Merge pull request #1122 from writefreely/ap-likes

Support ActivityPub Likes

Closes T906

activitypub.go

@@ -22,6 +22,7 @@ import (
 	"net/http/httputil"
 	"net/url"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -45,6 +46,11 @@ const (
 	apCacheTime = time.Minute
 )
 
+var (
+	apCollectionPostIRIRegex = regexp.MustCompile("/api/collections/([a-z0-9\\-]+)/posts/([a-z0-9\\-]+)$")
+	apDraftPostIRIRegex      = regexp.MustCompile("/api/posts/([a-z0-9\\-]+)$")
+)
+
 var instanceColl *Collection
 
 func initActivityPub(app *App) {
@@ -351,11 +357,60 @@ func handleFetchCollectionInbox(app *App, w http.ResponseWriter, r *http.Request
 	a := streams.NewAccept()
 	p := c.PersonObject()
 	var to *url.URL
-	var isFollow, isUnfollow bool
+	var isFollow, isUnfollow, isLike, isUnlike bool
+	var likePostID, unlikePostID string
 	fullActor := &activitystreams.Person{}
 	var remoteUser *RemoteUser
 
 	res := &streams.Resolver{
+		LikeCallback: func(l *streams.Like) error {
+			isLike = true
+
+			// 1) Use the Like concrete type here
+			// 2) Errors are propagated to res.Deserialize call below
+			m["@context"] = []string{activitystreams.Namespace}
+			b, _ := json.Marshal(m)
+			if debugging {
+				log.Info("Like: %s", b)
+			}
+
+			_, likeID := l.GetId()
+			if likeID == nil {
+				log.Error("Didn't resolve Like ID")
+			}
+			if p := l.HasObject(0); p == streams.NoPresence {
+				return fmt.Errorf("no object for Like activity at index 0")
+			}
+
+			obj := l.Raw().GetObjectIRI(0)
+			/*
+			   // TODO: handle this more robustly
+			   l.ResolveObject(&streams.Resolver{
+			     LinkCallback: func(link *streams.Link) error {
+			       return nil
+			     },
+			   }, 0)
+			*/
+
+			if obj == nil {
+				return fmt.Errorf("didn't get ObjectIRI to Like")
+			}
+			likePostID, err = parsePostIDFromURL(app, obj)
+			if err != nil {
+				return err
+			}
+
+			// Finally, get actor information
+			_, from := l.GetActor(0)
+			if from == nil {
+				return fmt.Errorf("No valid actor string")
+			}
+			fullActor, remoteUser, err = getActor(app, from.String())
+			if err != nil {
+				return err
+			}
+			return nil
+		},
 		FollowCallback: func(f *streams.Follow) error {
 			isFollow = true
 
@@ -394,8 +449,6 @@ func handleFetchCollectionInbox(app *App, w http.ResponseWriter, r *http.Request
 			return impart.RenderActivityJSON(w, m, http.StatusOK)
 		},
 		UndoCallback: func(u *streams.Undo) error {
-			isUnfollow = true
-
 			m["@context"] = []string{activitystreams.Namespace}
 			b, _ := json.Marshal(m)
 			if debugging {
@@ -403,6 +456,37 @@ func handleFetchCollectionInbox(app *App, w http.ResponseWriter, r *http.Request
 			}
 
 			a.AppendObject(u.Raw())
+
+			// Check type -- we handle Undo:Like and Undo:Follow
+			_, err := u.ResolveObject(&streams.Resolver{
+				LikeCallback: func(like *streams.Like) error {
+					isUnlike = true
+
+					_, from := like.GetActor(0)
+					obj := like.Raw().GetObjectIRI(0)
+					if obj == nil {
+						return fmt.Errorf("didn't get ObjectIRI for Undo Like")
+					}
+					unlikePostID, err = parsePostIDFromURL(app, obj)
+					if err != nil {
+						return err
+					}
+					fullActor, remoteUser, err = getActor(app, from.String())
+					if err != nil {
+						return err
+					}
+					return nil
+				},
+				// TODO: add FollowCallback for more robust handling
+			}, 0)
+			if err != nil {
+				return err
+			}
+			if isUnlike {
+				return nil
+			}
+
+			isUnfollow = true
 			_, to = u.GetActor(0)
 			// TODO: get actor from object.object, not object
 			obj := u.Raw().GetObjectIRI(0)
@@ -435,6 +519,81 @@ func handleFetchCollectionInbox(app *App, w http.ResponseWriter, r *http.Request
 		return err
 	}
 
