For a little less than a year, I’ve been writing code built atop Twitter, specifically Matt Gemmell’s MGTwitterEngine. I’ve got a few things running on this code, which I’ve not talked about publicly (other than minor hints on Twitter), but have been well-received by the few people who have seen it. Still, these projects have needed to extend both MGTwitterEngine and related libraries to add functionality or fix bugs. I’ll spend this blog post documenting some of those changes across the different projects.
Most of these changes were made to make the engine’s behavior a bit more extensible. Here’s the GitHub repository.
MGTwitterEngineIDis a typedef for unsigned long long values. Everywhere a user ID or tweet ID is returned, it will return one of these. You will want to check your existing Twitter code to make sure there are no potential Twitpocalypse-related problems, updating old data types to the new
- Subclasses of
MGTwitterEnginecan now override a new method,
-_sendRequest:withRequestType:responseType:, if they want to use custom networking code (such as with an
NSURLRequestqueue class). I use this to implement both Twitter’s password authentication and OAuth, and decide at runtime which to use.
- Added a
MGTwitterEngineDelegate, which can be used to update your UI.
- Fixed a few bugs in the YAJL parser which crashed or parsed incorrectly.
Things I still need to do:
In my custom subclass ofUpdate: Thanks to Uli Kusterer, the dependency on
MGTwitterEngine, I use a class I wrote called
TCDownload, which I’ll talk about below. There are still a few references to it in my
MGTwitterEngineclass; those should be fairly straightforward to remove.
TCDownloadhas been removed. The changes have been merged from his fork into mine.
- Add full support for Twitter lists. I have some basic Twitter list functionality working in a private subclass, but far from all of it. There are some problems with the YAJL parser that don’t appear easily fixable with the stock
MGTwitterEngine(specifically, the API key for the list description is the same as the key for the user’s bio, and these are overwriting each other internally). I’m going to look into replacing the manual parsers
- Add full support for new-style retweets. Haven’t started this yet.
- Add support for geolocation in incoming and outgoing tweets. Haven’t started this yet.
I’ve forked yajl to support 64-bit tweet IDs, mainly by changing the callback methods and the string parser from
strtoull. Here is the GitHub repository.
This is a repository of scattered classes which serve various purposes. There are two classes which are relevant for our discussion,
TCOAuthDownload. You will need the
TCDownload class if you use the vanilla
MGTwitterEngine fork, although I’ll be removing those dependencies. Here is the GitHub repository
TCDownloadis a generic wrapper that encapsulates an HTTP request to the interwebs. It wraps NSURLRequest and NSURLConnection under the hood. It automatically queues request and gets callbacks on a background thread (although you can change either of these). I use it a few places inside my
MGTwitterEnginefork, but removed most of those changes and put them in a subclass.
TCOAuthDownloadis a subclass of
TCDownloadwhich accepts OAuth tokens and sends out requests with the correct headers. It relies on the
OAuthConsumerframework, which I’ll talk about below.
This framework deals with OAuth. Twitter has officially announced that basic auth will be dead in June 2010, so getting on the OAuth bandwagon now is a good idea. Here’s my fork of the OAuthConsumer framework on GitHub.
- Changed the signature code to use Common Crypto instead of the C libraries’ HMAC APIs. This seems to work more consistently on both Mac and iPhone.
- Added a
-parseHTTPKey:value:method which is used to parse extended attributes in OAuth access tokens. Twitter uses this to pass some special metadata, like the username of the logged-in user. Subclasses of
OATokencan extend this to parse those tokens.
This isn’t strictly a tool for doing Twitter development, but it can be handy when learning how to implement the OAuth login flow. I posted about it more back in January, and you can find the code and a prebuilt app over at GitHub.