add basic support for post editing

README.md

@@ -75,6 +75,7 @@ Users are authenticated using TLS client certificates; see [Gemini protocol spec
 * /users/whisper creates a post visible to followers.
 * /users/say creates a public post.
 * /users/reply replies to a post.
+* /users/edit edits a post.
 * /users/follow sends a follow request to a user.
 * /users/unfollow deletes a follow request.
 * /users/outbox is equivalent to /outbox but also includes a link to /users/follow or /users/unfollow.
@@ -133,6 +134,10 @@ User A is allowed to send a message to user B only if B follows A.
 | Post        | Post author | Mentions and followers of reply author         |
 | Public post | Post author | Mentions, followers of reply author and Public |
 
+### Post Editing
+
+/users/edit only changes the content and the last update timestamp of a post. It does **not** change the post audience and mentioned users.
+
 ## Implementation Details
 
 ### The "Nobody" User

fed/edit.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2023 Dima Krasner
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package fed
+
+import (
+	"context"
+	"crypto/sha256"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"github.com/dimkr/tootik/ap"
+	"github.com/dimkr/tootik/cfg"
+	"time"
+)
+
+func Edit(ctx context.Context, db *sql.DB, note *ap.Object, newContent string) error {
+	now := time.Now()
+
+	note.Content = newContent
+	note.Updated = &now
+
+	body, err := json.Marshal(note)
+	if err != nil {
+		return fmt.Errorf("Failed to marshal note: %w", err)
+	}
+
+	updateID := fmt.Sprintf("https://%s/update/%x", cfg.Domain, sha256.Sum256([]byte(fmt.Sprintf("%s|%d", note.ID, now.Unix()))))
+
+	update, err := json.Marshal(ap.Activity{
+		Context: "https://www.w3.org/ns/activitystreams",
+		ID:      updateID,
+		Type:    ap.UpdateActivity,
+		Actor:   note.AttributedTo,
+		Object:  note,
+		To:      note.To,
+		CC:      note.CC,
+	})
+	if err != nil {
+		return fmt.Errorf("Failed to marshal update: %w", err)
+	}
+
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return fmt.Errorf("Failed to begin transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	if _, err := tx.ExecContext(
+		ctx,
+		`UPDATE notes SET object = ? WHERE id = ?`,
+		string(body),
+		note.ID,
+	); err != nil {
+		return fmt.Errorf("Failed to update note: %w", err)
+	}
+
+	if _, err := tx.ExecContext(
+		ctx,
+		`INSERT INTO outbox (activity) VALUES(?)`,
+		string(update),
+	); err != nil {
+		return fmt.Errorf("Failed to insert update activity: %w", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("Failed to update note: %w", err)
+	}
+
+	return nil
+}

front/edit.go

@@ -0,0 +1,107 @@
+/*
+Copyright 2023 Dima Krasner
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package front
+
+import (
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"github.com/dimkr/tootik/ap"
+	"github.com/dimkr/tootik/cfg"
+	"github.com/dimkr/tootik/fed"
+	"github.com/dimkr/tootik/text"
+	"github.com/dimkr/tootik/text/plain"
+	"math"
+	"net/url"
+	"path/filepath"
+	"regexp"
+	"time"
+)
+
+func init() {
+	handlers[regexp.MustCompile(`^/users/edit/[0-9a-f]{64}`)] = edit
+}
+
+func edit(w text.Writer, r *request) {
+	if r.User == nil {
+		w.Redirect("/users")
+		return
+	}
+
+	if r.URL.RawQuery == "" {
+		w.Status(10, "Post content")
+		return
+	}
+
+	hash := filepath.Base(r.URL.Path)
+
+	var noteString string
+	if err := r.QueryRow(`select object from notes where hash = ? and author = ?`, hash, r.User.ID).Scan(&noteString); err != nil && errors.Is(err, sql.ErrNoRows) {
+		r.Log.Warn("Attempted to edit non-existing post", "hash", hash, "error", err)
+		w.Error()
+		return
+	} else if err != nil {
+		r.Log.Warn("Failed to fetch post to edit", "hash", hash, "error", err)
+		w.Error()
+		return
+	}
+
+	var note ap.Object
+	if err := json.Unmarshal([]byte(noteString), &note); err != nil {
+		r.Log.Warn("Failed to unmarshal post to edit", "hash", hash, "error", err)
+		w.Error()
+		return
+	}
+
+	var edits int
+	if err := r.QueryRow(`select count(*) from outbox where activity->>'object.id' = ? and (activity->>'type' = 'Update' or activity->>'type' = 'Create')`, note.ID).Scan(&edits); err != nil {
+		r.Log.Warn("Failed to count post edits", "hash", hash, "error", err)
+		w.Error()
+		return
+	}
+
+	lastEditTime := note.Published
+	if note.Updated != nil && *note.Updated != (time.Time{}) {
+		lastEditTime = *note.Updated
+	}
+
+	canEdit := lastEditTime.Add(time.Minute * time.Duration(math.Pow(4, float64(edits))))
+	if time.Now().Before(canEdit) {
+		r.Log.Warn("Throttled request to edit post", "note", note.ID, "can", canEdit)
+		w.Status(40, "Please try again later")
+		return
+	}
+
+	content, err := url.QueryUnescape(r.URL.RawQuery)
+	if err != nil {
+		w.Error()
+		return
+	}
+
+	if len(content) > cfg.MaxPostsLength {
+		w.Status(40, "Post is too long")
+		return
+	}
+
+	if err := fed.Edit(r.Context, r.DB, &note, plain.ToHTML(content)); err != nil {
+		r.Log.Error("Failed to update post", "note", note.ID, "error", err)
+		w.Error()
+		return
+	}
+
+	w.Redirectf("/users/view/%s", hash)
+}

front/print.go

@@ -196,6 +196,10 @@ func (r *request) PrintNote(w text.Writer, note *ap.Object, author *ap.Actor, gr
 		title = note.Published.Format(time.DateOnly)
 	}
 
+	if note.Updated != nil && *note.Updated != (time.Time{}) {
+		title += " ┃ edited"
+	}
+
 	var parentAuthor ap.Actor
 	if note.InReplyTo != "" {
 		var parentAuthorString string
@@ -312,6 +316,9 @@ func (r *request) PrintNote(w text.Writer, note *ap.Object, author *ap.Actor, gr
 			return true
 		})
 
+		if r.User != nil && note.AttributedTo == r.User.ID {
+			w.Link(fmt.Sprintf("/users/edit/%x", sha256.Sum256([]byte(note.ID))), "😱 Edit")
+		}
 		if r.User != nil {
 			w.Link(fmt.Sprintf("/users/reply/%x", sha256.Sum256([]byte(note.ID))), "💬 Reply")
 		}

migrations/005_edits.go

@@ -0,0 +1,14 @@
+package migrations
+
+import (
+	"context"
+	"database/sql"
+)
+
+func edits(ctx context.Context, tx *sql.Tx) error {
+	if _, err := tx.ExecContext(ctx, `CREATE INDEX outboxobjectid ON outbox(activity->>'object.id')`); err != nil {
+		return err
+	}
+
+	return nil
+}

migrations/add.sh

@@ -27,7 +27,7 @@ import (
 	"database/sql"
 )
 
-func $1(ctx context.Context, db *sql.DB) error {
+func $1(ctx context.Context, tx *sql.Tx) error {
 	// do stuff
 
 	return nil