Browser Live-Reload (DevReload)

Development-only middleware that makes open browser tabs reload automatically while running under regius dev.

Features

• Opt-in via DEV_RELOAD_ENABLED — regius dev sets it automatically for the dev process, so no app code or config is needed
• When enabled it mounts three endpoints under DEV_RELOAD_PATH (default /__dev):
  • GET /__dev/reload.js — the same-origin reload client (no inline scripts, CSP-safe)
  • GET /__dev/stream — an SSE stream announcing a per-process boot ID (tabs reconnect after a restart and reload when the ID changes; a retry: 500 hint keeps the reconnect fast)
  • POST /__dev/notify — loopback-only trigger that pushes a reload event to connected tabs (used by regius dev after CSS-only Tailwind rebuilds; requests with proxy headers are rejected so a spoofed X-Forwarded-For cannot bypass the check)
• <script src="/__dev/reload.js" defer></script> is injected before the closing </body> of HTML responses. Non-HTML responses pass through untouched, HTML fragments without a </body> tag are left alone, Content-Length is dropped when injecting, and a mid-stream Flush gives up injection so streaming handlers keep working
• Responses without a Content-Type are sniffed with http.DetectContentType — the same rule net/http applies — so pages render identically with and without the middleware
• When disabled (the default) the middleware is a pure passthrough and nothing is mounted: production behavior is byte-identical

warning

Never set DEV_RELOAD_ENABLED=true in production. The notify endpoint can force connected tabs to reload, and the injected script adds a development-only SSE connection to every page.

Environment Variables

DEV_RELOAD_ENABLED=false        # set automatically by `regius dev`
DEV_RELOAD_PATH=/__dev          # base path for the reload endpoints