Fix bugs with delivering messages.

This was uncovered during writing tests where both the Social and
Federative APIs are enabled. The actorObject interface was overused
partially due to my earlier confusion; the introduction of the internal
actor interface resolved this.

Finally, the HttpClient interface was introduced to be able to mock out
calls in testing. It may also prove useful for future applications using
this library.

pub/fed.go

@@ -66,7 +66,7 @@ func NewSocialPubber(clock Clock, app Application, socialApp SocialApp, cb Callb
 // servers. All are required unless explicitly stated otherwise.
 type DeliveryOptions struct {
 	// Client to use when sending http requests to federating peers.
-	Client *http.Client
+	Client HttpClient
 	// Agent string to send in http requests.
 	Agent string
 	// Maximum unnesting done when determining who to send messages to. Must
@@ -110,7 +110,7 @@ func NewFederatingPubber(clock Clock, app Application, fApp FederateApp, cb Call
 
 // NewPubber provides a Pubber that implements both the Social API and the
 // Federating API in ActivityPub.
-func NewPubber(clock Clock, app Application, sApp SocialApp, fApp FederateApp, server, client Callbacker, d DeliveryOptions) Pubber {
+func NewPubber(clock Clock, app Application, sApp SocialApp, fApp FederateApp, client, server Callbacker, d DeliveryOptions) Pubber {
 	return &federator{
 		Clock:            clock,
 		App:              app,
@@ -151,7 +151,7 @@ type federator struct {
 	// Client is used to federate with other ActivityPub servers.
 	//
 	// It is only required if EnableServer is true.
-	Client *http.Client
+	Client HttpClient
 	// Agent is the User-Agent string to use in HTTP headers when
 	// federating with another server. It will automatically be appended
 	// with '(go-fed ActivityPub)'.

pub/interfaces.go

@@ -25,6 +25,11 @@ type Clock interface {
 	Now() time.Time
 }
 
+// HttpClient sends http requests.
+type HttpClient interface {
+	Do(req *http.Request) (*http.Response, error)
+}
+
 // Application is provided by users of this library in order to implement a
 // social-federative-web application.
 //
@@ -184,6 +189,13 @@ type typeIder interface {
 	Serialize() (m map[string]interface{}, e error)
 }
 
+// actor is an object that is an ActivityPub Actor. The specification is more
+// strict than what we include here, only for our internal use.
+type actor interface {
+	HasInbox() (ok bool)
+	GetInbox() (v url.URL)
+}
+
 // actorObject is an object that has "actor" or "attributedTo" properties,
 // representing the author or originator of the object.
 type actorObject interface {

pub/internal.go

@@ -63,7 +63,7 @@ func isPublic(s string) bool {
 
 // dereference makes an HTTP GET request to an IRI in order to obtain the
 // ActivityStream representation.
-func dereference(c *http.Client, u url.URL, agent string) ([]byte, error) {
+func dereference(c HttpClient, u url.URL, agent string) ([]byte, error) {
 	// TODO: (section 7.1) The server MUST dereference the collection (with the user's credentials)
 	req, err := http.NewRequest("GET", u.String(), nil)
 	if err != nil {
@@ -86,7 +86,7 @@ func dereference(c *http.Client, u url.URL, agent string) ([]byte, error) {
 
 // postToOutbox will attempt to send a POST request to the given URL with the
 // body set to the provided bytes.
-func postToOutbox(c *http.Client, b []byte, to url.URL, agent string) error {
+func postToOutbox(c HttpClient, b []byte, to url.URL, agent string) error {
 	byteCopy := make([]byte, 0, len(b))
 	copy(b, byteCopy)
 	buf := bytes.NewBuffer(byteCopy)
@@ -234,11 +234,11 @@ func (c *federator) prepare(o deliverableObject) ([]url.URL, error) {
 // resolveInboxes takes a list of Actor id URIs and returns them as concrete
 // instances of actorObject. It applies recursively when it encounters a target
 // that is a Collection or OrderedCollection.
-func (c *federator) resolveInboxes(r []url.URL, depth int, max int) ([]actorObject, error) {
+func (c *federator) resolveInboxes(r []url.URL, depth int, max int) ([]actor, error) {
 	if depth >= max {
 		return nil, nil
 	}
-	a := make([]actorObject, 0, len(r))
+	a := make([]actor, 0, len(r))
 	for _, u := range r {
 		// Do not retry here -- if a dereference fails, then fail the
 		// entire delivery.
@@ -250,7 +250,7 @@ func (c *federator) resolveInboxes(r []url.URL, depth int, max int) ([]actorObje
 		if err = json.Unmarshal(resp, &m); err != nil {
 			return nil, err
 		}
-		var actor actorObject
+		var actor actor
 		var co *streams.Collection
 		var oc *streams.OrderedCollection
 		var cp *streams.CollectionPage
@@ -314,7 +314,7 @@ func (c *federator) resolveInboxes(r []url.URL, depth int, max int) ([]actorObje
 }
 
