Mirror availability

A RuleSet branch may list ordered mirrors plus a fallback URL. When that branch wins, lit.onl serves a page loader; the visitor’s browser probes each mirror and opens the first that succeeds, otherwise the fallback.

Requires Growth+ Rules and Premium for the mirror action. In the Rules item editor, open Destination → Mirrors (the ? link lands here).

Why a loader?

A normal server 302 cannot see whether the visitor’s network blocks a destination. Probes run in the browser on the lit.onl interstitial (after password / confirm-leave when those apply).

Simple setup (no token)

1. Add a mirror HTTPS URL and leave Check on open (default).
2. Leave Token empty.
3. Ensure the mirror URL is CORS-readable from the browser (or the probe fails and the next mirror / fallback is used).

country in CN -> mirror https://a.example/app else https://fallback.example/

Optional token proof

Use a short random string (not a password) only if you want stronger proof than “URL returned 2xx”. Then set check to well_known, html, or both, and publish the token:

{ "token": "lit-mrr-9f3a…" }

at https://your-origin/.well-known/lit-mirror.json with CORS readable (for example Access-Control-Allow-Origin: *).

Also accepted: a raw JSON string "lit-mrr-9f3a…". Match is exact string equality.

Check modes

• open — GET the mirror URL succeeds with any 2xx (no token). Default when the token is empty.
• well_known — /.well-known/lit-mirror.json must match (token required).
• html — page body must contain the token substring (token required).
• both — try well-known, then HTML (token required). Default when a token is set.

Branch shape

{
  "id": "m1",
  "when": { "field": "country", "op": "in", "value": ["CN"] },
  "url": "https://fallback.example/",
  "mirrors": [
    { "url": "https://a.example/app", "token": "org-secret", "check": "both" },
    { "url": "https://b.example/app", "check": "open" }
  ]
}

Field	Meaning
url	Required HTTPS fallback after all mirrors fail
mirrors[].url	Destination to open if the probe succeeds (HTTPS)
mirrors[].token	Optional shared secret (max 128 chars). Required for well_known / html / both
mirrors[].check	open · well_known · html · both

Caps: max 5 mirrors per branch; HTTPS only.

Probe failure

Network error, timeout (~2.5s), non-2xx, missing/mismatched token, or CORS block → try the next mirror, then the branch fallback URL.

Plan gate

Capability	Free	Core	Growth	Premium
Rules library / conditions	—	—	Yes	Yes
Mirrors + page loader	—	—	No	Yes

RediRL

country in CN -> mirror https://a.example/app token "secret" check both, https://b.example/app check open else https://fallback.example/

Full language reference: RediRL.