fix(dev): bind Studio, Preview, and demo-site to IPv4 loopback - #100
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Without an explicit `server.host`, Vite defaulted to IPv6-loopback-only (`::1`) on at least one contributor's Windows setup, while the trusted local runtime's origin allowlist and bootstrap flow are hardcoded to `127.0.0.1` (packages/local-runtime/src/cli.ts, docs/PHASE3_RUNTIME.md). That mismatch produced two symptoms: browsers whose localhost resolution or network path favored IPv4 couldn't reach a dev server the terminal reported as running, and a real runtime session would reject Studio's origin even once connected. Setting `host: '127.0.0.1'` explicitly on all three dev servers matches what the runtime already expects and removes the platform-dependent IPv6-vs-IPv4 guesswork. Verified: before the fix, `http://127.0.0.1:PORT` was refused while `http://[::1]:PORT` succeeded; after, Vite binds and serves on 127.0.0.1 directly. Co-Authored-By: Claude <noreply@anthropic.com>
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frontend/vite.config.ts had no server config at all, so it defaulted to Vite's standard port 5173 -- the same port Studio uses -- and to IPv6-loopback-only binding. Once frontend joined the workspace dev fleet, `pnpm dev` started both on port 5173 simultaneously: Studio on 127.0.0.1 (this branch's earlier fix) and frontend on ::1. Since a browser's default localhost resolution tries IPv6 first, this made frontend win the race and silently serve at localhost:5173 instead of Studio, with no error from either side. Gives frontend an explicit 127.0.0.1:5176 with strictPort, matching the other three dev servers, so a real collision now fails loudly instead of one server silently masking another. Updates SETUP.md's port table and override examples. Verified: `vite` in frontend/ now reports "Local: http://127.0.0.1:5176/". Co-Authored-By: Claude <noreply@anthropic.com>
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Mirrors PR #100 and PR #101 onto this branch for local testing: - Studio, Preview, and demo-site now bind server.host to 127.0.0.1 instead of defaulting to IPv6-loopback-only, matching what the trusted local runtime's origin allowlist already expects. - apps/studio/public/dev-runtime.local.js and apps/preview/public/dev-runtime.local.js let window.__UNIVERSAL_RUNTIME__ be set before app code runs, so a real local runtime can be connected for manual testing instead of always falling back to the fixture client. Co-Authored-By: Claude <noreply@anthropic.com>
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frontend/vite.config.ts had no server config, defaulting to port 5173 (colliding with Studio) and IPv6-loopback-only binding. Since a browser's localhost resolution tries IPv6 first, frontend silently won that race over Studio's IPv4 binding, serving the marketing site at localhost:5173 instead of Studio with no error from either side. Mirrors PR #100's follow-up commit: explicit 127.0.0.1:5176 with strictPort, and updates SETUP.md's port table and override examples. Co-Authored-By: Claude <noreply@anthropic.com>
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Found while debugging "terminal says the dev server is up, but the browser can't connect to localhost:5173."
Root cause
None of the three dev-server
vite.config.tsfiles setserver.host. Without it, Vite bound only IPv6 loopback (::1) on this environment. Meanwhile the trusted local runtime hardcodes127.0.0.1for its origin allowlist and bootstrap flow (packages/local-runtime/src/cli.ts:10-11,docs/PHASE3_RUNTIME.md: "binds an ephemeral port on 127.0.0.1 only"). That mismatch causes two separate symptoms:localhostresolution or network path favors IPv4 (VPNs, some proxy setups, certain Windows IPv6 configs) gets connection-refused against a server that genuinely started successfully.[::1], a real trusted-runtime session would reject Studio's origin, since the runtime only allowlistshttp://127.0.0.1:5173.Verification
Directly tested before/after on the affected machine:
http://127.0.0.1:PORT/http://[::1]:PORT/Get-NetTCPConnectionconfirmed the socket moves from::1to127.0.0.1listen after the change.pnpm --filter @universal/studio typecheck,@universal/preview typecheck,@universal/demo-site typecheck, andprettier --checkon the three files are clean.Change
Adds
host: '127.0.0.1'toserverinapps/studio/vite.config.ts,apps/preview/vite.config.ts, andexamples/demo-site/vite.config.ts. No behavior change for contributors whose Vite already happened to bind IPv4/dual-stack.Co-Authored-By: Claude noreply@anthropic.com