Using the Apps framework

Using the Apps framework

Use the ZAF SDK to interact with the Apps framework directly from your iframe. The SDK provides a ZAFClient global object that allows cross-frame communication between your app and the host Zendesk product. For details, see the ZAF Client API doc.

Getting the SDK

Import the ZAF SDK from https://static.zdassets.com/zendesk_app_framework_sdk/2.0/zaf_sdk.min.js. Example:

<script type="text/javascript" src="https://static.zdassets.com/zendesk_app_framework_sdk/2.0/zaf_sdk.min.js"></script>

Using the URL in your app ensures the SDK is automatically updated with the latest 2.0 patch releases, including any bug fixes. For more information, see Framework Versions.

Working with framework APIs

The get, set and invoke methods of a ZAFClient object provide an interface between your iframe and the framework APIs. Due to the nature of cross-frame communication, every interaction between your iframe and the framework happens asynchronously. get, set and invoke return a JavaScript Promise object with the result of the call.

get

var client = ZAFClient.init();
client.get('ticket.requester.name').then(function(data) {
  console.log(data); // { "ticket.requester.name": "Mikkel Svane" }
});

set

var client = ZAFClient.init();
client.set('ticket.type', 'task');

invoke

var client = ZAFClient.init();
client.invoke('comment.appendText', 'My printer is on fire');

Bulk calls

The get, set and invoke methods of ZAFClient support bulk calls.

Bulk get

var client = ZAFClient.init();
client.get(['ticket.subject', 'ticket.requester.name']).then(function(data) {
  console.log(data); // { 'ticket.subject': 'Help, my printer is on fire', 'ticket.requester.name': 'Mikkel Svane' }
});

Bulk set

var client = ZAFClient.init();
client.set({ 'ticket.subject': 'Printer Overheating Incident', 'ticket.type': 'incident' }).then(function(data) {
  console.log(data); // { 'ticket.subject': 'Printer Overheating Incident', 'ticket.type': 'incident' }
});

Bulk invoke

var client = ZAFClient.init();
client.invoke({
  'ticket.comment.appendText': ['My printer is on fire'],
  'ticketFields:priority.hide': []
});

Error handling

If an error occurs when calling get, set or invoke with a single path, the promise is rejected with an error. Errors can occur in case the path is invalid or given an invalid argument.

Example:

// invalid path
client.get('nonExistentPath').then(function(data) {
  console.log(data); // never run
}).catch(function(error) {
  console.log(error.toString()); // "APIUnavailable: "nonExistentPath" Could not find handler for: "nonExistentPath"
});

// invalid argument
client.set('ticket.form.id', -1).then(function(data) {
  console.log(data); // never run
}).catch(function(error) {
  console.log(error.toString()); // Error: "ticket.form.id" Invalid Ticket Form ID
});

When making bulk calls, the promise is always resolved. However, if one of the paths is invalid or if the call is given invalid arguments, the framework includes an errors property with the failed paths as keys and their error objects as values.

Example:

// invalid path
client.get(['ticket.subject', 'nonExistentPath']).then(function(data) {
  console.log(data);
  /*
    {
      'ticket.subject': 'Help, my printer is on fire',
      'errors': {
        'nonExistentPath': Error("Could not find handler for: 'nonExistentPath'")
      }
    }
  */
});

// invalid argument
client.set({
  'ticket.subject': 'Printer Overheating Incident',
  'ticket.form.id': -1
}).then(function(data) {
  console.log(data);
  /*
    {
      'ticket.subject': 'Help, my printer is on fire',
      'errors': {
        'ticket.form.id': Error("Invalid Ticket Form ID")
      }
    }
  */
});

Additional resources

For a complete list of available APIs, see the following docs:

• Core Apps API
• Support Apps API
• Chat Apps API
• Sell Apps API

Working with framework events

Use the on method of a ZAFClient object to listen for events. For available events, see the listings by location in the following docs:

• Core Apps API
• Support Apps API
• Chat Apps API
• Sell Apps API

Example:

var client = ZAFClient.init();
client.on('ticket.updated', function() {
  handleTicketUpdated();
});

Hook Events

Hook events allow your app to hook into product events and block the completion of the event until your app responds.

