Cloudflare Docs
Workers
Edit this page
Give us feedback
Set theme to dark (⇧+D)

Rewrite links

Rewrite URL links in HTML using the HTMLRewriter. This is useful for JAMstack websites.
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 pyodide.ffi import create_proxy
from js import HTMLRewriter, fetch
async def on_fetch(request):
old_url = "developer.mozilla.org"
new_url = "mynewdomain.com"
class AttributeRewriter:
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(old_url, new_url))
href = create_proxy(AttributeRewriter("href"))
src = create_proxy(AttributeRewriter("src"))
rewriter = HTMLRewriter.new().on("a", href).on("img", src)
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