CommLink.js

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

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://update.greasyfork.org/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());
    }
}