If your event handler returns a promise, the UI will wait until the promise resolves. Alternatively the event handler can abort the user request by returning false or a string to show as an error message. In the following example, the handler for the ticket.save hook event prevents the user from saving the ticket:

var client = ZAFClient.init();
client.on('ticket.save', function() {
  return false;
});

You can register multiple hook events. However, for the event to continue processing (for example, for the ticket save to be committed), all promises returned by the event handlers must be successfully resolved. If any event handler returns a rejected promise, throws an exception, or returns false or a string, the event is aborted. If a string is returned directly or passed with the promise rejection, the string is displayed as an error message in the UI.

Example:

var client = ZAFClient.init();
client.on('ticket.save', function() {
  return client.get('ticket.comment.text').then(function(data) {
    return fetch('https://myapi.example.org/is_polite?comment=' + data['ticket.comment.text']).catch(function() {
      throw 'You must be more polite';
    });
  });
});

Hook events have a 30-second timeout period during which your app must respond. Otherwise the event will be aborted by default.

Making HTTP requests

You can use the ZAF client's request() method to safely make HTTP requests, such as REST API calls, from a client-side Zendesk app. See Making API requests from a Zendesk app.

Authenticating Zendesk in your server-side app

A Zendesk app can consist of a web application running on a remote server that generates and serves all the HTML loaded in an iframe in a Zendesk product. No application logic or content is stored in the Zendesk infrastructure. When the app opens in the product, Zendesk must request the initial page from the server-side app. Subsequent page requests to the server usually originate from the iframed app itself.

If you're building a server-side app, one security feature to consider is verifying that an HTTP request for the initial page originates from a legitimate Zendesk product instance.

To help you, Zendesk can include a JSON Web Token (JWT) in the request for the initial page. After receiving the request, your server-side app can check the signed token to validate that the request originated from a legitimate Zendesk product instance. This helps prevent downgrade attacks.

The signed token also contains a number of attributes (known as claims) that your server-side app can use to look up externally stored values associated with your Zendesk Support account.

Zendesk includes the JWT token only in requests for the initial page of the app. This page is specified in the location object in the app's manifest.json file. Example:

"location": {
  "support": {
    "ticket_sidebar": {
      "signed": true,
      "url": "https://myapp.example.org/"
    }
  }
}

Note: This feature is only available for apps that specify a page on a remote server in the location object. It's not available for apps that specify a page hosted on the Zendesk infrastructure, such as "assets/iframe.html".

Enabling the JWT token in Zendesk

To get Zendesk to include a JWT token in its request for the initial app page, include one of the following properties in your app's manifest.json file:

• To include a JWT token for the app in all locations, add "signedUrls": true to the top-level manifest object. Example:

  {
    "name": "My App",
    "signedUrls": true,
    "location": { ... },
    ...
  }

or

• To include a JWT token for the app only in a specific location, add "signed": true to the named location in the location object. Example:

  "name": "My App",
  "location": {
    "support": {
      "ticket_sidebar": {
        "signed": true,
        "url": "https://myapp.example.org/"
      }
    }
  },

Handling the JWT token in your server-side app

Once the JWT token is enabled, Zendesk does the following:

• Changes the request method for the initial page from GET to POST
• Includes the JWT token in a field named token in the POST request's form data

As a result, make sure your server-side app performs the following tasks:

• Handles POST requests for the initial page of the app
• Gets the token from the request's form data
• Validates the JWT token

Zendesk signs the JWT token with RSA using the SHA-256 hash algorithm ("RS256" in RFC7519). Your server-side app should use a JWT client library that supports this signature algorithm. Validating that the JWT algorithm used to encode the token is RS256 helps prevent downgrade attacks. A list of popular JWT libraries is available at jwt.io.

