[feature] Support new model of interaction flow for forward compat with v0.21.0 (#4394)

~~Still WIP!~~

This PR allows v0.20.0 of GtS to be forward-compatible with the interaction request / authorization flow that will fully replace the current flow in v0.21.0.

Basically, this means we need to recognize LikeRequest, ReplyRequest, and AnnounceRequest, and in response to those requests, deliver either a Reject or an Accept, with the latter pointing towards a LikeAuthorization, ReplyAuthorization, or AnnounceAuthorization, respectively. This can then be used by the remote instance to prove to third parties that the interaction has been accepted by the interactee. These Authorization types need to be dereferencable to third parties, so we need to serve them.

As well as recognizing the above "polite" interaction request types, we also need to still serve appropriate responses to "impolite" interaction request types, where an instance that's unaware of interaction policies tries to interact with a post by sending a reply, like, or boost directly, without wrapping it in a WhateverRequest type.

Doesn't fully close https://codeberg.org/superseriousbusiness/gotosocial/issues/4026 but gets damn near (just gotta update the federating with GtS documentation).

Migrations tested on both Postgres and SQLite.

Co-authored-by: kim <grufwub@gmail.com>
Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4394
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

internal/ap/interfaces.go

@@ -143,13 +143,13 @@ func ToAcceptable(t vocab.Type) (Acceptable, bool) {
 	return acceptable, true
 }
 
-// IsApprovable returns whether AS vocab type name
-// is something that can be cast to Approvable.
-func IsApprovable(typeName string) bool {
+// IsAuthorizationable returns whether AS vocab type name
+// is something that can be cast to Authorizationable.
+func IsAuthorizationable(typeName string) bool {
 	switch typeName {
-	case ObjectLikeApproval,
-		ObjectReplyApproval,
-		ObjectAnnounceApproval:
+	case ObjectLikeAuthorization,
+		ObjectReplyAuthorization,
+		ObjectAnnounceAuthorization:
 		return true
 	default:
 		return false
@@ -157,12 +157,12 @@ func IsApprovable(typeName string) bool {
 }
 
 // ToAcceptable safely tries to cast vocab.Type as Approvable.
-func ToApprovable(t vocab.Type) (Approvable, bool) {
-	approvable, ok := t.(Approvable)
-	if !ok || !IsApprovable(t.GetTypeName()) {
+func ToAuthorizationable(t vocab.Type) (Authorizationable, bool) {
+	authable, ok := t.(Authorizationable)
+	if !ok || !IsAuthorizationable(t.GetTypeName()) {
 		return nil, false
 	}
-	return approvable, true
+	return authable, true
 }
 
 // IsAttachmentable returns whether AS vocab type name
@@ -188,6 +188,36 @@ func ToAttachmentable(t vocab.Type) (Attachmentable, bool) {
 	return attachmentable, true
 }
 
+// IsAnnounceable returns whether AS vocab type name
+// is something that can be cast to vocab.ActivityStreamsAnnounce.
+func IsAnnounceable(typeName string) bool {
+	return typeName == ActivityAnnounce
+}
+
+// ToAnnounceable safely tries to cast vocab.Type as vocab.ActivityStreamsAnnounce.
+func ToAnnounceable(t vocab.Type) (vocab.ActivityStreamsAnnounce, bool) {
+	announceable, ok := t.(vocab.ActivityStreamsAnnounce)
+	if !ok || t.GetTypeName() != ActivityAnnounce {
+		return nil, false
+	}
+	return announceable, true
+}
+
+// IsLikeable returns whether AS vocab type name
+// is something that can be cast to vocab.ActivityStreamsLike.
+func IsLikeable(typeName string) bool {
+	return typeName == ActivityLike
+}
+
+// ToAnnouncToLikeableeable safely tries to cast vocab.Type as vocab.ActivityStreamsLike.
+func ToLikeable(t vocab.Type) (vocab.ActivityStreamsLike, bool) {
+	likeable, ok := t.(vocab.ActivityStreamsLike)
+	if !ok || t.GetTypeName() != ActivityLike {
+		return nil, false
+	}
+	return likeable, true
+}
+
 // Activityable represents the minimum activitypub interface for representing an 'activity'.
 // (see: IsActivityable() for types implementing this, though you MUST make sure to check
 // the typeName as this bare interface may be implementable by non-Activityable types).
@@ -258,11 +288,6 @@ type Statusable interface {
 	WithReplies
 }
 
