1 files changed, 369 insertions, 0 deletions
diff --git a/internal/federation/dereferencing/status.go b/internal/federation/dereferencing/status.go
new file mode 100644
index 000000000..b05f6e72c
--- /dev/null
+++ b/internal/federation/dereferencing/status.go
@@ -0,0 +1,369 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   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 dereferencing
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/url"
+
+	"github.com/go-fed/activity/streams"
+	"github.com/go-fed/activity/streams/vocab"
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/ap"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+)
+
+// EnrichRemoteStatus takes a status that's already been inserted into the database in a minimal form,
+// and populates it with additional fields, media, etc.
+//
+// EnrichRemoteStatus is mostly useful for calling after a status has been initially created by
+// the federatingDB's Create function, but additional dereferencing is needed on it.
+func (d *deref) EnrichRemoteStatus(username string, status *gtsmodel.Status) (*gtsmodel.Status, error) {
+	if err := d.populateStatusFields(status, username); err != nil {
+		return nil, err
+	}
+
+	if err := d.db.UpdateByID(status.ID, status); err != nil {
+		return nil, fmt.Errorf("EnrichRemoteStatus: error updating status: %s", err)
+	}
+
+	return status, nil
+}
+
+// GetRemoteStatus completely dereferences a remote status, converts it to a GtS model status,
+// puts it in the database, and returns it to a caller. The boolean indicates whether the status is new
+// to us or not. If we haven't seen the status before, bool will be true. If we have seen the status before,
+// it will be false.
+//
+// If refresh is true, then even if we have the status in our database already, it will be dereferenced from its
+// remote representation, as will its owner.
+//
+// If a dereference was performed, then the function also returns the ap.Statusable representation for further processing.
+//
+// SIDE EFFECTS: remote status will be stored in the database, and the remote status owner will also be stored.
+func (d *deref) GetRemoteStatus(username string, remoteStatusID *url.URL, refresh bool) (*gtsmodel.Status, ap.Statusable, bool, error) {
+	new := true
+
+	// check if we already have the status in our db
+	maybeStatus := &gtsmodel.Status{}
+	if err := d.db.GetWhere([]db.Where{{Key: "uri", Value: remoteStatusID.String()}}, maybeStatus); err == nil {
+		// we've seen this status before so it's not new
+		new = false
+
+		// if we're not being asked to refresh, we can just return the maybeStatus as-is and avoid doing any external calls
+		if !refresh {
+			return maybeStatus, nil, new, nil
+		}
+	}
+
+	statusable, err := d.dereferenceStatusable(username, remoteStatusID)
+	if err != nil {
+		return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error dereferencing statusable: %s", err)
+	}
+
+	accountURI, err := ap.ExtractAttributedTo(statusable)
+	if err != nil {
+		return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error extracting attributedTo: %s", err)
+	}
+
+	// do this so we know we have the remote account of the status in the db
+	_, _, err = d.GetRemoteAccount(username, accountURI, false)
+	if err != nil {
+		return nil, statusable, new, fmt.Errorf("GetRemoteStatus: couldn't derive status author: %s", err)
+	}
+
+	gtsStatus, err := d.typeConverter.ASStatusToStatus(statusable)
+	if err != nil {
+		return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error converting statusable to status: %s", err)
+	}
+
+	if new {
+		ulid, err := id.NewULIDFromTime(gtsStatus.CreatedAt)
+		if err != nil {
+			return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error generating new id for status: %s", err)
+		}
+		gtsStatus.ID = ulid
+
+		if err := d.populateStatusFields(gtsStatus, username); err != nil {
+			return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error populating status fields: %s", err)
+		}
+
+		if err := d.db.Put(gtsStatus); err != nil {
+			return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error putting new status: %s", err)
+		}
+	} else {
+		gtsStatus.ID = maybeStatus.ID
+
+		if err := d.populateStatusFields(gtsStatus, username); err != nil {
+			return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error populating status fields: %s", err)
+		}
+
+		if err := d.db.UpdateByID(gtsStatus.ID, gtsStatus); err != nil {
+			return nil, statusable, new, fmt.Errorf("GetRemoteStatus: error updating status: %s", err)
+		}
+	}
+
+	return gtsStatus, statusable, new, nil
+}
+
+func (d *deref) dereferenceStatusable(username string, remoteStatusID *url.URL) (ap.Statusable, error) {
+	if blocked, err := d.blockedDomain(remoteStatusID.Host); blocked || err != nil {
