m->d fix a few markdown escaping problems

m2d/converters/event-to-message.js

@@ -22,13 +22,48 @@ const BLOCK_ELEMENTS = [
 	"TFOOT", "TH", "THEAD", "TR", "UL"
 ]
 
+/** @type {[RegExp, string][]} */
+const markdownEscapes = [
+	[/\\/g, '\\\\'],
+	[/\*/g, '\\*'],
+	[/^-/g, '\\-'],
+	[/^\+ /g, '\\+ '],
+	[/^(=+)/g, '\\$1'],
+	[/^(#{1,6}) /g, '\\$1 '],
+	[/`/g, '\\`'],
+	[/^~~~/g, '\\~~~'],
+	[/\[/g, '\\['],
+	[/\]/g, '\\]'],
+	[/^>/g, '\\>'],
+	[/_/g, '\\_'],
+	[/^(\d+)\. /g, '$1\\. ']
+ ]
+
 const turndownService = new TurndownService({
 	hr: "----",
 	headingStyle: "atx",
 	preformattedCode: true,
-	codeBlockStyle: "fenced"
+	codeBlockStyle: "fenced",
 })
 
+/**
+ * Markdown characters in the HTML content need to be escaped, though take care not to escape the middle of bare links
+ * @param {string} string
+ */
+// @ts-ignore bad type from turndown
+turndownService.escape = function (string) {
+	const escapedWords = string.split(" ").map(word => {
+		if (word.match(/^https?:\/\//)) {
+			return word
+		} else {
+			return markdownEscapes.reduce(function (accumulator, escape) {
+				return accumulator.replace(escape[0], escape[1])
+		 	}, word)
+		}
+	})
+	return escapedWords.join(" ")
+}
+
 turndownService.remove("mx-reply")
 
 turndownService.addRule("strikethrough", {
@@ -67,7 +102,6 @@ turndownService.addRule("spoiler", {
 turndownService.addRule("inlineLink", {
 	filter: function (node, options) {
 		return (
-			options.linkStyle === "inlined" &&
 			node.nodeName === "A" &&
 			node.getAttribute("href")
 		)
@@ -275,8 +309,9 @@ async function eventToMessage(event, guild, di) {
 				content = `* ${displayName} ${content}`
 			}
 
-			// Markdown needs to be escaped
+			// Markdown needs to be escaped, though take care not to escape the middle of links
-			content = content.replace(/([*_~`#])/g, `\\$1`)
+			// @ts-ignore bad type from turndown
+			content = turndownService.escape(content)
 		}
 	} else if (event.type === "m.room.message" && (event.content.msgtype === "m.file" || event.content.msgtype === "m.video" || event.content.msgtype === "m.audio" || event.content.msgtype === "m.image")) {
 		content = ""

m2d/converters/event-to-message.test.js

@@ -64,11 +64,11 @@ test("event2message: body is used when there is no formatted_body", async t => {
 	)
 })
 
