index.js

const pubkey = Buffer.from(globalThis.DISCORD_PUBKEY || "", "hex")
const DiscordSig = require("./crypto")()
const { Response } = require("node-fetch")
const commands = require("./commands")

addEventListener("fetch", event => {
    event.respondWith(handleRequest(event.request))
})

async function handleRequest(request){
    const url = new URL(request.url)
    if(request.method == "POST" && url.pathname == "/"){
        const timestamp = Buffer.from(request.headers.get("X-Signature-Timestamp") || "")
        const sig = Buffer.from(request.headers.get("X-Signature-Ed25519") || "", "hex")

        const body = await request.text()
        const hashbody = Buffer.concat([timestamp, Buffer.from(body)])
        const sig_ok = await DiscordSig.verify(pubkey, sig, hashbody)

        if(sig_ok){
            const payload = JSON.parse(body)
            const response = JSON.stringify(await handlePayload(payload))
            console.log(`Command response: ${response}`)
            return new Response(response, {headers: {"Content-Type": "application/json"}, status: 200})
        }
        else {
            return new Response("Signature Validation Failed", {status: 401})
        }
    }
}

async function handlePayload(payload){
    console.log(`Got payload type: ${payload.type}`)
    switch(payload.type){
        case 1: return {type: 1}
        case 2:
            return {type: 4, data: await handleInteraction(payload)}
    }
}

async function handleInteraction(payload) {
    const args = {};
    (payload.data.options || []).forEach(option => {
        args[option.name] = option.value
    });
    console.log(`Invoke: ${payload.data.name}(${JSON.stringify(args)})`)
    const cmd = commands[payload.data.name]
    const resp = await (() => {
        switch(cmd.length){
            case 1:
                return cmd(args)
            case 2:
                return cmd(args, {user: payload.member, channel: payload.channel, guild: payload.guild, id: payload.id})
        }
    })()
    console.log(`Response: ${JSON.stringify(resp)}`)
    if (resp.content) {
        return resp
    }
    else{
        return { content: resp }
    }
}