Files
Parchment/forms/kernel/kernel.js
2025-12-22 04:53:00 -06:00

158 lines
3.7 KiB
JavaScript

import fs from "fs"
import path from "path"
import * as z from "zod"
import { WebSocketServer } from "ws"
import { fileURLToPath } from "url"
const __dirname = path.dirname(fileURLToPath(import.meta.url))
const DATA_DIR = path.resolve(__dirname)
const DATA_FILE = path.join(DATA_DIR, "master.forms")
if (!fs.existsSync(DATA_DIR)) {
fs.mkdirSync(DATA_DIR, { recursive: true })
}
if (!fs.existsSync(DATA_FILE)) {
fs.writeFileSync(DATA_FILE, "")
}
class Kernel {
port
seq = 0
clients = new Set()
schemas = new Map()
constructor(port = 10000) {
this.port = port
this.loadData()
this.wss = new WebSocketServer({ port: this.port })
this.wss.on("connection", ws => this.onConnection(ws))
console.log(`[kernel] running on ws://localhost:${port}`)
}
loadData() {
const data = fs.readFileSync(DATA_FILE, "utf8")
if (!data) return
const lines = data.trim().split("\n")
const last = lines[lines.length - 1]
if (last) {
const entry = JSON.parse(last)
this.seq = entry.seq
}
}
onConnection(ws) {
this.clients.add(ws)
ws.on("message", msg => this.onMessage(ws, msg))
ws.on("close", () => this.clients.delete(ws))
ws.send(JSON.stringify({
type: "hello",
seq: this.seq
}))
}
onMessage(ws, raw) {
let msg
try {
msg = JSON.parse(raw.toString())
} catch {
return
}
switch(msg.op) {
case "add":
this.add(msg.type, msg.data)
break;
case "register":
this.register(msg.type, msg.schema)
break;
case "replay":
this.replay(ws, msg.type, msg.fromSeq)
break;
default:
console.error("error: unknown message operation: ", msg.op)
}
}
register(name, schema) {
try {
schema = z.fromJSONSchema(schema)
} catch(e) {
console.error("register() error: bad schema ", schema, e)
return
}
this.schemas.set(name, schema)
console.log(`[kernel] registered form "${name}"`)
}
add(name, data) {
let schema = this.schemas.get(name)
if(!schema) {
console.error("No schema for this form: ", name)
return
}
try {
schema.parse(data)
} catch(e) {
console.error("error parsing data : ", data, " for schema ", name, e)
}
const entry = {
seq: ++this.seq,
time: Date.now(),
name,
data
}
fs.appendFileSync(DATA_FILE, JSON.stringify(entry) + "\n")
const payload = JSON.stringify({
type: "add",
...entry
})
for (const ws of this.clients) {
if (ws.readyState === ws.OPEN) {
ws.send(payload)
}
}
}
replay(ws, form, fromSeq = 0) {
const stream = fs.createReadStream(DATA_FILE, { encoding: "utf8" })
let buffer = ""
stream.on("data", chunk => {
buffer += chunk
let idx
while ((idx = buffer.indexOf("\n")) >= 0) {
const line = buffer.slice(0, idx)
buffer = buffer.slice(idx + 1)
if (!line) continue
const entry = JSON.parse(line)
if (entry.seq > fromSeq && entry.form === form) {
ws.send(JSON.stringify({
type: "form:update",
...entry
}))
}
}
})
}
}
new Kernel()