Add AmendOrderAsync method to BinanceRestClientSpotApiTrading

Reduce the quantity of an existing open order
See https://developers.binance.com/docs/binance-spot-api-docs/websocket-api/trading-requests#order-amend-keep-priority-trade

Author: DShaurin

Binance.Net.UnitTests/RestRequestTests.cs

@@ -160,6 +160,7 @@ public async Task ValidateSpotTradingCalls()
             await tester.ValidateAsync(client => client.SpotApi.Trading.CancelOrderAsync("ETHUSDT", 123), "CancelOrder");
             await tester.ValidateAsync(client => client.SpotApi.Trading.CancelAllOrdersAsync("ETHUSDT"), "CancelAllOrders");
             await tester.ValidateAsync(client => client.SpotApi.Trading.ReplaceOrderAsync("ETHUSDT", Enums.OrderSide.Sell, Enums.SpotOrderType.Limit, Enums.CancelReplaceMode.AllowFailure, 123, quantity: 1), "ReplaceOrder", nestedJsonProperty: "data");
+            await tester.ValidateAsync(client => client.SpotApi.Trading.AmendOrderAsync("ETHUSDT", 123, newQty: 0.5), "AmendOrder");
             await tester.ValidateAsync(client => client.SpotApi.Trading.GetOrderAsync("ETHUSDT", 123), "GetOrder");
             await tester.ValidateAsync(client => client.SpotApi.Trading.GetOpenOrdersAsync("ETHUSDT"), "GetOpenOrders");
             await tester.ValidateAsync(client => client.SpotApi.Trading.GetOrdersAsync("ETHUSDT"), "GetOrders");

Binance.Net/Clients/SpotApi/BinanceRestClientSpotApiTrading.cs

@@ -308,6 +308,46 @@ public async Task<WebCallResult<BinanceReplaceOrderResult>> ReplaceOrderAsync(st
         }
         #endregion
 
+        #region Amend Order
+
+        /// <inheritdoc />
+        public async Task<WebCallResult<BinanceAmendedOrderResult>> AmendOrderAsync(
+            string symbol,
+            decimal newQty,
+            long? orderId = null,
+            string? origClientOrderId = null,
+            string? newClientOrderId = null,
+            int? receiveWindow = null,
+            CancellationToken ct = default)
+        {
+            if (!orderId.HasValue && string.IsNullOrEmpty(origClientOrderId))
+                throw new ArgumentException("Either orderId or origClientOrderId must be sent");
+
+            if (newClientOrderId != null)
+            {
+                newClientOrderId = LibraryHelpers.ApplyBrokerId(
+                    newClientOrderId,
+                    LibraryHelpers.GetClientReference(() => _baseClient.ClientOptions.BrokerId, _baseClient.Exchange, "Spot"),
+                    36,
+                    _baseClient.ClientOptions.AllowAppendingClientOrderId);
+            }
+
+            var parameters = new ParameterCollection
+            {
+                { "symbol", symbol },
+                { "newQty", newQty.ToString(CultureInfo.InvariantCulture) }
+            };
+            parameters.AddOptionalParameter("orderId", orderId?.ToString(CultureInfo.InvariantCulture));
+            parameters.AddOptionalParameter("origClientOrderId", origClientOrderId);
+            parameters.AddOptionalParameter("newClientOrderId", newClientOrderId);
+            parameters.AddOptionalParameter("recvWindow", receiveWindow?.ToString(CultureInfo.InvariantCulture) ?? _baseClient.ClientOptions.ReceiveWindow.TotalMilliseconds.ToString(CultureInfo.InvariantCulture));
+
+            var request = _definitions.GetOrCreate(HttpMethod.Put, "api/v3/order/amend/keepPriority", BinanceExchange.RateLimiter.SpotRestIp, 4, true);
+            return await _baseClient.SendAsync<BinanceAmendedOrderResult>(request, parameters, ct).ConfigureAwait(false);
+        }
+
+        #endregion
+
         #region Query Order
 
         /// <inheritdoc />

Binance.Net/Interfaces/Clients/SpotApi/IBinanceRestClientSpotApiTrading.cs

@@ -197,6 +197,32 @@ Task<WebCallResult<BinanceReplaceOrderResult>> ReplaceOrderAsync(string symbol,
             int? receiveWindow = null,
             CancellationToken ct = default);
 
+        /// <summary>
+        /// Amends an existing open order (reduces quantity)
+        /// <para>
+        /// Docs:<br />
+        /// <a href="https://developers.binance.com/docs/binance-spot-api-docs/rest-api/trading-endpoints#order-amend-keep-priority-trade" /><br />
+        /// Endpoint:<br />
+        /// PUT /api/v3/order/amend/keepPriority
+        /// </para>
+        /// </summary>
+        /// <param name="symbol">["<c>symbol</c>"] The symbol the order is for, for example `ETHUSDT`</param>
+        /// <param name="orderId">["<c>orderId</c>"] The order id of the order. Either this or origClientOrderId should be provided</param>
+        /// <param name="origClientOrderId">["<c>origClientOrderId</c>"] The client order id of the order. Either this or orderId should be provided</param>
+        /// <param name="newClientOrderId">["<c>newClientOrderId</c>"] The new client order id for the order after being amended</param>
+        /// <param name="newQuantity">["<c>newQuantity</c>"] The new quantity (must be greater than 0 and less than the order's quantity)</param>
+        /// <param name="receiveWindow">The receive window for which this request is active</param>
+        /// <param name="ct">Cancellation token</param>
+        /// <returns>The amended order details</returns>
+        Task<WebCallResult<BinanceAmendedOrderResult>> AmendOrderAsync(
+            string symbol,
+            decimal newQuantity,
+            long? orderId = null,
+            string? origClientOrderId = null,
+            string? newClientOrderId = null,
+            int? receiveWindow = null,
+            CancellationToken ct = default);
+
         /// <summary>
         /// Retrieves data for a specific order. Either orderId or origClientOrderId should be provided.
         /// <para>

Binance.Net/Objects/Models/Spot/BinanceAmendedOrderResult.cs

@@ -0,0 +1,27 @@
+namespace Binance.Net.Objects.Models.Spot
+{
+    /// <summary>
+    /// The result of amending an order
+    /// </summary>
+    [SerializationModel]
+    public record BinanceAmendedOrderResult
+    {
+        /// <summary>
+        /// ["<c>transactTime</c>"] Transaction time
+        /// </summary>
+        [JsonPropertyName("transactTime")]
+        public DateTime TransactTime { get; set; }
+
+        /// <summary>
+        /// ["<c>executionId</c>"] Execution ID
+        /// </summary>
+        [JsonPropertyName("executionId")]
+        public long ExecutionId { get; set; }
+
+        /// <summary>
+        /// ["<c>amendedOrder</c>"] The amended order details
+        /// </summary>
+        [JsonPropertyName("amendedOrder")]
+        public BinanceOrder AmendedOrder { get; set; } = default!;
+    }
+}