+	// Handle synchronous activities
+	if isLike {
+		t, err := app.db.Begin()
+		if err != nil {
+			log.Error("Unable to start transaction: %v", err)
+			return fmt.Errorf("unable to start transaction: %v", err)
+		}
+
+		var remoteUserID int64
+		if remoteUser != nil {
+			remoteUserID = remoteUser.ID
+		} else {
+			remoteUserID, err = apAddRemoteUser(app, t, fullActor)
+		}
+
+		// Add like
+		_, err = t.Exec("INSERT INTO remote_likes (post_id, remote_user_id, created) VALUES (?, ?, "+app.db.now()+")", likePostID, remoteUserID)
+		if err != nil {
+			if !app.db.isDuplicateKeyErr(err) {
+				t.Rollback()
+				log.Error("Couldn't add like in DB: %v\n", err)
+				return fmt.Errorf("Couldn't add like in DB: %v", err)
+			} else {
+				t.Rollback()
+				log.Error("Couldn't add like in DB: %v\n", err)
+				return fmt.Errorf("Couldn't add like in DB: %v", err)
+			}
+		}
+
+		err = t.Commit()
+		if err != nil {
+			t.Rollback()
+			log.Error("Rolling back after Commit(): %v\n", err)
+			return fmt.Errorf("Rolling back after Commit(): %v\n", err)
+		}
+
+		if debugging {
+			log.Info("Successfully liked post %s by remote user %s", likePostID, remoteUser.URL)
+		}
+		return impart.RenderActivityJSON(w, "", http.StatusOK)
+	} else if isUnlike {
+		t, err := app.db.Begin()
+		if err != nil {
+			log.Error("Unable to start transaction: %v", err)
+			return fmt.Errorf("unable to start transaction: %v", err)
+		}
+
+		var remoteUserID int64
+		if remoteUser != nil {
+			remoteUserID = remoteUser.ID
+		} else {
+			remoteUserID, err = apAddRemoteUser(app, t, fullActor)
+		}
+
+		// Remove like
+		_, err = t.Exec("DELETE FROM remote_likes WHERE post_id = ? AND remote_user_id = ?", unlikePostID, remoteUserID)
+		if err != nil {
+			t.Rollback()
+			log.Error("Couldn't delete Like from DB: %v\n", err)
+			return fmt.Errorf("Couldn't delete Like from DB: %v", err)
+		}
+
+		err = t.Commit()
+		if err != nil {
+			t.Rollback()
+			log.Error("Rolling back after Commit(): %v\n", err)
+			return fmt.Errorf("Rolling back after Commit(): %v\n", err)
+		}
+
+		if debugging {
+			log.Info("Successfully un-liked post %s by remote user %s", unlikePostID, remoteUser.URL)
+		}
+		return impart.RenderActivityJSON(w, "", http.StatusOK)
+	}
+
 	go func() {
 		if to == nil {
 			if debugging {
@@ -469,6 +628,7 @@ func handleFetchCollectionInbox(app *App, w http.ResponseWriter, r *http.Request
 			if remoteUser != nil {
 				followerID = remoteUser.ID
 			} else {
+				// TODO: use apAddRemoteUser() here, instead!
 				// Add follower locally, since it wasn't found before
 				res, err := t.Exec("INSERT INTO remoteusers (actor_id, inbox, shared_inbox, url) VALUES (?, ?, ?, ?)", fullActor.ID, fullActor.Inbox, fullActor.Endpoints.SharedInbox, fullActor.URL)
 				if err != nil {
@@ -964,6 +1124,34 @@ func unmarshalActor(actorResp []byte, actor *activitystreams.Person) error {
 	return nil
 }
 
+func parsePostIDFromURL(app *App, u *url.URL) (string, error) {
+	// Get post ID from URL
+	var collAlias, slug, postID string
+	if m := apCollectionPostIRIRegex.FindStringSubmatch(u.String()); len(m) == 3 {
+		collAlias = m[1]
+		slug = m[2]
+	} else if m = apDraftPostIRIRegex.FindStringSubmatch(u.String()); len(m) == 2 {
+		postID = m[1]
+	} else {
+		return "", fmt.Errorf("unable to match objectIRI: %s", u)
+	}
+
+	// Get postID if all we have is collection and slug
+	if collAlias != "" && slug != "" {
+		c, err := app.db.GetCollection(collAlias)
+		if err != nil {
+			return "", err
+		}
+		p, err := app.db.GetPost(slug, c.ID)
+		if err != nil {
+			return "", err
+		}
+		postID = p.ID
+	}
+
+	return postID, nil
+}
+
 func setCacheControl(w http.ResponseWriter, ttl time.Duration) {
 	w.Header().Set("Cache-Control", fmt.Sprintf("public, max-age=%.0f", ttl.Seconds()))
 }

database.go

@@ -115,6 +115,7 @@ type writestore interface {
 	DispersePosts(userID int64, postIDs []string) (*[]ClaimPostResult, error)
 	ClaimPosts(cfg *config.Config, userID int64, collAlias string, posts *[]ClaimPostRequest) (*[]ClaimPostResult, error)
 
