chore: add swqos client

pkg/swqos/clients/flash_block_client.go

@@ -0,0 +1,90 @@
+package clients
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/gagliardetto/solana-go"
+)
+
+type FlashBlockBundleRequest struct {
+	Transactions []string `json:"transactions"`
+}
+
+type FlashBlockClient struct {
+	sendTxUrl     string
+	sendBundleUrl string
+
+	client *http.Client
+}
+
+func NewFlashBlockClient(sendTxUrl string, sendBundleUrl string) *FlashBlockClient {
+	// create custom transport with keep-alive enabled
+	transport := &http.Transport{
+		MaxIdleConns:        100,
+		MaxIdleConnsPerHost: 10,
+		IdleConnTimeout:     65 * time.Second,
+		DisableKeepAlives:   false, // enable keep-alive
+	}
+
+	client := &http.Client{
+		Transport: transport,
+		Timeout:   30 * time.Second,
+	}
+
+	return &FlashBlockClient{
+		sendTxUrl:     sendTxUrl,
+		sendBundleUrl: sendBundleUrl,
+		client:        client,
+	}
+}
+
+func (c *FlashBlockClient) SendTransaction(ctx context.Context, tx *solana.Transaction) error {
+	return c.SendBundle(ctx, []*solana.Transaction{tx})
+}
+
+func (c *FlashBlockClient) SendBundle(ctx context.Context, txs []*solana.Transaction) error {
+	request := FlashBlockBundleRequest{
+		Transactions: make([]string, 0, len(txs)),
+	}
+
+	for _, tx := range txs {
+		request.Transactions = append(request.Transactions, tx.MustToBase64())
+	}
+
+	jsonData, err := json.Marshal(request)
+	if err != nil {
+		return err
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.sendBundleUrl, bytes.NewReader(jsonData))
+	if err != nil {
+		return err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "0b1ef3abade04426") // TODO: maybe config?
+
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return err
+	}
+
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("status code: %d, body: %s", resp.StatusCode, string(body))
+	}
+
+	return nil
+}