features discord webhook

---

🔔 Discord Webhook Notifier

DiscordWebhookNotifier sends embedded alerts to a Discord channel when relevant events occur. All using the standard java.net.http.HttpClient (Java 11+) API — no JDA, no OkHttp, no external dependencies.

Configuration

discord:
  webhook_url: ""              # ← Leave empty to disable
  threshold_amount: 100000     # Notify if |tx| > threshold
  username: "Vault Bot"
  avatar_url: ""               # optional avatar URL

Activation condition: enabled = !webhook_url.isEmpty() && HttpClient != null. If the JVM cannot instantiate HttpClient.newBuilder(), the notifier is silently disabled.

HttpClient (No External Libraries)

HttpClient.newBuilder()
  .connectTimeout(Duration.ofSeconds(5))
  .followRedirects(HttpClient.Redirect.NORMAL)
  .build();

Each request uses:

• HttpRequest.BodyPublishers.ofString(json, UTF_8) — POST JSON method
• HttpResponse.BodyHandlers.discarding() — does not parse response
• Global 8s timeout + CompletableFuture.orTimeout(10s, TimeUnit.SECONDS)

HTTP codes outside the 2xx range are logged as a warning: [Discord] Webhook returned HTTP 404.

Events That Trigger an Embed

DiscordWebhookNotifier is registered as a listener of TransactionLogService:

Trigger Event	Embed Color	Rule / Key Fields
Transaction > threshold	Green/Red	`
Anti-dupe window detects	Orange/Red	hard=true red 0xff0000, soft=false orange 0xffa500.
Batch flush with error	Red	buildErrorEmbed — batch_size + 400-char truncated exception

Embed Structure: Transaction > Threshold

{
  "username": "Vault Bot",
  "avatar_url": "...",
  "embeds": [{
    "title": "💸 Large Transaction: PLAYER_PAY",
    "description": "From Notch → Player123",
    "color": 65372,
    "timestamp": "2024-01-01T12:00:00.000Z",
    "fields": [
      { "name": "TxID",     "value": "`a1b2c3d4e5f60789`", "inline": true  },
      { "name": "Currency", "value": "default",             "inline": true  },
      { "name": "Amount",   "value": "**$ 1.5M**",          "inline": true  },
      { "name": "From",     "value": "`Notch`",              "inline": true  },
      { "name": "To",       "value": "`Player123`",          "inline": true  },
      { "name": "World",    "value": "world",                "inline": true  },
      { "name": "Metadata", "value": "• note: rent payment\n• qp: 50%", "inline": false }
    ]
  }]
}

Color depends on flow (green if recipient gains, red if loses). i18n keys for titles/fields are looked up in:

• discord.threshold.title, discord.threshold.desc
• discord.dupe.title, discord.error.title
• discord.tx_type.PLAYER_PAY etc. (24+ keys, one per TxType)
• discord.field.txid, discord.field.currency, discord.field.amount...

All embeds use the language defined in config.language (of the 11 supported). If a key is missing, the raw TxType name is shown as a fallback.

Anti-spam LRU (500 IDs)

To avoid spam from repeated flushes, a RollingLinkedHashSet extends LinkedHashSet<String> of 500 max entries is used. When it reaches max size, it evicts the oldest by insertion order.

Registered keys:

• Normal transactions → raw txId
• Duplicates → DUPE: prefix + txId

If the key already exists in the set, the embed is silently discarded.