Tauri Plugin keygen

This plugin helps you implement timed licensing (with trial) and feature-base licensing for your Tauri desktop app using the Keygen Licensing API.

It handles license validation requests, verifies response signatures, caches valid responses, and manages the machine file for offline licensing.

Licensed state is managed in the Tauri App State (Rust back-end), and can be accessed via JavaSript Guest bindings in the front-end.

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📖 Table of Contents

• Table of Contents
• Video Tutorial
• Install
• Setup
  • Custom Configs
  • with_custom_domain
• Usage
  • Timed License - with trial
  • Feature Base License
• JavaScript Guest Bindings
  • getLicense
  • getLicenseKey
  • validateKey
  • validateCheckoutKey
  • resetLicense
  • resetLicenseKey

📺 Video Tutorial

⬇️ Install

This plugin is made for Tauri v1. But, it'll be updated on Tauri v2 stable release.

🦀 Add the following line to src-tauri/cargo.toml to install the core plugin:

[dependencies]
tauri-plugin-keygen = { git = "https://github.com/bagindo/tauri-plugin-keygen", branch = "main" }

👾 Install the JavaScript Guest bindings:

npm add https://github.com/bagindo/tauri-plugin-keygen#main

🔌 Setup

First, sign-up for a free account and get your Keygen Account ID and Keygen Verify Key.

Then, add them to the plugin builder in src-tauri/src/main.rs

fn main() {
    tauri::Builder::default()
        // register plugin
        .plugin(
            tauri_plugin_keygen::Builder::new(
                "17905469-e476-49c1-eeee-3d60e99dc590", // 👈 Keygen Account ID
                "1e1e411ee29eee8e85ee460ee268921ee6283ee625eee20f5e6e6113e4ee2739", // 👈 Keygen (Public) Verify Key
            )
            .build(),
        )
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}

⚙️ Custom Configs

Optionally, you can specify custom configs to the plugin builder.

fn main() {
    tauri::Builder::default()
        // register plugin
        .plugin(
            tauri_plugin_keygen::Builder::new(
                "17905469-e476-49c1-eeee-3d60e99dc590", // 👈 Keygen Account ID
                "1e1e411ee29eee8e85ee460ee268921ee6283ee625eee20f5e6e6113e4ee2739", // 👈 Keygen (Public) Verify Key
            )
            // chain custom config as needed
            .api_url("https:://licensing.myapp.com") // 👈 Self-hosted Keygen API url
            .version_header("1.7") // 👈 add Keygen-Version on request header
            .cache_lifetime(1440) // 👈 Response cache lifetime in minutes
            .build(),
        )
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}

🌐 with_custom_domain

You don't need to specify your Keygen Account ID if you're using Keygen Custom Domain.

fn main() {
    tauri::Builder::default()
        // register plugin
        .plugin(
            tauri_plugin_keygen::Builder::with_custom_domain(
                "https://licensing.myapp.com", // 👈 Your Keygen Custom Domain
                "1e1e411ee29eee8e85ee460ee268921ee6283ee625eee20f5e6e6113e4ee2739", // 👈 Keygen (Public) Verify Key
            )
            // chain custom config as needed
            .version_header("1.7") // 👈 add Keygen-Version on request header
            .cache_lifetime(1440) // 👈 Response cache lifetime in minutes
            .build(),
        )
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}

[!NOTE] Chaining the api_url config won't matter here.

⚡ Usage

⏱️ Timed License - with trial

In this example, the app's main page is guarded by a layout route _licensed.tsx, that will re-direct users to the validation page if they don't have a valid license.

Watch the video tutorial for the step-by-step implementation.

The main code snippets:

🎖️ Feature Base License

In this example, users can access the app without having a license, except when they want to add an image to an ESP item.

Watch the video tutorial for the step-by-step implementation.

The main code snippets:

👾 JavaScript Guest Bindings

Available JavaScript APIs:

• getLicense
• getLicenseKey
• validateKey
• validateCheckoutKey
• resetLicense
• resetLicenseKey

🎫 getLicense()

Get the current license from the LicensedState in the Tauri App State.

Returns KeygenLicense or null.

import { getLicense } from "tauri-plugin-keygen-api";

const beforeLoad = async function () => {
  let license = await getLicense();

  if (license !== null) {
    // {
    //   key: "55D303-EEA5CA-C59792-65D3BF-54836E-V3",
    //   entitlements: [],
    //   valid: true,
    //   expiry: "2024-06-22T02:04:09.028Z",
    //   code: "VALID",
    //   detail: "is valid",
    //   metadata: {},
    //   policyId: "9d930fd2-c1ef-4fdc-a55c-5cb8c571fc34",
    // }
    ...
  }
}

How does this plugin manages LicensedState?

🔍 On App Loads: Look for offline license

When your Tauri app loads, this plugin will look for any offline licenses in the [APP_DATA]/keygen/ directory.

