NestJS Proxy module

This is fork based on Finastra - Node Proxy Lib

How to use

You can import the module like so :

app.module.ts

ProxyModule.forRootAsync({
  imports: [EnvService],
  useClass: ProxyConfigService,
}),

proxy-config.service.ts

import { Injectable } from '@nestjs/common';
import { EnvService } from '../environments/env.service';
import { ProxyModuleOptions, ProxyModuleOptionsFactory } from './proxy.interface';

@Injectable()
export class ProxyConfigService implements ProxyModuleOptionsFactory {
  constructor(private env: EnvService) {}

  createModuleConfig(): ProxyModuleOptions {
    return {
      services: this.env.get('ALL_SERVICES') ?? {},
      allowedCookies: [],
      config: {},
    };
  }
}

Environments

env.ts

import { z } from 'zod';

function refineServiceUrl(service: string) {
  return z
    .string()
    .url()
    .transform((value) => ({ [service]: value }));
}

export const envSchema = z
  .object({
    // Application
    NODE_ENV: z
      .enum(['development', 'production', 'test'])
      .default('development'),
    APP_PORT: z.number({ coerce: true }).default(8081),

    // Services
    SERVICE_DOG: refineServiceUrl('dog'),
    SERVICE_ANIME: refineServiceUrl('anime'),
  })
  .transform((values) => {
    const servicesSchema = z.record(z.string(), z.string());
    const SERVICES: Record<string, string> = {};

    for (const envKey of Object.keys(values)) {
      if (String(envKey).startsWith('SERVICE_')) {
        Object.assign(SERVICES, values[envKey]);
      }
    }

    return {
      ...values,
      ALL_SERVICES: servicesSchema.parse(SERVICES),
    };
  });

export type Env = z.infer<typeof envSchema>;

You can configure all services in .env file.

# Services
SERVICE_DOG="https://dog.ceo/api/breeds/image/random"
SERVICE_ANIME="https://animechan.io/api/v1/quotes/random"

When the application starts, all environments starting with SERVICE_ are transformed and stored in a new variable ALL_SERVICES which is used to configure the available routes.

env.service.ts

Import where you want EnvService to get typed all environments.

Configuration

Whether synchronously or asynchronously, the module takes two parameters (both optionals).

• services : which is a collection of urls with a given id so that you can query them more efficiently
• config : which is the configuration from http-proxy which we're using under the hood. Find the official documentation of this configuration here.

Token forwarding

In this repository fork, by default, OAuth token are forwarded to the service call being proxied.

Warning

Be careful to only forward tokens to internal services. Don't forward the token to third party services.

Cookies forwarding

Cookies are not proxied by default. You can opt in by listing the cookie names in the allowedCookies option:

allowedCookies: ['cookie1', 'cookie2'],

Default module configuration

If you do not provide any, the default proxy configuration for this module can be found in proxy.constants.ts, under defaultProxyOptions

Client-side usage examples

const serverUri = 'http://localhost:3000';
const serviceName = 'dog';

fetch(serverUri, {
  headers: {
    'x-service-name': serviceName
  }
});

Forked by Finastra - Node Proxy Lib

Modified by Gabriel Duarte