Apple Push Notification Library for Haskell

Chris Moos — Mon, 13 Jul 2009 20:40:29 +0000

I have been working with Apple’s Push Notification service recently and decided to make a library to send notifications with Haskell. It is very simple and has a few helpers to make notifications with an alert, sound, etc,.

ApplePush Hackage

ApplePush Documentation

When using the library, you must use an SSL tunnel, because Haskell’s SSL support is incomplete. I use stunnel4, which works great, and offloads the SSL processing as well. Here are some basic instructions on getting started with the library.

Stunnel setup

Download your certificate from Apple. If you are using a Mac, export the certificate (.cer) into a directory. Also, export your private key as a .p12 file. Stunnel needs the certificate/key in one file, in the following format:

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-----BEGIN RSA PRIVATE KEY-----
YOUR KEY
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
YOUR CERTIFICATE
-----END CERTIFICATE-----

Run the following commands to convert and concatenate your certificate/private key.

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openssl x509 -in cert.cer -inform DER -outform PEM -out cert.pem
openssl pkcs12 -in key.p12 -out key.pem -nodes
cat key.pem cert.pem > certs.pem

Create a file called tun.conf, which will configure stunnel.

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client=yes
debug=5
foreground=no
pid=tun.pid
[service]
accept=2195
connect=gateway.sandbox.push.apple.com:2195
cert=certs.pem

This will bind stunnel to the local port 2195, and tunnel traffic via SSL to gateway.sandbox.push.apple.com:2195.

Next run the following command to start stunnel.

1	stunnel tun.conf

ApplePush Haskell Library

Let’s update our cabal packages, and then install.

1 2	cabal update cabal install ApplePush

In addition to the library, an application, called applepushtest, is also installed so that you can test the library and your SSL tunnel setup. Let’s try it out.

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c10k:~ chris$ ~/.cabal/bin/applepushtest
Apple Push Test, Version 0.1
usage: applepushtest device_token(hex)

You must pass a parameter, device_token, to the application. This tells the library which device to send the notification to. This token must be retrieved in your client application using registerForRemoteNotificationTypes:. Once you have your token, run the following command.

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c10k:~ chris$ ~/.cabal/bin/applepushtest (yourtoken)
Device Token: (yourtoken)
Message> hey
Message> whats up?
Message> test!!
Message>

To use the library in your application, check out Main.hs for an example.

Haskell AIM Client – a cool proof of concept

Chris Moos — Tue, 26 May 2009 18:29:21 +0000

Haskell has been my favorite programming language in the past month, and for good reason. Its (purely) functional and has strong, static typing.

The language feels more graceful to me, where design and function are key. It is a joy to program in and I would love to keep exploring it.

On my path to learning a new language, I usually try to implement something to get some real-world experience. In this instance, I have chosen to implement an Open AIM client. AIM operates on the legacy TOC(text based) protocol, or the feature full OSCAR protocol, which is what most AIM clients use. I decided that OSCAR would be more fun to do, especially with the three step login process.

The client that I wrote is very simple — handles login to AIM and just sits there. It can get IM’s though. The bulk of the AIM client that I enjoyed writing was the protocol handlers, and implementing the login process.

It would be very easy to extend this client to be a bot, if you are looking for a practical use for it. For me, the learning experience is enough.

The main function is listed below.

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start_aim = do
putStrLn "Haskell AIM Client - OSCAR Protocol"
appKey <- getAppKey
screenName <- getScreenName
password <- getPassword
let clientInfo = AIMClientInfo 1 "HaskellClient" appKey
result <- aim_open_auth clientInfo screenName password
case result of
Just info -> do
boss_result <- aim_boss_session clientInfo info
case boss_result of
Just si -> aim_oscar_login si
Nothing -> putStrLn "Unable to authenticate with BOSS server."
Nothing -> return ()

If you want to try out this AIM client, you must have an Open AIM Developer key.

The first step is to download the source and use cabal to configure, build, and install it.

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# wget http://www.moostrax.com/cmoos/haim.tar.gz
# tar -xzf haim.tar.gz
# cd haim
# cabal configure && cabal build && cabal install

And then run it.

1	# ~/.cabal/bin/haim

The output will look something like this:

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Haskell AIM Client - OSCAR Protocol
An Open AIM Developer key is required: http://developer.aim.com/manageKeys.jsp
Open AIM Key>
AIM Screen Name>
AIM Password>
Connected to AIM server.
Entered OSCAR client loop.
Login accepted by OSCAR server. Setting up rights.
Max Watchers: 2000
Max Buddies: 1000
Max Temp Buddies: 160
Max Denies: 1000

Like I said, the client is very simple, and just sits and waits. When you login you will see some information about your buddy list, and other AIM login data.

chris moos's blog » haskell

Apple Push Notification Library for Haskell

Stunnel setup

ApplePush Haskell Library

Haskell AIM Client – a cool proof of concept