Tag Archives: Ruby

Notes from NH Ruby/Rails, 21-Feb-2011

Posted on by
Reply

Eight attendees made it to the February meeting of the New Hampshire Ruby Rails group at the New Hampshire Innovation Commercialization Center. A round of introductions included the usual suspects and several new people with interesting backgrounds and interests.

Brian Turnbull talked about Ruby debugging. He had a sample he created on Github Ruby comes with it’s own debugging library, but you can add a good one with a gem: ruby-debug.
Commands:
list – lists the code currently load
next – steps through the code listed, but skips over subroutines.
step – steps into the code
where – dumps the stack
finish – finishes the current subroutine call
display – dumps a value
(commonly use display value.inspect to make a cleaner display)
pp – pretty print, evaluates any Ruby code you want
edit – launches the EDITOR variable in our shell
catch – catch exceptions
cont – continue
break – set a breakpoint

,,, and so forth. Use the help, it is your friend.

The second example is far more complex, with a Sinatra app using OmniAuth and an LDAP provider. Following the supplied documentation, the app crashes on startup. (That’s what you get for reading the docs!) Debug and another tool – rbtrace to the rescue! Excellent demo of the problem and how the tools can debug them.

Notes from NH Ruby/Rails, 17-Jan-2011: Brian Turnbull, OmniAuth, Nick Plante, Mirah

Posted on by
Reply

Seven members attended the New Hampshire Ruby / Rails group meeting held on 17-January-2011 at the New Hampshire Innovation Commercialization Center (NH-ICC). We had two presentations: Brian Turnbull talked about OmniAuth and Nick Plante showed a project he’s doing with Mirah on the Android platform.
Brian Turnbull is an engineer working for ARRIS and injects Ruby into his build tools whenever he gets the chance. A recent project required authentication against multiple providers and he did some research on OmniAuth. Brian presented a slideshow explaining the basic concepts of authentication and how they’re implemented in OmniAuth. Apparently, OmniAuth was the authentication method of choice during the most recent RailsRumble, used by most of the contestants. Brian outlined the process needed for working with an existing provider and demonstrated it with clear and simple code. He followed that up by showing how to build your own custom provider and authentication strategy. Brian’s sample code can be found on his github account.
Nick Plante has been working on an Android rich client app as part of a web-based social application that’s soon to launch. Nick told us that working on Java for Android has reinforced his love of Ruby. There’s not yet a good port of Ruby to the Android platform, but he has been impressed with the Mirah language, a hybrid solution that compiles to bytecode and runs natively on the JVM. He has developed a Ruby generator called protoform to construct the skeletons of a Mirah app. He gave us a tour of the components and built a simple “Hello, World” app, deployed and ran it on his Android VM.
Thanks to Brian for organizing the meeting and for the OmniAuth presentation, to Nick for talking about his Mirah project and to the NH-ICC for providing the fine facilities.

Notes from CentraLUG, 6-Dec-2010: David Berube, MySQL Operations

Posted on by
Reply

Six people attended the December 2010 meeting of the Central New Hampshire Linux Group, held at the New Hampshire Technical Institute‘s Library from 7 to 9 PM. David Berube was the featured speaker, talking about his experience with large scale high-performance MySQL applications.

David is an independent software developer and consultant. One of his larger projects over the past couple of years has been an application for scheduling actors for auditions. This involves agents and projects, auditions, roles, videos and a number of other entities in a complex and fast-moving application. He’s used Ruby on Rails, PHP, MySQL, a NOSQL database, Amazon S3, A rack of Mac Minis, BSD, Linux, and a number of other elements. He had some insightful things to say about the development process, managing a client project, handling difficult requirements, scaling up million-row databases for subsecond response times and more. It was a meeting well worth attending.

There were a lot of useful tools and reference sites mentioned, and I was only able to take note of a few: Useful Ruby add-ons: New Relic, Query Reviewer, Percona Operations Day, Cacti for data aggregation. An In-depth discussion of NoSQL (“Not Only SQL”) Databases: what are they, what are they good for, what are the liabilities? A good discussion of the trade-offs of using NoSQL, reference to the NHRuby presentation on Redis a few months ago, and more.

Thanks to David for an informative presentation, to the attendees for a dynamic interactive session, and to the NHTI Library for the facilities. Future meetings at the Concord location have been suspended, we encourage our regulars to attend the Manchester ManchLUG meetings. If you haven’t already, consider subscribing to the announcement list so you’ll know when there’s an upcoming meeting. (Subscribers to the discussion list will automatically receive the announcements, too.)

Notes from Ruby SIG, 16-Aug-2010

Posted on by
Reply

The New Hampshire Ruby/Rails group met as usual on the 3rd Monday of the month. We met at the New Hampshire Innovation Commercialization Center, a new space near the Pease airfield. Mark Galvin, NHICC’s Managing Director, was kind enough to offer the space for our meeting and tell us about the ICC. Eleven members attended the meeting.

As we often do, we started with a round of introductions. It’s always interesting to find out who’s there and what they’re up to. I mentioned the GNHLUG calendar and Nick plugged the upcoming Rails Rumble. Near the end of the meeting, we plugged the NorthEast RailsCamp, coming up on it’s third meeting, this one in Stowe, VT. 5 alums from previous camps were there, and all loved it. There may still be a ticket or two left, even though the site says zero – you’d better hurry!

We were lucky enough to have two presentations tonight.

Brian Turnbull presented “Interfacing Ruby with C.” He explained he needed to do some automation with a “black box” his company was using, and their documentation consisted of a C API and a DLL. Rather than developing an entire application in C, he used Ruby to interface to the C API and then could develop an easy-to-modify Ruby app. That turned out to be a good idea, as the final product he delivered turned out to be very different from the initial request, and having the ability to rapidly re-develop in Ruby was a success. To show us how to use C to access Ruby and vice-versa, Brian used a simple example of a “leaky bucket stack,” a fixed-length stack that would lose the oldest item as the stack was pushed. It was a great example in that it had enough complex behavior to be useful, while simple enough to explain and translate into C without too much effort. First, we reviewed the pure Ruby implementation. Brian proceeded to build up the equivalent code in C, calling Ruby array functionality and data types where appropriate. He then showed how to configure the C extension from from Ruby, build, compile, debug and run from the ruby command line.

See the example code and slides (I’ll update the URL when available). Also http://github.com/bturnbull/padpaws for his more advanced C example.

Brian Cardarella, @bcardarella, http://bcardarella.com, presented his gem, client-side validation, which he developed while working on the “Raise Your Vote” site for the Democratic National Committee. The Raise Your Vote site is intended to assist in voter registration by collecting data online and generating matching PDFs of the voter application. Naturally, 50 states have fifty different forms, with different requirements. He wanted to avoid duplicating the server-side validations with hand-maintained client side code, as the regular changing of requirements and the difficulty of keeping business rules in synch across the two languages would doom the project. He wrote client-cisde_validations to use the declarative validations within the entity models to generate the equivalent Javascript code. Client-side_validations has remarkable depth and breadth, handling nearly all of the common and exceptional types of valiation (Brian notes the few difficult cases in his slides). You can find the code on GitHub (gem code, examples) and the slides here: client_side_validations.pdf

Thanks to Brian Cardarella for travelling all the way to Portsmouth and thanks to both Brians for their fine presentations. Thanks to Nick Plante and Brian Turnbull for organizing and promoting the meeting and the group. And thanks to Mark Galvin and the New Hampshire Innovation Commercialization Center for providing the fine facilities!