💱 Translate removing AMM liquidity

And simplify the go newTxBuilder preconditions
stellar · Nov 24, 2024 · be7abb0 · be7abb0
1 parent 535b09b
commit be7abb0
Showing 1 changed file with 73 additions and 19 deletions.
diff --git a/docs/learn/encyclopedia/sdex/liquidity-on-stellar-sdex-liquidity-pools.mdx b/docs/learn/encyclopedia/sdex/liquidity-on-stellar-sdex-liquidity-pools.mdx
@@ -873,8 +873,7 @@ func newTxBuilder(source *horizonclient.AccountRequest) (*txnbuild.Transaction,
 	txParams := txnbuild.TransactionParams{
 		SourceAccount:        &account,
 		BaseFee:              txnbuild.MinBaseFee,
-		Preconditions:        txnbuild.Preconditions{TimeBounds: txnbuild.NewTimeout(360)},
-		Operations:           nil,
+		Timebounds:           txnbuild.NewTimeout(360),
 		IncrementSequenceNum: true,
 	}
 	return txnbuild.NewTransaction(txParams)
@@ -1264,30 +1263,28 @@ If you own shares of a particular pool, you can withdraw reserves from it. The o
 <CodeExample>
 
 ```python
-def removeLiquidity(
-  source: Keypair, poolId: str, sharesAmount: Decimal
-) -> dict[str, Any]:
+def removeLiquidity(source, poolId, sharesAmount):
   poolInfo = server.liquidity_pools().liquidity_pool(poolId).call()
   totalShares = Decimal(poolInfo["total_shares"])
   minReserveA = (
-    sharesAmount
-    / totalShares
-    * Decimal(poolInfo["reserves"][0]["amount"])
-    * Decimal("0.95")
+      sharesAmount
+      / totalShares
+      * Decimal(poolInfo["reserves"][0]["amount"])
+      * Decimal("0.95") # 95% safety factor
   )
   minReserveB = (
-    sharesAmount
-    / totalShares
-    * Decimal(poolInfo["reserves"][1]["amount"])
-    * Decimal("0.95")
+      sharesAmount
+      / totalShares
+      * Decimal(poolInfo["reserves"][1]["amount"])
+      * Decimal("0.95")
   )
   tx = (
-    newTxBuilder(source.public_key)
+      newTxBuilder(source.public_key)
       .appendLiquidityPoolWithdrawOp(
-        liquidityPoolId=poolId,
-        amount=f"{sharesAmount:.7f}",
-        minAmountA=f"{minReserveA:.7f}",
-        minAmountB=f"{minReserveB:.7f}",
+          liquidityPoolId=poolId,
+          amount=f"{sharesAmount:.7f}",
+          minAmountA=f"{minReserveA:.7f}",
+          minAmountB=f"{minReserveB:.7f}",
       )
       .build()
   )
@@ -1304,7 +1301,7 @@ function removeLiquidity(source, signer, poolId, sharesAmount) {
     .then((poolInfo) => {
       let totalShares = poolInfo.total_shares;
       let minReserveA =
-        (sharesAmount / totalShares) * poolInfo.reserves[0].amount * 0.95;
+        (sharesAmount / totalShares) * poolInfo.reserves[0].amount * 0.95; // 95% safety factor
       let minReserveB =
         (sharesAmount / totalShares) * poolInfo.reserves[1].amount * 0.95;
 
@@ -1325,11 +1322,68 @@ function removeLiquidity(source, signer, poolId, sharesAmount) {
 ```
 
 ```java
+public Map<String, Object> removeLiquidity(KeyPair source, String poolId, String sharesAmount) throws Exception {
+  Map<String, Object> poolInfo = server.liquidityPools()
+    .liquidityPool(poolId)
+    .call();
+
+  double totalShares = Double.parseDouble(poolInfo.get("total_shares").toString());
+  double reserveA = Double.parseDouble(((Map<String, String>) ((List<Object>) poolInfo.get("reserves")).get(0)).get("amount"));
+  double reserveB = Double.parseDouble(((Map<String, String>) ((List<Object>) poolInfo.get("reserves")).get(1)).get("amount"));
+
+  double minReserveA = (Double.parseDouble(sharesAmount) / totalShares) * reserveA * 0.95; // 95% safety factor
+  double minReserveB = (Double.parseDouble(sharesAmount) / totalShares) * reserveB * 0.95;
 
+  Transaction transaction = newTxBuilder(source)
+    .addOperation(
+      new LiquidityPoolWithdrawOperation.Builder(
+        poolId,
+        sharesAmount,
+        String.format("%.7f", minReserveA),
+        String.format("%.7f", minReserveB)
+      ).build()
+    )
+    .build();
+
+  transaction.sign(source);
+  return server.submitTransaction(transaction);
+}
 ```
 
 ```go
+func removeLiquidity(source *keypair.Full, poolID string, sharesAmount float64) {
+	poolRequest := horizonclient.LiquidityPoolRequest{LiquidityPoolID: poolID}
+	poolInfo, err := client.LiquidityPoolDetail(poolRequest)
+	check(err)
+
+	totalShares, err := strconv.ParseFloat(poolInfo.TotalShares, 64)
+	check(err)
+	reserveA, err := strconv.ParseFloat(poolInfo.Reserves[0].Amount, 64)
+	check(err)
+	reserveB, err := strconv.ParseFloat(poolInfo.Reserves[1].Amount, 64)
+	check(err)
 
+	minReserveA := (sharesAmount / totalShares) * reserveA * 0.95 // 95% safety factor
+	minReserveB := (sharesAmount / totalShares) * reserveB * 0.95
+
+	sourceAccount := &horizonclient.AccountRequest{AccountID: source.Address()}
+	tx := newTxBuilder(sourceAccount)
+	tx.Operations = []txnbuild.Operation{
+		&txnbuild.LiquidityPoolWithdraw{
+			LiquidityPoolID: poolID,
+			Amount:          formatFloat(sharesAmount),
+			MinAmountA:      formatFloat(minReserveA),
+			MinAmountB:      formatFloat(minReserveB),
+		},
+	}
+
+	tx, err := tx.Build()
+	check(err)
+	signedTx, err := tx.Sign(txnbuild.NetworkTest, source)
+	check(err)
+	resp, err := client.SubmitTransaction(signedTx)
+	check(err)
+}
 ```
 
 </CodeExample>