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CommLink.js

A userscript library for cross-window communication via the userscript storage

Fra og med 08.07.2023. Se den nyeste version.

Dette script bør ikke installeres direkte. Det er et bibliotek, som andre scripts kan inkludere med metadirektivet // @require https://update.greatest.deepsurf.us/scripts/470418/1217207/CommLinkjs.js 

/* CommLink.js
 - Version: 1.0.1
 - Author: Haka
 - Description: A userscript library for cross-window communication via the userscript storage
 - GitHub: https://github.com/AugmentedWeb/CommLink
 */

class CommLinkHandler {
    constructor(commlinkID, configObj) {
        this.commlinkID = commlinkID;
        this.singlePacketResponseWaitTime = configObj?.singlePacketResponseWaitTime || 1500;
        this.maxSendAttempts = configObj?.maxSendAttempts || 3;
        this.statusCheckInterval = configObj?.statusCheckInterval || 1;
        this.silentMode = configObj?.silentMode || false;

        this.commlinkValueIndicator = 'commlink-packet-';
        this.commands = {};
        this.listeners = [];

        const missingGrants = ['GM_getValue', 'GM_setValue', 'GM_deleteValue', 'GM_listValues']
            .filter(grant => !GM_info.script.grant.includes(grant));

        if(missingGrants.length > 0 && !this.silentMode) {
            alert(`[CommLink] The following userscript grants are missing: ${missingGrants.join(', ')}. CommLink will not work.`);
        }

        this.getStoredPackets()
          .filter(packet => Date.now() - packet.date > 2e4)
          .forEach(packet => this.removePacketByID(packet.id));
    }

    setIntervalAsync(callback, interval = this.statusCheckInterval) {
        let running = true;

        async function loop() {
            while(running) {
                try {
                    await callback();

                    await new Promise((resolve) => setTimeout(resolve, interval));
                } catch (e) {
                    continue;
                }
            }
        };

        loop();

        return { stop: () => running = false };
    }

    getUniqueID() {
        return ([1e7]+-1e3+4e3+-8e3+-1e11).replace(/[018]/g, c =>
            (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
        )
    }

    getCommKey(packetID) {
        return this.commlinkValueIndicator + packetID;
    }

    getStoredPackets() {
        return GM_listValues()
            .filter(key => key.includes(this.commlinkValueIndicator))
            .map(key => GM_getValue(key));
    }

    addPacket(packet) {
        GM_setValue(this.getCommKey(packet.id), packet);
    }

    removePacketByID(packetID) {
        GM_deleteValue(this.getCommKey(packetID));
    }

    findPacketByID(packetID) {
        return GM_getValue(this.getCommKey(packetID));
    }

    editPacket(newPacket) {
        GM_setValue(this.getCommKey(newPacket.id), newPacket);
    }

    send(platform, cmd, d) {
        return new Promise(async resolve => {
            const packetWaitTimeMs = this.singlePacketResponseWaitTime;
            const maxAttempts = this.maxSendAttempts;

            let attempts = 0;

            for (;;) {
                attempts++;

                const packetID = this.getUniqueID();
                const attemptStartDate = Date.now();

                const packet = { sender: platform, id: packetID, command: cmd, data: d, date: attemptStartDate };

                if(!this.silentMode)
                    console.log(`[CommLink Sender] Sending packet! (#${attempts} attempt):`, packet);

                this.addPacket(packet);

                for (;;) {
                    const poolPacket = this.findPacketByID(packetID);
                    const packetResult = poolPacket?.result;

                    if (poolPacket && packetResult) {
                        if(!this.silentMode)
                            console.log(`[CommLink Sender] Got result for a packet (${packetID}):`, packetResult);

                        resolve(poolPacket.result);

                        attempts = maxAttempts; // stop main loop

                        break;
                    }

                    if (!poolPacket || Date.now() - attemptStartDate > packetWaitTimeMs) {
                        break;
                    }

                    await new Promise(res => setTimeout(res, this.statusCheckInterval));
                }

                this.removePacketByID(packetID);

                if (attempts == maxAttempts) {
                    break;
                }
            }

            return resolve(null);
        });
    }

    registerSendCommand(name, obj) {
        this.commands[name] = async data => await this.send(obj?.commlinkID || this.commlinkID , name, obj?.data || data);
    }

    registerListener(sender, commandHandler) {
        const listener = {
            sender,
            commandHandler,
            intervalObj: this.setIntervalAsync(this.receivePackets.bind(this), this.statusCheckInterval),
        };

        this.listeners.push(listener);
    }

    receivePackets() {
        this.getStoredPackets().forEach(packet => {
            this.listeners.forEach(listener => {
                if(packet.sender === listener.sender && !packet.hasOwnProperty('result')) {
                    const result = listener.commandHandler(packet);

                    packet.result = result;

                    this.editPacket(packet);

                    if(!this.silentMode) {
                        if(packet.result == null)
                            console.log('[CommLink Receiver] Possibly failed to handle packet:', packet);
                        else
                            console.log('[CommLink Receiver] Successfully handled a packet:', packet);
                    }
                }
            });
        });
    }

    kill() {
        this.listeners.forEach(listener => listener.intervalObj.stop());
    }
}