![Houston](https://raw.github.com/nomad/nomad.github.io/assets/houston-banner.png) Push Notifications don't have to be difficult. Houston is a simple gem for sending Apple Push Notifications. Pass your credentials, construct your message, and send it. In a production application, you will probably want to schedule or queue notifications into a background job. Whether you're using [queue_classic](https://github.com/ryandotsmith/queue_classic), [resque](https://github.com/resque/resque), or rolling you own infrastructure, integrating Houston couldn't be simpler. Another caveat is that Houston doesn't manage device tokens for you. For that, you should check out [Helios](http://github.com/helios-framework/helios). > Houston is named for [Houston, TX](http://en.wikipedia.org/wiki/Houston), the metonymical home of [NASA's Johnson Space Center](http://en.wikipedia.org/wiki/Lyndon_B._Johnson_Space_Center), as in _Houston, We Have Liftoff!_. > It's part of a series of world-class command-line utilities for iOS development, which includes [Cupertino](https://github.com/nomad/cupertino) (Apple Dev Center management), [Shenzhen](https://github.com/nomad/shenzhen) (Building & Distribution), [Venice](https://github.com/nomad/venice) (In-App Purchase Receipt Verification), [Dubai](https://github.com/nomad/dubai) (Passbook pass generation), and [Nashville](https://github.com/nomad/nashville) (iTunes Store API). > This project is also part of a series of open source libraries covering the mission-critical aspects of an iOS app's infrastructure. Be sure to check out its sister projects: [GroundControl](https://github.com/mattt/GroundControl), [SkyLab](https://github.com/mattt/SkyLab), [houston](https://github.com/nomad/houston), and [Orbiter](https://github.com/mattt/Orbiter). ## Installation $ gem install houston ## Usage ```ruby require 'houston' # Environment variables are automatically read, or can be overridden by any specified options. You can also # conveniently use `Houston::Client.development` or `Houston::Client.production`. APN = Houston::Client.development APN.certificate = File.read('/path/to/apple_push_notification.pem') # An example of the token sent back when a device registers for notifications token = '' # Create a notification that alerts a message to the user, plays a sound, and sets the badge on the app notification = Houston::Notification.new(device: token) notification.alert = 'Hello, World!' # Notifications can also change the badge count, have a custom sound, have a category identifier, indicate available Newsstand content, or pass along arbitrary data. notification.badge = 57 notification.sound = 'sosumi.aiff' notification.category = 'INVITE_CATEGORY' notification.content_available = true notification.mutable_content = true notification.custom_data = { foo: 'bar' } notification.url_args = %w[boarding A998] notification.thread_id = 'notify-team-ios' # And... sent! That's all it takes. APN.push(notification) ``` To generate a `.pem` file, it is recommended to use [fastlane pem](https://fastlane.tools/pem), which completely automates the process of creating the certificate. ## Configuration Houston will attempt to load configuration data from environment variables, if they're present. The following variables will be used. | Environment Variable | Description | | --- | --- | | `APN_GATEWAY_URI` | The base URI for the APNS service to use. If left blank, will use the default APNS Production Gateway URI. | | `APN_FEEDBACK_URI` | The base URI for the APNS feedback service to use. If left blank, will use the default APNS Production Feedback URI. | | `APN_CERTIFICATE` | The file path to a valid APNS push certificate in `.pem` format (see "[Converting Your Certificate](#converting-your-certificate)" below). | | `APN_CERTIFICATE_DATA` | The contents of a valid APNS push certificate in `.pem` format (see "[Converting Your Certificate](#converting-your-certificate)" below); used in lieu of `APN_CERTIFICATE` if that variable is not provided. | | `APN_CERTIFICATE_PASSPHRASE` | If the APNS certificate is protected by a passphrase, provide this variable to use when decrypting it. | | `APN_TIMEOUT` | The timeout used when communicating with APNS. If not provided, the default of 0.5 seconds is used. | ### Error Handling If an error occurs when sending a particular notification, its `error` attribute will be populated: ```ruby puts "Error: #{notification.error}." if notification.error ``` ### Silent Notifications To send a silent push notification, set `sound` to an empty string (`''`): ```ruby