Your JWT library will need a public key to decode the token. You can get your app's public key with the Get App Public Key endpoint in the Zendesk REST API:

https://{subdomain}.zendesk.com/api/v2/apps/{app_id}/public_key.pem

where {subdomain} is the subdomain of your Zendesk Support instance, and {app_id} is the ID of your app. You can get your app id with the List All Apps endpoint:

https://{subdomain}.zendesk.com/api/v2/apps.json

The key is generated when an app is created in Zendesk Support and doesn't change if you update the app later.

Note: You can only get the app's public key if the app has already been created in a Zendesk Support account. So before you can modify your server-side app to validate the JWT token, you must upload the app package (consisting only of the manifest file and any in-product branding assets) to the Zendesk Support instance. Uploading an app doesn't enable it in the user interface yet.

The following example shows one way a server-side app can handle the Zendesk JWT token. The Ruby app uses the JWT gem, the Zendesk API client for Ruby, and the Sinatra web framework. The code is explained after the example.

require 'jwt'
require 'sinatra'
require 'zendesk_api'

client = ZendeskAPI::Client.new do |config|
  ## Change these values with your credentials
  config.url = 'https://mysubdomain.zendesk.com/api/v2'
  config.username = '[email protected]/token'
  config.password = ENV['ZENDESK_API_TOKEN']
  
  # The token should be obtained from an environment variable for security
  
end

app_id = 101 # Set this to your App ID
rsa_public_pem = client.connection.get("apps/#{app_id}/public_key.pem").body
puts "Validating against App ID #{app_id} with public key:"
puts rsa_public_pem
rsa_public = OpenSSL::PKey::RSA.new(rsa_public_pem)

set :protection, except: :frame_options

post '/' do
  decoded_token = JWT.decode params[:token], rsa_public, true, algorithm: 'RS256'
  jwt_claims = decoded_token.first
  user_info = client.connection.get(jwt_claims["sub"]).body
  user_name = user_info["user"]["name"]
  account_url = jwt_claims["iss"]
  "Welcome #{user_name} from #{account_url}!"
end

Note: If running this server-side app locally (example, http://localhost:4567), allow mixed content in your browser by clicking the shield icon on the right (Chrome) or the lock icon on the left (Firefox).

The app performs the following tasks:

1. Creates a REST API client with the Zendesk client for Ruby:

   client = ZendeskAPI::Client.new do |config|
     ...
   end

2. Uses the client to make a Zendesk REST API request to get the app's public key:

   rsa_public_pem = client.connection.get("apps/#{app_id}/public_key.pem").body

3. Uses a Sinatra url route to handle POST requests for the initial page of the app ('/'):

   post '/' do
     ...
   end

4. Gets the token from the request and validates it:

   post '/' do
     decoded_token = JWT.decode params[:token], rsa_public, true, algorithm: 'RS256'
     ...

For a Python example, see Securing the app in the "Building a server-side app" tutorial series.

JWT claims

The JWT token contains a number of attributes (known as claims) that your server-side app can use to look up values associated with your Zendesk Support account.

Note: The JWT token does not grant access to any data in the Zendesk product instance apart from that provided in the JWT claims. An external method of authentication (such as API token or OAuth) is required to fetch further information from the Zendesk product account, and is outside the scope of this document. For more information, see Security and Authentication in the Zendesk REST API documentation.

