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  1. Products
  2. Cloudflare for Platforms
  3. ...
  4. Get started
  5. Local development

Local development

To test your Dispatch Worker, user Worker and Outbound Worker before deploying to production, you can use Wrangler for development and testing.

​​ 1. Create a user worker

$ npm create cloudflare@latest customer-worker-1

When following the interactive prompts, answer the questions as below:

  • Select no to using TypeScript.
  • Select no to deploying your application.

Update the src/index.js file for customer-worker-1:

src/index.js
export default {
  async fetch(request) {
    // make a subrequest to the internet
    const response = await fetch('https://example.com');
    return new Response(`user worker got "${await response.text()}" from fetch`);
  }

}

Update the wrangler.toml file for customer-worker-1 and add the dispatch namespace:

wrangler.toml
# ... other content above ...



dispatch_namespace = "my-namespace"

​​ 2. Create a dispatch worker

$ npm create cloudflare@latest dispatch-worker

When following the interactive prompts, answer the questions as below:

  • Select no to using TypeScript.
  • Select no to deploying your application.

Update the src/index.js file for dispatch-worker:

src/index.js
export default {
  async fetch(request, env) {
    // get the user Worker, specifying parameters that the Outbound Worker will see when it intercepts a user worker's subrequest
    const customerScript = env.DISPATCH_NAMESPACE.get(
      "customer-worker-1",
      {},
      {
        outbound: {
          paramCustomerName: 'customer-1'
        }
      }
    );
    // invoke user Worker
    return await customerScript.fetch(request);
  }

}

Update the wrangler.toml file for dispatch-worker and add the dispatch namespace binding:

wrangler.toml
# ... other content above ...



[[dispatch_namespaces]]

binding = "DISPATCH_NAMESPACE"

namespace = "my-namespace"

outbound = { service = "outbound-worker", parameters = ["paramCustomerName"] }

​​ 3. Create an Outbound Worker

$ npm create cloudflare@latest outbound-worker

When following the interactive prompts, answer the questions as below:

  • Select no to using TypeScript.
  • Select no to deploying your application.

Update the src/index.js file for outbound-worker:

src/index.js
export default {
  async fetch(request, env) {
    const { paramCustomerName } = env;
    // use the parameters passed by the dispatcher to know what this user this request is for
    // and return custom content back to the user worker
    return new Response(`intercepted a request for ${paramCustomerName} by the outbound`);
  }

}

​​ 4. Start local dev session for your Workers

In separate terminals, start a local dev session for each of your Workers.

For your dispatcher Worker:

$ cd dispatch-worker

$ npx wrangler@dispatch-namespaces-dev dev --port 8600

For your outbound Worker:

$ cd outbound-worker

$ npx wrangler@dispatch-namespaces-dev dev --port 8601

And for your user Worker:

$ cd customer-worker-1

$ npx wrangler@dispatch-namespaces-dev dev --port 8602

​​ 5. Test your requests

Send a request to your dispatcher Worker:

$ curl http://localhost:8600

# -> user worker got "intercepted a request for customer-1 by the outbound" from fetch