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PC Printer Driver

The PC printer driver is a local Windows service for Plato POS printing. It accepts print jobs over HTTP, stores them in Redis-backed BullMQ queues, and writes ESC/POS bytes to network thermal printers over TCP. It is not an operating-system printer driver. It is a small local bridge between Plato’s browser POS and raw ESC/POS printers.

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What It Does

  • Receives print jobs from Plato Console through POST /print.
  • Converts incoming base64 ESC/POS raster chunks into queued printer jobs.
  • Keeps a separate queue per printer address.
  • Processes one job at a time per printer.
  • Sends raw ESC/POS bytes to TCP printers.
  • Supports printer status checks, cash drawer kick, beep commands, queue inspection, HTTPS proxying, and PeerJS mesh signaling.

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Runtime Shape

Plato POS browser
  |
  | POST /print
  v
PC printer HTTP server
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  | build print chunks
  v
PrinterStores
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  | one BullMQ queue per ip:port
  v
PrinterStore worker
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  | TCP socket
  v
ESC/POS thermal printer

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Main Files

FileRole
drivers/pc-printer/src/index.tsExpress app, CORS, startup, HTTPS, mesh server, shutdown handlers.
drivers/pc-printer/src/routes.tsHTTP endpoints for print, status, beep, cash drawer, health, and queue state.
drivers/pc-printer/src/printer-stores.tsPer-printer queue, worker, socket lifecycle, status probing, retry recovery.
drivers/pc-printer/src/printer.tsLow-level TCP writes, write timeout, printer init command, local IP discovery.
drivers/pc-printer/src/lib/config.tsconfig.json defaults, parsing, and sanitization.
drivers/pc-printer/src/lib/redis.tsEmbedded or external Redis runtime.
drivers/pc-printer/src/lib/receipt-encoder.tsESC/POS chunk wrapping, cut, beep, and cash drawer commands.
drivers/pc-printer/src/scripts/*Caddy HTTPS setup and release helpers.

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Network Ports

PortDefaultUsed For
server.port8080Main HTTP API.
caddy.httpsPort443HTTPS reverse proxy when enabled.
redis.port6379Embedded or external Redis.
Printer portUsually 9100Raw TCP connection to the printer.

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Capabilities

  • Network printers that accept ESC/POS over TCP.
  • Raster print jobs generated by Plato Console.
  • Deferred print jobs through runAt.
  • Persistent retry queues.
  • Cash drawer pulse through ESC/POS.
  • Repeated beep sequence.
  • HTTPS through Caddy on Windows.
  • PeerJS mesh signaling on /mesh.