Merge pull request #8 from pusher/handle-invalid-token-resp

Handle invalid token response from google

fcm.go

@@ -82,10 +82,28 @@ func (c *fcmClient) GetInstanceInfo(token string) (*InstanceInformationResponse,
 	defer response.Body.Close()
 
 	switch response.StatusCode {
+	case 400:
+		errorResponseBytes, err := io.ReadAll(response.Body)
+		if err != nil {
+			return nil, fmt.Errorf("unable to read response from google: %w", err)
+		}
+
+		errorBody := ErrorResponse{}
+		err = json.Unmarshal(errorResponseBytes, &errorBody)
+		if err != nil {
+			return nil, fmt.Errorf("unable to read response from google: %w", err)
+		}
+
+		if errorBody.Error == "InvalidToken" {
+			return nil, ErrInvalidToken
+		}
+
+		return nil, ErrInvalidRequest
+
 	case 401, 403:
-		return nil, fmt.Errorf("invalid FCM Service Account File")
+		return nil, ErrInalidFCMServiceAccountFile
 	case 404:
-		return nil, fmt.Errorf("device not found")
+		return nil, ErrDeviceNotFound
 	}
 
 	if response.StatusCode > 299 {

gcm_test.go

@@ -92,7 +92,7 @@ type stubHttpClient struct {
 	Requests      []string
 }
 
-func (c *stubHttpClient) send(apiKey string, message HttpMessage) (*HttpResponse, error) {
+func (c *stubHttpClient) send(ctx context.Context, apiKey string, message HttpMessage) (*HttpResponse, error) {
 	response := &HttpResponse{}
 	err := json.Unmarshal([]byte(multicastReply[c.InvocationNum]), &response)
 	c.InvocationNum++

requests.go

@@ -1,5 +1,16 @@
 package googlemessaging
 
+import (
+	"errors"
+)
+
+var (
+	ErrInvalidToken                = errors.New("invalid token")
+	ErrDeviceNotFound              = errors.New("device not found")
+	ErrInvalidRequest              = errors.New("invalid request")
+	ErrInalidFCMServiceAccountFile = errors.New("invalid fcm service account file")
+)
+
 type FcmMessageBody struct {
 	Message *FcmHttpMessage `json:"message"`
 }
@@ -52,3 +63,7 @@ type FcmSendHttpResponse struct {
 type InstanceInformationResponse struct {
 	AuthorizedEntity string `json:"authorizedEntity"`
 }
+
+type ErrorResponse struct {
+	Error string `json:"error"`
+}