 // getInboxes extracts the 'inbox' IRIs from actors.
-func getInboxes(a []actorObject) []url.URL {
+func getInboxes(a []actor) []url.URL {
 	var u []url.URL
 	for _, actor := range a {
 		if actor.HasInbox() {
@@ -393,9 +393,10 @@ func dedupeIRIs(recipients, ignored []url.URL) (out []url.URL) {
 		ignoredMap[elem] = true
 	}
 	outMap := make(map[url.URL]bool, len(recipients))
-	for k, _ := range outMap {
-		if !ignoredMap[k] {
+	for _, k := range recipients {
+		if !ignoredMap[k] && !outMap[k] {
 			out = append(out, k)
+			outMap[k] = true
 		}
 	}
 	return
@@ -559,7 +560,7 @@ func getAudienceIRIs(o deliverableObject) []url.URL {
 
 // doForCollectionPage applies a function over a collection and its subsequent
 // pages recursively. It returns the first non-nil error it encounters.
-func doForCollectionPage(h *http.Client, agent string, cb func(c vocab.CollectionPageType) error, c vocab.CollectionPageType) error {
+func doForCollectionPage(h HttpClient, agent string, cb func(c vocab.CollectionPageType) error, c vocab.CollectionPageType) error {
 	err := cb(c)
 	if err != nil {
 		return err
@@ -614,7 +615,7 @@ func doForCollectionPage(h *http.Client, agent string, cb func(c vocab.Collectio
 // doForOrderedCollectionPage applies a function over a collection and its
 // subsequent pages recursively. It returns the first non-nil error it
 // encounters.
-func doForOrderedCollectionPage(h *http.Client, agent string, cb func(c vocab.OrderedCollectionPageType) error, c vocab.OrderedCollectionPageType) error {
+func doForOrderedCollectionPage(h HttpClient, agent string, cb func(c vocab.OrderedCollectionPageType) error, c vocab.OrderedCollectionPageType) error {
 	err := cb(c)
 	if err != nil {
 		return err

pub/resolvers.go

@@ -37,11 +37,11 @@ func ToPubObject(m map[string]interface{}) (t []PubObject, e error) {
 
 func getActorObject(m map[string]interface{}) (actorObject, error) {
 	var a actorObject
-	err := toActorResolver(&a).Deserialize(m)
+	err := toActorObjectResolver(&a).Deserialize(m)
 	return a, err
 }
 
-func toActorResolver(a *actorObject) *streams.Resolver {
+func toActorObjectResolver(a *actorObject) *streams.Resolver {
 	return &streams.Resolver{
 		AnyObjectCallback: func(i vocab.ObjectType) error {
 			if o, ok := i.(actorObject); ok {
@@ -52,7 +52,18 @@ func toActorResolver(a *actorObject) *streams.Resolver {
 	}
 }
 
-func toActorCollectionResolver(a *actorObject, c **streams.Collection, oc **streams.OrderedCollection, cp **streams.CollectionPage, ocp **streams.OrderedCollectionPage) *streams.Resolver {
+func toActorResolver(a *actor) *streams.Resolver {
+	return &streams.Resolver{
+		AnyObjectCallback: func(i vocab.ObjectType) error {
+			if o, ok := i.(actor); ok {
+				*a = o
+			}
+			return nil
+		},
+	}
+}
+
+func toActorCollectionResolver(a *actor, c **streams.Collection, oc **streams.OrderedCollection, cp **streams.CollectionPage, ocp **streams.OrderedCollectionPage) *streams.Resolver {
 	r := toActorResolver(a)
 	r.CollectionCallback = func(i *streams.Collection) error {
 		*c = i