feat: #9109, ability to delete a post's diffs

public/language/en-GB/topic.json

@@ -183,8 +183,10 @@
 	"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.restore-description": "A new revision will be appended to this post's edit history after restoring.",
 	"diffs.post-restored": "Post successfully restored to earlier revision",
+	"diffs.delete": "Delete this revision",
+	"diffs.deleted": "Revision deleted",
 
 	"timeago_later": "%1 later",
 	"timeago_earlier": "%1 earlier",

public/src/client/topic/diffs.js

@@ -1,6 +1,6 @@
 'use strict';
 
-define('forum/topic/diffs', ['api', 'forum/topic/images'], function (api) {
+define('forum/topic/diffs', ['api', 'bootbox', 'forum/topic/images'], function (api, bootbox) {
 	var Diffs = {};
 
 	Diffs.open = function (pid) {
@@ -8,6 +8,44 @@ define('forum/topic/diffs', ['api', 'forum/topic/images'], function (api) {
 			return;
 		}
 
+		openModal(pid);
+	};
+
+	Diffs.load = function (pid, since, postContainer) {
+		if (!config.enablePostHistory) {
+			return;
+		}
+
+		api.get(`/posts/${pid}/diffs/${since}`, {}).then((data) => {
+			data.deleted = !!parseInt(data.deleted, 10);
+
+			app.parseAndTranslate('partials/posts_list', 'posts', {
+				posts: [data],
+			}, function (html) {
+				postContainer.empty().append(html);
+			});
+		}).catch(app.alertError);
+	};
+
+	Diffs.restore = function (pid, since, modal) {
+		if (!config.enablePostHistory) {
+			return;
+		}
+
+		api.put(`/posts/${pid}/diffs/${since}`, {}).then(() => {
+			modal.modal('hide');
+			app.alertSuccess('[[topic:diffs.post-restored]]');
+		}).catch(app.alertError);
+	};
+
+	Diffs.delete = function (pid, timestamp, modal) {
+		api.del(`/posts/${pid}/diffs/${timestamp}`).then(() => {
+			openModal(pid, modal);
+			app.alertSuccess('[[topic:diffs.deleted]]');
+		}).catch(app.alertError);
+	};
+
+	function openModal(pid, modal) {
 		var localeStringOpts = { year: 'numeric', month: 'short', day: 'numeric', hour: 'numeric', minute: 'numeric' };
 
 		api.get(`/posts/${pid}/diffs`, {}).then((data) => {
@@ -23,12 +61,18 @@ define('forum/topic/diffs', ['api', 'forum/topic/images'], function (api) {
 				}),
 				numDiffs: data.timestamps.length,
 				editable: data.editable,
+				deletable: data.deletable,
 			}, function (html) {
-				var modal = bootbox.dialog({
-					title: '[[topic:diffs.title]]',
-					message: html,
-					size: 'large',
-				});
+				const modalExists = !!modal;
+				if (modalExists) {
+					modal.find('.modal-body').html(html);
+				} else {
+					modal = bootbox.dialog({
+						title: '[[topic:diffs.title]]',
+						message: html,
+						size: 'large',
+					});
+				}
 
 				if (!data.timestamps.length) {
 					return;
@@ -36,51 +80,35 @@ define('forum/topic/diffs', ['api', 'forum/topic/images'], function (api) {
 
 				var selectEl = modal.find('select');
 				var revertEl = modal.find('button[data-action="restore"]');
+				var deleteEl = modal.find('button[data-action="delete"]');
 				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) === 0);
+					deleteEl.prop('disabled', data.timestamps.indexOf(this.value) === 0);
 				});
 
 				revertEl.on('click', function () {
 					Diffs.restore(pid, selectEl.val(), modal);
 				});
 
+				deleteEl.on('click', function () {
+					Diffs.delete(pid, selectEl.val(), modal);
+				});
+
 				modal.on('shown.bs.modal', function () {
 					Diffs.load(pid, selectEl.val(), postContainer);
 					revertEl.prop('disabled', true);
+					deleteEl.prop('disabled', true);
 				});
-			});
-		}).catch(app.alertError);
-	};
-
-	Diffs.load = function (pid, since, postContainer) {
-		if (!config.enablePostHistory) {
-			return;
-		}
 
-		api.get(`/posts/${pid}/diffs/${since}`, {}).then((data) => {
-			data.deleted = !!parseInt(data.deleted, 10);
-
-			app.parseAndTranslate('partials/posts_list', 'posts', {
-				posts: [data],
-			}, function (html) {
-				postContainer.empty().append(html);
+				if (modalExists) {
+					modal.trigger('shown.bs.modal');
+				}
 			});
 		}).catch(app.alertError);
-	};
-
-	Diffs.restore = function (pid, since, modal) {
-		if (!config.enablePostHistory) {
-			return;
-		}
-
-		api.put(`/posts/${pid}/diffs/${since}`, {}).then(() => {
-			modal.modal('hide');
-			app.alertSuccess('[[topic:diffs.post-restored]]');
-		}).catch(app.alertError);
-	};
+	}
 
 	return Diffs;
 });

src/api/posts.js

@@ -260,9 +260,14 @@ postsAPI.getDiffs = async (caller, data) => {
 	let usernames = await user.getUsersFields(uids, ['username']);
 	usernames = usernames.map(userObj => (userObj.uid ? userObj.username : null));
 
