Learn more about Ditto’s authentication methods in Authentication and Authorization.

​
API

To see fully working examples, see the code samples on GitHub.

​
Creating Your Client

To start with online authentication you need to use the onlineWithAuthentication identity type when creating your Ditto client. This identity type requires you to provide a two callbacks to handle authentication requests from Ditto:
  • authenticationRequired: Called when Ditto initially needs to authenticate
  • authenticationExpiringSoon: Called when Ditto needs to refresh the authentication token
If you do not implement authenticationExpiringSoon, sync will stop when the token expires.
struct AuthDelegate: DittoAuthenticationDelegate {
    func authenticationRequired(authenticator: DittoAuthenticator) {
        // Called when Ditto initially needs to authenticate
        authenticator.login(token: accessToken, provider: "my-auth-webhook") { clientInfo, err in
            // If err is nil, login was successful
            print("Login request completed. Error? \(err)")
        }
    }

    func authenticationExpiringSoon(
        authenticator: DittoAuthenticator, 
        secondsRemaining: Int64
    ) {
        // Called when Ditto needs to refresh the authentication token
        authenticator.login(token: accessToken, provider: "my-auth-webhook") { clientInfo, err in
            // If err is nil, login was successful
            print("Login request completed. Error? \(err)")
        }
    }
}

let identity = DittoIdentity.onlineWithAuthentication(
    appID: "REPLACE_ME_WITH_YOUR_APP_ID", 
    enableDittoCloudSync: false, // This is required to be set to false to use the correct URLs
    customAuthURL: URL(string: "REPLACE_ME_WITH_YOUR_AUTH_URL"),
    authenticationDelegate: AuthDelegate()
)

// Set the Ditto Websocket URL
var config = DittoTransportConfig()
config.connect.webSocketURLs.insert("wss://REPLACE_ME_WITH_YOUR_WEBSOCKET_URL")

// Optionally enable all P2P transports if using P2P Sync
// Do not call this if only using Ditto Cloud Sync
config.enableAllPeerToPeer()

ditto.transportConfig = config   

let ditto = Ditto(identity: identity)
try! ditto.startSync()

​
Login

Login takes two parameters:
  • Token: This can be any string value. Most auth services use a JWT (JSON Web Token), but you can send any token you want from the client. For example, during testing you may want to create a secret code for development use. This string will be sent in a POST request to the HTTP route.
  • Provider: This must be a string value matching the name of one of your configured authentication webhooks. If you have multiple authentication webhooks, you can select which webhook your application should use by changing the provider.

​
When should you call ditto.auth.login?

Along with the callbacks above, you can also call ditto.auth.login manually. This is useful if you know specific times when your app will be online. For an example implementation of authentication for Android, see the Ditto open-source demo chat app’s “authentication” branch in the getditto GitHub repository. 
ditto.auth.login(token: accessToken, provider: "my-auth-webhook") { clientInfo, err in
    // If err is nil, login was successful
    print("Login request completed. Error? \(err)")
}

​
Logout

Logout will stop sync, shut down all replication sessions, and remove any cached authentication credentials. Note that this does not remove any data from the store. If you wish to delete data from the store then use the optional cleanupFn parameter to perform any required cleanup. The cleanupFn is an optional function that will be called with the relevant Ditto instance as the sole argument that allows you to perform any required cleanup of the store as part of the logout process. 
ditto.auth.logout(cleanup: { ditto in
    ditto.store.execute("EVICT FROM tasks");
})

​
Tutorial

  • This section will require knowledge of writing server-side HTTP endpoints and handlers. The server side sample code is written in JavaScript (NodeJS with an Express-like API), however you can use any framework or language of your choosing.
  • We will use Auth0 in this tutorial. But you can use any third-party identity provider. Each app can use multiple identity providers.
  • In this tutorial, you’ll build a simple application so users can log in with a a third-party provider using Auth0. We assume that you have already completed the Auth0 tutorial on their documentation before starting this tutorial.
  • For the full application code in JavaScript and Swift, see the code samples on GitHub.

