add domain whois/dns support, refactor codebase

internal/server/router.go

@@ -0,0 +1,64 @@
+package server
+
+import (
+	"net"
+	"net/http"
+	"strings"
+
+	"ipinfo/internal/db"
+	"ipinfo/utils"
+)
+
+// newRouter creates the main request router and applies middleware.
+func newRouter(geoIP *db.GeoIPManager) http.Handler {
+	mux := http.NewServeMux()
+
+	// Register handlers
+	mux.Handle("/health", utils.HealthCheck())
+	mux.HandleFunc("/favicon.ico", faviconHandler)
+	mux.HandleFunc("/", rootHandler(geoIP))
+
+	// Chain middleware
+	var handler http.Handler = mux
+	handler = loggingMiddleware(handler)
+
+	return handler
+}
+
+// rootHandler is the main routing logic that inspects the path.
+func rootHandler(geoIP *db.GeoIPManager) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		// Apply gzip compression where accepted
+		w = newGzipResponseWriter(w, r)
+		if gw, ok := w.(gzipResponseWriter); ok {
+			defer gw.Close()
+		}
+
+		path := strings.Trim(r.URL.Path, "/")
+		parts := strings.Split(path, "/")
+		firstPart := ""
+		if len(parts) > 0 {
+			firstPart = parts[0]
+		}
+
+		// Route to ASN handler
+		if strings.HasPrefix(strings.ToLower(firstPart), "as") {
+			handleASNLookup(w, r, path, geoIP)
+			return
+		}
+
+		// Route to Domain handler
+		isDomain := strings.Contains(firstPart, ".") && net.ParseIP(firstPart) == nil && firstPart != ""
+		if isDomain {
+			if len(parts) > 1 {
+				sendJSONError(w, "Invalid request for domain. Field lookups are not supported.", http.StatusBadRequest)
+				return
+			}
+			handleDomainLookup(w, r, firstPart)
+			return
+		}
+
+		// Default to IP handler
+		handleIPLookup(w, r, path, geoIP)
+	}
+}