Add discussions support

classes/CSteamDiscussion.js

@@ -0,0 +1,221 @@
+const Cheerio = require('cheerio');
+const SteamID = require('steamid');
+const StdLib = require('@doctormckay/stdlib');
+
+const SteamCommunity = require('../index.js');
+const Helpers = require('../components/helpers.js');
+
+const EDiscussionType = require('../resources/EDiscussionType.js');
+
+
+/**
+ * Scrape a discussion's DOM to get all available information
+ * @param {string} url - SteamCommunity url pointing to the discussion to fetch
+ * @param {function} callback - First argument is null/Error, second is object containing all available information
+ */
+SteamCommunity.prototype.getSteamDiscussion = function(url, callback) {
+	// Construct object holding all the data we can scrape
+	let discussion = {
+		id: null,
+		type: null,
+		appID: null,
+		forumID: null,
+		gidforum: null, // This is some id used as parameter 2 in post requests
+		topicOwner: null, // This is some id used as parameter 1 in post requests
+		author: null,
+		postedDate: null,
+		title: null,
+		content: null,
+		commentsAmount: null, // I originally wanted to fetch all comments by default but that would have been a lot of potentially unused data
+		answerCommentIndex: null,
+		accountCanComment: null // Is this account allowed to comment on this discussion?
+	};
+
+	// Get DOM of discussion
+	return StdLib.Promises.callbackPromise(null, callback, true, async (resolve, reject) => {
+		let result = await this.httpRequest({
+			method: 'GET',
+			url: url + '?l=en',
+			source: 'steamcommunity'
+		});
+
+
+		try {
+
+			/* --------------------- Preprocess output --------------------- */
+
+			// Load output into cheerio to make parsing easier
+			let $ = Cheerio.load(result.textBody);
+
+			// Get breadcrumbs once. Depending on the type of discussion, it either uses "forum" or "group" breadcrumbs
+			let breadcrumbs = $('.forum_breadcrumbs').children();
+
+			if (breadcrumbs.length == 0) breadcrumbs = $('.group_breadcrumbs').children();
+
+			// Steam redirects us to the forum page if the discussion does not exist which we can detect by missing breadcrumbs
+			if (!breadcrumbs[0]) {
+				reject(new Error('Discussion not found'));
+				return;
+			}
+
+			/* --------------------- Find and map values --------------------- */
+
+			// Determine type from URL as some checks will deviate, depending on the type
+			if (url.includes('steamcommunity.com/discussions/forum'))     discussion.type = EDiscussionType.Forum;
+			if (/steamcommunity.com\/app\/.+\/discussions/g.test(url))    discussion.type = EDiscussionType.App;
+			if (/steamcommunity.com\/groups\/.+\/discussions/g.test(url)) discussion.type = EDiscussionType.Group;
+			if (/steamcommunity.com\/app\/.+\/eventcomments/g.test(url))  discussion.type = EDiscussionType.Eventcomments;
+
+
+			// Get appID from breadcrumbs if this discussion is associated to one
+			if (discussion.type == EDiscussionType.App) {
+				let appIdHref = breadcrumbs[0].attribs.href.split('/');
+
+				discussion.appID = appIdHref[appIdHref.length - 1];
+			}
+
+
+			// Get forumID from breadcrumbs - Ignore for type Eventcomments as it doesn't have multiple forums
+			if (discussion.type != EDiscussionType.Eventcomments) {
+				let forumIdHref;
+
+				if (discussion.type == EDiscussionType.Group) { // Groups have an extra breadcrumb so we need to shift by 2
+					forumIdHref = breadcrumbs[4].attribs.href.split('/');
+				} else {
+					forumIdHref = breadcrumbs[2].attribs.href.split('/');
+				}
+
+				discussion.forumID = forumIdHref[forumIdHref.length - 2];
+			}
+
+
+			// Get id, gidforum and topicOwner. The first is used in the URL itself, the other two only in post requests
+			let gids = $('.forum_paging > .forum_paging_controls').attr('id').split('_');
+
+			discussion.id = gids[4];
+			discussion.gidforum = gids[3];
+			discussion.topicOwner = gids[2];
+
+
+			// Find postedDate and convert to timestamp
+			let posted = $('.topicstats > .topicstats_label:contains("Date Posted:")').next().text();
+
+			discussion.postedDate = Helpers.decodeSteamTime(posted.trim());
+
+
+			// Find commentsAmount
