From bbea84c60529b30135e56876d272bed298743aba Mon Sep 17 00:00:00 2001
From: Alain Brenzikofer <alain@integritee.network>
Date: Tue, 9 Jun 2026 14:32:36 +0200
Subject: [PATCH] support multiple fallback links for splx contact and channels

---
 scripts/resolver/README.md       | 18 ++++++++++++++----
 scripts/resolver/snrc-resolve.py | 23 ++++++++++++++++++++---
 2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/scripts/resolver/README.md b/scripts/resolver/README.md
index 49d1a4e89..78df84b9c 100644
--- a/scripts/resolver/README.md
+++ b/scripts/resolver/README.md
@@ -151,8 +151,11 @@ curl -s http://127.0.0.1:8000/resolve/foobar.testing | jq .
   "nickname": "Foo",
   "website": "https://foo.bar",
   "location": "",
-  "simplexContact": "https://smp16.simplex.im/a#Q_F00BA7",
-  "simplexChannel": "",
+  "simplexContact": [
+    "https://smp16.simplex.im/a#Q_F00BA7",
+    "https://smp11.simplex.im/a#Q_F00BA8"
+  ],
+  "simplexChannel": [],
   "eth": null,
   "btc": "bc1qpzht4wp64yg7z6sgl07vvrnepyux740juynfcn",
   "xmr": "4ANzdVJFxLtCKcBgNGkFSEA41zJFgrTX93LWt9UR6xpg7YNCsdrSV817cw2xKT8NXeS5euBBqTApS2u8kRTxMhyiDGN3Qgt",
@@ -162,6 +165,13 @@ curl -s http://127.0.0.1:8000/resolve/foobar.testing | jq .
 }
 ```
 
+`simplexContact` and `simplexChannel` are arrays so a name can advertise
+multiple SMP servers for redundancy. Clients SHOULD try the URLs in
+order; the first entry is the primary and the rest are fallbacks. The
+on-chain text record stores them as a single comma-separated string
+(`"url1,url2,url3"`); this resolver splits, trims whitespace, and drops
+empty entries before returning.
+
 All field names are lowercase-initial and contain no dots, so they map
 directly onto Haskell record fields and can be consumed via aeson's
 `Generic`-derived `FromJSON` without a key-rewriting layer. Equivalent
@@ -173,8 +183,8 @@ data SnrcRecord = SnrcRecord
   , nickname       :: Text
   , website        :: Text
   , location       :: Text
-  , simplexContact :: Text
-  , simplexChannel :: Text
+  , simplexContact :: [Text]
+  , simplexChannel :: [Text]
   , eth            :: Maybe Text
   , btc            :: Maybe Text
   , xmr            :: Maybe Text
diff --git a/scripts/resolver/snrc-resolve.py b/scripts/resolver/snrc-resolve.py
index 469d9f22c..f3de0cdff 100755
--- a/scripts/resolver/snrc-resolve.py
+++ b/scripts/resolver/snrc-resolve.py
@@ -12,10 +12,15 @@ deployment on Ethereum mainnet (or any compatible ENS-shaped registry)
 and returns a flat JSON document with these fields:
 
   name, nickname, website, location,
-  simplexContact, simplexChannel,
+  simplexContact, simplexChannel,    -- list[str], primary first
   eth, btc, xmr, dot,
   owner, resolver
 
+`simplexContact` and `simplexChannel` are arrays so a name can advertise
+multiple SMP servers for redundancy. Clients SHOULD try the URLs in the
+order returned. The on-chain text record stores them as a single
+comma-separated string; this resolver splits and trims into a list.
+
 All keys are valid Haskell record-field identifiers (lowercase initial,
 no dots), so consumers can derive aeson FromJSON instances directly
 without a key-rewriting layer.
@@ -367,6 +372,18 @@ TEXT_KEYS = [
 ]
 
 
+def split_csv(value: str) -> list:
+    """Split a comma-separated text record into an ordered list of entries.
+
+    Trims whitespace around each element and drops empties so trailing
+    commas, doubled commas, and all-whitespace inputs all yield clean
+    output. Single-value records yield a 1-element list; empty inputs
+    yield `[]`. Used for `simplex.contact` / `simplex.channel`, which
+    store one-or-more SMP-server URLs as a single comma-joined string.
+    """
+    return [item.strip() for item in value.split(",") if item.strip()]
+
+
 def resolve(name: str):
     tld = name.rsplit(".", 1)[-1]
     registry = REGISTRIES.get(tld)
@@ -412,8 +429,8 @@ def resolve(name: str):
         "nickname": nickname,
         "website": texts.get("url", ""),
         "location": texts.get("location", ""),
-        "simplexContact": texts.get("simplex.contact", ""),
-        "simplexChannel": texts.get("simplex.channel", ""),
+        "simplexContact": split_csv(texts.get("simplex.contact", "")),
+        "simplexChannel": split_csv(texts.get("simplex.channel", "")),
         "eth": addr_multicoin(resolver_addr, node, COIN_ETH),
         "btc": addr_multicoin(resolver_addr, node, COIN_BTC),
         "xmr": addr_multicoin(resolver_addr, node, COIN_XMR),