Houston::Notification.new(sound: '', content_available: true) ``` ### Mutable Notifications To send a mutable push notification (supported by iOS 10+), set `mutable_content` to `true`: ```ruby Houston::Notification.new(mutable_content: true) ``` ### Persistent Connections If you want to manage your own persistent connection to Apple push services, such as for background workers, here's how to do it: ```ruby certificate = File.read('/path/to/apple_push_notification.pem') passphrase = '...' connection = Houston::Connection.new(Houston::APPLE_DEVELOPMENT_GATEWAY_URI, certificate, passphrase) connection.open notification = Houston::Notification.new(device: token) notification.alert = 'Hello, World!' connection.write(notification.message) connection.close ``` ### Feedback Service Apple provides a feedback service to query for unregistered device tokens, these are devices that have failed to receive a push notification and should be removed from your application. You should periodically query for and remove these devices, Apple audits providers to ensure they are removing unregistered devices. To obtain the list of unregistered device tokens: ```ruby Houston::Client.development.devices ``` In practice, you'll use a reference to instance of the APN object you create (see the Usage section). Here's a rake job that marks device tokens as invalid based on the feedback service from Apple. This example assumes devices are tracked in a model called Device (i.e. `User.devices`). In `lib/tasks/notifications.rake`: ```ruby namespace :notifications do task device_token_feedback: [:environment] do APN.unregistered_devices.each do |device_hash| # Format: { token: token, timestamp: timestamp } device = Device.find_by(token: device_hash[:token]) next unless device.present? # Remove device token device.update_attribute(:device_token, nil) end end end ``` ## Versioning Houston 2.0 supports the new [enhanced notification format](https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/CommunicatingWIthAPS.html#//apple_ref/doc/uid/TP40008194-CH101-SW4). Support for the legacy notification format is available in 1.x releases. ## Command Line Tool Houston also comes with the `apn` binary, which provides a convenient way to test notifications from the command line. $ apn push "" -c /path/to/apple_push_notification.pem -m "Hello from the command line! " ## Enabling Push Notifications on iOS ### Objective-C ```objective-c // AppDelegate.m - (void)applicationDidFinishLaunching:(UIApplication *)application { // ... [[UIApplication sharedApplication] registerForRemoteNotificationTypes:(UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound)]; } - (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken { NSLog(@"application:didRegisterForRemoteNotificationsWithDeviceToken: %@", deviceToken); // Register the device token with a webservice } - (void)application:(UIApplication *)application didFailToRegisterForRemoteNotificationsWithError:(NSError *)error { NSLog(@"Error: %@", error); } ``` ### Swift ```swift // AppDelegate.swift func application(_ application: UIApplication, willFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool { application.registerForRemoteNotifications() return true } func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) { // Register the device token with a webservice } func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) { print("error \(error)") } ``` ## Converting Your Certificate > These instructions come from the [APN on Rails](https://github.com/PRX/apn_on_rails) project, which is another great option for sending push notifications. Once you have the certificate from Apple for your application, export your key and the apple certificate as p12 files. Here is a quick walkthrough on how to do this: 1. Click the disclosure arrow next to your certificate in Keychain Access and select the certificate and the key. 2. Right click and choose `Export 2 items…`. 3. Choose the p12 format from the drop down and name it `cert.p12`. Now convert the p12 file to a pem file: **Unencrypted private key (do not store this certificate in version control)** $ openssl pkcs12 -in cert.p12 -out apple_push_notification.pem -nodes -clcerts **Encrypted private key** $ openssl pkcs12 -in cert.p12 -out apple_push_notification.pem -aes256 -clcerts You'll have to specify the password in the `APN_CERTIFICATE_PASSPHRASE` environment variable if you use the encrypted option. ## Creator Mattt Thompson ([@mattt](https://twitter.com/mattt)) ## License Houston is available under the MIT license. See the LICENSE file for more info.