); |
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if (isCacheExpired) { |
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// Om cachen är utgången eller inte finns --> uppdatera databasen |
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await updateBike( |
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dbData.id, |
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dbData.status, |
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dbData.charge, |
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dbData.coords |
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); |
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// Uppdatera cachen med ny data och tidsstämpel |
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this.cachedBikeData[bikeId] = { |
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...cacheEntry, |
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data: cachedData, |
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timestamp: Date.now() |
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}; |
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} else { |
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// Annars uppdatera endast cachad data |
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this.cachedBikeData[bikeId].data = cachedData; |
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} |
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}, |
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/** |
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* Broadcasts a message to all clients. |
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* @param {Object} message - The message to broadcast. |
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*/ |
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broadcastToClients(message) { |
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this.clients.forEach(client => client.write(`data: ${JSON.stringify(message)}\n\n`)); |
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}, |
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/** |
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* Broadcasts a message to a specific bike. |
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* @param {Number} bikeId - The ID of the bike to which the message should be broadcast. |
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* @param {Object} message - The message to broadcast. |
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*/ |
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broadcastToBike(bikeId, message) { |
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const bike = this.cachedBikeData[bikeId]; |
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if (bike && bike.res) { |
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bike.res.write(`data: ${JSON.stringify(message)}\n\n`); |
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} |
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} |
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}; |
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export default clientManager; |
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JuliaLind /
vteam-server
