Merge pull request 'feat(bridge): publish the player-vendor market index as vendor.listing' (#5) from feat/vendor-listing into edge

Reviewed-on: #5

overlay/Config/Bridge.cfg

@@ -83,6 +83,29 @@ PointsProfileEnabled=true
 # board for anyone in the top N.
 PointsProfileRank=false
 
+# Player-vendor market index (https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/v3.md §8). Every player vendor's shop name,
+# owner, location and priced inventory, published as one vendor.listing frame per vendor so the
+# website can offer the search the in-game Vendor Search gump offers. Honours each player's own
+# in-game opt-out (the vendor's VendorSearch flag) — hide your vendor in game and it is hidden
+# on the site too.
+MarketEnabled=true
+
+# Sweep interval. UNLIKE every other sweep here, a tick does NOT walk the whole world: it
+# inventories at most MarketSweepBatch vendors and a persistent cursor round-robins through the
+# rest, so the per-tick cost is bounded by the batch rather than by how many vendors exist. Full
+# coverage takes ceil(vendors / batch) x MarketSweepSeconds — 500 vendors at the defaults is one
+# complete pass every 20 minutes, and the site labels the data with how stale it may be.
+#
+# Lower this (or raise the batch) for faster coverage; both trade directly against per-tick cost,
+# and the expensive part is the item walk, which recurses into every container a vendor is selling.
+MarketSweepSeconds=60
+MarketSweepBatch=25
+
+# Per-vendor listing cap, after which the frame carries "truncated": true. A commodity reseller
+# with thousands of stacked resources is a real thing, and an uncapped frame for one is measured
+# in megabytes. Clamped to 1..5000.
+MarketMaxListings=250
+
 # Shard ruleset (https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/v3.md §5). One world.ruleset frame — expansion, which
 # systems are on, skill/stat caps, account and house limits, champion scroll rules —
 # emitted on every sidecar connect (and on [bridge reload), so the website's rules page

overlay/Scripts/Custom/Bridge/BridgeBoot.cs

@@ -166,6 +166,7 @@ namespace Server.Custom.Bridge
                     BridgePresence.Rearm();
                     BridgeHousing.Rearm();
                     BridgePoints.Rearm();
+                    BridgeMarket.Rearm();
                     // Not a sweep, so it has nothing to re-arm — but an operator who just edited a
                     // .cfg wants the change on the site now, not after a shard restart.
                     BridgeRuleset.Emit();
@@ -186,6 +187,7 @@ namespace Server.Custom.Bridge
                     BridgePresence.SweepOnce();
                     BridgeHousing.SweepOnce();
                     BridgePoints.SweepOnce();
+                    BridgeMarket.SweepOnce();
                     e.Mobile.SendMessage("Bridge: ran one sweep of each stream.");
                     e.Mobile.SendMessage("Bridge: {0}", BridgeSweeps.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgeChamps.Status());
@@ -194,6 +196,7 @@ namespace Server.Custom.Bridge
                     e.Mobile.SendMessage("Bridge: {0}", BridgePresence.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgeHousing.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgePoints.Status());
+                    e.Mobile.SendMessage("Bridge: {0}", BridgeMarket.Status());
                     break;
 
                 default:
@@ -209,6 +212,7 @@ namespace Server.Custom.Bridge
                     e.Mobile.SendMessage("Bridge: {0}", BridgePresence.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgeHousing.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgePoints.Status());
+                    e.Mobile.SendMessage("Bridge: {0}", BridgeMarket.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgePages.Status());
                     e.Mobile.SendMessage("Bridge: {0}", BridgeRuleset.Status());
                     break;

overlay/Scripts/Custom/Bridge/BridgeConfig.cs

@@ -36,6 +36,12 @@ namespace Server.Custom.Bridge
         public static int PresenceSweepSeconds { get; private set; }
         public static int HousingSweepSeconds { get; private set; }
         public static int PointsSweepSeconds { get; private set; }
+        public static int MarketSweepSeconds { get; private set; }
+
+        // ---- player-vendor market index (https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/v3.md §8) ----
+        public static bool MarketEnabled { get; private set; }
+        public static int MarketSweepBatch { get; private set; }
+        public static int MarketMaxListings { get; private set; }
 
