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HTTPS And Mesh

The PC printer driver can expose HTTPS through Caddy and PeerJS signaling through /mesh.

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HTTPS Conditions

HTTPS starts only when all of these are true:
  • features.httpsEnabled is true.
  • caddy.enabled is true.
  • The runtime platform is Windows.
  • Certificates exist in assets/certs.
  • Caddy can be installed or reused.
If HTTPS setup fails, the driver logs the error and continues with HTTP.

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Certificate Files

Required files: 
assets/certs/ca.crt
assets/certs/server.crt
assets/certs/server.key
The driver copies them into the Caddy working folder: 
assets/caddy/ca.crt
assets/caddy/server.crt
assets/caddy/server.key
The CA certificate can be downloaded from: 
http://<driver-ip>:8080/ca.crt

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Caddy Install

Caddy setup uses this order:
  1. Reuse assets/caddy/bin/caddy.exe if already installed with .installed.
  2. Copy bundled caddy.exe from known local paths.
  3. Download Caddy from GitHub release URL.
The configured Caddy version defaults to 2.6.4.

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Generated Caddyfile

The driver writes a Caddyfile like: 
{
  auto_https disable_redirects
}

plato-printer.local {
  reverse_proxy localhost:8080

  handle /mesh/* {
    reverse_proxy localhost:8080 {
      header_up Connection {http.request.header.Connection}
      header_up Upgrade {http.request.header.Upgrade}
    }
  }

  tls "assets/caddy/server.crt" "assets/caddy/server.key"
}
If caddy.httpsPort is not 443, the site address includes the port.

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Caddy Runtime

Caddy runs as a child process with:
  • XDG_DATA_HOME set to assets/caddy/data
  • XDG_CONFIG_HOME set to assets/caddy/config
  • working directory set to assets/caddy
If Caddy exits unexpectedly, the driver retries up to 5 times with a 2000ms delay.

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Mesh Signaling

When features.meshEnabled is true, the driver mounts PeerJS at: 
ws://<driver-host>:8080/mesh
wss://plato-printer.local/mesh
GET /mesh-status returns:
  • whether mesh is enabled
  • mesh path
  • port
  • connected peer IDs
  • peer count
Mesh is signaling only. Print jobs still use the HTTP endpoints.

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Common HTTPS Problems

SymptomLikely CauseFix
Browser blocks HTTPS driver URLCA certificate not trustedInstall ca.crt on the POS device.
https://plato-printer.local does not resolveDNS/hosts missingAdd local DNS or hosts entry to driver IP.
Port 443 unavailableAnother service is using itStop the other service or change caddy.httpsPort.
HTTPS skipped on macOS/LinuxCode is Windows-onlyUse HTTP in development or test Caddy separately.
Windows 7 startup errorCaddy version not 2.6.4Set caddy.version back to 2.6.4.