feat: implement History API service with Swagger documentation and routing

internal/services/goongService.go

@@ -0,0 +1,114 @@
+package services
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"history-api/pkg/cache"
+	"history-api/pkg/config"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+type GoongService interface {
+	ProxyRequest(ctx context.Context, method string, targetURL string, headers map[string]string, reqBody []byte) (int, map[string]string, []byte, error)
+}
+
+type CacheEntry struct {
+	StatusCode int               `json:"status_code"`
+	Headers    map[string]string `json:"headers"`
+	Body       []byte            `json:"body"`
+}
+
+type goongService struct {
+	redis cache.Cache
+}
+
+func NewGoongService(redis cache.Cache) GoongService {
+	return &goongService{
+		redis: redis,
+	}
+}
+
+func (s *goongService) ProxyRequest(ctx context.Context, method string, targetURL string, headers map[string]string, reqBody []byte) (int, map[string]string, []byte, error) {
+	apiKey, err := config.GetConfig("GOONG_API_KEY")
+	if err != nil {
+		return 500, nil, nil, fmt.Errorf("GOONG_API_KEY is not configured")
+	}
+
+	fullTargetURL := targetURL
+	if !strings.HasPrefix(fullTargetURL, "http://") && !strings.HasPrefix(fullTargetURL, "https://") {
+		fullTargetURL = "https://" + fullTargetURL
+	}
+
+	parsedUrl, err := url.Parse(fullTargetURL)
+	if err != nil || parsedUrl.Host == "" {
+		return 400, nil, nil, fmt.Errorf("invalid target URL")
+	}
+
+	if !strings.HasSuffix(parsedUrl.Host, "goong.io") {
+		return 403, nil, nil, fmt.Errorf("only goong.io domains are allowed")
+	}
+
+	q := parsedUrl.Query()
+	q.Set("api_key", apiKey)
+	parsedUrl.RawQuery = q.Encode()
+	finalURL := parsedUrl.String()
+
+	cacheKey := fmt.Sprintf("goong_proxy:%s", finalURL)
+
+	if method == http.MethodGet {
+		var entry CacheEntry
+		if err := s.redis.Get(ctx, cacheKey, &entry); err == nil && len(entry.Body) > 0 {
+			return entry.StatusCode, entry.Headers, entry.Body, nil
+		}
+	}
+
+	req, err := http.NewRequestWithContext(ctx, method, finalURL, nil)
+	if err != nil {
+		return 500, nil, nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	if len(reqBody) > 0 {
+		req.Body = io.NopCloser(bytes.NewReader(reqBody))
+	}
+
+	for k, v := range headers {
+		lowerK := strings.ToLower(k)
+		if lowerK == "host" || lowerK == "connection" || lowerK == "accept-encoding" {
+			continue
+		}
+		req.Header.Set(k, v)
+	}
+
+	client := &http.Client{Timeout: 15 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		return 500, nil, nil, fmt.Errorf("failed to fetch from target: %w", err)
+	}
+	defer resp.Body.Close()
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return 500, nil, nil, fmt.Errorf("failed to read response body: %w", err)
+	}
+
+	respHeaders := make(map[string]string)
+	for k, v := range resp.Header {
+		respHeaders[k] = v[0]
+	}
+
+	if method == http.MethodGet && resp.StatusCode == http.StatusOK {
+		entry := CacheEntry{
+			StatusCode: resp.StatusCode,
+			Headers:    respHeaders,
+			Body:       respBody,
+		}
+		_ = s.redis.Set(ctx, cacheKey, entry, 24*time.Hour)
+	}
+
+	return resp.StatusCode, respHeaders, respBody, nil
+}