         // ---- points / loyalty leaderboards (https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/v3.md §7) ----
         public static bool PointsLeaderboardEnabled { get; private set; }
@@ -149,6 +155,36 @@ namespace Server.Custom.Bridge
             // on every profile build. See BridgeProfile.WritePoints.
             PointsProfileRank = Config.Get("Bridge.PointsProfileRank", false);
 
+            // Player-vendor market index. Unlike every other sweep, this one does NOT walk its whole
+            // collection per tick: MarketSweepBatch caps how many vendors are inventoried, and a
+            // persistent cursor round-robins through the rest, so the per-tick cost is bounded by
+            // the batch rather than by how many vendors the world holds.
+            MarketEnabled = Config.Get("Bridge.MarketEnabled", true);
+
+            MarketSweepSeconds = Config.Get("Bridge.MarketSweepSeconds", 60);
+            if (MarketSweepSeconds < 1)
+                MarketSweepSeconds = 1;
+
+            // Bounded below at 1 (a batch of 0 would advance the cursor nowhere and publish nothing,
+            // silently) and above at 500, past which the batch stops bounding anything on any
+            // realistic shard and the tick is a whole-world pass by another name.
+            MarketSweepBatch = Config.Get("Bridge.MarketSweepBatch", 25);
+            if (MarketSweepBatch < 1)
+                MarketSweepBatch = 1;
+            if (MarketSweepBatch > 500)
+                MarketSweepBatch = 500;
+
+            // Per-vendor listing cap. BridgeJson.Parse caps INBOUND frames at 1 MB; outbound is
+            // uncapped and the sidecar's read_line will allocate whatever arrives, so the cap here
+            // is what keeps one commodity reseller with 8,000 stacked resources from emitting a
+            // multi-megabyte frame. Over the cap the frame carries "truncated": true and the site
+            // says so.
+            MarketMaxListings = Config.Get("Bridge.MarketMaxListings", 250);
+            if (MarketMaxListings < 1)
+                MarketMaxListings = 1;
+            if (MarketMaxListings > 5000)
+                MarketMaxListings = 5000;
+
             // The ruleset frame is not a sweep — it is emitted once per sidecar connect (and on
             // `[bridge reload`), so it has no interval. PublicConnectAddress is the ONE connection
             // detail the bridge will publish, and only because an operator typed it here for that

