abac-wasm: Browser & Node.js

abac-wasm provides WebAssembly bindings for the abac-rs engine, bringing attribute-based access control to browser and Node.js environments through a JSON-based API.

Quick Start

import init, { AbacPolicyWasm } from 'abac-wasm';

await init();

const policy = new AbacPolicyWasm();

// Add a rule
policy.addRuleFromJson(JSON.stringify({
  name: "allow-engineers-read",
  dimensions: {
    role: [{ type: "String", value: "engineer" }],
    action: [{ type: "String", value: "read" }],
    resource: "all"
  },
  rule_type: "Allow",
  enabled: true
}));

// Evaluate a request
const result = policy.evaluateJson(JSON.stringify({
  dimensions: {
    role: { value: { type: "String", value: "engineer" } },
    action: { value: { type: "String", value: "read" } },
    resource: { value: { type: "String", value: "dashboard" } }
  }
}));

const decision = JSON.parse(result);
console.log(decision.allowed); // true

Rule Builder

Use AbacRuleBuilderWasm to construct rules without manual JSON:

import { AbacRuleBuilderWasm } from 'abac-wasm';

const builder = new AbacRuleBuilderWasm("allow-admin-all");
builder.addDimension("role", JSON.stringify([
  { type: "String", value: "admin" }
]));
builder.addDimensionAll("resource");  // wildcard — matches any resource
builder.setEnabled(true);

const ruleJson = builder.buildJson();
policy.addRuleFromJson(ruleJson);

Custom Matchers

Register JavaScript callbacks for custom matching logic on specific dimensions. This is useful for threshold comparisons, range checks, or any matching that goes beyond exact equality:

policy.registerMatcher("temperature_high", (ruleValue, requestValue, requestGroups) => {
  if (ruleValue === "all") return true;
  if (!Array.isArray(ruleValue)) return false;

  const actual = requestValue.type === "Float" ? requestValue.value : null;
  if (actual == null) return false;

  return ruleValue.some(t => {
    const threshold = t.type === "Float" ? t.value : null;
    return threshold != null && actual >= threshold;
  });
});

Error Handling

All errors are structured JavaScript objects with type and message fields:

try {
  policy.addRuleFromJson("invalid json");
} catch (e) {
  console.log(e.type);    // "JsonError"
  console.log(e.message); // parsing error details
}

Error types: JsonError (malformed JSON), PolicyError (rule limit or conflict), ValidationError (invalid field values), TemporalError (invalid temporal rule validity window).

API Reference

See the full API listing in API Documentation.

For build instructions, see WebAssembly Builds.