Add cache for abbreviated city names

flights/city.go

@@ -58,6 +58,10 @@ func decodeInnerObject(body *bufio.Reader) ([][][][]interface{}, error) {
 }
 
 func (s *Session) AbbrCity(city string, lang language.Tag) (string, error) {
+	if abbrCity, ok := s.Cities.Load(city); ok {
+		return abbrCity, nil
+	}
+
 	resp, err := s.doRequestCity(city, lang)
 	if err != nil {
 		return "", err
@@ -95,6 +99,8 @@ func (s *Session) AbbrCity(city string, lang language.Tag) (string, error) {
 		return "", fmt.Errorf("the requested city name didn't match the found. requested: %s found: %s", city, foundCity)
 	}
 
+	s.Cities.Store(city, serializedCity)
+
 	return serializedCity, nil
 }
 

flights/city_test.go

@@ -88,7 +88,7 @@ func TestAbbrCity(t *testing.T) {
 	)
 
 	session := &Session{
-		httpClientMock,
+		client: httpClientMock,
 	}
 
 	cityA := "Athens"

flights/price_graph_test.go

@@ -47,7 +47,7 @@ func TestGetPriceGraph(t *testing.T) {
 	)
 
 	session := &Session{
-		httpClientMock,
+		client: httpClientMock,
 	}
 
 	offers, err := session.GetPriceGraph(time.Now().AddDate(0, 0, 2), time.Now().AddDate(0, 0, 5), 0, "Athens", "Warsaw", currency.PLN, language.English)

flights/session.go

@@ -2,19 +2,37 @@ package flights
 
 import (
 	"net/http"
+	"sync"
 	"time"
 )
 
-type Client interface {
+type Map[K comparable, V any] struct {
+	m sync.Map
+}
+
+func (m *Map[K, V]) Load(key K) (value V, ok bool) {
+	v, ok := m.m.Load(key)
+	if !ok {
+		return value, ok
+	}
+	return v.(V), ok
+}
+
+func (m *Map[K, V]) Store(key K, value V) { m.m.Store(key, value) }
+
+type HttpClient interface {
 	Do(req *http.Request) (*http.Response, error)
 }
 
 type Session struct {
-	client Client
+	Cities Map[string, string]
+
+	client HttpClient
 }
 
 func New() *Session {
 	return &Session{
+		Cities: Map[string, string]{},
 		client: &http.Client{
 			Timeout: 30 * time.Second,
 		},