Worker script to rewrite body HTML

Developers Workers
#1

Hi,
I’m looking for a worker script that rewrite’s URLs in the response body.
I found a few example scripts, but none workers will accept.

I wonder if somebody can help me with the script found here titled " Rewrite URLs"

I am currently seeing an error when attempting to use the script
"Uncaught ReferenceError: Cannot access 'AttributeRewriter' before initialization at line 7"

#2

Seems to be an issue with the example. The class is used before it is defined (greetings from C :smile:)

Try the following

class AttributeRewriter
{
	constructor(attributeName)
	{
		this.attributeName = attributeName;
	}

	element(element)
	{
		const attribute = element.getAttribute(this.attributeName);
		if (attribute) element.setAttribute(this.attributeName, attribute.replace('myolddomain.com', 'mynewdomain.com'));
	}
}

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

async function handleRequest(req)
{
	const res = await fetch(req);
	return rewriter.transform(res);
}

addEventListener('fetch', event => {
	event.respondWith(handleRequest(event.request));
})

@fallon @jpugh

4 Likes
#3

awesome, thank you so much

#4

what if I wanted to rewrite more than 1 domain, any chance you could help me out with that?

#5

Concatenating another replace() call to .replace() should do the trick.

#6

Thanks all, we’re updating this in the docs today. Appreciate the initial bug report @jackpea!

#8

Please check out https://www.w3schools.com/jsref/jsref_replace.asp. Thats a very fundamental JavaScript question and you’ll need to understand what it is doing before copy/pasting anything. You basically need to call replace on replace.

1 Like
#9

Thanks for pointing that out @jackpea and helping troubleshoot @sandro!