+		return nil, fmt.Errorf("DereferenceStatusable: domain %s is blocked", remoteStatusID.Host)
+	}
+
+	transport, err := d.transportController.NewTransportForUsername(username)
+	if err != nil {
+		return nil, fmt.Errorf("DereferenceStatusable: transport err: %s", err)
+	}
+
+	b, err := transport.Dereference(context.Background(), remoteStatusID)
+	if err != nil {
+		return nil, fmt.Errorf("DereferenceStatusable: error deferencing %s: %s", remoteStatusID.String(), err)
+	}
+
+	m := make(map[string]interface{})
+	if err := json.Unmarshal(b, &m); err != nil {
+		return nil, fmt.Errorf("DereferenceStatusable: error unmarshalling bytes into json: %s", err)
+	}
+
+	t, err := streams.ToType(context.Background(), m)
+	if err != nil {
+		return nil, fmt.Errorf("DereferenceStatusable: error resolving json into ap vocab type: %s", err)
+	}
+
+	// Article, Document, Image, Video, Note, Page, Event, Place, Mention, Profile
+	switch t.GetTypeName() {
+	case gtsmodel.ActivityStreamsArticle:
+		p, ok := t.(vocab.ActivityStreamsArticle)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsArticle")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsDocument:
+		p, ok := t.(vocab.ActivityStreamsDocument)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsDocument")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsImage:
+		p, ok := t.(vocab.ActivityStreamsImage)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsImage")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsVideo:
+		p, ok := t.(vocab.ActivityStreamsVideo)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsVideo")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsNote:
+		p, ok := t.(vocab.ActivityStreamsNote)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsNote")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsPage:
+		p, ok := t.(vocab.ActivityStreamsPage)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsPage")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsEvent:
+		p, ok := t.(vocab.ActivityStreamsEvent)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsEvent")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsPlace:
+		p, ok := t.(vocab.ActivityStreamsPlace)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsPlace")
+		}
+		return p, nil
+	case gtsmodel.ActivityStreamsProfile:
+		p, ok := t.(vocab.ActivityStreamsProfile)
+		if !ok {
+			return nil, errors.New("DereferenceStatusable: error resolving type as ActivityStreamsProfile")
+		}
+		return p, nil
+	}
+
+	return nil, fmt.Errorf("DereferenceStatusable: type name %s not supported", t.GetTypeName())
+}
+
+// populateStatusFields fetches all the information we temporarily pinned to an incoming
+// federated status, back in the federating db's Create function.
+//
+// When a status comes in from the federation API, there are certain fields that
+// haven't been dereferenced yet, because we needed to provide a snappy synchronous
+// response to the caller. By the time it reaches this function though, it's being
+// processed asynchronously, so we have all the time in the world to fetch the various
+// bits and bobs that are attached to the status, and properly flesh it out, before we
+// send the status to any timelines and notify people.
+//
+// Things to dereference and fetch here:
+//
+// 1. Media attachments.
+// 2. Hashtags.
+// 3. Emojis.
+// 4. Mentions.
+// 5. Posting account.
+// 6. Replied-to-status.
+//
+// SIDE EFFECTS:
+// This function will deference all of the above, insert them in the database as necessary,
+// and attach them to the status. The status itself will not be added to the database yet,
+// that's up the caller to do.
+func (d *deref) populateStatusFields(status *gtsmodel.Status, requestingUsername string) error {
+	l := d.log.WithFields(logrus.Fields{
+		"func":   "dereferenceStatusFields",
+		"status": fmt.Sprintf("%+v", status),
+	})
+	l.Debug("entering function")
+
+	// make sure we have a status URI and that the domain in question isn't blocked
+	statusURI, err := url.Parse(status.URI)
+	if err != nil {
+		return fmt.Errorf("DereferenceStatusFields: couldn't parse status URI %s: %s", status.URI, err)
+	}
+	if blocked, err := d.blockedDomain(statusURI.Host); blocked || err != nil {
+		return fmt.Errorf("DereferenceStatusFields: domain %s is blocked", statusURI.Host)
+	}
+
+	// we can continue -- create a new transport here because we'll probably need it
+	t, err := d.transportController.NewTransportForUsername(requestingUsername)
+	if err != nil {
+		return fmt.Errorf("error creating transport: %s", err)
+	}
+
+	// in case the status doesn't have an id yet (ie., it hasn't entered the database yet), then create one
+	if status.ID == "" {
+		newID, err := id.NewULIDFromTime(status.CreatedAt)
+		if err != nil {
+			return err
+		}
+		status.ID = newID
+	}
+
+	// 1. Media attachments.
