sentry tunnel via cloudflare workers

worker.js

const corsHeaders = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Methods": "*",
  "Access-Control-Allow-Headers": "Content-Type",
  "Access-Control-Max-Age": "86400",
};

// Set known project IDs for the Sentry projects you want to accept through this proxy
const knownProjectIds = []; // TODO: fill this

async function handleRequest(request) {
  const host = "sentry.io";

  const envelope = await request.text();
  const pieces = envelope.split("\n", 2);
  const header = JSON.parse(pieces[0]);

  if (header["dsn"]) {
    const dsn = new URL(header["dsn"]);

    console.log(`[dsn.pathname] `, dsn.pathname);

    const projectId = parseInt(dsn.pathname.split("/").filter(Boolean)[0]);

    if (knownProjectIds.includes(projectId)) {
      console.log(`made it here`);

      const response = await fetch(
        `https://${host}/api/${projectId}/envelope/`,
        {
          method: "POST",
          headers: {
            "Content-Type": "application/x-sentry-envelope",
          },
          body: envelope,
        }
      );

      return new Response(response.body, {
        status: response.status,
        statusText: response.statusText,
        headers: {
          ...response.headers,
          ...corsHeaders,
        },
      });
    }
  }

  // Return a 404 Not Found response for all other requests
  return new Response(null, { status: 404 });
}

function handleOptions(request) {
  // Make sure the necessary headers are present
  // for this to be a valid pre-flight request
  let headers = request.headers;
  if (
    headers.get("Origin") !== null &&
    headers.get("Access-Control-Request-Method") !== null &&
    headers.get("Access-Control-Request-Headers") !== null
  ) {
    // Handle CORS pre-flight request.
    // If you want to check or reject the requested method + headers
    // you can do that here.
    let respHeaders = {
      ...corsHeaders,
      // Allow all future content Request headers to go back to browser
      // such as Authorization (Bearer) or X-Client-Name-Version
      "Access-Control-Allow-Headers": request.headers.get(
        "Access-Control-Request-Headers"
      ),
    };

    return new Response(null, {
      headers: respHeaders,
    });
  } else {
    // Handle standard OPTIONS request.
    // If you want to allow other HTTP Methods, you can do that here.
    return new Response(null, {
      headers: {
        Allow: "*",
      },
    });
  }
}

export default {
  async fetch(request) {
    if (request.method === "OPTIONS") {
      return await handleOptions(request);
    }
    return await handleRequest(request);
  },
};