Refactor video access route

- Move errors to separate files instead of embedding
- Consistent interface for error generation
- Move renderVideo function into route
- Fix unhandled FetchError regression from dbbe950

api/video.js

@@ -14,6 +14,9 @@ class InstanceError extends Error {
 	}
 }
 
+class MessageError extends Error {
+}
+
 function formatOrder(format) {
 	// most significant to least significant
 	// key, max, order, transform
@@ -90,96 +93,11 @@ function sortFormats(video, preference) {
 	return formats
 }
 
-async function renderVideo(video, {user, settings, id, instanceOrigin}, locals = {}) {
-	try {
-		if (!video) throw new Error("The instance returned null.")
-		if (video.error) throw new InstanceError(video.error, video.identifier)
-
-		// process stream list ordering
-		const formats = sortFormats(video, settings.quality)
-
-		// process length text and view count
-		for (const rec of video.recommendedVideos) {
-			converters.normaliseVideoInfo(rec)
-		}
-
-		// get subscription data
-		const subscribed = user.isSubscribed(video.authorId)
-
-		// process watched videos
-		user.addWatchedVideoMaybe(video.videoId)
-		const watchedVideos = user.getWatchedVideos()
-		if (watchedVideos.length) {
-			for (const rec of video.recommendedVideos) {
-				rec.watched = watchedVideos.includes(rec.videoId)
-			}
-		}
-
-		// normalise view count
-		if (!video.second__viewCountText && video.viewCount) {
-			video.second__viewCountText = converters.viewCountToText(video.viewCount)
-		}
-
-		// rewrite description
-		video.descriptionHtml = converters.rewriteVideoDescription(video.descriptionHtml, id)
-
-		return render(200, "pug/video.pug", Object.assign(locals, {video, formats, subscribed, instanceOrigin}))
-	} catch (e) {
-		// show an appropriate error message
-		// these should probably be split out to their own files
-		let message = pug.render("pre= error", {error: e.stack || e.toString()})
-		if (e instanceof fetch.FetchError) {
-			const template = `
-p The selected instance, #[code= instanceOrigin], did not respond correctly.
-`
-			message = pug.render(template, {instanceOrigin})
-		} else if (e instanceof InstanceError) {
-			if (e.identifier === "RATE_LIMITED_BY_YOUTUBE" || e.message === "Could not extract video info. Instance is likely blocked.") {
-				const template = `
-.blocked-explanation
-	img(src="/static/images/instance-blocked.svg" width=552 height=96)
-	.rows
-		.row
-			h3.actor You
-			| Working
-		.row
-			h3.actor CloudTube
-			| Working
-		.row
-			h3.actor Instance
-			| Blocked by YouTube
-		.row
-			h3.actor YouTube
-			| Working
-p.
-	CloudTube needs a working NewLeaf/Invidious instance in order to get data about videos.
-	However, the selected instance, #[code= instanceOrigin], has been temporarily blocked by YouTube.
-p.
-	You will be able to watch this video if you select a working instance in settings.
-	#[br]#[a(href="/settings") Go to settings →]
-p.
-	(Tip: Try #[code https://invidious.snopyta.org] or #[code https://invidious.site].)
-p.
-	This situation #[em will] be improved in the future!
-`
-				message = pug.render(template, {instanceOrigin})
-			} else {
-				const template = `
-p #[strong= error.message]
-if error.identifier
-	p #[code= error.identifier]
-p That error was generated by #[code= instanceOrigin].
-`
-				message = pug.render(template, {instanceOrigin, error: e})
-			}
-		}
-		return render(500, "pug/video.pug", {video: {videoId: id}, error: true, message})
-	}
-}
-
 module.exports = [
 	{
 		route: "/watch", methods: ["GET", "POST"], upload: true, code: async ({req, url, body}) => {
+			// Prepare data needed to render video page
+
 			const user = getUser(req)
 			const settings = user.getSettingsOrDefaults()
 			const id = url.searchParams.get("v")
@@ -196,23 +114,84 @@ module.exports = [
 			const sessionWatchedNext = sessionWatched.concat([id]).join("+")
 			if (continuous) settings.quality = 0 // autoplay with synced streams does not work
 
+			// Work out how to fetch the video
 			if (req.method === "GET") {
 				if (settings.local) { // skip to the local fetching page, which will then POST video data in a moment
 					return render(200, "pug/local-video.pug", {id})
 				}
 				var instanceOrigin = settings.instance
 				var outURL = `${instanceOrigin}/api/v1/videos/${id}`
-				var video = await request(outURL).then(res => res.json())
+				var videoFuture = request(outURL).then(res => res.json())
 			} else { // req.method === "POST"
 				var instanceOrigin = "http://localhost:3000"
-				var video = JSON.parse(new URLSearchParams(body.toString()).get("video"))
+				var videoFuture = JSON.parse(new URLSearchParams(body.toString()).get("video"))
 			}
 