+	//
+	// At this point we should know:
+	// * the media type of the file we're looking for (a.File.ContentType)
+	// * the blurhash (a.Blurhash)
+	// * the file type (a.Type)
+	// * the remote URL (a.RemoteURL)
+	// This should be enough to pass along to the media processor.
+	attachmentIDs := []string{}
+	for _, a := range status.GTSMediaAttachments {
+		l.Tracef("dereferencing attachment: %+v", a)
+
+		// it might have been processed elsewhere so check first if it's already in the database or not
+		maybeAttachment := &gtsmodel.MediaAttachment{}
+		err := d.db.GetWhere([]db.Where{{Key: "remote_url", Value: a.RemoteURL}}, maybeAttachment)
+		if err == nil {
+			// we already have it in the db, dereferenced, no need to do it again
+			l.Tracef("attachment already exists with id %s", maybeAttachment.ID)
+			attachmentIDs = append(attachmentIDs, maybeAttachment.ID)
+			continue
+		}
+		if _, ok := err.(db.ErrNoEntries); !ok {
+			// we have a real error
+			return fmt.Errorf("error checking db for existence of attachment with remote url %s: %s", a.RemoteURL, err)
+		}
+		// it just doesn't exist yet so carry on
+		l.Debug("attachment doesn't exist yet, calling ProcessRemoteAttachment", a)
+		deferencedAttachment, err := d.mediaHandler.ProcessRemoteAttachment(t, a, status.AccountID)
+		if err != nil {
+			l.Errorf("error dereferencing status attachment: %s", err)
+			continue
+		}
+		l.Debugf("dereferenced attachment: %+v", deferencedAttachment)
+		deferencedAttachment.StatusID = status.ID
+		deferencedAttachment.Description = a.Description
+		if err := d.db.Put(deferencedAttachment); err != nil {
+			return fmt.Errorf("error inserting dereferenced attachment with remote url %s: %s", a.RemoteURL, err)
+		}
+		attachmentIDs = append(attachmentIDs, deferencedAttachment.ID)
+	}
+	status.Attachments = attachmentIDs
+
+	// 2. Hashtags
+
+	// 3. Emojis
+
+	// 4. Mentions
+	// At this point, mentions should have the namestring and mentionedAccountURI set on them.
+	//
+	// We should dereference any accounts mentioned here which we don't have in our db yet, by their URI.
+	mentions := []string{}
+	for _, m := range status.GTSMentions {
+
+		if m.ID != "" {
+			continue
+			// we've already populated this mention, since it has an ID
+		}
+
+		mID, err := id.NewRandomULID()
+		if err != nil {
+			return err
+		}
+		m.ID = mID
+
+		uri, err := url.Parse(m.MentionedAccountURI)
+		if err != nil {
+			l.Debugf("error parsing mentioned account uri %s: %s", m.MentionedAccountURI, err)
+			continue
+		}
+
+		m.StatusID = status.ID
+		m.OriginAccountID = status.GTSAuthorAccount.ID
+		m.OriginAccountURI = status.GTSAuthorAccount.URI
+
+		targetAccount, _, err := d.GetRemoteAccount(requestingUsername, uri, false)
+		if err != nil {
+			continue
+		}
+
+		// by this point, we know the targetAccount exists in our database with an ID :)
+		m.TargetAccountID = targetAccount.ID
+		if err := d.db.Put(m); err != nil {
+			return fmt.Errorf("error creating mention: %s", err)
+		}
+		mentions = append(mentions, m.ID)
+	}
+	status.Mentions = mentions
+
+	// status has replyToURI but we don't have an ID yet for the status it replies to
+	if status.InReplyToURI != "" && status.InReplyToID == "" {
+		replyToStatus := &gtsmodel.Status{}
+		if err := d.db.GetWhere([]db.Where{{Key: "uri", Value: status.InReplyToURI}}, replyToStatus); err == nil {
+			// we have the status
+			status.InReplyToID = replyToStatus.ID
+			status.InReplyToAccountID = replyToStatus.AccountID
+		}
+	}
+
+	return nil
+}