129 lines
3.3 KiB
TypeScript
129 lines
3.3 KiB
TypeScript
import { HandlerContext } from "$fresh/server.ts";
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import {
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ImageMagick,
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initializeImageMagick,
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MagickGeometry,
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} from "https://deno.land/x/imagemagick_deno@0.0.14/mod.ts";
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import { parseMediaType } from "https://deno.land/std@0.175.0/media_types/parse_media_type.ts";
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await initializeImageMagick();
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const cache = new Map<string, Promise<Response>>();
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async function getRemoteImage(image: string) {
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const sourceRes = await fetch(image);
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if (!sourceRes.ok) {
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return "Error retrieving image from URL.";
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}
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const mediaType = parseMediaType(sourceRes.headers.get("Content-Type")!)[0];
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if (mediaType.split("/")[0] !== "image") {
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return "URL is not image type.";
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}
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return {
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buffer: new Uint8Array(await sourceRes.arrayBuffer()),
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mediaType,
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};
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}
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function getWidthHeight(
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current: { width: number; height: number },
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final: { width: number; height: number },
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) {
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const ratio = (current.width / final.width) > (current.height / final.height)
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? (current.height / final.height)
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: (current.width / final.width);
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return new MagickGeometry(
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current.width / ratio,
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current.height / ratio,
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);
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}
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function modifyImage(
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imageBuffer: Uint8Array,
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params: { width: number; height: number; mode: "resize" | "crop" },
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) {
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return new Promise<Uint8Array>((resolve) => {
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ImageMagick.read(imageBuffer, (image) => {
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const sizingData = getWidthHeight(image, params);
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if (params.mode === "resize") {
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image.resize(sizingData);
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} else {
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image.crop(sizingData);
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}
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image.write((data) => resolve(data));
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});
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});
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}
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function parseParams(reqUrl: URL) {
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const height = Number(reqUrl.searchParams.get("height")) || 0;
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const width = Number(reqUrl.searchParams.get("width")) || 0;
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if (height === 0 && width === 0) {
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//return "Missing non-zero 'height' or 'width' query parameter.";
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}
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if (height < 0 || width < 0) {
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return "Negative height or width is not supported.";
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}
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const maxDimension = 2048;
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if (height > maxDimension || width > maxDimension) {
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return `Width and height cannot exceed ${maxDimension}.`;
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}
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return {
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height,
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width,
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};
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}
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async function getImageResponse(
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imageUrl: string,
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remoteImage: { buffer: Uint8Array; mediaType: string },
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params: { width: number; height: number },
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): Promise<Response> {
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const modifiedImage = await modifyImage(remoteImage.buffer, {
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...params,
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mode: "resize",
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});
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const response = new Response(modifiedImage, {
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headers: {
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"Content-Type": remoteImage.mediaType,
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},
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});
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return response;
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}
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export const handler = async (
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_req: Request,
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_ctx: HandlerContext,
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): Promise<Response> => {
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const imageUrl = Deno.env.get("SILVERBULLET_SERVER") + "/Recipes/images/" +
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_ctx.params.image;
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const url = new URL(_req.url);
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const params = parseParams(url);
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if (typeof params === "string") {
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return new Response(params, { status: 400 });
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}
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const remoteImage = await getRemoteImage(imageUrl);
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if (typeof remoteImage === "string") {
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return new Response(remoteImage, { status: 400 });
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}
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const imageId = `${imageUrl}.${params.width}.${params.height}`;
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if (cache.has(imageId)) {
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return (await cache.get(imageId)!).clone();
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}
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const response = getImageResponse(imageUrl, remoteImage, params);
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cache.set(imageId, response);
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return response;
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};
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