[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/api/activitypub/users/authorizationget.go

@@ -0,0 +1,56 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package users
+
+import (
+	"net/http"
+
+	apiutil "code.superseriousbusiness.org/gotosocial/internal/api/util"
+	"code.superseriousbusiness.org/gotosocial/internal/gtserror"
+	"github.com/gin-gonic/gin"
+)
+
+// AuthorizationGETHandler serves an accepted interaction request as a
+// LikeAuthorization, ReplyAuthorization, or AnnounceAuthorization type.
+func (m *Module) AuthorizationGETHandler(c *gin.Context) {
+	username, errWithCode := apiutil.ParseUsername(c.Param(apiutil.UsernameKey))
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	reqID, errWithCode := apiutil.ParseID(c.Param(apiutil.IDKey))
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	contentType, err := apiutil.NegotiateAccept(c, apiutil.ActivityPubHeaders...)
+	if err != nil {
+		apiutil.ErrorHandler(c, gtserror.NewErrorNotAcceptable(err, err.Error()), m.processor.InstanceGetV1)
+		return
+	}
+
+	resp, errWithCode := m.processor.Fedi().AuthorizationGet(c.Request.Context(), username, reqID)
+	if errWithCode != nil {
+		apiutil.ErrorHandler(c, errWithCode, m.processor.InstanceGetV1)
+		return
+	}
+
+	apiutil.JSONType(c, http.StatusOK, contentType, resp)
+}

internal/api/activitypub/users/inboxpost_test.go

@@ -192,7 +192,7 @@ func (suite *InboxPostTestSuite) newDelete(actorIRI string, objectIRI string, de
 
 	// Set the To of the delete as public
 	deleteTo := streams.NewActivityStreamsToProperty()
-	deleteTo.AppendIRI(ap.PublicURI())
+	deleteTo.AppendIRI(ap.PublicIRI())
 	delete.SetActivityStreamsTo(deleteTo)
 
 	// set some random-ass ID for the activity

internal/api/activitypub/users/user.go

@@ -58,6 +58,8 @@ const (
 	StatusRepliesPath = StatusPath + "/replies"
 	// AcceptPath is for serving accepts of a status.
 	AcceptPath = BasePath + "/" + uris.AcceptsPath + "/:" + apiutil.IDKey
+	// AuthorizationsPath is for serving authorizations of an interaction.
+	AuthorizationsPath = BasePath + "/" + uris.AuthorizationsPath + "/:" + apiutil.IDKey
 )
 
 type Module struct {
@@ -80,4 +82,5 @@ func (m *Module) Route(attachHandler func(method string, path string, f ...gin.H
 	attachHandler(http.MethodGet, StatusRepliesPath, m.StatusRepliesGETHandler)
 	attachHandler(http.MethodGet, OutboxPath, m.OutboxGETHandler)
 	attachHandler(http.MethodGet, AcceptPath, m.AcceptGETHandler)
+	attachHandler(http.MethodGet, AuthorizationsPath, m.AuthorizationGETHandler)
 }

internal/api/client/statuses/statusboost_test.go

@@ -730,7 +730,7 @@ func (suite *StatusBoostTestSuite) TestPostBoostImplicitAccept() {
 		suite.FailNow(err.Error())
 	}
 	suite.NotZero(intReq.AcceptedAt)
-	suite.NotEmpty(intReq.URI)
+	suite.NotEmpty(intReq.InteractionURI)
 }
 
 func TestStatusBoostTestSuite(t *testing.T) {

internal/api/client/statuses/statusfave_test.go

@@ -337,7 +337,7 @@ func (suite *StatusFaveTestSuite) TestPostFaveImplicitAccept() {
 		suite.FailNow(err.Error())
 	}
 	suite.NotZero(intReq.AcceptedAt)
-	suite.NotEmpty(intReq.URI)
+	suite.NotEmpty(intReq.InteractionURI)
 
 	// Check visibility of status to public after posting fave.
 	visible, err = visFilter.StatusVisible(ctx, nil, dbStatus)

internal/api/model/interaction.go

@@ -41,6 +41,4 @@ type InteractionRequest struct {
 	AcceptedAt string `json:"accepted_at,omitempty"`
 	// The timestamp that the interaction request was rejected (ISO 8601 Datetime). Field omitted if request not rejected (yet).
 	RejectedAt string `json:"rejected_at,omitempty"`
-	// URI of the Accept or Reject. Only set if accepted_at or rejected_at is set, else omitted.
-	URI string `json:"uri,omitempty"`
 }