Claim Identifier	Name	Description	Example	Reference
exp	Expiration Time	The expiration time on or after which the JWT must not be accepted for processing	1466728968	RFC7519 Section 4.1.4
nbf	Not Before	The time before which the JWT must not be accepted for processing	1466747798	RFC7519 Section 4.1.5
iss	Issuer	The issuer of the token, in the form of the Zendesk Support account hostname	support.zendesk.com	RFC7519 Section 4.1.1
aud	Audience	The audience of which the token is valid for, in the form of a URI referencing the particular installation of the app which is being loaded	https://support.zendesk.com/api/v2/apps/installations/1000.json	RFC7519 Section 4.1.3
iat	Issued At	The time at which the JWT was issued, which can be used to determine the age of the JWT. Set by Zendesk	1466747858	RFC7519 Section 4.1.6
sub	Subject	The subject of the JWT, in the form of a URI referencing the particular user that is loading the app	https://support.zendesk.com/api/v2/users/1000.json	RFC7519 Section 4.1.2
cnf	Confirmation	The identity of the proof-of-possession key, in the form of an object containing the URL to the app's public key, in JSON Web Key format	{"jku": "https://support.zendesk.com/api/v2/apps/100/public_key.json"}	RFC7800 Section 3.1
qsh	Query String Hash	A SHA256 hash of the canonical request string (method&uri-path&canonical-query-string)	bbe6b8ce792dccd999af6be72952d37c3bb07613d05c7576c5ff1d9eeed2ebdb	Atlassian Connect Documentation
context	App Instance Context	An object containing the context in which the app is running, including the product and location properties	{"context": {"product": "support", "location": "ticket_sidebar"}}	N/A

Using local storage

App assets hosted by Zendesk have their own unique url. This means apps have their own local storage, which is not shared by other apps.

However, if users have different installations of the same app, the asset url will be the same for the different installations. As a result, it's good practice to scope local storage keys to each installation to prevent conflicts between different installations running on the same browser. Example:

var client = ZAFClient.init();

function setKey(key, val) {
  return client.metadata().then(function(metadata) {
    return localStorage.setItem(metadata.installationId + ":" + key, val);
  });
}

function getKey(key) {
  return client.metadata().then(function(metadata) {
    return localStorage.getItem(metadata.installationId + ":" + key);
  });
}

setKey("username", "agent_extraordinaire");

getKey("username").then(function(username) {
  console.log(username); // agent_extraordinaire
});

Messaging between locations

The framework makes it possible for your app to interact with another instance of itself running in a different app location via the instances API. For more information, see instances.

Example

The example below demonstrates triggering an event from one instance and listening to it from another. For this example we named the event incoming_call. In your own code, you can choose whatever name is appropriate.

The app in this example must run in the nav_bar and top_bar locations. The manifest would contain a snippet like this:

{
  "location": {
    "support": {
      "nav_bar": "assets/nav_bar.html",
      "top_bar": "assets/top_bar.html"
    }
  }
}

The top bar app runs the following code:

var client = ZAFClient.init();

client.on('incoming_call', function() {
  client.invoke('popover');
});

The nav bar app runs the following code:

var client = ZAFClient.init();

var topBarClientPromise = client.get('instances').then(function(instancesData) {
  var instances = instancesData.instances;
  for (var instanceGuid in instances) {
    if (instances[instanceGuid].location === 'top_bar') {
      return client.instance(instanceGuid);
    }
  }
});

topBarClientPromise.then(function(topBarClient) {
  // trigger an incoming_call event on the top bar
  topBarClient.trigger('incoming_call');
});

Using modal dialogs

You can show an iframe in the modal location using the instances.create API. Modals are currently only available in Zendesk Support.

Note: Apps using the signed urls feature must define the modal location in their manifest, specifying the url to be used.

Example

To open a modal that displays the current Wikipedia home page, use:

var client = ZAFClient.init();

client.invoke('instances.create', {
  location: 'modal',
  url: 'https://en.m.wikipedia.org/wiki/Main_Page',
  size: { // optional
    width: '450px',
    height: '300px'
  }
}).then(function(modalContext) {
  // The modal is on the screen now!
  var modalClient = client.instance(modalContext['instances.create'][0].instanceGuid);
  modalClient.on('modal.close', function() {
    // The modal has been closed.
  });
});

Note: The maximum recommended width and height are 80vw and 80vh. Scrollbars are displayed if your content is larger than the width or height of the modal.

Testing and debugging

You can use ZCLI to run and test your apps locally. Refer to Testing your Zendesk app locally.