Reference
Client SDK
Node.js

Node.js Client API

💡

Before going through this guide, make sure you follow the Oso Cloud Quickstart to get your Oso Cloud API Key properly set in your environment.

First, install the oso-cloud package on NPM:


npm install oso-cloud

Instantiating an Oso Cloud client

The Oso Cloud client provides an Oso class that takes your Oso Cloud URL and API key:


const { Oso } = require("oso-cloud");
const oso = new Oso("https://cloud.osohq.com", YOUR_API_KEY);
// Later, in an async function:
await oso.tell("has_role", user, role, resource);
// Wherever authorization needs to be performed
if (await oso.authorize(user, action, resource)) {
// Action is allowed
}

ℹ️

You should instantiate one client and share it across your application. Under the hood, it reuses connections to avoid paying the cost of negotiating a new connection on every request.

Specifying an Oso Fallback host

If you have deployed Oso Fallback nodes to your infrastructure, you may specify the host when instantiating the Oso Cloud client.


// Assumes Oso Fallback is hosted at http://localhost:8080
const oso = new Oso("https://cloud.osohq.com", YOUR_API_KEY, {
fallbackUrl: "http://localhost:8080",
});

Passing application entities into the client

Under the hood, Oso Cloud represents an entity in your application as a combination of a type and an ID, which together uniquely identify the entity. The Node client represents these entities as objects with both type and id properties. For example:


const alice = { type: "User", id: "alice" };
const anvilsRepository = { type: "Repostory", id: "anvils" };

You will pass objects like these into nearly every function call you make to the Node client.

Management API

Add fact: oso.tell(name, ...args)

Adds a fact named name with the provided arguments. Example:


await oso.tell("has_role", { type: "User", id: "bob" }, "owner", {
type: "Organization",
id: "acme",
});

ℹ️

For Oso Cloud developer accounts, bulkTell, bulkDelete, and bulk calls are limited to 20 facts. If you attempt to send more than 20 facts, these functions will throw an error.

Add many facts: oso.bulkTell([...[name, ...args]])

Adds many facts at once. Example:


await oso.bulkTell([
[
"has_role",
{ type: "User", id: "bob" },
"owner",
{ type: "Organization", id: "acme" },
],
[
"has_role",
{ type: "User", id: "bob" },
"maintainer",
{ type: "Repository", id: "anvils" },
],
]);

Delete fact: oso.delete(name, ...args)

Deletes a fact. Does not throw an error when the fact is not found. Example:


await oso.delete("has_role", { type: "User", id: "bob" }, "maintainer", {
type: "Repository",
id: "anvils",
});

Delete many facts: oso.bulkDelete([...[name, ...args]])

Deletes many facts at once. Does not throw an error when some of the facts are not found. Example:


await oso.bulkDelete([
[
"has_role",
{ type: "User", id: "bob" },
"owner",
{ type: "Organization", id: "acme" },
],
[
"has_role",
{ type: "User", id: "bob" },
"maintainer",
{ type: "Repository", id: "anvils" },
],
]);

Transactionally delete and add facts: oso.bulk(delete, tell)

Deletes and adds many facts in one atomic transaction. The deletions are performed before the adds. null can be used as a wildcard in facts in delete. Does not throw an error when the facts to delete are not found. Example:


await oso.bulk(
[
// All `has_role` facts linking User:bob and Repository:anvils will be deleted.
[
"has_role",
{ type: "User", id: "bob" },
null,
{ type: "Repository", id: "anvils" },
],
],
[
// This fact will be added.
[
"has_role",
{ type: "User", id: "bob" },
"maintainer",
{ type: "Repository", id: "anvils" },
],
]
);

List facts: oso.get(name, ...args)

ℹ️

For Oso Cloud developer accounts, Get calls are limited to 1000 results. If you have more than 1000 facts, the function will throw an error.

Lists facts that are stored in Oso Cloud. Can be used to check the existence of a particular fact, or used to fetch all facts that have a particular argument:


// Get one fact:
await oso.get("has_role", { type: "User", id: "bob" }, "admin", {
type: "Repository",
id: "anvils",
});
// => [
// [
// "has_role",
// {type: "User", id: "bob"},
// {type: "String", id: "admin"},
// {type: "Repository", id: "anvils"}
// ]
// ]
// List all role-related facts on the `anvils` repo
await oso.get("has_role", null, null, { type: "Repository", id: "anvils" });
// => [
// [
// "has_role",
// {type: "User", id: "bob"},
// {type: "String", id: "admin"},
// {type: "Repository", id: "anvils"}
// ],
// //...other has_role facts
// ]

Note that null behaves like a wildcard: passing null, null, anvils means "find all facts where anvils is the third argument, regardless of other arguments".

Check API

ℹ️

For Oso Cloud developer accounts, * the number of context facts per request is limited to 20; and * the number of records returned is limited to 1000.

Context facts

You may provide an array of context facts as an optional argument to any of the Check API methods. When Oso Cloud performs a check, it will consider these context facts in addition to any other facts you've previously added. Context facts are only used in the API call in which they're provided— they do not persist across requests. Learn more about context facts.

Check a permission: oso.authorize(actor, action, resource)

Determines whether or not an action is allowed, based on a combination of authorization data and policy logic. Example:


const alice = { type: "User", id: "alice" };
const anvilsRepository = { type: "Repository", id: "anvils" };
const authorized = await oso.authorize(alice, "read", anvilsRepository);
if (!authorized) {
throw new Error("Action is not allowed");
}

You may provide an array of context facts as an optional fourth argument to this method. Example:


const issue = { type: "Issue", id: "anvils-1" };
const authorized = await oso.authorize(alice, "read", issue, [
["has_relation", issue, "parent", anvilsRepository], // a context fact
]);

Check authorized resources: oso.authorizeResources(actor, action, resources)

Returns a subset of resources on which an actor can perform a particular action. Ordering and duplicates, if any exist, are preserved.

