Fabrizio Giordano

The Web Development Series is supported by Rackspace, the better way to do hosting. Learn more about Rackspace’s hosting solutions here.

Gowalla CTO and co-founder Scott Raymond knows a thing or two about Ruby — and about Cocoa, scaling, handling huge amounts of location data, mobile apps and NoSQL.

Gowalla is a Ruby shop, and as the captain of that particular ship, Raymond has had quite a bit of experience building a popular web app from the ground up using Ruby on Rails.

In a recent e-mail interview, we found out what Raymond had to say about those experiences and what he has learned from them over the past three and a half years.

Much has been made of Ruby/Rails’ perceived flaws when it comes to scaling. In your experience, what are the unique challenges of working with this language and framework and trying to scale an app for a nation-wide consumer audience?

Most of the “Rails can’t scale” noise is outdated or was misguided in the first place. In general, the question of scalability applies at the level of architecture and systems, and not really at the level of languages and frameworks.

That said, languages and frameworks do definitely have performance and efficiency characteristics that need to be considered. Ruby’s standard interpreter doesn’t have a great reputation for being fast, but as part of a larger, well-architected system, it is very rarely the bottleneck.

So, as a developer for a popular service, the challenge becomes trying to foresee which actions will be the most frequently requested, which data types will be the fastest growing, and which actions are the most performance-sensitive. In my experience, it’s harder to predict these things than you would think. I have spent many hours trying to “pre-scale” parts of the app that never became a problem, which often leads to maintenance headaches.

You guys collect and store a massive amount of location data for your app. How do you use Ruby and Rails for this type of data in these amounts?

We use a variety of storage systems for different purposes. Our biggest database is PostgreSQL — it currently stores the canonical records for most of our data, including users, spots, and checkins.

We also rely heavily on Redis for all kinds of things, like friendships, counters and queues. We use lots of memcached for ephemeral things, Varnish for HTTP caches and Solr to keep fuzzy spot searches fast.

Increasingly, we’re using Cassandra to store a lot of stream-like data — things like activity feeds and audit logs. I expect that our usage of Cassandra will grow a lot this year, and that we’ll also start relying on Hadoop to help us understand our data better.

Here is a simplified example of how we store and retrieve checkins, using a custom-build timeline service, called Chronologic, which is backed by Cassandra:

When you’re not coding in Ruby, what other languages/tools do you use? Or, if you had to choose another language for Gowalla, what would it be?

When I’m coding at work these days, it’s usually on our iOS client — so Cocoa/Objective-C is where I’m spending most of my time.

But for server-side work, I see us gradually moving toward a more services-oriented architecture. We are always looking at our application today and trying to identify pieces of functionality that can be isolated into services that have their own data storage and deployment patterns. So far, all of those services are written in Ruby, but I won’t be surprised if some of them end up being written in Scala, or with Node.js, or something else. But when it comes to the central web application that powers gowalla.com, I’m very happy with it being Ruby/Rails.

Here is a section of one of the view controllers in the Gowalla iPhone application. This code handles authenticating with a third-party service.

From a fan via Twitter: Was the traditional ActiveRecord modeling enough or did you have to use an NoSQL alternative?

Every Rails app that I’ve ever worked on has had to break away from the “ActiveRecord way” at some point, for some part of the app. But it’s not an all-or-nothing question. Most of the time, the standard relational/ActiveRecord approach works perfectly well, and the convenience of following the Rails golden path is completely worthwhile. But most interesting apps will run into at least a few points where the standard tools break down, and you need to access your data differently.

Fortunately, it’s a wonderful time for alternative data stores. Just look through the Heroku add-ons page — you’ve got Redis, MySQL, CouchDB, Memcache, MongoDB, Solr and more — all available as hosted services. It’s incredibly freeing to be able to tinker with these tools without worrying about up-front installation and configuration.

The example from the second question is a prime example of this. Scaling activity streams with a relational database in fairly real time is tricky — it often breaks down when one user has millions of followers, or when one user follows millions of others. To make it work, we created a service called Chronologic that manages any kind of timeline, and exposes a relatively simple interface to the Rails application. Under the covers, Chronologic uses Cassandra for most of its storage.

