feat: allow post diffs to be restored, #8406

public/language/en-GB/topic.json

@@ -161,6 +161,9 @@
 	"diffs.no-revisions-description": "This post has <strong>%1</strong> revisions.",
 	"diffs.current-revision": "current revision",
 	"diffs.original-revision": "original revision",
+	"diffs.restore": "Restore this revision",
+	"diffs.restore-description": "A new revision will be appended to this post's edit history.",
+	"diffs.post-restored": "Post successfully restored to earlier revision",
 
 	"timeago_later": "%1 later",
 	"timeago_earlier": "%1 earlier"

public/src/client/topic/diffs.js

@@ -10,13 +10,13 @@ define('forum/topic/diffs', ['forum/topic/images', 'benchpress', 'translator'],
 
 		var localeStringOpts = { year: 'numeric', month: 'short', day: 'numeric', hour: 'numeric', minute: 'numeric' };
 
-		socket.emit('posts.getDiffs', { pid: pid }, function (err, timestamps) {
+		socket.emit('posts.getDiffs', { pid: pid }, function (err, data) {
 			if (err) {
 				return app.alertError(err.message);
 			}
 
 			Benchpress.parse('partials/modals/post_history', {
-				diffs: timestamps.map(function (timestamp) {
+				diffs: data.timestamps.map(function (timestamp) {
 					timestamp = parseInt(timestamp, 10);
 
 					return {
@@ -24,7 +24,8 @@ define('forum/topic/diffs', ['forum/topic/images', 'benchpress', 'translator'],
 						pretty: new Date(timestamp).toLocaleString(config.userLang.replace('_', '-'), localeStringOpts),
 					};
 				}),
-				numDiffs: timestamps.length,
+				numDiffs: data.timestamps.length,
+				editable: data.editable,
 			}, function (html) {
 				translator.translate(html, function (html) {
 					var modal = bootbox.dialog({
@@ -33,19 +34,26 @@ define('forum/topic/diffs', ['forum/topic/images', 'benchpress', 'translator'],
 						size: 'large',
 					});
 
-					if (!timestamps.length) {
+					if (!data.timestamps.length) {
 						return;
 					}
 
 					var selectEl = modal.find('select');
+					var revertEl = modal.find('button[data-action="restore"]');
 					var postContainer = modal.find('ul.posts-list');
 
 					selectEl.on('change', function () {
 						Diffs.load(pid, this.value, postContainer);
+						revertEl.prop('disabled', data.timestamps.indexOf(this.value) === -1);
+					});
+
+					revertEl.on('click', function () {
+						Diffs.restore(pid, selectEl.val(), modal);
 					});
 
 					modal.on('shown.bs.modal', function () {
 						Diffs.load(pid, selectEl.val(), postContainer);
+						revertEl.prop('disabled', true);
 					});
 				});
 			});
@@ -72,5 +80,20 @@ define('forum/topic/diffs', ['forum/topic/images', 'benchpress', 'translator'],
 		});
 	};
 
+	Diffs.restore = function (pid, since, modal) {
+		if (!config.enablePostHistory) {
+			return;
+		}
+
+		socket.emit('posts.restoreDiff', { pid: pid, since: since }, function (err) {
+			if (err) {
+				return app.alertError(err);
+			}
+
+			modal.modal('hide');
+			app.alertSuccess('[[topic:diffs.post-restored]]');
+		});
+	};
+
 	return Diffs;
 });

src/posts/diffs.js

@@ -33,12 +33,14 @@ module.exports = function (Posts) {
 		return await db.getListRange('post:' + pid + ':diffs', 0, -1);
 	};
 
-	Diffs.save = async function (pid, oldContent, newContent) {
+	Diffs.save = async function (data) {
+		const { pid, uid, oldContent, newContent } = data;
 		const now = Date.now();
 		const patch = diff.createPatch('', newContent, oldContent);
 		await Promise.all([
 			db.listPrepend('post:' + pid + ':diffs', now),
 			db.setObject('diff:' + pid + '.' + now, {
+				uid: uid,
 				pid: pid,
 				patch: patch,
 			}),
@@ -46,6 +48,31 @@ module.exports = function (Posts) {
 	};
 
