First release

src/site/api/proxy.js

@@ -0,0 +1,61 @@
+const constants = require("../../lib/constants")
+const {request} = require("../../lib/utils/request")
+const {proxy} = require("pinski/plugins")
+const gm = require("gm")
+
+module.exports = [
+	{route: "/imageproxy", methods: ["GET"], code: async (input) => {
+		/** @type {URL} */
+		// check url param exists
+		const completeURL = input.url
+		const params = completeURL.searchParams
+		if (!params.get("url")) return [400, "Must supply `url` query parameter"]
+		try {
+			var url = new URL(params.get("url"))
+		} catch (e) {
+			return [400, "`url` query parameter is not a valid URL"]
+		}
+		// check url protocol
+		if (url.protocol !== "https:") return [400, "URL protocol must be `https:`"]
+		// check url host
+		if (!["fbcdn.net", "cdninstagram.com"].some(host => url.host.endsWith(host))) return [400, "URL host is not allowed"]
+		if (!["png", "jpg"].some(ext => url.pathname.endsWith(ext))) return [400, "URL extension is not allowed"]
+		const width = +params.get("width")
+		if (typeof width === "number" && !isNaN(width) && width > 0) {
+			/*
+				This uses graphicsmagick to force crop the image to a square.
+				Some thumbnails aren't square and will be stretched on the page without this.
+				If I cropped the images client side, it would have to be done with CSS background-image, which means no <img srcset>.
+			*/
+			return request(url).then(res => {
+				const image = gm(res.body).gravity("Center").crop(width, width, 0, 0).repage("+")
+				return {
+					statusCode: 200,
+					contentType: "image/jpeg",
+					headers: {
+						"Cache-Control": constants.image_cache_control
+					},
+					stream: image.stream("jpg")
+				}
+				/*
+					Alternative buffer-based method for sending file:
+
+					return new Promise(resolve => {
+						image.toBuffer((err, buffer) => {
+							if (err) console.error(err)
+							resolve({
+								statusCode: 200,
+								contentType: "image/jpeg",
+								content: buffer
+							})
+						})
+					})
+				*/
+			})
+		} else {
+			return proxy(url, {
+				"Cache-Control": constants.image_cache_control
+			})
+		}
+	}}
+]