overlay/Scripts/Custom/Bridge/BridgeMarket.cs

@@ -0,0 +1,591 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using Server.Items;
+using Server.Mobiles;
+using Server.Multis;
+using Server.Engines.VendorSearching;
+
+namespace Server.Custom.Bridge
+{
+    /// <summary>
+    ///     The shard-wide player-vendor index (https://gitea.whitlocktech.com/RunicGateway/docs/src/branch/main/link/v3.md §8). Every player vendor's
+    ///     shop name, owner, location and priced inventory, published as one authoritative
+    ///     <c>vendor.listing</c> frame per vendor, so the website can offer the search the in-game
+    ///     Vendor Search gump offers — from outside the game.
+    ///
+    ///     ---- Why this is a sweep and not an RPC ----
+    ///
+    ///     The obvious shape is a <c>market.snapshot</c> request/reply like vendor.snapshot next
+    ///     door. It cannot work: the sidecar's rpc router correlates on the FIRST frame carrying a
+    ///     matching reqId and resolves a single oneshot, so a chunked reply sharing one reqId would
+    ///     deliver chunk 1 to the HTTP caller and LEAK chunks 2..N onto the broadcast feed. A
+    ///     whole-world snapshot in one frame is not an option either — the reply timeout is 10 s and
+    ///     40,000 listings do not serialize in time.
+    ///
+    ///     So it is a diff sweep on the broadcast stream, shaped like <see cref="BridgeHousing"/>:
+    ///     one frame per vendor, authoritative for that vendor, plus vendor.listing.remove when one
+    ///     goes away. The per-account <c>vendor.snapshot</c> RPC is untouched; the player portal
+    ///     keeps using it.
+    ///
+    ///     ---- The two perf traps, and what this does about them ----
+    ///
+    ///     1. **VendorSearch.GetItemName is a packet builder, not a field read.** It constructs an
+    ///        ObjectPropertyList, calls GetProperties, serialises it and then byte-parses the
+    ///        resulting packet — PER ITEM. Across a full pass that is a multi-hundred-millisecond
+    ///        stall on the Core thread. It is never called here. The frame carries `itemId`, `hue`,
+    ///        `amount`, `price`, the plain `item.Name` field (null for most items) and
+    ///        `item.LabelNumber`; the website resolves display names against its own cliloc table,
+    ///        exactly as char.profile.equipment already does.
+    ///
+    ///        (On any modern client the call would not even work: every current client ships its
+    ///        Cliloc.* files compressed, ServUO's bundled Ultima.StringList reads only the old plain
+    ///        layout, so VendorSearch.StringList is null and GetItemName returns item.Name anyway.
+    ///        The in-game gump has the same gap.)
+    ///
+    ///     2. **A full pass is unbounded in world size.** 500 vendors × 80 listings is ~40,000 item
+    ///        reads, and the reusable public GetItems(Container, List&lt;Item&gt;) recurses into
+    ///        sub-containers, so the real count runs ABOVE the top-level pack.Items a naive estimate
+    ///        would use. So the sweep is amortized: a persistent round-robin cursor over
+    ///        PlayerVendor.PlayerVendors advances at most MarketSweepBatch vendors per tick, which
+    ///        makes the PER-TICK cost bounded independently of how many vendors exist. Full coverage
+    ///        takes ceil(vendors / batch) × MarketSweepSeconds. This is the one genuinely new pattern
+    ///        versus the other sweeps, which all walk their whole collection every tick.
+    ///
+    ///     ---- Privacy ----
+    ///
+    ///     `pv.VendorSearch` is ServUO's own per-vendor opt-out and DoSearch filters on it, so a
+    ///     player who hid their vendor in game is hidden on the website too: an opted-out vendor is
+    ///     skipped entirely and the seen-set removal then drops it from the board. Map.Internal and
+    ///     a null Backpack are skipped for the same reason DoSearch skips them.
+    ///
+    ///     Owner is written as flat `ownerSerial`/`ownerName` — never through BridgeJson.Actor,
+    ///     which would add `acct` and `webId`. Same argument BridgePoints makes: this is the widest-
+    ///     audience surface the bridge has, and the site resolves serial → user from its own
+    ///     shard_account_links mirror when staff need it.
+    /// </summary>
+    public static class BridgeMarket
+    {
+        private static Timer _timer;
+
+        // vendor serial -> last-emitted signature.
+        private static readonly Dictionary<Serial, string> _last = new Dictionary<Serial, string>();
+
+        // Round-robin cursor: an INDEX into PlayerVendor.PlayerVendors, not a serial. The list is
+        // mutated by placement/deletion between ticks, so the cursor is a hint, not a promise — it
+        // is wrapped and clamped every tick, and a shifted list at worst re-visits or defers a
+        // vendor by one cycle. Tracking a serial instead would cost a lookup to find "where was I"
+        // and buy nothing: the sweep is idempotent per vendor.