+	GetPostLikeCounts(postID string) (int64, error)
 	GetPostsCount(c *CollectionObj, includeFuture bool)
 	GetPosts(cfg *config.Config, c *Collection, page int, includeFuture, forceRecentFirst, includePinned bool) (*[]PublicPost, error)
 	GetAllPostsTaggedIDs(c *Collection, tag string, includeFuture bool) ([]string, error)
@@ -1174,6 +1175,12 @@ func (db *datastore) GetPost(id string, collectionID int64) (*PublicPost, error)
 		return nil, ErrPostUnpublished
 	}
 
+	// Get additional information needed before processing post data
+	p.LikeCount, err = db.GetPostLikeCounts(p.ID)
+	if err != nil {
+		return nil, err
+	}
+
 	res := p.processPost()
 	if ownerName.Valid {
 		res.Owner = &PublicUser{Username: ownerName.String}
@@ -1236,6 +1243,18 @@ func (db *datastore) GetPostProperty(id string, collectionID int64, property str
 	return res, nil
 }
 
+func (db *datastore) GetPostLikeCounts(postID string) (int64, error) {
+	var count int64
+	err := db.QueryRow("SELECT COUNT(*) FROM remote_likes WHERE post_id = ?", postID).Scan(&count)
+	switch {
+	case err == sql.ErrNoRows:
+		count = 0
+	case err != nil:
+		return 0, err
+	}
+	return count, nil
+}
+
 // GetPostsCount modifies the CollectionObj to include the correct number of
 // standard (non-pinned) posts. It will return future posts if `includeFuture`
 // is true.

database_activitypub.go

@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2024 Musing Studio LLC.
+ *
+ * This file is part of WriteFreely.
+ *
+ * WriteFreely is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, included
+ * in the LICENSE file in this source code package.
+ */
+
+package writefreely
+
+import (
+	"database/sql"
+	"fmt"
+	"github.com/writeas/web-core/activitystreams"
+	"github.com/writeas/web-core/log"
+)
+
+func apAddRemoteUser(app *App, t *sql.Tx, fullActor *activitystreams.Person) (int64, error) {
+	// Add remote user locally, since it wasn't found before
+	res, err := t.Exec("INSERT INTO remoteusers (actor_id, inbox, shared_inbox, url) VALUES (?, ?, ?, ?)", fullActor.ID, fullActor.Inbox, fullActor.Endpoints.SharedInbox, fullActor.URL)
+	if err != nil {
+		t.Rollback()
+		return -1, fmt.Errorf("couldn't add new remoteuser in DB: %v", err)
+	}
+
+	remoteUserID, err := res.LastInsertId()
+	if err != nil {
+		t.Rollback()
+		return -1, fmt.Errorf("no lastinsertid for followers, rolling back: %v", err)
+	}
+
+	// Add in key
+	_, err = t.Exec("INSERT INTO remoteuserkeys (id, remote_user_id, public_key) VALUES (?, ?, ?)", fullActor.PublicKey.ID, remoteUserID, fullActor.PublicKey.PublicKeyPEM)
+	if err != nil {
+		if !app.db.isDuplicateKeyErr(err) {
+			t.Rollback()
+			log.Error("Couldn't add follower keys in DB: %v\n", err)
+			return -1, fmt.Errorf("couldn't add follower keys in DB: %v", err)
+		} else {
+			t.Rollback()
+			log.Error("Couldn't add follower keys in DB: %v\n", err)
+			return -1, fmt.Errorf("couldn't add follower keys in DB: %v", err)
+		}
+	}
+
+	return remoteUserID, nil
+}

migrations/migrations.go

@@ -71,6 +71,7 @@ var migrations = []Migration{
 	New("support newsletters", supportLetters),                      // V12 -> V13
 	New("support password resetting", supportPassReset),             // V13 -> V14
 	New("speed up blog post retrieval", addPostRetrievalIndex),      // V14 -> V15
+	New("support ActivityPub likes", supportRemoteLikes),            // V15 -> V16 (v0.16.0)
 }
 
