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).

API Reference

See the full API listing in API Documentation.

For build instructions, see WebAssembly Builds.