Grocer

grocer interfaces with the Apple Push Notification Service to send push notifications to iOS devices.

There are other gems out there to do this, but grocer plans to be the cleanest, most extensible, and friendliest.

Requirements

• Ruby/MRI 1.9.x, JRuby 1.7.x in 1.9 mode, Rubinius in 1.9 mode

Installation

Add this line to your application's Gemfile:

gem 'grocer'

If you are using JRuby, you will also need to add this to enable full OpenSSL support:

gem 'jruby-openssl'

Usage

Connecting

# `certificate` is the only required option; the rest will default to the values
# shown here.
#
# Information on obtaining a `.pem` file for use with `certificate` is shown
# later.
pusher = Grocer.pusher(
  certificate: "/path/to/cert.pem",      # required
  passphrase:  "",                       # optional
  gateway:     "gateway.push.apple.com", # optional; See note below.
  port:        2195,                     # optional
  retries:     3                         # optional
)

Notes

• certificate: If you don't have the certificate stored in a file, you can pass any object that responds to read. Example: certificate: StringIO.new(pem_string)
• gateway: Defaults to different values depending on the RAILS_ENV or RACK_ENV environment variables. If set to production, defaults to gateway.push.apple.com, if set to test, defaults to localhost (see Acceptance Testing later), otherwise defaults to gateway.sandbox.push.apple.com.
• retries: The number of times grocer will retry writing to or reading from the Apple Push Notification Service before raising any errors to client code.

Sending Notifications

# `device_token` and either `alert` or `badge` are required.
#
# Information on obtaining `device_token` is shown later.
notification = Grocer::Notification.new(
  device_token: "fe15a27d5df3c34778defb1f4f3880265cc52c0c047682223be59fb68500a9a2",
  alert:        "Hello from Grocer!",
  badge:        42,
  sound:        "siren.aiff",         # optional
  expiry:       Time.now + 60*60,     # optional; 0 is default, meaning the message is not stored
  identifier:   1234                  # optional
)

pusher.push(notification)

It is desirable to reuse the same connection to send multiple notifications, as is recommended by Apple.

pusher = Grocer.pusher(connection_options)
notifications.each do |notification|
  pusher.push(notification)
end

Custom Payloads

The Apple documentation says "Providers can specify custom payload values outside the Apple-reserved aps namespace." To specify a custom payload, set Grocer::Notification#custom.

notification = Grocer::Notification.new(
  device_token: "...",
  alert:        "Hello from Grocer",
  custom: {
    "acme2": ["bang", "whiz"]
  }
)

# Generates a JSON payload like:
# {"aps": {"alert": "Hello from Grocer"}, "acme2": ["bang", "whiz"]}

Passbook Notifications

A Grocer::PassbookNotification is a specialized kind of notification which does not require any payload. That is, you need not (and Apple explicitly says not to) send any payload for a Passbook notification. If you do, it will be ignored.

notification = Grocer::PassbookNotification.new(device_token: "...")
# Generates a JSON payload like:
# {"aps": {}}

Newsstand Notifications

Grocer also supports the special Newsstand 'content-available' notification. Grocer::NewsstandNotification can be used for this. Like Grocer::PassbookNotification, it is a specialized kind of notification which does not require any payload. Likewise, anything you add to it will be ignored.

notification = Grocer::NewsstandNotification.new(device_token: "...")
# Generates a JSON payload like:
# {"aps": {"content-available":1}}

Feedback

# `certificate` is the only required option; the rest will default to the values
# shown here.
feedback = Grocer.feedback(
  certificate: "/path/to/cert.pem",       # required
  passphrase:  "",                        # optional
  gateway:     "feedback.push.apple.com", # optional; See note below.
  port:        2196                       # optional
  retries:     3                          # optional
)

feedback.each do |attempt|
  puts "Device #{attempt.device_token} failed at #{attempt.timestamp}"
end

Notes

• gateway: Defaults to feedback.push.apple.com only when running in a production environment, as determined by either the RAILS_ENV or RACK_ENV environment variables. In all other cases, it defaults to the sandbox gateway, feedback.sandbox.push.apple.com.
• retries: The number of times grocer will retry writing to or reading from the Apple Push Notification Service before raising any errors to client code.

Acceptance Testing

Grocer ships with framework to setup a real looking APNS server. It listens on a real SSL-capable socket bound to localhost.

You can setup an APNS client to talk to it, then inspect the notifications the server received.

The server simply exposes a blocking queue where notifications are placed when they are received. It is your responsibility to timeout if a message is not received in a reasonable amount of time.

For example, in RSpec:

require 'timeout'

describe "apple push notifications" do
  before do
    @server = Grocer.server(port: 2195)
    @server.accept # starts listening in background
  end

  after do
    @server.close
  end

  specify "As a user, I receive notifications on my phone when awesome things happen" do
    # ... exercise code that would send APNS notifications ...

    Timeout.timeout(3) {
      notification = @server.notifications.pop # blocking
      expect(notification.alert).to eq("An awesome thing happened")
    }
  end
end

Device Token

A device token is obtained from within the iOS app. More details are in Apple's Registering for Remote Notifications documentation.

The key code for this purpose is:

- (void)applicationDidFinishLaunching:(UIApplication *)app {
   // other setup tasks here....
   [[UIApplication sharedApplication] registerForRemoteNotificationTypes:(UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound)];
}

- (void)application:(UIApplication *)app didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)devToken {
    NSLog(@"Got device token: %@", [devToken description]);

    [self sendProviderDeviceToken:[devToken bytes]]; // custom method; e.g., send to a web service and store
}

- (void)application:(UIApplication *)app didFailToRegisterForRemoteNotificationsWithError:(NSError *)err {
    NSLog(@"Error in registration. Error: %@", err);
}

Certificate File

Login to the iOS Provisioning Portal (App IDs).

Configure the appropriate certificate for push notifications and download the certificate:

Open the file in Keychain Access, then expand the certificate to show both the certificate and the private key. Command select so both are highlighted:

Control click and select to export the 2 items:

Save the items as a .p12 file. Open a terminal window and run the following command:

openssl pkcs12 -in exported_certificate.p12 -out certificate.pem -nodes -clcerts

The certificate.pem file that is generated can be used with grocer.

Support Channels

GitHub Issues and Pull Requests are the primary venues for communicating issues and discussing possible features. Several of us also regularly hang out in the #grocer channel on Freenode; feel free to pop in and ask questions there as well. Thanks! ❤️