 	Diffs.load = async function (pid, since, uid) {
+		const post = await postDiffLoad(pid, since, uid);
+
+		// Clear editor data (as it is outdated for this content)
+		delete post.edited;
+		post.editor = null;
+
+		post.content = String(post.content || '');
+
+		const result = await plugins.fireHook('filter:parse.post', { postData: post });
+		result.postData.content = translator.escape(result.postData.content);
+		return result.postData;
+	};
+
+	Diffs.restore = async function (pid, since, uid, req) {
+		const post = await postDiffLoad(pid, since, uid);
+
+		return await Posts.edit({
+			uid: uid,
+			pid: pid,
+			content: post.content,
+			req: req,
+		});
+	};
+
+	async function postDiffLoad(pid, since, uid) {
 		// Retrieves all diffs made since `since` and replays them to reconstruct what the post looked like at `since`
 		since = parseInt(since, 10);
 
@@ -57,33 +84,16 @@ module.exports = function (Posts) {
 			Posts.getPostSummaryByPids([pid], uid, { parse: false }),
 			Posts.diffs.get(pid, since),
 		]);
-		const data = {
-			post: post,
-			diffs: diffs,
-		};
-		postDiffLoad(data);
-		const result = await plugins.fireHook('filter:parse.post', { postData: data.post });
-		result.postData.content = translator.escape(result.postData.content);
-		return result.postData;
-	};
-
-	function postDiffLoad(data) {
-		data.post = data.post[0];
-		data.post.content = validator.unescape(data.post.content);
 
 		// Replace content with re-constructed content from that point in time
-		data.post.content = data.diffs.reduce(function (content, currentDiff) {
+		post[0].content = diffs.reduce(function (content, currentDiff) {
 			const result = diff.applyPatch(content, currentDiff.patch, {
 				fuzzFactor: 1,
 			});
 
 			return typeof result === 'string' ? result : content;
-		}, data.post.content);
+		}, validator.unescape(post[0].content));
 
-		// Clear editor data (as it is outdated for this content)
-		delete data.post.edited;
-		data.post.editor = null;
-
-		data.post.content = String(data.post.content || '');
+		return post[0];
 	}
 };

src/posts/edit.js

@@ -46,7 +46,12 @@ module.exports = function (Posts) {
 		await Posts.setPostFields(data.pid, postData);
 
 		if (meta.config.enablePostHistory === 1) {
-			await Posts.diffs.save(data.pid, oldContent, data.content);
+			await Posts.diffs.save({
+				pid: data.pid,
+				uid: data.uid,
+				oldContent: oldContent,
+				newContent: data.content,
+			});
 		}
 		await Posts.uploads.sync(data.pid);
 

src/socket.io/posts/diffs.js

@@ -2,13 +2,19 @@
 
 const posts = require('../../posts');
 const privileges = require('../../privileges');
+const websockets = require('..');
 
 module.exports = function (SocketPosts) {
 	SocketPosts.getDiffs = async function (socket, data) {
 		await privilegeCheck(data.pid, socket.uid);
 		const timestamps = await posts.diffs.list(data.pid);
+		const cid = await posts.getCidByPid(data.pid);
+		const canEdit = await privileges.categories.can('edit', cid, socket.uid);
 		timestamps.unshift(Date.now());
-		return timestamps;
+		return {
+			timestamps: timestamps,
+			editable: canEdit,
+		};
 	};
 
 	SocketPosts.showPostAt = async function (socket, data) {
@@ -27,4 +33,15 @@ module.exports = function (SocketPosts) {
 			throw new Error('[[error:no-privileges]]');
 		}
 	}
+
+	SocketPosts.restoreDiff = async function (socket, data) {
+		const cid = await posts.getCidByPid(data.pid);
+		const canEdit = await privileges.categories.can('edit', cid, socket.uid);
+		if (!canEdit) {
+			throw new Error('[[error:no-privileges]]');
+		}
+
+		const edit = await posts.diffs.restore(data.pid, data.since, socket.uid, websockets.reqFromSocket(socket));
+		websockets.in('topic_' + edit.topic.tid).emit('event:post_edited', edit);
+	};
 };