​
Configure Ditto

​To use an “Online With Authentication” identity, go to your app in the portal and find the Authentication Mode & Webhook Settings section. Ensure that “With Authentication” is selected like so:
Below, a section called Authentication Webhooks will be editable. Once your Authentication Webhook Endpoint(s) is deployed and ready, you can register it in the portal. Add a Name and URL.
  • Provide a unique name.
  • The URL parameter is the fully qualified URL of the webhook that you deploy yourself. Please include https:// at the beginning of your URL.
You can use this example webhook to test your application. However, you should use your own webhook in production. The example simply authenticates all requests for 7 days of offline usage. Once configured, you should see a webhook that looks like this in your portal app settings:

​
Configure Auth0

The second step is to configure Auth0. Follow these steps:
  1. Create a new Auth0 application.
  2. Configure the allowed callbacks and origins for your application. Make sure to add the callback URL for your application.
  3. Configure the allowed grant types for your application. For this tutorial, we will use the “Authorization Code” grant type.
  4. Create a new API in Auth0. This will represent the API that your application will access.
Next, you need to configure Ditto. Follow the steps that were outlined earlier in this article. Now that you have configured Auth0 and Ditto, you can start integrating them into your application. If you already have an Auth0 account… …log in, skip the next section, and proceed to the part titled Register your app with Auth0. If you don’t have an Auth0 account yet… …you can sign up for one here - it’s free. Register your app with Auth0
  1. In the menu on the left side of the Auth0 dashboard, click on Applications. This will expand the Applications menu. Select the first item in that menu, which also has the name Applications. You will now be on the Applications page. It lists all the applications that you have registered so that Auth0 can handle their login/logout processes.
  2. Create a new registration for your app. Do this by clicking the Create application button near the top right of the page.
You can follow the prompts and instructions on the Auth0 site for more details. From the Auth0 portal you will need to retrieve the following information for your Android app:
  • Domain
  • Client ID
You can store these as String resources in your app. On the Auth0 portal, you will need to build your callback URL and logout URL. Again, see the Auth0 website for details on how to do this.

​
References

Auth0 Tutorial Auth0 Website - Android Getting Started / Onboarding

​
Integrating Auth0 with Ditto

Assuming you have a login button in the HTML:
JS
<button onClick={login}>Login</button>
We attach a login function to the button.
JS
import createAuth0Client from '@auth0/auth0-spa-js';
// OR for React
import { useAuth0 } from '@auth0/auth0-react';

// configure your auth0 client...

async function login () {
  await auth0.loginWithRedirect({
    redirect_uri: window.location.origin
  });
  startDitto()
}
We can then create a startDitto function that gets the access token and starts a new Ditto instance, and passes the token to your server route you created in the previous section.
The provider name given to the Ditto Client must match a provider name in the portal (e.g., replit-auth). If you have multiple providers, ensure you specify the provider name that you want your app to use.
JS
import createAuth0Client from '@auth0/auth0-spa-js';
// OR for React
import { useAuth0 } from '@auth0/auth0-react';
import { init, Ditto } from "@dittolive/ditto"

// configure your auth0 client...

let ditto

(async () => {
  await init() // you need to call this at least once before using any of the Ditto API

  function startDitto () {
    let token = await auth0.getAccessTokenSilently();

    const authHandler = {
      authenticationRequired: async function(authenticator) {
        await authenticator.login(token, "replit-auth");
        console.log("Login request completed.");
      },
      authenticationExpiringSoon: function(authenticator, secondsRemaining) {
        console.log(`Auth token expiring in ${secondsRemaining} seconds`)
        await authenticator.login(token, "replit-auth");
        console.log("Login request completed.");
      }
    }

    const identity = {
      type: 'onlineWithAuthentication',
      appID: "REPLACE_ME_WITH_YOUR_APP_ID",
      customAuthURL: "REPLACE_ME_WITH_YOUR_AUTH_URL",
      enableDittoCloudSync: false, // This is required to be set to false to use the correct URLs
      authHandler
    }

    ditto = new Ditto(identity, '/persistence/file/path')
    const config = new TransportConfig()
    config.connect.websocketURLs.push('wss://REPLACE_ME_WITH_YOUR_WEBSOCKET_URL')