-			return renderVideo(video, {
-				user, settings, id, instanceOrigin
-			}, {
-				mediaFragment, autoplay, continuous, sessionWatched, sessionWatchedNext
-			})
+			try {
+				// Fetch the video
+				const video = await videoFuture
+
+				// Error handling
+				if (!video) throw new MessageError("The instance returned null.")
+				if (video.error) throw new InstanceError(video.error, video.identifier)
+
+				// process stream list ordering
+				const formats = sortFormats(video, settings.quality)
+
+				// process length text and view count
+				for (const rec of video.recommendedVideos) {
+					converters.normaliseVideoInfo(rec)
+				}
+
+				// get subscription data
+				const subscribed = user.isSubscribed(video.authorId)
+
+				// process watched videos
+				user.addWatchedVideoMaybe(video.videoId)
+				const watchedVideos = user.getWatchedVideos()
+				if (watchedVideos.length) {
+					for (const rec of video.recommendedVideos) {
+						rec.watched = watchedVideos.includes(rec.videoId)
+					}
+				}
+
+				// normalise view count
+				if (!video.second__viewCountText && video.viewCount) {
+					video.second__viewCountText = converters.viewCountToText(video.viewCount)
+				}
+
+				// rewrite description
+				video.descriptionHtml = converters.rewriteVideoDescription(video.descriptionHtml, id)
+
+				return render(200, "pug/video.pug", {
+					video, formats, subscribed, instanceOrigin, mediaFragment, autoplay, continuous,
+					sessionWatched, sessionWatchedNext
+				})
+
+			} catch (error) {
+				// Something went wrong, somewhere! Find out where.
+
+				let errorType = "unrecognised-error"
+				const locals = {instanceOrigin, error}
+
+				// Sort error category
+				if (error instanceof fetch.FetchError) {
+					errorType = "fetch-error"
+				} else if (error instanceof MessageError) {
+					errorType = "message-error"
+				} else if (error instanceof InstanceError) {
+					if (error.identifier === "RATE_LIMITED_BY_YOUTUBE" || error.message === "Could not extract video info. Instance is likely blocked.") {
+						errorType = "rate-limited"
+					} else {
+						errorType = "instance-error"
+					}
+				}
+
+				// Create appropriate formatted message
+				const message = render(0, `pug/errors/${errorType}.pug`, locals).content
+
+				return render(500, "pug/video.pug", {video: {videoId: id}, error: true, message})
+			}
 		}
 	}
 ]

pug/errors/fetch-error.pug

@@ -0,0 +1,5 @@
+p The selected instance, #[code= instanceOrigin], was unreachable.
+details
+  summary If the instance is on a private network
+  p The instance URL was resolved by the server. If the instance is on a private network, CloudTube will not be able to connect back to it.
+  p To get around this error, you may be able to use local mode, or you can run your own CloudTube within the network.

pug/errors/instance-error.pug

@@ -0,0 +1,4 @@
+p #[strong= error.message]
+if error.identifier
+  p #[code= error.identifier]
+p That error was generated by #[code= instanceOrigin].

pug/errors/message-error.pug

@@ -0,0 +1 @@
+pre= error.toString()

pug/errors/rate-limited.pug

@@ -0,0 +1,25 @@
+.blocked-explanation
+  img(src="/static/images/instance-blocked.svg" width=552 height=96)
+  .rows
+    .row
+      h3.actor You
+      | Working
+    .row
+      h3.actor CloudTube
+      | Working
+    .row
+      h3.actor Instance
+      | Blocked by YouTube
+    .row
+      h3.actor YouTube
+      | Working
+p.
+  CloudTube needs a working NewLeaf/Invidious instance in order to get data about videos.
+  However, the selected instance, #[code= instanceOrigin], has been temporarily blocked by YouTube.
+p.
+  You will be able to watch this video if you select a working instance in settings.
+  #[br]#[a(href="/settings") Go to settings →]
+p.
+  (Tip: Try #[code https://invidious.snopyta.org] or #[code https://invidious.site].)
+p.
+  This situation #[em will] be improved in the future!

pug/errors/unrecognised-error.pug

@@ -0,0 +1 @@
+pre= error.stack || error.toString()

server.js

@@ -16,6 +16,7 @@ const {setInstance} = require("pinski/plugins")
 	server.addRoute("/static/css/main.css", "sass/main.sass", "sass")
 
 	server.addPugDir("pug", ["pug/includes"])
+	server.addPugDir("pug/errors")
 	server.addRoute("/cant-think", "pug/cant-think.pug", "pug")
 	server.addRoute("/privacy", "pug/privacy.pug", "pug")
 	server.addRoute("/js-licenses", "pug/js-licenses.pug", "pug")