Connecting to the Private eXecution Environment (PXE)

PXE is a component of the Aztec Protocol that provides a private execution environment for your application.

As an app developer, the PXE interface provides you with access to the user's accounts and their private state, as well as a connection to the network for accessing public global state.

The Aztec Sandbox runs a local PXE and an Aztec Node, both connected to a local Ethereum development node like Anvil. The Sandbox also includes a set of pre-initialized accounts that you can use from your app.

In this section, we'll connect to the Sandbox from our project.

Create PXE client

We'll use the createPXEClient function from aztec.js to connect to the Sandbox. Sandbox exposes a HTTP JSON-RPC interface of PXE. By default it runs on localhost:8080. To test the connection works, we'll request and print the node's chain id.

Let's create our first file src/index.mjs with the following contents:

all

import { createPXEClient } from '@aztec/aztec.js';

const { PXE_URL = 'http://localhost:8080' } = process.env;

async function main() {
  const pxe = await createPXEClient(PXE_URL);
  const { l1ChainId } = await pxe.getNodeInfo();
  console.log(`Connected to chain ${l1ChainId}`);
}

main().catch(err => {
  console.error(`Error in app: ${err}`);
  process.exit(1);
});

^{_{Source code: yarn-project/end-to-end/src/sample-dapp/connect.mjs#L1-L16}}

Make sure the Sandbox is running and run the example

node src/index.mjs

and you should see the following output:

Connected to chain 31337

info

Should the above fail due to a connection error, make sure the Sandbox is running locally and on port 8080.

Load user accounts

In sandbox PXE comes with a set of pre-initialized accounts that you can use from your app. Let's try loading the accounts:

showAccounts

async function showAccounts(pxe) {
  const accounts = await pxe.getRegisteredAccounts();
  console.log(`User accounts:\n${accounts.map(a => a.address).join('\n')}`);
}

^{_{Source code: yarn-project/end-to-end/src/sample-dapp/index.mjs#L12-L17}}

Call the showAccounts function from main, run again the above, and you should see something like:

User accounts:
0x0c8a6673d7676cc80aaebe7fa7504cf51daa90ba906861bfad70a58a98bf5a7d
0x226f8087792beff8d5009eb94e65d2a4a505b70baf4a9f28d33c8d620b0ba972
0x0e1f60e8566e2c6d32378bdcadb7c63696e853281be798c107266b8c3a88ea9b

Next steps

With a working connection to PXE, let's now setup our application by compiling and deploying our contracts.