+	const cid = await posts.getCidByPid(data.pid);
+	const isModerator = await privileges.users.isModerator(cid, caller.uid);
+
 	let canEdit = true;
 	try {
-		await user.isPrivilegedOrSelf(caller.uid, post.uid);
+		if (!isModerator) {
+			await user.isPrivilegedOrSelf(caller.uid, post.uid);
+		}
 	} catch (e) {
 		canEdit = false;
 	}
@@ -276,6 +281,7 @@ postsAPI.getDiffs = async (caller, data) => {
 			username: usernames[idx],
 		})),
 		editable: canEdit,
+		deletable: isModerator,
 	};
 };
 

src/controllers/write/posts.js

@@ -1,6 +1,7 @@
 'use strict';
 
 const posts = require('../../posts');
+const privileges = require('../../privileges');
 
 const api = require('../../api');
 const helpers = require('../helpers');
@@ -94,3 +95,19 @@ Posts.restoreDiff = async (req, res) => {
 	helpers.formatApiResponse(200, res, await api.posts.restoreDiff(req, { ...req.params }));
 };
 
+Posts.deleteDiff = async (req, res) => {
+	if (!parseInt(req.params.pid, 10)) {
+		throw new Error('[[error:invalid-data]]');
+	}
+
+	const cid = await posts.getCidByPid(req.params.pid);
+	const isModerator = privileges.users.isModerator(cid, req.uid);
+
+	if (!isModerator) {
+		return helpers.formatApiResponse(403, res, new Error('[[error:no-privileges]]'));
+	}
+
+	await posts.diffs.delete(req.params.pid, req.params.timestamp, req.uid);
+
+	helpers.formatApiResponse(200, res);
+};

src/posts/diffs.js

@@ -71,28 +71,79 @@ module.exports = function (Posts) {
 		});
 	};
 
-	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);
+	Diffs.delete = async function (pid, timestamp, uid) {
+		getValidatedTimestamp(timestamp);
 
-		if (isNaN(since) || since > Date.now()) {
+		const [post, diffs, timestamps] = await Promise.all([
+			Posts.getPostSummaryByPids([pid], uid, { parse: false }),
+			Diffs.get(pid),
+			Diffs.list(pid),
+		]);
+
+		const timestampIndex = timestamps.indexOf(timestamp);
+		const lastTimestampIndex = timestamps.length - 1;
+
+		if (timestamp === String(post[0].timestamp)) {
+			return Promise.all([
+				db.delete(`diff:${pid}.${timestamps[lastTimestampIndex]}`),
+				db.listRemoveAll(`post:${pid}:diffs`, timestamps[lastTimestampIndex]),
+			]);
+		}
+		if (timestampIndex === 0 || timestampIndex === -1) {
 			throw new Error('[[error:invalid-data]]');
 		}
 
+		const postContent = validator.unescape(post[0].content);
+		const versionContents = {};
+		for (let i = 0, content = postContent; i < timestamps.length; ++i) {
+			versionContents[timestamps[i]] = applyPatch(content, diffs[i]);
+			content = versionContents[timestamps[i]];
+		}
+
+		/* eslint-disable no-await-in-loop */
+		for (let i = lastTimestampIndex; i >= timestampIndex; --i) {
+			const newContentIndex = i === timestampIndex ? i - 2 : i - 1;
+			const timestampToUpdate = newContentIndex + 1;
+			const newContent = newContentIndex < 0 ? postContent : versionContents[timestamps[newContentIndex]];
+			const patch = diff.createPatch('', newContent, versionContents[timestamps[i]]);
+			await db.setObject('diff:' + pid + '.' + timestamps[timestampToUpdate], { patch });
+		}
+
+		return Promise.all([
+			db.delete(`diff:${pid}.${timestamp}`),
+			db.listRemoveAll(`post:${pid}:diffs`, timestamp),
+		]);
+	};
+
+	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 = getValidatedTimestamp(since);
+
 		const [post, diffs] = await Promise.all([
 			Posts.getPostSummaryByPids([pid], uid, { parse: false }),
 			Posts.diffs.get(pid, since),
 		]);
 
 		// Replace content with re-constructed content from that point in time
-		post[0].content = diffs.reduce(function (content, currentDiff) {
-			const result = diff.applyPatch(content, currentDiff.patch, {
-				fuzzFactor: 1,
-			});
-
-			return typeof result === 'string' ? result : content;
-		}, validator.unescape(post[0].content));
+		post[0].content = diffs.reduce(applyPatch, validator.unescape(post[0].content));
 
 		return post[0];
 	}
+
+	function getValidatedTimestamp(timestamp) {
+		timestamp = parseInt(timestamp, 10);
+
+		if (isNaN(timestamp) || timestamp > Date.now()) {
+			throw new Error('[[error:invalid-data]]');
+		}
+
+		return timestamp;
+	}
+
+	function applyPatch(content, aDiff) {
+		const result = diff.applyPatch(content, aDiff.patch, {
+			fuzzFactor: 1,
+		});
+		return typeof result === 'string' ? result : content;
+	}
 };

src/routes/write/posts.js

@@ -29,6 +29,7 @@ module.exports = function () {
 	setupApiRoute(router, 'get', '/:pid/diffs', [middleware.authenticateOrGuest, middleware.assert.post], controllers.write.posts.getDiffs);
 	setupApiRoute(router, 'get', '/:pid/diffs/:since', [middleware.authenticateOrGuest, middleware.assert.post], controllers.write.posts.loadDiff);
 	setupApiRoute(router, 'put', '/:pid/diffs/:since', [...middlewares, middleware.assert.post], controllers.write.posts.restoreDiff);
+	setupApiRoute(router, 'delete', '/:pid/diffs/:timestamp', [...middlewares, middleware.assert.post], controllers.write.posts.deleteDiff);
 
 	return router;
 };