+			discussion.commentsAmount = Number($('.topicstats > .topicstats_label:contains("Posts:")').next().text());
+
+
+			// Get discussion title & content
+			discussion.title = $('.forum_op > .topic').text().trim();
+			discussion.content = $('.forum_op > .content').text().trim();
+
+
+			// Find comment marked as answer
+			let hasAnswer = $('.commentthread_answer_bar');
+
+			if (hasAnswer.length != 0) {
+				let answerPermLink = hasAnswer.next().children('.forum_comment_permlink').text().trim();
+
+				// Convert comment id to number, remove hashtag and subtract by 1 to make it an index
+				discussion.answerCommentIndex = Number(answerPermLink.replace('#', '')) - 1;
+			}
+
+
+			// Check if this account is allowed to comment on this discussion
+			let cannotReplyReason = $('.topic_cannotreply_reason');
+
+			discussion.accountCanComment = cannotReplyReason.length == 0;
+
+
+			// Find author and convert to SteamID object - Ignore for type Eventcomments as they are posted by the "game", not by an Individual
+			if (discussion.type != EDiscussionType.Eventcomments) {
+				let authorLink = $('.forum_op_author').attr('href');
+
+				Helpers.resolveVanityURL(authorLink, (err, data) => { // This request takes <1 sec
+					if (err) {
+						reject(err);
+						return;
+					}
+
+					discussion.author = new SteamID(data.steamID);
+
+					// Resolve when ID was resolved as otherwise owner will always be null
+					resolve(new CSteamDiscussion(this, discussion));
+				});
+			} else {
+				resolve(new CSteamDiscussion(this, discussion));
+			}
+
+		} catch (err) {
+			reject(err);
+		}
+	});
+};
+
+
+/**
+ * Constructor - Creates a new Discussion object
+ * @class
+ * @param {SteamCommunity} community
+ * @param {{ id: string, type: EDiscussionType, appID: string, forumID: string, gidforum: string, topicOwner: string, author: SteamID, postedDate: Object, title: string, content: string, commentsAmount: number, answerCommentIndex: number, accountCanComment: boolean }} data
+ */
+function CSteamDiscussion(community, data) {
+	/**
+	 * @type {SteamCommunity}
+	 */
+	this._community = community;
+
+	// Clone all the data we received
+	Object.assign(this, data);
+}
+
+
+/**
+ * Scrapes a range of comments from this discussion
+ * @param {number} startIndex - Index (0 based) of the first comment to fetch
+ * @param {number} endIndex - Index (0 based) of the last comment to fetch
+ * @param {function} callback - First argument is null/Error, second is array containing the requested comments
+ */
+CSteamDiscussion.prototype.getComments = function(startIndex, endIndex, callback) {
+	this._community.getDiscussionComments(`https://steamcommunity.com/app/${this.appID}/discussions/${this.forumID}/${this.id}`, startIndex, endIndex, callback);
+};
+
+
+/**
+ * Posts a comment to this discussion's comment section
+ * @param {String} message - Content of the comment to post
+ * @param {function} callback - Takes only an Error object/null as the first argument
+ */
+CSteamDiscussion.prototype.comment = function(message, callback) {
+	this._community.postDiscussionComment(this.topicOwner, this.gidforum, this.id, message, callback);
+};
+
+
+/**
+ * Delete a comment from this discussion's comment section
+ * @param {String} gidcomment - ID of the comment to delete
+ * @param {function} callback - Takes only an Error object/null as the first argument
+ */
+CSteamDiscussion.prototype.deleteComment = function(gidcomment, callback) {
+	this._community.deleteDiscussionComment(this.topicOwner, this.gidforum, this.id, gidcomment, callback);
+};
+
+
+/**
+ * Subscribes to this discussion's comment section
+ * @param {function} callback - Takes only an Error object/null as the first argument
+ */
+CSteamDiscussion.prototype.subscribe = function(callback) {
+	this._community.subscribeDiscussionComments(this.topicOwner, this.gidforum, this.id, callback);
+};
+
+
+/**
+ * Unsubscribes from this discussion's comment section
+ * @param {function} callback - Takes only an Error object/null as the first argument
+ */
+CSteamDiscussion.prototype.unsubscribe = function(callback) {
+	this._community.unsubscribeDiscussionComments(this.topicOwner, this.gidforum, this.id, callback);
+};