What kind of gem testing do you use, if any?

We use Shoulda, Factory Girl and FlexMock for testing our Ruby/Rails code. After each commit, a local continuous integration server runs the test suite and notifies the developers via Campfire of any failures.

What side project(s) are you working on right now?

Most of my “side” projects these days are tangentially work-related — small experiments to learn about a new database or library, to try out a new web service or as a proof-of-concept for a new technique. My work directly is littered with dozens of tiny re-writes of our iPhone client, each exploring some new UI idea, networking optimization, etc.

---

Series supported by Rackspace

---

The Web Development Series is supported by Rackspace, the better way to do hosting. No more worrying about web hosting uptime. No more spending your time, energy and resources trying to stay on top of things like patching, updating, monitoring, backing up data and the like. Learn why.

---

More Dev & Design Resources from Mashable:

---

– HOW TO: Transfer Your Blog From WordPress.com to WordPress.org [VIDEO]
– A Beginner’s Guide to Integrated Development Environments
– 10 Chrome Web Apps to Check Out
– HOW TO: Make Your WordPress Blog More Like Tumblr
– 10 Tools for Getting Web Design Feedback

Image courtesy of Flickr, Robert Scoble.

More About: gowalla, node, programming, RoR, ruby, Ruby on Rails, Web Development, web development series

For more Dev & Design coverage:

• Follow Mashable Dev & Design on Twitter
• Become a Fan on Facebook
• Subscribe to the Dev & Design channel
• Download our free apps for Android, Mac, iPhone and iPad

Smartphones are supposed to be easy to develop apps for. But as new versions of mobile operating systems proliferate, fragmentation is wrecking that hope.

That’s why Israeli firm MoMinis is launching a new game development and distribution platform today. The two-dimensional casual games created with the MoMinis Studio can automatically run on virtually all mobile operating systems. It’s a great idea if the company can execute on it, since it could reduce development costs, developer hassles, and speed time to market at a time when getting a hit game onto multiple platforms is extremely important.

But there’s a lot of competition and the idea has been tried before. Real Networks promised the ability to do the same thing with its Emerge platform in 2009, targeting as many as 1,700 older feature phones. Moblyng, meanwhile, offered an ability to create cross-platform games for smartphones, web sites and Facebook. Also, MoMinis doesn’t support the iPhone, at least not until the second quarter.

But the Israelis say their system works and it has already gone through an extensive beta testing program.

Such cross-platform development tools are important because Android has splintered into different versions. Rovio, the maker of the huge hit Angry Birds, complained that it had to create two versions of its game for Android — one that would run on more recent versions of Google’s mobile operating system and another that would run on early software and phones without much processing power.

Even worse than that, Android is splitting into different distribution channels. Developers can upload games to the Android Market run by Google. But to reach more consumers, the developers also have to redo the game to upload it to the redundant Android stores built by carriers such as Vodafone, Verizon, Telefonica, Orange and web site Amazon. MoMinis can reach all of those companies with its games, automatically.

Mobile gaming revenue topped $5.6 billion in 2010, but it’s hard for developers to reach a worldwide audience, said Eyal Rabinovich, co-founder of MoMinis. While there are a lot of riches to be had across all of the mobile markets, the developers have so many fragmentation issues that it feels like they’re picking up a million dollars penny by penny. Too often, developers don’t have enough resources to invest development time in the smaller platforms. That leads to less product diversity.

Tel Aviv-based MoMinis has backing from Japanese trading giant Mitsui and has distribution agreements with NTT DoCoMo, Japan’s largest mobile operator. MoMinis will publish 100 localized games created with the MoMinis Studio for NTT DoCoMo’s 56 million mobile subscribers.

Like Sun Microsystems once promised with its Java programming environment, MoMinis says its goal is to “develop once, deploy anywhere.” The tools are available as a free download. One of the priorities built into the MoMinis system is the ability for developers to get paid swiftly. MoMinis strives to provide a single ecosystem that automatically supports all platforms.