If a machine file (📄 machine.lic) is found, it will verify and decrypt the machine file, parse it into a License object, and load it into the Tauri App State.

If there's no machine file, it'll look for the cache in 📂 validation_cache, verify its signature, parse the cache into a License object, and load it into the Tauri App State.

🚫 No valid license

If no offline license is found, or if any of the offline license found is invalid due to any of the following reasons:

• Failed to decrypt the machine file
• The machine file ttl has expired
• Failed to verify the response cache signature
• The cache's age has exceed the allowed cache_lifetime
• The parsed license object has expired

the LicensedState in the Tauri App State will be set to None (serialized to null in the front-end).

🔄 State Update

You can't update the LicensedState directly.

Aside than initiating the state from the offline licenses on app loads, this plugin will update the licensed state with the verified response from validateKey() or validateCheckoutKey(), and reset it back to None when you call resetLicense().

🗝️ getLicenseKey()

Get the cached license key.

Returns string or null.

The license key is cached separately from the offline licenses, so that when the offline licenses expired and getLicense() returns null, you can re-validate without asking the user to re-enter their key.

import { getLicense, getLicenseKey } from "tauri-plugin-keygen-api";

const beforeLoad = async function () => {
  let license = await getLicense();
  let licenseKey = await getLicenseKey();

  if (license === null) {
    throw redirect({
      to: "/validate", // the equivalent of a Login page in an Auth based system
      search: {
        cachedKey: licenseKey || "", // pass the cached licenseKey
      },
    });
  }
}

[!TIP] Instead of re-directing to the validate page, you can re-validate the cached licenseKey in the background. Checkout the video tutorial to see how you can do this.

🚀 validateKey()

Send license validation and machine activation requests.

Returns KeygenLicense. Throws KeygenError.

import {
  type KeygenLicense,
  type KeygenError,
  validateKey,
} from "tauri-plugin-keygen-api";

const validate = async (key: string, entitlements: string[] = []) => {
  let license: KeygenLicense;

  try {
    license = await validateKey({
      key,
      entitlements,
    });
  } catch (e) {
    const { code, detail } = e as KeygenError;
    console.log(`Err: ${code}: ${detail}`);
    return;
  }

  if (license.valid) {
    ...
  } else {
    const { code, detail } = license;
    console.log(`Invalid: ${code}: ${detail}`);
  }
};

What happens under the hood when you call validateKey()?

🆔 Parsing Machine Fingerprint

This plugin parses the user's machine fingerprint and includes it in both license validation and machine activation requests.

[!TIP] You can utilize machine fingerprints to prevent users from using multiple trial licenses (instead of buying one). To do this, set the machineUniquenessStrategy attribute to UNIQUE_PER_POLICY on your trial policy.

See the video tutorial for more details.

🔏 Verifying Response Signature

A bad actor could redirect requests to a local licensing server under their control, which, by default, sends "valid" responses. This is known as a spoofing attack.

To ensure that the response received actually originates from Keygen's servers and has not been altered, this plugin checks the response's signature and verifies it using the Verify Key you provided in the plugin builder.

A bad actor could also "record" web traffic between Keygen and your desktop app, then "replay" valid responses. For example, they might replay responses that occurred before their trial license expired, in an attempt to use your software with an expired license. This is known as a replay attack.

To prevent that, this plugin will reject any response that's older than 5 minutes, even if the signature is valid.

🔄 Updating State and Cache

Once the response is verified, this plugin will update the LicensedState in the Tauri App State with a License object parsed from the response.

If the License is valid and cacheValidResponse is true, the verified response will be cached for later use as an offline license.

🚀 💻 validateCheckoutKey()

Call validateKey(), then download the machine file for offline licensing.

Returns KeygenLicense. Throws KeygenError.

import {
  type KeygenLicense,
  type KeygenError,
  validateCheckoutKey,
} from "tauri-plugin-keygen-api";

const validate = async (key: string, entitlements: string[] = []) => {
  let license: KeygenLicense;

  try {
    license = await validateCheckoutKey({
      key,
      entitlements,
      ttlSeconds: 604800 /* 1 week*/,
    });
  } catch (e) {
    const { code, detail } = e as KeygenError;
    console.log(`Err: ${code}: ${detail}`);
    return;
  }

  if (license.valid) {
    ...
  } else {
    const { code, detail } = license;
    console.log(`Invalid: ${code}: ${detail}`);
  }
};

As with validateKey(), it will also parse the machine fingerprint, verify the response signature, and update the Tauri App State.

The only different is that when it received a valid license, instead of caching the response, this plugin will download the machine.lic file for offline licensing.

🔃 resetLicense()

Delete all the offline licenses (validation cache and machine file) in [APP_DATA/keygen/] and set the LicensedState in the Tauri App State to None.

🔃 resetLicenseKey()

Delete the cached license key on [APP_DATA]/keygen/.