+        private static int _cursor;
+
+        private static long _sweeps, _emitted, _removed, _scanned, _skipped, _truncated;
+
+        // Per-tick cost, in milliseconds. Reported by `[bridge status` because the
+        // whole design of this sweep is a claim about that number — the batch cap is what makes it
+        // independent of world size — and an operator tuning MarketSweepBatch is otherwise tuning
+        // blind. `_maxMs` is the one that matters: the Core thread runs this between frames, so the
+        // worst tick is the budget, not the average.
+        private static double _lastMs, _maxMs;
+        private static readonly System.Diagnostics.Stopwatch _clock = new System.Diagnostics.Stopwatch();
+
+        // Reused across ticks. The item walk is single-threaded (Core thread) and the list is
+        // cleared before each vendor, so one buffer serves the whole sweep — the alternative is a
+        // fresh List<Item> per vendor per tick, which at 25 vendors × every 60 s is pure garbage.
+        private static readonly List<Item> _items = new List<Item>();
+
+        public static void Initialize()
+        {
+            if (!BridgeConfig.Enabled)
+                return;
+
+            EventSink.ServerStarted += OnServerStarted;
+        }
+
+        private static void OnServerStarted()
+        {
+            BridgeLink.Connected_Core += OnConnected;
+            Rearm();
+        }
+
+        private static void OnConnected()
+        {
+            // A new sidecar knows nothing, so drop the diff state and start the round-robin from
+            // the top. The re-emit of the whole world is self-throttled by the batch window — this
+            // is the one place the amortized sweep pays for itself twice, because a reconnect on a
+            // whole-world sweep would otherwise be the biggest burst the bridge ever produces.
+            _last.Clear();
+            _cursor = 0;
+        }
+
+        /// <summary>Stops and recreates the timer from current config. Called by `[bridge reload`.</summary>
+        public static void Rearm()
+        {
+            Stop();
+
+            _timer = Timer.DelayCall(
+                TimeSpan.FromSeconds(BridgeConfig.MarketSweepSeconds),
+                TimeSpan.FromSeconds(BridgeConfig.MarketSweepSeconds),
+                MarketSweep);
+        }
+
+        public static void Stop()
+        {
+            if (_timer != null) { _timer.Stop(); _timer = null; }
+        }
+
+        /// <summary>
+        ///     A bare (key-less) string value, or JSON null.
+        ///
+        ///     <see cref="BridgeJson.Escape"/> takes a non-null string — it dereferences
+        ///     <c>value.Length</c> immediately — and <see cref="BridgeJson.Str"/> writes the `,"key":`
+        ///     prefix itself, so neither serves a value written inside a hand-built object. Most of
+        ///     what this frame writes is legitimately null (an item's plain Name is null for nearly
+        ///     every item, a vendor standing in the street has no house), so this is the common path
+        ///     rather than an edge case.
+        /// </summary>
+        private static void Text(StringBuilder sb, string value)
+        {
+            if (value == null)
+                sb.Append("null");
+            else
+                BridgeJson.Escape(sb, value);
+        }
+
+        public static string Status()
+        {
+            var all = PlayerVendor.PlayerVendors;
+
+            return String.Format(
+                "market(enabled={0} sweeps={1} scanned={2} emitted={3} removed={4} skipped={5} truncated={6} tracked={7} vendors={8} cursor={9} batch={10} lastMs={11:F2} maxMs={12:F2})",
+                BridgeConfig.MarketEnabled, _sweeps, _scanned, _emitted, _removed, _skipped,
+                _truncated, _last.Count, all == null ? 0 : all.Count, _cursor,
+                BridgeConfig.MarketSweepBatch, _lastMs, _maxMs);
+        }
+
+        /// <summary>Runs one sweep now. Wired into `[bridge sweepnow`.</summary>
+        public static void SweepOnce()
+        {
+            MarketSweep();
+        }
+
+        /// <summary>
+        ///     One tick: at most <c>MarketSweepBatch</c> vendors starting at the cursor, then the
+        ///     removal pass.
+        ///
+        ///     The removal pass is the part the batching makes subtle. `_last` holds every vendor
+        ///     seen in ANY previous tick, but this tick only visited a window — so "not in this
+        ///     tick's seen set" does NOT mean gone. Removals are therefore decided against the
+        ///     CURRENT vendor list (plus the opt-out/validity rules), not against the window, which
+        ///     is a cheap pass over serials rather than a second inventory walk.
+        /// </summary>
+        private static void MarketSweep()
+        {
+            try
+            {
+                if (!BridgeConfig.MarketEnabled)
+                    return;
+
+                _sweeps++;
+
+                if (!BridgeLink.Connected)
+                    return; // nothing is listening; do not fill the queue with perishable snapshots
