add collapse id for notification management (#68)

ref #62

push/header.go

@@ -12,6 +12,10 @@ type Headers struct {
 	// This should be a UUID with 32 lowercase hexadecimal digits.
 	ID string
 
+	// CollapseID is used to update an existing notification that has the same
+	// identifier (Notification Management in iOS 10).
+	CollapseID string
+
 	// Apple will retry delivery until this time. The default behavior only tries once.
 	Expiration time.Time
 
@@ -34,6 +38,10 @@ func (h *Headers) set(reqHeader http.Header) {
 		reqHeader.Set("apns-id", h.ID)
 	} // when omitted, Apple will generate a UUID for you
 
+	if h.CollapseID != "" {
+		reqHeader.Set("apns-collapse-id", h.CollapseID)
+	}
+
 	if !h.Expiration.IsZero() {
 		reqHeader.Set("apns-expiration", strconv.FormatInt(h.Expiration.Unix(), 10))
 	}

push/header_test.go

@@ -9,6 +9,7 @@ import (
 func TestHeaders(t *testing.T) {
 	headers := Headers{
 		ID:          "uuid",
+		CollapseID:  "game1.score.identifier",
 		Expiration:  time.Unix(12622780800, 0),
 		LowPriority: true,
 		Topic:       "bundle-id",
@@ -18,6 +19,7 @@ func TestHeaders(t *testing.T) {
 	headers.set(reqHeader)
 
 	testHeader(t, reqHeader, "apns-id", "uuid")
+	testHeader(t, reqHeader, "apns-collapse-id", "game1.score.identifier")
 	testHeader(t, reqHeader, "apns-expiration", "12622780800")
 	testHeader(t, reqHeader, "apns-priority", "5")
 	testHeader(t, reqHeader, "apns-topic", "bundle-id")
@@ -29,6 +31,7 @@ func TestNilHeader(t *testing.T) {
 	headers.set(reqHeader)
 
 	testHeader(t, reqHeader, "apns-id", "")
+	testHeader(t, reqHeader, "apns-collapse-id", "")
 	testHeader(t, reqHeader, "apns-expiration", "")
 	testHeader(t, reqHeader, "apns-priority", "")
 	testHeader(t, reqHeader, "apns-topic", "")
@@ -40,6 +43,7 @@ func TestEmptyHeaders(t *testing.T) {
 	headers.set(reqHeader)
 
 	testHeader(t, reqHeader, "apns-id", "")
+	testHeader(t, reqHeader, "apns-collapse-id", "")
 	testHeader(t, reqHeader, "apns-expiration", "")
 	testHeader(t, reqHeader, "apns-priority", "")
 	testHeader(t, reqHeader, "apns-topic", "")