Cloudflare Developers•16mo ago

Modifying Request Host

👋 heyo I'm trying to create a simple worker that takes a request and replaces the host. I have a basic worker running but i want it to be able to pass through the body, all the headers and anything else custom in the original request (e.g. the ip). Note: I didn't use redirect because I want to use the response before returning it to the user. Any thoughts? I also tried req.clone_mut() then changing the path but that didn't work.

use worker::*;

#[event(fetch)]
async fn main(req: Request, _env: Env, _ctx: Context) -> Result<Response> {
    let url = req.url()?;
    let prod_url = Url::parse("https://example.com")?.join(url.path())?;

    // TODO(jqphu): forward headers too.
    let prod_request = Request::new(&prod_url.to_string(), req.method())?;
    let prod_response = Fetch::Request(prod_request).send().await;

    prod_response
}

use worker::*;

#[event(fetch)]
async fn main(req: Request, _env: Env, _ctx: Context) -> Result<Response> {
    let url = req.url()?;
    let prod_url = Url::parse("https://example.com")?.join(url.path())?;

    // TODO(jqphu): forward headers too.
    let prod_request = Request::new(&prod_url.to_string(), req.method())?;
    let prod_response = Fetch::Request(prod_request).send().await;

    prod_response
}

4 Replies

Justin (will never dm)OP•16mo ago

Hmm found: https://developers.cloudflare.com/workers/examples/modify-request-property/ Maybe I need to use the underlying web_sys::Request and call web_sys::Request::new_with_str_and_init. Let me see if I can get that to work

Modify request property · Cloudflare Workers docs

Documentation for Cloudflare Workers, a serverless execution environment that allows you to create entirely new applications or augment existing ones …

Justin (will never dm)OP•16mo ago

Hmm I think the problem is I don't know how to call the Request constructor with another request object. Like in the example:

    const newRequest = new Request(
      url.toString(),
      new Request(request, newRequestInit)
    );

    const newRequest = new Request(
      url.toString(),
      new Request(request, newRequestInit)
    );

web_sys::Request does not seem to expose this interface, they all take a RequestInit not a Request (unless there's a way to go from a Request -> RequestInit easily?)

Unknown User•16mo ago

Message Not Public

Justin (will never dm)OP•16mo ago

I tried that but unfortunately I needed to modify the URL. So Kinded needed a

pub fn new_with_str_and_request(
    nput: &str,
    init: &Request
) -> Result<Request, JsValue>

pub fn new_with_str_and_request(
    nput: &str,
    init: &Request
) -> Result<Request, JsValue>

which somehow worked in JavaScript. Ended up just writing it in javascript instead 😛 https://github.com/jqphu/shadow-traffic

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Modifying Request Host