+
+                _clock.Restart();
+
+                var all = PlayerVendor.PlayerVendors;
+
+                if (all == null || all.Count == 0)
+                {
+                    Reap(null);
+                    return;
+                }
+
+                // A live set of every serial that SHOULD be on the board right now, built as the
+                // window is walked plus a cheap pass over the rest. Built here rather than reusing
+                // a field so a throwing vendor cannot leave a half-built set behind.
+                var present = new HashSet<Serial>();
+
+                var count = all.Count;
+                var batch = Math.Min(BridgeConfig.MarketSweepBatch, count);
+
+                if (_cursor >= count)
+                    _cursor = 0;
+
+                for (int i = 0; i < count; i++)
+                {
+                    var vendor = all[i];
+
+                    if (Eligible(vendor))
+                        present.Add(vendor.Serial);
+                }
+
+                for (int n = 0; n < batch; n++)
+                {
+                    var index = (_cursor + n) % count;
+                    var vendor = all[index];
+
+                    if (!Eligible(vendor))
+                    {
+                        _skipped++;
+                        continue;
+                    }
+
+                    // One bad vendor must not cost the rest of the window: the item walk touches
+                    // arbitrary Item subclasses on a shard running modified scripts.
+                    try
+                    {
+                        SweepVendor(vendor);
+                    }
+                    catch (Exception ex)
+                    {
+                        Console.WriteLine("[Bridge] market sweep threw for 0x{0:X}: {1}",
+                            vendor.Serial.Value, ex.Message);
+                    }
+                }
+
+                _cursor = count == 0 ? 0 : (_cursor + batch) % count;
+
+                Reap(present);
+            }
+            catch (Exception ex)
+            {
+                Console.WriteLine("[Bridge] market sweep threw: {0}", ex.Message);
+            }
+            finally
+            {
+                // In `finally` so a throwing tick still records what it cost — a sweep that blows
+                // the budget and then throws is exactly the one worth seeing in the status line.
+                if (_clock.IsRunning)
+                {
+                    _clock.Stop();
+                    _lastMs = _clock.Elapsed.TotalMilliseconds;
+                    if (_lastMs > _maxMs)
+                        _maxMs = _lastMs;
+
+                    WarnIfSlow();
+                }
+            }
+        }
+
+        /// <summary>
+        ///     Per-tick budget, milliseconds. The batch cap exists to hold a tick under this
+        ///     regardless of world size, so exceeding it means MarketSweepBatch is too large for
+        ///     this shard's shops — the one thing an operator needs told, and the one thing
+        ///     `[bridge status` cannot tell them unprompted. Generous: a tick is off the frame
+        ///     budget, and the alternative to a rare 50 ms tick is a permanently stale market.
+        /// </summary>
+        private const double SlowTickMs = 50.0;
+
+        // At most one warning a minute. A shard whose batch is genuinely too big would otherwise
+        // print every MarketSweepSeconds forever, and a log nobody can read is a log nobody reads.
+        private static DateTime _lastWarn = DateTime.MinValue;
+
+        private static void WarnIfSlow()
+        {
+            if (_lastMs <= SlowTickMs)
+                return;
+
+            var now = DateTime.UtcNow;
+
+            if (now - _lastWarn < TimeSpan.FromMinutes(1))
+                return;
+
+            _lastWarn = now;
+
+            Console.WriteLine(
+                // ASCII only. The ServUO console writes in the OS code page, so an em dash here
+                // renders as "???" in the log an operator would paste into an issue.
+                "[Bridge] market sweep took {0:F1} ms (budget {1:F0} ms) - lower Bridge.MarketSweepBatch (now {2}) if this persists",
+                _lastMs, SlowTickMs, BridgeConfig.MarketSweepBatch);
+        }
+
+        /// <summary>
+        ///     The same filter DoSearch applies, so the website's index is the in-game index.
+        ///     <c>VendorSearch</c> is the player's own opt-out toggle and is honoured first.
+        /// </summary>
+        private static bool Eligible(PlayerVendor vendor)
+        {
+            return vendor != null
+                && !vendor.Deleted
+                && vendor.VendorSearch
+                && vendor.Map != null
+                && vendor.Map != Map.Internal
+                && vendor.Backpack != null;
+        }
+
+        /// <summary>
+        ///     Drops from the board every tracked vendor that is no longer eligible.
+        ///     <paramref name="present"/> null means "there are no vendors at all", which clears it.