-test("event2message: any markdown in body is escaped", async t => {
+test("event2message: any markdown in body is escaped, except strikethrough", async t => {
 	t.deepEqual(
 		await eventToMessage({
 			content: {
-				body: "testing **special** ~~things~~ which _should_ *not* `trigger` @any <effects>",
+				body: "testing **special** ~~things~~ which _should_ *not* `trigger` @any <effects>, except strikethrough",
 				msgtype: "m.text"
 			},
 			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
@@ -85,7 +85,67 @@ test("event2message: any markdown in body is escaped", async t => {
 			messagesToEdit: [],
 			messagesToSend: [{
 				username: "cadence [they]",
-				content: "testing \\*\\*special\\*\\* \\~\\~things\\~\\~ which \\_should\\_ \\*not\\* \\`trigger\\` @any <effects>",
+				content: "testing \\*\\*special\\*\\* ~~things~~ which \\_should\\_ \\*not\\* \\`trigger\\` @any <effects>, except strikethrough",
+				avatar_url: undefined
+			}]
+		}
+	)
+})
+
+test("event2message: links in formatted body are not broken", async t => {
+	t.deepEqual(
+		await eventToMessage({
+			type: "m.room.message",
+			sender: "@cadence:cadence.moe",
+			content: {
+				msgtype: "m.text",
+				body: "kyuugryphon I wonder what the midjourney text description of this photo is https://upload.wikimedia.org/wikipedia/commons/f/f3/After_gay_pride%2C_rainbow_flags_flying_along_Beach_Street_%2814853144744%29.jpg",
+				format: "org.matrix.custom.html",
+				formatted_body: "<a href=\"https://matrix.to/#/@_ooye_kyuugryphon:cadence.moe\">kyuugryphon</a> I wonder what the midjourney text description of this photo is https://upload.wikimedia.org/wikipedia/commons/f/f3/After_gay_pride%2C_rainbow_flags_flying_along_Beach_Street_%2814853144744%29.jpg"
+			},
+			origin_server_ts: 1693739630700,
+			unsigned: {
+				age: 39,
+				transaction_id: "m1693739630587.160"
+			},
+			event_id: "$zANQGOdnHKZj48lrajojsejH86KNYST26imgb2Sw1Jg",
+			room_id: "!kLRqKKUQXcibIMtOpl:cadence.moe"
+		}),
+		{
+			messagesToDelete: [],
+			messagesToEdit: [],
+			messagesToSend: [{
+				username: "cadence [they]",
+				content: "<@111604486476181504> I wonder what the midjourney text description of this photo is https://upload.wikimedia.org/wikipedia/commons/f/f3/After_gay_pride%2C_rainbow_flags_flying_along_Beach_Street_%2814853144744%29.jpg",
+				avatar_url: undefined
+			}]
+		}
+	)
+})
+
+test("event2message: links in plaintext body are not broken", async t => {
+	t.deepEqual(
+		await eventToMessage({
+			type: "m.room.message",
+			sender: "@cadence:cadence.moe",
+			content: {
+				msgtype: "m.text",
+				body: "I wonder what the midjourney text description of this photo is https://upload.wikimedia.org/wikipedia/commons/f/f3/After_gay_pride%2C_rainbow_flags_flying_along_Beach_Street_%2814853144744%29.jpg",
+			},
+			origin_server_ts: 1693739630700,
+			unsigned: {
+				age: 39,
+				transaction_id: "m1693739630587.160"
+			},
+			event_id: "$zANQGOdnHKZj48lrajojsejH86KNYST26imgb2Sw1Jg",
+			room_id: "!kLRqKKUQXcibIMtOpl:cadence.moe"
+		}),
+		{
+			messagesToDelete: [],
+			messagesToEdit: [],
+			messagesToSend: [{
+				username: "cadence [they]",
+				content: "I wonder what the midjourney text description of this photo is https://upload.wikimedia.org/wikipedia/commons/f/f3/After_gay_pride%2C_rainbow_flags_flying_along_Beach_Street_%2814853144744%29.jpg",
 				avatar_url: undefined
 			}]
 		}
@@ -99,7 +159,7 @@ test("event2message: basic html is converted to markdown", async t => {
 				msgtype: "m.text",
 				body: "wrong body",
 				format: "org.matrix.custom.html",
-				formatted_body: "this <strong>is</strong> a <em><strong>test</strong> <u>of</u></em> <del>formatting</del>"
+				formatted_body: "this <strong>is</strong> a <em><strong>test</strong> <u>of</u></em> <del><em>formatting</em></del>"
 			},
 			event_id: "$g07oYSZFWBkxohNEfywldwgcWj1hbhDzQ1sBAKvqOOU",
 			origin_server_ts: 1688301929913,
@@ -115,7 +175,7 @@ test("event2message: basic html is converted to markdown", async t => {
 			messagesToEdit: [],
 			messagesToSend: [{
 				username: "cadence [they]",
-				content: "this **is** a _**test** __of___ ~~formatting~~",
+				content: "this **is** a _**test** __of___ ~~_formatting_~~",
 				avatar_url: undefined
 			}]
 		}
@@ -449,7 +509,7 @@ test("event2message: m.emote plaintext works", async t => {
 			messagesToEdit: [],
 			messagesToSend: [{
 				username: "cadence [they]",
-				content: "\\* cadence [they] tests an m.emote message",
+				content: "\\* cadence \\[they\\] tests an m.emote message",
 				avatar_url: undefined
 			}]
 		}