feat: implement coinank openapi netPositions interface (#1258)

- implement Net long & Net short interface

provider/coinank/net_positions.go

@@ -0,0 +1,46 @@
+package coinank
+
+import (
+	"context"
+	"encoding/json"
+	"nofx/provider/coinank/coinank_enum"
+	"strconv"
+)
+
+// NetPositions Net long & Net short
+func (c *CoinankClient) NetPositions(ctx context.Context, exchange coinank_enum.Exchange,
+	symbol string, interval coinank_enum.Interval, endTime int64, size int) ([]NetPositionsResponse, error) {
+	paramsMap := make(map[string]string, 5)
+	paramsMap["exchange"] = string(exchange)
+	paramsMap["symbol"] = symbol
+	paramsMap["interval"] = string(interval)
+	paramsMap["endTime"] = strconv.FormatInt(endTime, 10)
+	if size < 1 {
+		size = 10
+	}
+	paramsMap["size"] = strconv.Itoa(size)
+	resp, err := c.Get(ctx, "/api/netPositions/getNetPositions", paramsMap)
+	if err != nil {
+		return nil, err
+	}
+	var result CoinankResponse[[]NetPositionsResponse]
+	err = json.Unmarshal([]byte(resp), &result)
+	if err != nil {
+		return nil, err
+	}
+	if !result.Success {
+		return nil, HttpError
+	}
+	return result.Data, nil
+}
+
+type NetPositionsResponse struct {
+	Begin          int64  `json:"begin"` // begin timestamp
+	Interval       string `json:"interval"`
+	NetLongsHigh   int    `json:"netLongsHigh"`   // net long high
+	NetLongsClose  int    `json:"netLongsClose"`  // net long close
+	NetLongsLow    int    `json:"netLongsLow"`    // net long close
+	NetShortsClose int    `json:"netShortsClose"` // net short close
+	NetShortsHigh  int    `json:"netShortsHigh"`  // net short high
+	NetShortsLow   int    `json:"netShortsLow"`   // net short low
+}

provider/coinank/net_positions_test.go

@@ -0,0 +1,25 @@
+package coinank
+
+import (
+	"context"
+	"encoding/json"
+	"nofx/provider/coinank/coinank_enum"
+	"testing"
+	"time"
+)
+
+func TestNetPositions(t *testing.T) {
+	client := NewCoinankClient(coinank_enum.MainUrl, TestApikey)
+	resp, err := client.NetPositions(context.TODO(), coinank_enum.Binance, "BTCUSDT", coinank_enum.Hour1, time.Now().UnixMilli(), 10)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp[0].Begin <= 0 {
+		t.Errorf("begin timestamp error")
+	}
+	res, err := json.Marshal(resp)
+	if err != nil {
+		t.Error(err)
+	}
+	t.Logf("%s", res)
+}