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I have recently developed an interest in web services that enable users to store and share links on the Internet. Social bookmarking services are increasingly popular amongst bloggers, and could completely replace conventional bookmarks as ubiquitous broadband becomes reality. After comparing a number of available services, I finally settled on Simpy, which has several unique features and provides numerous advantages over competing services like del.icio.us. I'm particularly impressed with Simpy's support for third party development. Using the Simpy REST API, I can manipulate my bookmarks with virtually any programming language.

Although I initially had some problems with the authentication mechanism, I eventually managed to create a complete Ruby library for interacting with Simpy. Now officially released, the source code is available online through the Simpy Tools Sourceforge version control system. Documentation for the latest CVS version can be found here.

At the present time, simpyapi-ruby features support for adding, removing, modifying, and acquiring links as well as removing, renaming, and listing tags. Support for notes and watchlists will be implemented in a future version. Unsupported operations can still be performed with the generic Simpy::ClientBase.command method. Support is also provided for interfacing with Simpy RSS feeds.

The simpyapi-ruby library allows developers to leverage Ruby's syntactic sugar and interact with Simpy without having to parse, process, or manipulate XML data. Login and connection handling is all automatic, all you have to do is provide simpyapi-ruby with a Simpy username and password.

The simpyapi-ruby library is very easy to install. Simply run the setup.rb script included with the library. The library was designed with application development in mind (I plan to create a proof-of-concept GNOME utility for Simpy management), but it is also entirely suitable for simple scripting and web integration. For optimal exposure and licensing compatibility with other Simpy tools, my library is dual-licensed under the terms of the ASL and BSD licenses.

Tags: programming, ruby, tagging, simpy

Posted on 2006-06-21 0 comments

More Fun With Pcap

I'm currently expanding the functionality of my AOL Instant Messenger interceptor for a project I'm working on with a researcher from IBM. For this particular project, the script will need to be able to intercept timestamps and screen names in addition to the data the program is already equipped to capture. Timestamps are easy, because they are handled entirely by the client application and aren't really part of the protocol. It's really as easy as adding a #{Time.now} to the relevant output string.

Screen names are a lot more challenging. The OSCAR protocol only embeds the destination screen name in outgoing messages and the sender screen name in incoming messages. As a result, it is very difficult to identify the screen name of the other party associated with each message. The packet sniffer will have to intercept the screen names during the sign-on process and associate those screen names with a local network IP address. I'm not sure yet, but the fact that the OSCAR protocol uses encryption for login strings might make this a lot more interesting.

The script has to be able to intercept data from two separate network interfaces simultaneously. In other programming languages this might be a problem, but thanks to Ruby's excellent support for simple threading, I can do it with relative ease. The following is a trivial example that demonstrates how to monitor packets from multiple interfaces at the same time using Ruby:

pc1 = Pcaplet.new("-s 1500 -i eth1")
pc2 = Pcaplet.new("-s 1500 -i eth3")

f1 = Pcap::Filter.new("tcp", pc1.capture)
f2 = Pcap::Filter.new("tcp", pc2.capture)

def display dev, pck
  puts "#{dev}: #{pck.tcp_data}"
end


fork {
  pc1.each_packet {|pk| display "eth1", pk}
}

pc2.each_packet {|pk| display "eth3", pk}