-type InteractionPolicyAware interface {
-	WithInteractionPolicy
-	WithApprovedBy
-}
-
 // Pollable represents the minimum activitypub interface for representing a 'poll' (it's a subset of a status).
 // (see: IsPollable() for types implementing this, though you MUST make sure to check
 // the typeName as this bare interface may be implementable by non-Pollable types).
@@ -299,14 +324,14 @@ type Acceptable interface {
 	WithResult
 }
 
-// Approvable represents the minimum activitypub interface
-// for a LikeApproval, ReplyApproval, or AnnounceApproval.
-type Approvable interface {
+// Authorizationable represents the minimum interface for a
+// LikeAuthorization, ReplyAuthorization, AnnounceAuthorization.
+type Authorizationable interface {
 	vocab.Type
 
 	WithAttributedTo
-	WithObject
-	WithTarget
+	WithInteractingObject
+	WithInteractionTarget
 }
 
 // Attachmentable represents the minimum activitypub interface for representing a 'mediaAttachment'. (see: IsAttachmentable).
@@ -392,6 +417,16 @@ type ReplyToable interface {
 	WithInReplyTo
 }
 
+// InteractionRequestable represents the minimum interface for an interaction request
+// activity, eg., LikeRequest, ReplyRequest, AnnounceRequest, QuoteRequest, etc..
+type InteractionRequestable interface {
+	vocab.Type
+
+	WithActor
+	WithObject
+	WithInstrument
+}
+
 // CollectionIterator represents the minimum interface for interacting with a
 // wrapped Collection or OrderedCollection in order to access next / prev items.
 type CollectionIterator interface {
@@ -683,6 +718,12 @@ type WithObject interface {
 	SetActivityStreamsObject(vocab.ActivityStreamsObjectProperty)
 }
 
+// WithInstrument represents an activity with ActivityStreamsInstrumentProperty
+type WithInstrument interface {
+	GetActivityStreamsInstrument() vocab.ActivityStreamsInstrumentProperty
+	SetActivityStreamsInstrument(vocab.ActivityStreamsInstrumentProperty)
+}
+
 // WithTarget represents an activity with ActivityStreamsTargetProperty
 type WithTarget interface {
 	GetActivityStreamsTarget() vocab.ActivityStreamsTargetProperty
@@ -775,14 +816,44 @@ type WithPolicyRules interface {
 	GetGoToSocialApprovalRequired() vocab.GoToSocialApprovalRequiredProperty // Deprecated
 }
 
-// WithApprovedBy represents a Statusable with the approvedBy property.
+// WithApprovedBy represents an object with the approvedBy property.
 type WithApprovedBy interface {
 	GetGoToSocialApprovedBy() vocab.GoToSocialApprovedByProperty
 	SetGoToSocialApprovedBy(vocab.GoToSocialApprovedByProperty)
 }
 
-// WithVotersCount represents an activity or object the result property.
+// WithLikeAuthorization represents a Likeable with the likeAuthorization property.
+type WithLikeAuthorization interface {
+	GetGoToSocialLikeAuthorization() vocab.GoToSocialLikeAuthorizationProperty
+	SetGoToSocialLikeAuthorization(vocab.GoToSocialLikeAuthorizationProperty)
+}
+
+// WithReplyAuthorization represents a statusable with the replyAuthorization property.
+type WithReplyAuthorization interface {
+	GetGoToSocialReplyAuthorization() vocab.GoToSocialReplyAuthorizationProperty
+	SetGoToSocialReplyAuthorization(vocab.GoToSocialReplyAuthorizationProperty)
+}
+
+// WithAnnounceAuthorization represents an Announceable with the announceAuthorization property.
+type WithAnnounceAuthorization interface {
+	GetGoToSocialAnnounceAuthorization() vocab.GoToSocialAnnounceAuthorizationProperty
+	SetGoToSocialAnnounceAuthorization(vocab.GoToSocialAnnounceAuthorizationProperty)
+}
+
+// WithResult represents an activity or object with the result property.
 type WithResult interface {
 	GetActivityStreamsResult() vocab.ActivityStreamsResultProperty
 	SetActivityStreamsResult(vocab.ActivityStreamsResultProperty)
 }
+
+// WithInteractingObject represents an activity or object with the InteractingObject property.
+type WithInteractingObject interface {
+	GetGoToSocialInteractingObject() vocab.GoToSocialInteractingObjectProperty
+	SetGoToSocialInteractingObject(vocab.GoToSocialInteractingObjectProperty)
+}
+
+// WithInteractionTarget represents an activity or object with the InteractionTarget property.
+type WithInteractionTarget interface {
+	GetGoToSocialInteractionTarget() vocab.GoToSocialInteractionTargetProperty
+	SetGoToSocialInteractionTarget(vocab.GoToSocialInteractionTargetProperty)
+}