+        /// </summary>
+        private static void Reap(HashSet<Serial> present)
+        {
+            if (_last.Count == 0)
+                return;
+
+            List<Serial> gone = null;
+
+            foreach (var serial in _last.Keys)
+            {
+                if (present != null && present.Contains(serial))
+                    continue;
+
+                if (gone == null)
+                    gone = new List<Serial>();
+
+                gone.Add(serial);
+            }
+
+            if (gone == null)
+                return;
+
+            for (int i = 0; i < gone.Count; i++)
+            {
+                _last.Remove(gone[i]);
+                BridgeLink.Emit(BridgeJson.Begin("vendor.listing.remove").Ser("serial", gone[i]).End());
+                _removed++;
+            }
+        }
+
+        private static void SweepVendor(PlayerVendor vendor)
+        {
+            _scanned++;
+
+            CollectItems(vendor);
+
+            var sig = Signature(vendor);
+
+            string prior;
+            if (_last.TryGetValue(vendor.Serial, out prior) && prior == sig)
+                return; // nothing about this shop changed since it was last published
+
+            _last[vendor.Serial] = sig;
+            BridgeLink.Emit(WriteVendor(vendor));
+            _emitted++;
+        }
+
+        /// <summary>
+        ///     Every sellable item on one vendor, into the shared buffer.
+        ///
+        ///     Mirrors VendorSearch's own private GetItems(PlayerVendor): the vendor's own movable
+        ///     equipment (minus the backpack itself and hair layers, which are not merchandise)
+        ///     followed by a recursive walk of the backpack. The recursion uses the PUBLIC
+        ///     GetItems(Container, List&lt;Item&gt;) rather than a hand-rolled one so that ServUO's
+        ///     rule about which containers are sold whole (quivers, seed boxes, jewelry boxes, …)
+        ///     stays ServUO's to define — the predicate that decides it is private, and a copy here
+        ///     would silently diverge the first time that list changes.
+        /// </summary>
+        private static void CollectItems(PlayerVendor vendor)
+        {
+            _items.Clear();
+
+            var own = vendor.Items;
+
+            if (own != null)
+            {
+                for (int i = 0; i < own.Count; i++)
+                {
+                    var item = own[i];
+
+                    if (item == null || !item.Movable || item == vendor.Backpack)
+                        continue;
+
+                    if (item.Layer == Layer.Hair || item.Layer == Layer.FacialHair)
+                        continue;
+
+                    _items.Add(item);
+                }
+            }
+
+            if (vendor.Backpack != null)
+                VendorSearch.GetItems(vendor.Backpack, _items);
+        }
+
+        /// <summary>
+        ///     A listing's price, and whether it was priced by an enclosing container.
+        ///
+        ///     ServUO prices a container as a unit: an item inside a priced bag has no VendorItem of
+        ///     its own and inherits the bag's price, which DoSearch surfaces as `isChild`. Reproduced
+        ///     exactly, because a website that priced every item in a 40k bag at 40k would be lying
+        ///     about the shard.
+        /// </summary>
+        private static int PriceOf(PlayerVendor vendor, Item item, out bool child)
+        {
+            child = false;
+
+            var vi = vendor.GetVendorItem(item);
+
+            if (vi != null)
+                return vi.Price;
+
+            var parent = item.Parent as Container;
+
+            while (parent != null)
+            {
+                vi = vendor.GetVendorItem(parent);
+
+                if (vi != null)
+                {
+                    child = true;
+                    return vi.Price;
+                }
+
+                parent = parent.Parent as Container;
+            }
+
+            return 0;
+        }
+
+        /// <summary>
+        ///     The diff key. Location, shop name and owner are in it because they move a vendor's
+        ///     row on the site; every listing's serial, price and amount are in it because those are
+        ///     what a shopper searches on.
+        ///
+        ///     Built over the SAME buffer the frame is written from, in the same order, so a
+        ///     signature match really does mean an identical frame — a cheaper hash (count + a sum
+        ///     of serial^price, as §8.3 first proposed) collides on the common case of two items
+        ///     swapping prices, which is exactly what re-pricing a shop looks like.
+        /// </summary>
+        private static string Signature(PlayerVendor vendor)
+        {
+            var sb = new StringBuilder(256);
+
+            sb.Append(vendor.ShopName ?? "").Append('|');
+            sb.Append(vendor.Owner == null ? 0 : vendor.Owner.Serial.Value).Append('|');
+            sb.Append(vendor.Map == null ? "" : vendor.Map.Name).Append('|');
+            sb.Append(vendor.X).Append(',').Append(vendor.Y).Append('|');
