Rewrite links

export default {
	async fetch(request) {
		const OLD_URL = "developer.mozilla.org";
		const NEW_URL = "mynewdomain.com";

		class AttributeRewriter {
			constructor(attributeName) {
				this.attributeName = attributeName;
			}
			element(element) {
				const attribute = element.getAttribute(this.attributeName);
				if (attribute) {
					element.setAttribute(
						this.attributeName,
						attribute.replace(OLD_URL, NEW_URL),
					);
				}
			}
		}

		const rewriter = new HTMLRewriter()
			.on("a", new AttributeRewriter("href"))
			.on("img", new AttributeRewriter("src"));

		const res = await fetch(request);
		const contentType = res.headers.get("Content-Type");

		// If the response is HTML, it can be transformed with
		// HTMLRewriter -- otherwise, it should pass through
		if (contentType.startsWith("text/html")) {
			return rewriter.transform(res);
		} else {
			return res;
		}
	},
};

export default {
	async fetch(request): Promise<Response> {
		const OLD_URL = "developer.mozilla.org";
		const NEW_URL = "mynewdomain.com";

		class AttributeRewriter {
			constructor(attributeName) {
				this.attributeName = attributeName;
			}
			element(element) {
				const attribute = element.getAttribute(this.attributeName);
				if (attribute) {
					element.setAttribute(
						this.attributeName,
						attribute.replace(OLD_URL, NEW_URL),
					);
				}
			}
		}

		const rewriter = new HTMLRewriter()
			.on("a", new AttributeRewriter("href"))
			.on("img", new AttributeRewriter("src"));

		const res = await fetch(request);
		const contentType = res.headers.get("Content-Type");

		// If the response is HTML, it can be transformed with
		// HTMLRewriter -- otherwise, it should pass through
		if (contentType.startsWith("text/html")) {
			return rewriter.transform(res);
		} else {
			return res;
		}
	},
} satisfies ExportedHandler;

from workers import WorkerEntrypoint
from pyodide.ffi import create_proxy
from js import HTMLRewriter, fetch


class AttributeRewriter:
    old_url = "developer.mozilla.org"
    new_url = "mynewdomain.com"

    def __init__(self, attr_name):
        self.attr_name = attr_name

    def element(self, element):
        attr = element.getAttribute(self.attr_name)
        if attr:
            element.setAttribute(
                self.attr_name, attr.replace(self.old_url, self.new_url)
            )


href = create_proxy(AttributeRewriter("href"))
src = create_proxy(AttributeRewriter("src"))
rewriter = HTMLRewriter.new().on("a", href).on("img", src)


class Default(WorkerEntrypoint):
    async def fetch(self, request):
        res = await fetch(request)
        content_type = res.headers["Content-Type"]

        # If the response is HTML, it can be transformed with
        # HTMLRewriter -- otherwise, it should pass through
        if content_type.startswith("text/html"):
            return rewriter.transform(res)
        return res

import { Hono } from 'hono';
import { html } from 'hono/html';

const app = new Hono();

app.get('*', async (c) => {
  const OLD_URL = "developer.mozilla.org";
  const NEW_URL = "mynewdomain.com";

  class AttributeRewriter {
    attributeName: string;

    constructor(attributeName: string) {
      this.attributeName = attributeName;
    }

    element(element: Element) {
      const attribute = element.getAttribute(this.attributeName);
      if (attribute) {
        element.setAttribute(
          this.attributeName,
          attribute.replace(OLD_URL, NEW_URL)
        );
      }
    }
  }

  // Make a fetch request using the original request
  const res = await fetch(c.req.raw);
  const contentType = res.headers.get("Content-Type") || "";

  // If the response is HTML, transform it with HTMLRewriter
  if (contentType.startsWith("text/html")) {
    const rewriter = new HTMLRewriter()
      .on("a", new AttributeRewriter("href"))
      .on("img", new AttributeRewriter("src"));

    return new Response(rewriter.transform(res).body, {
      headers: res.headers
    });
  } else {
    // Pass through the response as is
    return res;
  }
});

export default app;