Inc payments: sample code for reading amount received.

2025-11-20 11:45:50 +00:00 · 2019-05-07 18:35:46 -07:00
parent 579afe766b
commit 5d6ea00931
3 changed files with 194 additions and 3 deletions
--- a/content/_code-samples/monitor-payments-websocket/read-amount-received.js
+++ b/content/_code-samples/monitor-payments-websocket/read-amount-received.js
@@ -0,0 +1,72 @@
+function CountXRPDifference(affected_nodes, address) {
+  // Helper to find an account in an AffectedNodes array and see how much
+  // its balance changed, if at all. Fortunately, each account appears at most
+  // once in the AffectedNodes array, so we can return as soon as we find it.
+
+  for (let i=0; i<affected_nodes.length; i++) {
+    if ((affected_nodes[i].hasOwnProperty("ModifiedNode"))) {
+      // modifies an existing ledger entry
+      let ledger_entry = affected_nodes[i].ModifiedNode
+      if (ledger_entry.LedgerEntryType === "AccountRoot" &&
+          ledger_entry.FinalFields.Account === address) {
+        if (!ledger_entry.PreviousFields.hasOwnProperty("Balance")) {
+          console.log("XRP balance did not change.")
+        }
+        // Balance is in PreviousFields, so it changed. Time for
+        // high-precision math!
+        const old_balance = new Big(ledger_entry.PreviousFields.Balance)
+        const new_balance = new Big(ledger_entry.FinalFields.Balance)
+        const diff_in_drops = new_balance.minus(old_balance)
+        const xrp_amount = diff_in_drops.div(10e6)
+        if (xrp_amount.gte(0)) {
+          console.log("Received "+xrp_amount.toString()+" XRP.")
+          return
+        } else {
+          console.log("Spent "+xrp_amount.abs().toString()+" XRP.")
+          return
+        }
+      }
+    } else if ((affected_nodes[i].hasOwnProperty("CreatedNode"))) {
+      // created a ledger entry. maybe the account just got funded?
+      let ledger_entry = affected_nodes[i].CreatedNode
+      if (ledger_entry.LedgerEntryType === "AccountRoot" &&
+          ledger_entry.NewFields.Account === address) {
+        const balance_drops = new Big(ledger_entry.NewFields.Balance)
+        const xrp_amount = balance_drops.div(10e6)
+        console.log("Received "+xrp_amount.toString()+" XRP (account funded).")
+        return
+      }
+    } // accounts cannot be deleted at this time, so we ignore DeletedNode
+  }
+
+  console.log("Did not find address in affected nodes.")
+  return
+}
+
+function CountXRPReceived(tx, address) {
+  if (tx.meta.TransactionResult !== "tesSUCCESS") {
+    console.log("Transaction failed.")
+    return
+  }
+  if (tx.transaction.TransactionType === "Payment") {
+    if (tx.transaction.Destination !== address) {
+      console.log("Not the destination of this payment.")
+      return
+    }
+    if (typeof tx.meta.delivered_amount === "string") {
+      const amount_in_drops = new Big(tx.meta.delivered_amount)
+      const xrp_amount = amount_in_drops.div(10e6)
+      console.log("Received " + xrp_amount.toString() + " XRP.")
+      return
+    } else {
+      console.log("Received non-XRP currency.")
+      return
+    }
+  } elif (["PaymentChannelClaim", "PaymentChannelFund", "OfferCreate",
+          "CheckCash", "EscrowFinish"].includes(tx.transaction.TransactionType) {
+    CountXRPDifference(tx.meta.AffectedNodes, address)
+  } else {
+    console.log("Not a currency-delivering transaction type (" +
+                tx.transaction.TransactionType + ").")
+  }
+}