 // CurrentVer returns the current migration version the application is on

migrations/v16.go

@@ -0,0 +1,38 @@
+/*
+ * Copyright © 2024 Musing Studio LLC.
+ *
+ * This file is part of WriteFreely.
+ *
+ * WriteFreely is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, included
+ * in the LICENSE file in this source code package.
+ */
+
+package migrations
+
+func supportRemoteLikes(db *datastore) error {
+	t, err := db.Begin()
+	if err != nil {
+		t.Rollback()
+		return err
+	}
+
+	_, err = t.Exec(`CREATE TABLE remote_likes (
+	post_id        ` + db.typeChar(16) + ` NOT NULL,
+	remote_user_id ` + db.typeInt() + ` NOT NULL,
+	created        ` + db.typeDateTime() + ` NOT NULL,
+	PRIMARY KEY (post_id,remote_user_id)
+)`)
+	if err != nil {
+		t.Rollback()
+		return err
+	}
+
+	err = t.Commit()
+	if err != nil {
+		t.Rollback()
+		return err
+	}
+
+	return nil
+}

posts.go

@@ -105,6 +105,7 @@ type (
 		Created        time.Time     `db:"created" json:"created"`
 		Updated        time.Time     `db:"updated" json:"updated"`
 		ViewCount      int64         `db:"view_count" json:"-"`
+		LikeCount      int64         `db:"like_count" json:"likes"`
 		Title          zero.String   `db:"title" json:"title"`
 		HTMLTitle      template.HTML `db:"title" json:"-"`
 		Content        string        `db:"content" json:"body"`
@@ -127,6 +128,7 @@ type (
 		IsTopLevel  bool           `json:"-"`
 		DisplayDate string         `json:"-"`
 		Views       int64          `json:"views"`
+		Likes       int64          `json:"likes"`
 		Owner       *PublicUser    `json:"-"`
 		IsOwner     bool           `json:"-"`
 		URL         string         `json:"url,omitempty"`
@@ -1184,6 +1186,7 @@ func fetchPostProperty(app *App, w http.ResponseWriter, r *http.Request) error {
 func (p *Post) processPost() PublicPost {
 	res := &PublicPost{Post: p, Views: 0}
 	res.Views = p.ViewCount
+	res.Likes = p.LikeCount
 	// TODO: move to own function
 	loc := monday.FuzzyLocale(p.Language.String)
 	res.DisplayDate = monday.Format(p.Created, monday.LongFormatsByLocale[loc], loc)

templates/collection-post.tmpl

@@ -55,6 +55,7 @@
 				{{range .PinnedPosts}}<a class="pinned{{if eq .Slug.String $.Slug.String}} selected{{end}}" href="{{if not $.SingleUser}}/{{$.Collection.Alias}}/{{.Slug.String}}{{else}}{{.CanonicalURL $.Host}}{{end}}">{{.PlainDisplayTitle}}</a>{{end}}
 				{{end}}
 				{{ if and .IsOwner .IsFound }}<span class="views" dir="ltr"><strong>{{largeNumFmt .Views}}</strong> {{pluralize "view" "views" .Views}}</span>
+                {{if .Likes}}<span class="views" dir="ltr"><strong>{{largeNumFmt .Likes}}</strong> {{pluralize "like" "likes" .Likes}}</span>{{end}}
 				<a class="xtra-feature" href="/{{if not .SingleUser}}{{.Collection.Alias}}/{{end}}{{.Slug.String}}/edit" dir="{{.Direction}}">Edit</a>
 				{{if .IsPinned}}<a class="xtra-feature unpin" href="/{{.Collection.Alias}}/{{.Slug.String}}/unpin" dir="{{.Direction}}" onclick="unpinPost(event, '{{.ID}}')">Unpin</a>{{end}}
 				{{ end }}

templates/user/stats.tmpl

@@ -51,11 +51,13 @@ td.none {
 			<th>Post</th>
 			{{if not .Collection}}<th>Blog</th>{{end}}
 			<th class="num">Total Views</th>
+			{{if .Federation}}<th class="num">Likes</th>{{end}}
 		</tr>
 		{{range .TopPosts}}<tr>
 			<td style="word-break: break-all;"><a href="{{if .Collection}}{{.Collection.CanonicalURL}}{{.Slug.String}}{{else}}/{{.ID}}{{end}}">{{if ne .DisplayTitle ""}}{{.DisplayTitle}}{{else}}<em>{{.ID}}</em>{{end}}</a></td>
 			{{ if not $.Collection }}<td>{{if .Collection}}<a href="{{.Collection.CanonicalURL}}">{{.Collection.Title}}</a>{{else}}<em>Draft</em>{{end}}</td>{{ end }}
 			<td class="num">{{.ViewCount}}</td>
+			{{if $.Federation}}<td class="num">{{.LikeCount}}</td>{{end}}
 		</tr>{{end}}
 	</table>