For a company like Rovio, which is closing in on 100 million downloads for Angry Birds, reaching all of the mobile markets quickly is extremely important. But it’s also relevant to any developer that is watching its costs and doesn’t have programmers dedicated to adapting games for slightly different markets. MoMinis says it can cut the time required for adapting a game to a platform by months.

While Moblyng allows developers to create web-based games, MoMinis focuses on creating games that are using native access to a mobile operating system. That allows the software to take full advantage of the abilities of the device. MoMinis also avoids fragmentation problems by compiling the game to a specific model of the device, with its unique screen resolution, operating system version, and processing power. MoMinis Studio uses its own programming language and creates its own format called a .mom file. The MoMinis Studio servers take a file from a developer and compile it to all different platforms, including Android, BlackBerry, mobile Java, and Symbian.

Developers using MoMinis now include Absolutist, Wheemplay, and Baby First TV. The company says its tools have been downloaded thousands of times and it is working with dozens of developers.  MoMinis provides its tools for free to developers and lets them distribute their content across a global distribution network. MoMinis says it makes money by sharing revenue of the games that are distributed on its network.

MoMinis says it can reach a wider distribution network than Unity Technologies can with its 3D game technology. While MoMinis does not support 3D games now, it says it will eventually do so in the future. Another rival is GameSalad, but that company is focused on the Apple iOS (iPad, iPhone and iPod Touch).

MoMinis was founded in 2008 and it has $5 million funding from Mitsui Ventures, the venture capital arm of Mitsui & Co. and BRM Capital. MoMinis has 25 employees.

Founders include Tzach Hadar, chief technology officer and a former member of an intelligence unit of the Israeli Defense Force. Rabinovich is a seasoned engineer who previous worked at Hegde-Tech Financial Engineering and Lipman Electronic Engineering. Zvi Rabinovich, co-founder, is vice president of research and development.

Tags: Android, Angry Birds, fragmentation

Companies: Apple, Google, MoMinis, Rovio

People: Eyal Rabinovich, Zvi Rabinovich

Smartphones are supposed to be easy to develop apps for. But as new versions of mobile operating systems proliferate, fragmentation is wrecking that hope.

That’s why Israeli firm MoMinis is launching a new game development and distribution platform today. The two-dimensional casual games created with the MoMinis Studio can automatically run on virtually all mobile operating systems. It’s a great idea if the company can execute on it, since it could reduce development costs, developer hassles, and speed time to market at a time when getting a hit game onto multiple platforms is extremely important.

But there’s a lot of competition and the idea has been tried before. Real Networks promised the ability to do the same thing with its Emerge platform in 2009, targeting as many as 1,700 older feature phones. Moblyng, meanwhile, offered an ability to create cross-platform games for smartphones, web sites and Facebook. Also, MoMinis doesn’t support the iPhone, at least not until the second quarter.

But the Israelis say their system works and it has already gone through an extensive beta testing program.

Such cross-platform development tools are important because Android has splintered into different versions. Rovio, the maker of the huge hit Angry Birds, complained that it had to create two versions of its game for Android — one that would run on more recent versions of Google’s mobile operating system and another that would run on early software and phones without much processing power.

Even worse than that, Android is splitting into different distribution channels. Developers can upload games to the Android Market run by Google. But to reach more consumers, the developers also have to redo the game to upload it to the redundant Android stores built by carriers such as Vodafone, Verizon, Telefonica, Orange and web site Amazon. MoMinis can reach all of those companies with its games, automatically.

Mobile gaming revenue topped $5.6 billion in 2010, but it’s hard for developers to reach a worldwide audience, said Eyal Rabinovich, co-founder of MoMinis. While there are a lot of riches to be had across all of the mobile markets, the developers have so many fragmentation issues that it feels like they’re picking up a million dollars penny by penny. Too often, developers don’t have enough resources to invest development time in the smaller platforms. That leads to less product diversity.

Tel Aviv-based MoMinis has backing from Japanese trading giant Mitsui and has distribution agreements with NTT DoCoMo, Japan’s largest mobile operator. MoMinis will publish 100 localized games created with the MoMinis Studio for NTT DoCoMo’s 56 million mobile subscribers.

