Added the subscription validator for in app billing

playstore/validator.go

@@ -0,0 +1,127 @@
+package playstore
+
+import (
+	"errors"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"code.google.com/p/goauth2/oauth"
+	"code.google.com/p/google-api-go-client/androidpublisher/v2"
+)
+
+const (
+	scope    = "https://www.googleapis.com/auth/androidpublisher"
+	authURL  = "https://accounts.google.com/o/oauth2/auth"
+	tokenURL = "https://accounts.google.com/o/oauth2/token"
+
+	timeout = time.Second * 5
+)
+
+var defaultConfig *oauth.Config
+var defaultTimeout = timeout
+
+// Init initializes the global configuration
+func Init() error {
+	defaultConfig = &oauth.Config{
+		Scope:    scope,
+		AuthURL:  authURL,
+		TokenURL: tokenURL,
+	}
+
+	clientID := os.Getenv("IAB_CLIENT_ID")
+	if clientID != "" {
+		defaultConfig.ClientId = clientID
+	}
+	if defaultConfig.ClientId == "" {
+		return errors.New("Client ID is required")
+	}
+
+	clientSecret := os.Getenv("IAB_CLIENT_SECRET")
+	if clientSecret != "" {
+		defaultConfig.ClientSecret = clientSecret
+	}
+	if defaultConfig.ClientSecret == "" {
+		return errors.New("Client Secret Key is required")
+	}
+
+	return nil
+}
+
+// InitWithConfig initializes the global configuration with parameters
+func InitWithConfig(config *oauth.Config) error {
+	if config.ClientId == "" {
+		return errors.New("Client ID is required")
+	}
+
+	if config.ClientSecret == "" {
+		return errors.New("Client Secret Key is required")
+	}
+
+	if config.Scope == "" {
+		config.Scope = scope
+	}
+
+	if config.AuthURL == "" {
+		config.AuthURL = authURL
+	}
+
+	if config.TokenURL == "" {
+		config.TokenURL = tokenURL
+	}
+
+	defaultConfig = config
+
+	return nil
+}
+
+// SetTimeout sets dial timeout duration
+func SetTimeout(t time.Duration) {
+	defaultTimeout = t
+}
+
+// The IABClient type is an interface to verify purchase token
+type IABClient interface {
+	VerifySubscription(string, string, string) (*androidpublisher.SubscriptionPurchase, error)
+}
+
+// The Client type implements VerifySubscription method
+type Client struct {
+	httpClient *http.Client
+}
+
+// New returns http client which has oauth token
+func New(token *oauth.Token) Client {
+	t := &oauth.Transport{
+		Token:  token,
+		Config: defaultConfig,
+		Transport: &http.Transport{
+			Dial: dialTimeout,
+		},
+	}
+
+	httpClient := t.Client()
+	return Client{httpClient}
+}
+
+// VerifySubscription Verifies subscription status
+func (c *Client) VerifySubscription(
+	packageName string,
+	subscriptionID string,
+	token string,
+) (*androidpublisher.SubscriptionPurchase, error) {
+	service, err := androidpublisher.New(c.httpClient)
+	if err != nil {
+		return nil, err
+	}
+
+	ps := androidpublisher.NewPurchasesSubscriptionsService(service)
+	result, err := ps.Get(packageName, subscriptionID, token).Do()
+
+	return result, err
+}
+
+func dialTimeout(network, addr string) (net.Conn, error) {
+	return net.DialTimeout(network, addr, defaultTimeout)
+}