1 files changed, 83 insertions, 0 deletions
diff --git a/src/server/img.ts b/src/server/img.ts
new file mode 100644
index 0000000..7006c3d
--- /dev/null
+++ b/src/server/img.ts
@@ -0,0 +1,83 @@
+import sharp from "sharp"
+import { createReadStream } from "node:fs"
+import { extname, join } from "node:path"
+import createError from "http-errors"
+import type express from "express"
+
+function transform(format: keyof sharp.FormatEnum, width?: number, height?: number): sharp.Sharp {
+	var transform = sharp().withMetadata()
+
+	if (format) {
+		transform = transform.toFormat(format)
+	}
+
+	if (width || height) {
+		transform = transform.resize({ width, height })
+	}
+
+	return transform
+}
+
+function errorHand(next: express.NextFunction) {
+	return function (err: NodeJS.ErrnoException) {
+		switch (err.code) {
+			case "ENOENT":
+				next()
+				break
+			case "EISDIR":
+			case "EPERM":
+				next(createError(401))
+				break
+			default:
+				next(err)
+		}
+	}
+}
+
+export default function (path: string) {
+	return async function (req: express.Request, res: express.Response, next: express.NextFunction) {
+		const err_handler = errorHand(next)
+
+		const filepath = join(path, req.path)
+		const ext = extname(filepath).substring(1)
+		if (![
+			"svg", "heic", "heif", "avif", "jpeg", "jpg", "jpe", "tile", "dz",
+			"png", "raw", "tiff", "tif", "webp", "gif", "jp2", "jpx", "j2k",
+			"j2c", "jxl"
+		].includes(ext)) {
+			return next()
+		}
+		const width = parseInt(String(req.query['width']))
+		const height = parseInt(String(req.query['height']))
+		var { format = ext } = req.query as { format?: string }
+		if (format == "svg") {
+			if (ext == "svg") {
+				const stream = createReadStream(filepath)
+				stream.on("error", err_handler)
+				res.format({
+					[format]: function () {
+						return stream.pipe(res)
+					}
+				})
+			} else {
+				return next(createError(400))
+			}
+			return
+		}
+
+		const stream = createReadStream(filepath)
+		stream.on("error", err_handler)
+		res.format({
+			[format]: function () {
+				return stream.pipe(
+					transform(
+						format as keyof sharp.FormatEnum,
+						!isNaN(width) ? width : undefined,
+						!isNaN(height) ? height : undefined
+					)
+				).pipe(res)
+			}
+		})
+	}
+}
+