feat(fcm): Support Proxy field in FCM AndroidNotification (#676)

* [chore] Release 4.12.0 (#561)

- Release 4.12.0

* Revert "[chore] Release 4.12.0 (#561)" (#565)

This reverts commit 32af2b8.

* Modifying the messaging package
- Adding Proxy Fields to AndroidNotification Struct

* fix the lint errors

* add tests to verify

* fix AndroidNotificationProxy unmarshalling problem

---------

Co-authored-by: Google Open Source Bot <[email protected]>
Co-authored-by: Lahiru Maramba <[email protected]>
Co-authored-by: Google Open Source Bot <[email protected]>

Author: 3 people

messaging/messaging.go

@@ -191,6 +191,7 @@ type AndroidNotification struct {
 	DefaultLightSettings  bool                          `json:"default_light_settings,omitempty"`
 	Visibility            AndroidNotificationVisibility `json:"-"`
 	NotificationCount     *int                          `json:"notification_count,omitempty"`
+	Proxy                 AndroidNotificationProxy      `json:"-"`
 }
 
 // MarshalJSON marshals an AndroidNotification into JSON (for internal use only).
@@ -217,6 +218,16 @@ func (a *AndroidNotification) MarshalJSON() ([]byte, error) {
 		visibility, _ = visibilities[a.Visibility]
 	}
 
+	var proxy string
+	if a.Proxy != proxyUnspecified {
+		proxies := map[AndroidNotificationProxy]string{
+			ProxyAllow:             "ALLOW",
+			ProxyDeny:              "DENY",
+			ProxyIfPriorityLowered: "IF_PRIORITY_LOWERED",
+		}
+		proxy, _ = proxies[a.Proxy]
+	}
+
 	var timestamp string
 	if a.EventTimestamp != nil {
 		timestamp = a.EventTimestamp.UTC().Format(rfc3339Zulu)
@@ -232,12 +243,14 @@ func (a *AndroidNotification) MarshalJSON() ([]byte, error) {
 		EventTimestamp string   `json:"event_time,omitempty"`
 		Priority       string   `json:"notification_priority,omitempty"`
 		Visibility     string   `json:"visibility,omitempty"`
+		Proxy          string   `json:"proxy,omitempty"`
 		VibrateTimings []string `json:"vibrate_timings,omitempty"`
 		*androidInternal
 	}{
 		EventTimestamp:  timestamp,
 		Priority:        priority,
 		Visibility:      visibility,
+		Proxy:           proxy,
 		VibrateTimings:  vibTimings,
 		androidInternal: (*androidInternal)(a),
 	}
@@ -251,6 +264,7 @@ func (a *AndroidNotification) UnmarshalJSON(b []byte) error {
 		EventTimestamp string   `json:"event_time,omitempty"`
 		Priority       string   `json:"notification_priority,omitempty"`
 		Visibility     string   `json:"visibility,omitempty"`
+		Proxy          string   `json:"proxy,omitempty"`
 		VibrateTimings []string `json:"vibrate_timings,omitempty"`
 		*androidInternal
 	}{
@@ -288,6 +302,19 @@ func (a *AndroidNotification) UnmarshalJSON(b []byte) error {
 		}
 	}
 
+	if temp.Proxy != "" {
+		proxies := map[string]AndroidNotificationProxy{
+			"ALLOW":               ProxyAllow,
+			"DENY":                ProxyDeny,
+			"IF_PRIORITY_LOWERED": ProxyIfPriorityLowered,
+		}
+		if prox, ok := proxies[temp.Proxy]; ok {
+			a.Proxy = prox
+		} else {
+			return fmt.Errorf("unknown proxy value: %q", temp.Proxy)
+		}
+	}
+
 	if temp.EventTimestamp != "" {
 		ts, err := time.Parse(rfc3339Zulu, temp.EventTimestamp)
 		if err != nil {
@@ -356,6 +383,23 @@ const (
 	VisibilitySecret
 )
 
+// AndroidNotificationProxy to control when a notification may be proxied.
+type AndroidNotificationProxy int
+
+const (
+	proxyUnspecified AndroidNotificationProxy = iota
+
+	// ProxyAllow tries to proxy this notification.
+	ProxyAllow
+
+	// ProxyDeny does not proxy this notification.
+	ProxyDeny
+
+	// ProxyIfPriorityLowered only tries to proxy this notification if its AndroidConfig's Priority was
+	// lowered from high to normal on the device.
+	ProxyIfPriorityLowered
+)
+
 // LightSettings to control notification LED.
 type LightSettings struct {
 	Color                  string

messaging/messaging_test.go

@@ -683,6 +683,63 @@ var validMessages = []struct {
 			"topic": "test-topic",
 		},
 	},
+	{
+		name: "AndroidNotificationProxyAllow",
+		req: &Message{
+			Android: &AndroidConfig{
+				Notification: &AndroidNotification{
+					Proxy: ProxyAllow,
+				},
+			},
+			Topic: "test-topic",
+		},
+		want: map[string]interface{}{
+			"android": map[string]interface{}{
+				"notification": map[string]interface{}{
+					"proxy": "ALLOW",
+				},
+			},
+			"topic": "test-topic",
+		},
+	},
+	{
+		name: "AndroidNotificationProxyDeny",
+		req: &Message{
+			Android: &AndroidConfig{
+				Notification: &AndroidNotification{
+					Proxy: ProxyDeny,
+				},
+			},
+			Topic: "test-topic",
+		},
+		want: map[string]interface{}{
+			"android": map[string]interface{}{
+				"notification": map[string]interface{}{
+					"proxy": "DENY",
+				},
+			},
+			"topic": "test-topic",
+		},
+	},
+	{
+		name: "AndroidNotificationProxyIfPriorityLowered",
+		req: &Message{
+			Android: &AndroidConfig{
+				Notification: &AndroidNotification{
+					Proxy: ProxyIfPriorityLowered,
+				},
+			},
+			Topic: "test-topic",
+		},
+		want: map[string]interface{}{
+			"android": map[string]interface{}{
+				"notification": map[string]interface{}{
+					"proxy": "IF_PRIORITY_LOWERED",
+				},
+			},
+			"topic": "test-topic",
+		},
+	},
 }
 
 var invalidMessages = []struct {