    ditto.setTransportConfig(config)
    ditto.startSync()
  }

  async function login () {
    await auth0.loginWithRedirect({
      redirect_uri: window.location.origin
    });
    startDitto()
  }
})()
To demonstrate that this Ditto client has been authenticated, let’s display the number of cars in the collection, and a button to add one item to it:
JSX
<div>
  <h1>Cars: {numberOfCars}</h1>
  <button onClick={addItem}>+1</button>
</div>
Once we start the ditto instance, we can create a liveQuery and create a button that adds items to a collection:
JS
let subscription = ditto.store.collection('cars').find("state == 'FOR_SALE'").subscribe()
let liveQuery = ditto.store.collection('cars').find("name == 'Toyota'").observeLocal((cars) => {
  numberOfCars = cars.length
})

function addItem () {
  ditto.store.collection('cars').upsert({
    "name": 'Toyota',
    "state": 'FOR_SALE'
  })
}
Log out
JS
let loggedIn = false
if (auth0.isAuthenticated()) {
  loggedIn = true
}
JS
if (loggedIn) {
  // render the logout button
  <button onClick={onLogoutClick}>Logout</button>
} else {
  <button onClick={login}>Login</button>
}
And then we can write the logout function and attach it to the button. We also recommend calling ditto.auth.logout with a callback function that evicts any data from the local database.
JS
function onLogoutClick() {
  ditto.auth.logout(() => {
    ditto.store.collection('cars').findAll().evict()
  })
  await auth0.logout({ returnTo: window.location.origin })
}
To make this usable for real-world applications, you can retrieve the user’s profile details such as email, username, and full name. See the official Auth0 documentation for your platform to add that functionality to your application Yay! You now have a fully functioning onlineWithAuthentication app. Build and run it on a device. For a full application example, see the example application on GitHub

​
Server

The authentication webhook needs to handle an HTTP POST request. Each client that will need to authenticate will send a payload to this webhook. The following section requires that you have knowledge of writing server side HTTP endpoints and responding with a JSON payload. Code samples of server side code are written with a NodeJS / Express syntax. You can use any language or framework on the server side.

​
Incoming POST body

​When your client device wants to authenticate using your webhook, your server will receive an HTTP post with a JSON payload that looks like:
JSON
{
  "appID": "YOUR_APP_ID_HERE", // the appID
  "provider": "my-auth", // this is the "Name" of the "Authentication Webhook"
  "token": "eyJhbGciOiJI..." // this is what each device will send to authenticate
}
Your can introspect these values by parsing out the request body:
JS
let express = require('express')
let cors = require('cors')
let body = require('body-parser')
let app = express()

app.use(cors())
app.use(body.json())

let app = express()

app.post('/', (req, res) => {
  const appID = req.body.appID
  const provider = req.body.provider
  const token = req.body.token
})
Generally, you will want to check the token for some sort of validity. Let’s assume you have some sort of library or logic to parse and validate the token is for a specific user. You can also use the clientInfo key in your JSON response to pass information back to client.
JS
app.post('/', async (req, res) => {
  const token = req.body.token;
  try {
    // The token that your server receives from ditto is always a string
    let parsedToken = JSON.parse(token)
    let payload = getDittoPermissions(parsedToken)
    res.json(payload)
  } catch (err) {
    res.json({
      "authenticate": err,
      "clientInfo": err.message
    })
  }
})
As a simple example, let’s grant full read & write permissions to all collections and all documents.
JS
app.post('/', async (req, res) => {
  const token = req.body.token;
  try {
    let payload = {
      "authenticate": true,
      "expirationSeconds": 28800,
      "userID": "123abc",
      "permissions": {
        "read": {
          "everything": true,
          "queriesByCollection": {}
        },
        "write": {
          "everything": true,
          "queriesByCollection": {}
        }
      }
    }
    res.json(payload)
  } catch (err) {
    res.json({
      "authenticate": err,
      "clientInfo": err.message
    })
  }
})
For more information on how to design your app’s permissions, see Data Authorization.

​
Deploy your server

​Now, the portal will attempt to reach this server. That means you must deploy it somewhere that this HTTP request is accessible. For testing, you can use a quick-deploy service such as Glitch.
Please be sure that this endpoint is not behind a firewall or VPN. If you cannot get around this requirement contact us.