ℹ️

For Oso Cloud developer accounts, the number of input resources is limited to 1000.

Example:


const alice = { type: "User", id: "alice" };
const anvilsRepository = { type: "Repository", id: "anvils" };
const acmeRepository = { type: "Repository", id: "acme" };
await oso.authorizeResources(alice, "read", [anvilsRepository, acmeRepository]);
// => [acmeRepository]

You may provide an array of context facts as an optional fourth argument to this method. Example:


const issueOnAcmeRepository = { type: "Issue", id: "acme-1" };
const issueOnAnvilsRepository = { type: "Issue", id: "anvils-2" };
await oso.authorizeResources(
alice,
"read",
[issueOnAnvilsRepository, issueOnAcmeRepository],
[
// context facts
["has_relation", issueOnAnvilsRepository, "parent", anvilsRepository][
("has_relation", issueOnAcmeRepository, "parent", acmeRepository)
],
]
);
// => [issueOnAcmeRepository]

List authorized resources: oso.list(actor, action, resourceType)

Fetches a list of resource IDs on which an actor can perform a particular action. Example:


const alice = { type: "User", id: "alice" };
const repositoryIds = await oso.list(alice, "read", "Repository");
// => ["acme"]

You may provide an array of context facts as an optional fourth argument to this method. Example:


const anvilsRepository = { type: "Repository", id: "anvils" };
const acmeRepository = { type: "Repository", id: "acme" };
const issueOnAcmeRepository = { type: "Issue", id: "acme-1" };
const issueOnAnvilsRepository = { type: "Issue", id: "anvils-2" };
const repositoryIds = await oso.list(alice, "read", "Issue", [
// context facts
["has_relation", issueOnAnvilsRepository, "parent", anvilsRepository][
("has_relation", issueOnAcmeRepository, "parent", acmeRepository)
],
]);
// => ["acme-1"]

List authorized actions: oso.actions(actor, resource)

Fetches a list of actions which an actor can perform on a particular resource. Example:


const alice = { type: "User", id: "alice" };
const acmeRepository = { type: "Repository", id: "acme" };
await oso.actions(user, acmeRepository);
// => ["read"]

You may provide an array of context facts as an optional third argument to this method. Example:


const issueOnAcmeRepository = { type: "Issue", id: "acme-1" };
await oso.actions(alice, issueOnAcmeRepository, [
["has_relation", issueOnAcmeRepository, "parent", acmeRepository], // a context fact
]);
// => ["read"]

Query for anything: oso.query(predicate, ...args)

Query Oso Cloud for any predicate and any combination of concrete and wildcard arguments. Unlike oso.get, which only lists facts you've added, you can use oso.query to list derived information about any rule in your policy. Example:


// Query for all the repos `User:bob` can `read`
await oso.query("allow", { type: "User", id: "bob" }, "read", {
type: "Repository",
});
// => [
// ["allow", {type: "User", id: "bob"}, "read", {type: "Repository", id: "acme"}],
// ["allow", {type: "User", id: "bob"}, "read", {type: "Repository", id: "anvils"}],
// ]
// Query for all the objects `User:admin` can `read`
await oso.query("allow", { type: "User", id: "admin" }, "read", null);
// => [
// // `User:admin` can `read` anything
// ["allow", {type: "User", id: "admin"}, "read", null],
// ]

You may pass a list of context facts with the query_with_context method. Example:


// Query for all the repos `User:bob` can `write` derived from context facts
await oso.query_with_context(
["allow", { type: "User", id: "bob" }, "write", { type: "Repository" }],
{
contextFacts: [
"has_permission",
{ type: "User", id: "bob" },
"write",
{ type: "Repository", id: "anvils" },
],
}
);
// => [
// ["allow", {type: "User", id: "bob"}, "write", {type: "Repo", id: "anvils"}],
// ]

Note that null behaves like a wildcard. Passing "allow", null, null, anvils means "find anyone who can do anything to anvils". null also behaves like a wildcard in return values from oso.query. Additionally, if you want to query over all instances of a particular type, pass an object with a type property but no id property. For example, "allow", bob, "read", {type: "Repository"} will query for all the objects of type "Repository" that bob can read.

Learn more about how to query Oso Cloud.

Policy API

Update the active policy: oso.policy(policy)

Updates the policy in Oso Cloud. The string passed into this method should be written in Polar. Example:


await oso.policy("actor User {}");

This command will run any tests defined in your policy. If one or more of these tests fail, your policy will not be updated.

Debugging

Request logs can be found in the Oso Cloud dashboard, but sometimes it's useful to print timings from the client so you can diagnose network problems. There are two configuration parameters you can set


var oso = new Oso(url, apiKey, { debug: { print: true } });

will print debug messages to stdout.


var oso = new Oso(url, apiKey, { debug: { file: "oso_debug.txt" } });

will append debug messages to the file you specify.

In both cases the messages will look like this. They show the route, the response code, the total request time and how much time was spent in Oso Cloud processing the request vs. network transport.


[oso] /facts 200 total: 4ms, server: 3ms network: 1ms
[oso] /policy 200 total: 9ms, server: 3ms network: 6ms
...

Talk to an Oso Engineer

If you'd like to learn more about using Oso Cloud in your app or have any questions about this guide, schedule a 1x1 with an Oso engineer. We're happy to help.

Get started with Oso Cloud →

Python