Azion `Types` package

The Types package provides global TypeScript types that are used across Azion’s platform, ensuring consistency and reducing redundancy throughout the codebase.

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Usage

Defining metadata

The Metadata interface provides a structured way to represent request metadata, including GeoIP information, remote address details, and server/TLS data.

TypeScript example:

import { Metadata } from 'azion/types';

const requestMetadata: Metadata = {
  geoip_asn: '12345',
  geoip_city: 'Sao Paulo',
  geoip_city_continent_code: 'SA',
  geoip_city_country_code: 'BR',
  geoip_city_country_name: 'Brazil',
  geoip_continent_code: 'SA',
  geoip_country_code: 'BR',
  geoip_country_name: 'Brazil',
  geoip_region: 'SP',
  geoip_region_name: 'Sao Paulo',
  remote_addr: '192.0.2.1',
  remote_port: '443',
  remote_user: 'user',
  server_protocol: 'HTTP/1.1',
  ssl_cipher: 'ECDHE-RSA-AES128-GCM-SHA256',
  ssl_protocol: 'TLSv1.2',
};

Working with FetchEvent

The FetchEvent interface extends the standard Event interface to include request and metadata properties, providing a complete context for handling fetch operations in the Azion environment.

TypeScript example:

import { FetchEvent, Metadata } from 'azion/types';

addEventListener('fetch', (event: FetchEvent) => {
  const { request } = event;
  const metadata: Metadata = request.metadata;

  console.log('Request URL:', request.url);
  console.log('Client IP:', metadata.remote_addr);
  console.log('GeoIP City:', metadata.geoip_city);

  event.respondWith(fetch(request));
});

Handling FirewallEvent

The FirewallEvent interface provides additional methods specific to firewall events, allowing for actions like denying requests, dropping connections, or adding headers to requests and responses.

TypeScript example:

import { FirewallEvent } from 'azion/types';

addEventListener('firewall', (event: FirewallEvent) => {
  const { request } = event;

  console.log('Request URL:', request.url);
  console.log('GeoIP Country:', request.metadata.geoip_country_name);

  if (request.metadata.geoip_country_code === 'CN') {
    event.deny();
  } else {
    event.continue();
  }
});