Like Sun Microsystems once promised with its Java programming environment, MoMinis says its goal is to “develop once, deploy anywhere.” The tools are available as a free download. One of the priorities built into the MoMinis system is the ability for developers to get paid swiftly. MoMinis strives to provide a single ecosystem that automatically supports all platforms.

For a company like Rovio, which is closing in on 100 million downloads for Angry Birds, reaching all of the mobile markets quickly is extremely important. But it’s also relevant to any developer that is watching its costs and doesn’t have programmers dedicated to adapting games for slightly different markets. MoMinis says it can cut the time required for adapting a game to a platform by months.

While Moblyng allows developers to create web-based games, MoMinis focuses on creating games that are using native access to a mobile operating system. That allows the software to take full advantage of the abilities of the device. MoMinis also avoids fragmentation problems by compiling the game to a specific model of the device, with its unique screen resolution, operating system version, and processing power. MoMinis Studio uses its own programming language and creates its own format called a .mom file. The MoMinis Studio servers take a file from a developer and compile it to all different platforms, including Android, BlackBerry, mobile Java, and Symbian.

Developers using MoMinis now include Absolutist, Wheemplay, and Baby First TV. The company says its tools have been downloaded thousands of times and it is working with dozens of developers.  MoMinis provides its tools for free to developers and lets them distribute their content across a global distribution network. MoMinis says it makes money by sharing revenue of the games that are distributed on its network.

MoMinis says it can reach a wider distribution network than Unity Technologies can with its 3D game technology. While MoMinis does not support 3D games now, it says it will eventually do so in the future. Another rival is GameSalad, but that company is focused on the Apple iOS (iPad, iPhone and iPod Touch).

MoMinis was founded in 2008 and it has $5 million funding from Mitsui Ventures, the venture capital arm of Mitsui & Co. and BRM Capital. MoMinis has 25 employees.

Founders include Tzach Hadar, chief technology officer and a former member of an intelligence unit of the Israeli Defense Force. Rabinovich is a seasoned engineer who previous worked at Hegde-Tech Financial Engineering and Lipman Electronic Engineering. Zvi Rabinovich, co-founder, is vice president of research and development.

Tags: Android, Angry Birds, fragmentation

Companies: Apple, Google, MoMinis, Rovio

People: Eyal Rabinovich, Zvi Rabinovich

Whatever you do with this tool is uniquely your responsibility. If you are not authorized to punch holes in the network you are attacking be aware that such action might get you in trouble with a lot of law enforcement agencies.
sqlmap goal is to detect and take advantage of SQL injection vulnerabilities in web applications. Once it detects one or more SQL injections on the target host, the user

Whatever you do with this tool is uniquely your responsibility. If you are not authorized to punch holes in the network you are attacking be aware that such action might get you in trouble with a lot of law enforcement agencies.
sqlmap goal is to detect and take advantage of SQL injection vulnerabilities in web applications. Once it detects one or more SQL injections on the target host, the user

Con un comunicato stampa giunto in redazione nelle scorse ore e ampiamente previsto, Apple ha annunciato le condizioni degli abbonamenti su App Store. Continua a valere la ratio del 30% su ogni transazione trattenuto per sé come per gli acquisti In-App, ma sulle regole c’è un nuovo giro di vite.

Fermo restando che in un libero mercato Cupertino ha tutto il diritto di offrire i propri servizi al prezzo che ritiene più congruo, l’impressione per molti osservatori è che la gabbia dorata sia diventata d’improvviso più asfittica. Lo schema infatti è sempre lo stesso:

Gli abbonamenti acquistati all’interno dell’App Store saranno venduti con lo stesso sistema di fatturazione App Store che è stato usato per comprare miliardi di applicazioni e di acquisti in-app. Gli Editori fissano il prezzo e la durata dell’abbonamento (settimanale, mensile, bimestrale, trimestrale, semestrale o annuale). Poi, con un solo clic, i clienti scelgono la lunghezza dell’abbonamento e ricevono automaticamente l’addebito in base alla lunghezza dell’impegno scelto (settimanale, mensile, ecc.). […] Apple processa di tutti i pagamenti, mantenendo lo stesso 30 percento che trattiene oggi per altri acquisti In-App.
Ma se da una parte Apple dà, dall’altra toglie senza pietà:

