Support iOS 12 Critical Alerts (#113)

* Support sound dictionaries for critical alerts

payload/builder.go

@@ -16,7 +16,7 @@ type aps struct {
 	Category         string      `json:"category,omitempty"`
 	ContentAvailable int         `json:"content-available,omitempty"`
 	MutableContent   int         `json:"mutable-content,omitempty"`
-	Sound            string      `json:"sound,omitempty"`
+	Sound            interface{} `json:"sound,omitempty"`
 	ThreadID         string      `json:"thread-id,omitempty"`
 	URLArgs          []string    `json:"url-args,omitempty"`
 }
@@ -34,6 +34,12 @@ type alert struct {
 	TitleLocKey  string   `json:"title-loc-key,omitempty"`
 }
 
+type sound struct {
+	Critical int     `json:"critical,omitempty"`
+	Name     string  `json:"name,omitempty"`
+	Volume   float32 `json:"volume,omitempty"`
+}
+
 // NewPayload returns a new Payload struct
 func NewPayload() *Payload {
 	return &Payload{
@@ -84,7 +90,7 @@ func (p *Payload) UnsetBadge() *Payload {
 // This will play a sound from the app bundle, or the default sound otherwise.
 //
 //	{"aps":{"sound":sound}}
-func (p *Payload) Sound(sound string) *Payload {
+func (p *Payload) Sound(sound interface{}) *Payload {
 	p.aps().Sound = sound
 	return p
 }
@@ -274,6 +280,26 @@ func (p *Payload) URLArgs(urlArgs []string) *Payload {
 	return p
 }
 
+// SoundName sets the name value on the aps sound dictionary.
+// This function makes the notification a critical alert, which should be pre-approved by Apple.
+// See: https://developer.apple.com/contact/request/notifications-critical-alerts-entitlement/
+//
+// {"aps":{"sound":{"critical":1,"name":name,"volume":1.0}}}
+func (p *Payload) SoundName(name string) *Payload {
+	p.aps().sound().Name = name
+	return p
+}
+
+// SoundVolume sets the volume value on the aps sound dictionary.
+// This function makes the notification a critical alert, which should be pre-approved by Apple.
+// See: https://developer.apple.com/contact/request/notifications-critical-alerts-entitlement/
+//
+// {"aps":{"sound":{"critical":1,"name":"default","volume":volume}}}
+func (p *Payload) SoundVolume(volume float32) *Payload {
+	p.aps().sound().Volume = volume
+	return p
+}
+
 // MarshalJSON returns the JSON encoded version of the Payload
 func (p *Payload) MarshalJSON() ([]byte, error) {
 	return json.Marshal(p.content)
@@ -289,3 +315,10 @@ func (a *aps) alert() *alert {
 	}
 	return a.Alert.(*alert)
 }
+
+func (a *aps) sound() *sound {
+	if _, ok := a.Sound.(*sound); !ok {
+		a.Sound = &sound{Critical: 1, Name: "default", Volume: 1.0}
+	}
+	return a.Sound.(*sound)
+}

payload/builder_test.go

@@ -44,6 +44,16 @@ func TestSound(t *testing.T) {
 	assert.Equal(t, `{"aps":{"sound":"Default.caf"}}`, string(b))
 }
 
+func TestSoundDictionary(t *testing.T) {
+	payload := NewPayload().Sound(map[string]interface{}{
+		"critical": 1,
+		"name":     "default",
+		"volume":   0.8,
+	})
+	b, _ := json.Marshal(payload)
+	assert.Equal(t, `{"aps":{"sound":{"critical":1,"name":"default","volume":0.8}}}`, string(b))
+}
+
 func TestContentAvailable(t *testing.T) {
 	payload := NewPayload().ContentAvailable()
 	b, _ := json.Marshal(payload)
@@ -154,6 +164,18 @@ func TestURLArgs(t *testing.T) {
 	assert.Equal(t, `{"aps":{"url-args":["a","b"]}}`, string(b))
 }
 
+func TestSoundName(t *testing.T) {
+	payload := NewPayload().SoundName("test")
+	b, _ := json.Marshal(payload)
+	assert.Equal(t, `{"aps":{"sound":{"critical":1,"name":"test","volume":1}}}`, string(b))
+}
+
+func TestSoundVolume(t *testing.T) {
+	payload := NewPayload().SoundVolume(0.5)
+	b, _ := json.Marshal(payload)
+	assert.Equal(t, `{"aps":{"sound":{"critical":1,"name":"default","volume":0.5}}}`, string(b))
+}
+
 func TestCombined(t *testing.T) {
 	payload := NewPayload().Alert("hello").Badge(1).Sound("Default.caf").Custom("key", "val")
 	b, _ := json.Marshal(payload)