OnTradeTransaction HOW

Example from file: examples/demos/lowlevel/03_streaming_methods.go

The OnTradeTransaction() method is the most detailed streaming method, which transmits all trading events occurring on the account in MetaTrader. It captures every step: from order opening to its execution and position closing.

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🧩 Code example

transactionReq := &pb.OnTradeTransactionRequest{}

transactionCtx, transactionCancel := context.WithCancel(ctx)
transactionChan, transactionErrChan := account.OnTradeTransaction(transactionCtx, transactionReq)

fmt.Printf("Streaming trade transactions (max %d events or %d seconds)...\n", MAX_EVENTS, MAX_SECONDS)
fmt.Println("  NOTE: This stream sends events for all trade-related transactions")

eventCount = 0
timeout = time.After(MAX_SECONDS * time.Second)

streamTransaction:
for {
    select {
    case transactionData, ok := <-transactionChan:
        if !ok {
            fmt.Println("  Stream closed by server")
            break streamTransaction
        }
        eventCount++
        fmt.Printf("  Event #%d: Type=%v\n", eventCount, transactionData.Type)

        if transactionData.TradeTransaction != nil {
            tx := transactionData.TradeTransaction
            fmt.Printf("    Transaction Type=%v Order=%d Deal=%d\n",
                tx.Type,
                tx.OrderTicket,
                tx.DealTicket)

            if tx.Symbol != "" {
                fmt.Printf("    Symbol=%s Price=%.5f Volume=%.2f\n",
                    tx.Symbol,
                    tx.Price,
                    tx.Volume)
            }
        }

        if eventCount >= MAX_EVENTS {
            fmt.Printf("  ✓ Received %d events, stopping stream\n", MAX_EVENTS)
            break streamTransaction
        }

    case err := <-transactionErrChan:
        if err != nil {
            helpers.PrintShortError(err, "Stream error")
            break streamTransaction
        }

    case <-timeout:
        fmt.Printf("  ⏱ Timeout after %d seconds (received %d events)\n", MAX_SECONDS, eventCount)
        break streamTransaction
    }
}
transactionCancel() // closes this stream on the server

---

🟢 Detailed Code Explanation

1️. Prepare Request

transactionReq := &pb.OnTradeTransactionRequest{}

Create an empty request — subscription applies to all trading events of the current account.

---

2️. Start the Stream

transactionCtx, transactionCancel := context.WithCancel(ctx)
transactionChan, transactionErrChan := account.OnTradeTransaction(transactionCtx, transactionReq)

The stream gets its own context, derived from ctx: transactionCancel() after the loop closes this stream on the server at once. Without it the stream would stay open, unread, until ctx itself ends — and every later stream of the demo would pile up next to it.

The method returns two channels:

• transactionChan — stream with events;
• transactionErrChan — connection errors.

The stream activates on any changes in orders, deals, and positions.

---

3️. Main Processing Loop

case transactionData, ok := <-transactionChan:

The loop receives each new event. Each message contains:

• event group type (transactionData.Type, always OrderUpdate for this stream),
• TradeTransaction structure with details (plus TradeRequest, TradeResult and AccountInfo).

---

4️. Process Trade Event

if transactionData.TradeTransaction != nil {
    tx := transactionData.TradeTransaction
    fmt.Printf("    Transaction Type=%v Order=%d Deal=%d\n", ...)

Useful fields:

Field	Description
Type	Transaction type (SUB_TRADE_TRANSACTION_DEAL_ADD, ..._ORDER_ADD, ..._ORDER_DELETE, etc.)
OrderTicket	Order number
DealTicket	Deal number
Symbol	Trading instrument
Price	Deal price
Volume	Deal volume in lots

---

5️. Display Detailed Information

if tx.Symbol != "" {
    fmt.Printf("    Symbol=%s Price=%.5f Volume=%.2f\n", ...)
}

If the broker transmits quotes and volume — this data is displayed immediately after the transaction. This allows building custom trading logs in real-time.

---

6️. Stream Termination

The stream stops when:

• event limit is reached (MAX_EVENTS),
• timeout occurs (MAX_SECONDS),
• connection error or stream closure by server.

---

📦 What the Server Returns

message OnTradeTransactionData {
  MT5_SUB_ENUM_EVENT_GROUP_TYPE type = 1;   // OrderUpdate for transaction events
  MqlTradeTransaction trade_transaction = 2;
  MqlTradeRequest trade_request = 3;
  MqlTradeResult trade_result = 4;
  string terminal_instance_guid_id = 5;
  OnEventAccountInfo account_info = 6;
}

message MqlTradeTransaction {
  uint64 deal_ticket = 1;
  uint64 order_ticket = 2;
  string symbol = 3;
  SUB_ENUM_TRADE_TRANSACTION_TYPE type = 4;
  // ... order_type, order_state, deal_type, order_time_type, expiration times,
  // price = 10, price_trigger_stop_limit, price_stop_loss, price_take_profit,
  // volume = 14, position_ticket, position_by_opposite_position
}

Each message corresponds to one trading operation.

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💡 Example Output

Streaming trade transactions (max 5 events or 10 seconds)...
  NOTE: This stream sends events for all trade-related transactions
  Event #1: Type=OrderUpdate
    Transaction Type=SUB_TRADE_TRANSACTION_DEAL_ADD Order=12345678 Deal=98765432
    Symbol=EURUSD Price=1.08645 Volume=0.10
  Event #2: Type=OrderUpdate
    Transaction Type=SUB_TRADE_TRANSACTION_ORDER_DELETE Order=12345678 Deal=0
  ✓ Received 5 events, stopping stream

---

🧠 What It's Used For

The OnTradeTransaction() method is used for:

• auditing all trading actions on the account;
• logging orders, deals, and modifications;
• reactive trading strategies responding to changes;
• analytics or gateway testing.

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💬 In Simple Terms

OnTradeTransaction() is a stream of all trading events in MetaTrader. It reports: "Order created", "Deal executed", "Order deleted", "Position closed".

This is the most complete and detailed stream, allowing you to see everything happening with orders and deals in real-time.