+
+            var limit = Math.Min(_items.Count, BridgeConfig.MarketMaxListings);
+
+            sb.Append(_items.Count).Append('|');
+
+            for (int i = 0; i < limit; i++)
+            {
+                var item = _items[i];
+
+                if (item == null || item.Deleted)
+                    continue;
+
+                bool child;
+                var price = PriceOf(vendor, item, out child);
+
+                if (price <= 0)
+                    continue;
+
+                sb.Append(item.Serial.Value.ToString("X")).Append(':')
+                  .Append(price).Append(':')
+                  .Append(item.Amount).Append(';');
+            }
+
+            return sb.ToString();
+        }
+
+        /// <summary>
+        ///     One vendor frame — authoritative for that vendor, so the website replaces its whole
+        ///     listing set from it rather than merging.
+        ///
+        ///     `location` is one nested object rather than flat map/x/y/region because it is ONE
+        ///     admin-configurable field on the site (`market.location`): the visibility projection
+        ///     matches literal JSON keys, so a nested object is what lets a single rule hide a
+        ///     vendor's whereabouts on both the live frame and the stored read model. Flat keys
+        ///     would need five rules that could drift apart.
+        ///
+        ///     `count` is the number of listings PUBLISHED, and `truncated` says the shop holds
+        ///     more. A shop over the cap is a real thing (commodity resellers run thousands of
+        ///     stacks) and the site says so rather than quietly showing a partial shop as complete.
+        /// </summary>
+        private static string WriteVendor(PlayerVendor vendor)
+        {
+            var sb = BridgeJson.Begin("vendor.listing")
+                .Ser("serial", vendor.Serial)
+                .Str("shopName", vendor.ShopName);
+
+            var owner = vendor.Owner;
+
+            if (owner != null)
+            {
+                sb.Ser("ownerSerial", owner.Serial);
+                sb.Str("ownerName", owner.Name);
+            }
+
+            sb.Append(",\"location\":{\"map\":");
+            Text(sb, vendor.Map == null ? null : vendor.Map.Name);
+            sb.Append(",\"x\":").Append(vendor.X);
+            sb.Append(",\"y\":").Append(vendor.Y);
+            sb.Append(",\"z\":").Append(vendor.Z);
+
+            var region = vendor.Region;
+            sb.Append(",\"region\":");
+            Text(sb, region == null ? null : region.Name);
+
+            // The house name is the sign's, which is what a player would be told to look for
+            // ("Bob's Villa"), not the house type. Null for a vendor standing outside one.
+            var house = vendor.House;
+            var sign = house == null ? null : house.Sign;
+            sb.Append(",\"house\":");
+            Text(sb, sign == null ? null : sign.GetName());
+
+            sb.Append('}');
+
+            var max = BridgeConfig.MarketMaxListings;
+            var published = 0;
+            var considered = 0;
+
+            var items = new StringBuilder(512);
+
+            for (int i = 0; i < _items.Count; i++)
+            {
+                var item = _items[i];
+
+                if (item == null || item.Deleted)
+                    continue;
+
+                bool child;
+                var price = PriceOf(vendor, item, out child);
+
+                // Unpriced items are inventory, not listings — DoSearch drops them the same way.
+                if (price <= 0)
+                    continue;
+
+                considered++;
+
+                if (published >= max)
+                    continue;
+
+                if (published > 0)
+                    items.Append(',');
+
+                items.Append("{\"serial\":\"0x").Append(item.Serial.Value.ToString("X")).Append('"');
+                items.Append(",\"itemId\":").Append(item.ItemID);
+                items.Append(",\"hue\":").Append(item.Hue);
+                items.Append(",\"amount\":").Append(item.Amount);
+                items.Append(",\"price\":").Append(price);
+
+                // The PLAIN Name field, which is null for most items — never GetItemName, which
+                // builds and parses a property packet per item. LabelNumber is the cliloc the
+                // website resolves against its own table.
+                items.Append(",\"name\":");
+                Text(items, item.Name);
+                items.Append(",\"cliloc\":").Append(item.LabelNumber);
+
+                if (child)
+                    items.Append(",\"child\":true");
+
+                items.Append('}');
+
+                published++;
+            }
+
+            sb.Num("count", published);
+            sb.Num("total", considered);
+            sb.Bool("truncated", considered > published);
+
+            if (considered > published)
+                _truncated++;
+
+            sb.Append(",\"items\":[").Append(items).Append(']');
+
+            return sb.End();
+        }
+    }
+}