Oso SDK with Express integration

The Oso SDK with Express integration provides helper functions to facilitate hooking Oso into the Express web framework.

Please Note: The SDK is currently released as a developer preview. Do not use this SDK for production workloads.

Install

npm install --save @osohq/express
yarn add @osohq/express

Usage

The Oso SDK should be initialized as early as possible in the main entry module. The Oso SDK can be hooked into Express as a centralized middleware or as a route middleware using the enforce function.

import { init } from '@osohq/express';
import express from 'express';

const oso = init({
    apiKey: 'YOUR_API_KEY',
    // ...
})

const enforcement = {
  action: 'view',
  resourceType: 'Org',
  resourceId: '123',
};

// Centralized enforcement
app.use(oso.enforce(enforcement));

// Per-route enforcement
app.get('/', oso.enforce(enforcement), (_req, _res) => {
  // ...
});

app.listen(5678);

After the Oso SDK is initialized, you may access it by calling globalOso():

import { globalOso } from '@osohq/node';

oso = globalOso();

The Oso SDK may be further configured by setting relevant fields in the ConfigOptions object passed on init.

Integration Options

By default,

• Actor ID is a hardcoded value of _. You may override the Actor ID using the setting defaultActorId when initializing the Oso SDK.
• Action is inferred from the HTTP method. If you have a different set of permissions from the defaults, you may override the mapped value by setting defaultAction when initializing the Oso SDK.
• HTTP 404 is returned on authorization failure. You may specify a custom error handler by setting defaultErrorHandler when initializing the Oso SDK.

User Identification

You may provide a function to determine the Actor Id by setting defaultActorId when initializing the Oso SDK.

import { init } from '@osohq/express';
import { Request } from 'express';

init({
  apiKey: 'YOUR_API_KEY',
  // Hardcode the actor Id to `admin`
  defaultActorId: (_req: Request) => 'admin',
});

Action Identification

You may provide a function to determine the action by setting defaultAction when initializing the Oso SDK.

import { init } from '@osohq/express';
import { Request } from 'express';

init({
  apiKey: 'YOUR_API_KEY',
  // Hardcode the action to `view`
  defaultAction: (_req: Request) => 'view',
});

Custom Error Handling

You can provide a function to determine the response on authorization failure.

import { init } from '@osohq/express';
import { Response, NextFunction } from 'express';

init({
  apiKey: 'YOUR_API_KEY',
  // Return HTTP 418 on authorization failure
  defaultErrorHandler: (res: Response, _next: NextFunction) => {
    res.send(418).send("I'm a teapot");
    return;
  },
});

Supported Versions

• Express: 4.x