La nostra filosofia è semplice: quando Apple porta un nuovo abbonato alla app, Apple guadagna un 30 percento, quando l’editore porta un utente esistente o un nuovo abbonato all’app, l’editore mantiene il 100 percento e Apple non guadagna nulla”, ha dichiarato Steve Jobs , CEO di Apple. “Tutto ciò che richiediamo è che, se un editore sta facendo una offerta di abbonamento al di fuori dell’app, le stesse (o migliori) offerte vengano proposte all’interno della applicazione, in modo che i clienti possano facilmente abbonarsi con un clic direttamente dall’app.”

Quindi gli editori sono liberi di usare anche i propri servizi di abbonamento, persino al di fuori dell’app stessa, purché la medesima offerta sia comunque fatta attraverso acquisti In-app. Va da sé che su queste transizioni non verrà riconosciuta alcuna revenue sharing né condivisione delle informazioni sui clienti con Apple. Inoltre, c’è una nuova regoletta che impedisce agli editori di fornire nelle app collegamenti URL esterni che permettano al cliente di acquistare contenuti o abbonamenti al di fuori dell’applicazione. Tradotto, significa che non è possibile traghettare sui propri sistemi di fatturazione i clienti trovati attraverso App store: una ricchezza, l’utenza stessa, che Apple intende trattenere all’interno del proprio ecosistema.

Si tratta di una proposta che rischia di risultare antieconomica persino per blasoni del calibro di Netflix ed Amazon, e c’è da scommettere che molti pur di non vendere l’anima a Cupertino salteranno giù dal treno, magari creando da sé meravigliosi siti multimediali in HTML 5 ottimizzati per gli schermi di iPad, HP Touch Pad e Blackberry PlayBook. Il rischio, parliamoci chiaro, è di regalare il mercato dell’editoria digitale alla mela così com’è già avvenuto con la musica, ma d’altro canto questo è il prezzo che paga chi non riesce davvero a rinnovarsi e a comprendere i cambiamenti in atto nell’utenza.

Ecco le regole degli abbonamenti su App Store é stato pubblicato su Melablog.it alle 09:56 di mercoledì 16 febbraio 2011.

Would it make sense to sell your products at below the manufacturing costs? I guess not, right? If you made a product and could sell it at a 300% margin, do you think that would be a good price?

Pricing is a difficult thing. What is a fair price? Should you make your products more expensive than your competitors’ products and focus on quality? Or should you always try to stay competitive?

There are two stories I like about pricing to give you a different perspective on things.

1: Intel and chip prices
The story goes that when Intel started producing microchips in their early years they sold them far below what it cost them to produce them. Intel’s founder, Gordon Moore, had famously predicted that the number of transistors would effectively double every year. In other words: next year you could buy the same chip for half the price, or a chip twice as fast for the price of today’s chip.

Moore took a calculated risk, priced his chips lower than other companies did and in the process created a market for affordable chips. In time, chips became cheaper and Intel started making profits, then huge profits and eventually (for a while) it became the biggest company in the world.

2: The 5 cent screw
A manager I know was asked to save a truck manufacturing company. He laid off some staff, cleaned up the product line and raised prices. One day he got a tour of some accessories. They showed him a screw that cost 5 cents to make which they sold for 30 cents. He asked them “What happens if that screw breaks?” The guy running the accessories department proudly explained it was a vital part of the engine and that without it the truck wouldn’t work. The manager then proposed to raise the prices of that one screw to $100.

The employees were appalled at the idea. You can’t sell a screw that you make for 5 cents for $100! It would be obscene! But the manager carefully explained that the manufacturing price wasn’t the guiding principe for pricing products: the perceived value for the clients is.

Do you have a products to sell? Do you price them based on what it costs to produce them? Would you consider selling them below their production value to build a market for yourself? Do you know the perceived value of your product?