Added ToX functions for Collection types

go.mod

@@ -2,6 +2,6 @@ module github.com/go-ap/activitypub
 
 require (
 	github.com/buger/jsonparser v0.0.0-20181023193515-52c6e1462ebd
-	github.com/go-ap/activitystreams v0.0.0-20190820195421-bd2f80c09306
+	github.com/go-ap/activitystreams v0.0.0-20190821202132-4a1645657eaa
 	github.com/go-ap/jsonld v0.0.0-20190630153951-3e340483bd9f
 )

helpers.go

@@ -11,6 +11,10 @@ type withActivityFn func (*activitystreams.Activity) error
 type withIntransitiveActivityFn func (*activitystreams.IntransitiveActivity) error
 type withQuestionFn func (*activitystreams.Question) error
 type withPersonFn func (*Person) error
+type withCollectionFn func (*activitystreams.Collection) error
+type withCollectionPageFn func (*activitystreams.CollectionPage) error
+type withOrderedCollectionFn func (*activitystreams.OrderedCollection) error
+type withOrderedCollectionPageFn func (*activitystreams.OrderedCollectionPage) error
 
 // OnObject
 func OnObject(it activitystreams.Item, fn withObjectFn) error {
@@ -74,3 +78,51 @@ func OnPerson(it activitystreams.Item, fn withPersonFn) error {
 	}
 	return fn(pers)
 }
+
+// OnCollection
+func OnCollection(it activitystreams.Item, fn withCollectionFn) error {
+	if it.GetType() != activitystreams.CollectionType {
+		return errors.New(fmt.Sprintf("%T[%s] can't be converted to Collection", it, it.GetType()))
+	}
+	col, err  := activitystreams.ToCollection(it)
+	if err != nil {
+		return err
+	}
+	return fn(col)
+}
+
+// OnCollectionPage
+func OnCollectionPage(it activitystreams.Item, fn withCollectionPageFn) error {
+	if it.GetType() != activitystreams.CollectionPageType {
+		return errors.New(fmt.Sprintf("%T[%s] can't be converted to Collection Page", it, it.GetType()))
+	}
+	col, err  := activitystreams.ToCollectionPage(it)
+	if err != nil {
+		return err
+	}
+	return fn(col)
+}
+
+// OnOrderedCollection
+func OnOrderedCollection(it activitystreams.Item, fn withOrderedCollectionFn) error {
+	if it.GetType() != activitystreams.OrderedCollectionType {
+		return errors.New(fmt.Sprintf("%T[%s] can't be converted to OrderedCollection", it, it.GetType()))
+	}
+	col, err  := activitystreams.ToOrderedCollection(it)
+	if err != nil {
+		return err
+	}
+	return fn(col)
+}
+
+// OnOrderedCollectionPage
+func OnOrderedCollectionPage(it activitystreams.Item, fn withOrderedCollectionPageFn) error {
+	if it.GetType() != activitystreams.OrderedCollectionPageType {
+		return errors.New(fmt.Sprintf("%T[%s] can't be converted to OrderedCollection Page", it, it.GetType()))
+	}
+	col, err  := activitystreams.ToOrderedCollectionPage(it)
+	if err != nil {
+		return err
+	}
+	return fn(col)
+}

helpers_test.go

@@ -129,3 +129,19 @@ func TestOnPerson(t *testing.T) {
 		t.Errorf("Unexpected error returned %s", err)
 	}
 }
+
+func TestOnCollection(t *testing.T) {
+	t.Skipf("TODO")
+}
+
+func TestOnCollectionPage(t *testing.T) {
+	t.Skipf("TODO")
+}
+
+func TestOnOrderedCollection(t *testing.T) {
+	t.Skipf("TODO")
+}
+
+func TestOnOrderedCollectionPage(t *testing.T) {
+	t.Skipf("TODO")
+}