Backstage Blog

• Announcements
• Security

On Monday, April 7th, 2014, a major security vulnerability in OpenSSL was made public. The vulnerability was filed as CVE-2014-0160 and later dubbed “Heartbleed”, because the bug lies within OpenSSL’s heartbeat extension, which is used for keepalive monitoring. As a result of the bug, process memory can be read out remotely by an attacker—potentially including certificates, keys, credentials, tokens, or other sensitive data processed by the server.

OpenSSL works as a cryptographic library that allows for authenticity and confidentiality across the entire Internet. Because the reported Heartbleed bug affects a vast number of internet services using OpenSSL to secure their services (such as HTTPS, SMTP, IMAPS, and POP3), a patched OpenSSL version was released…

• iOS
• Mobile
• Open Source
• Ruby

I’m excited to announce that SoundCloud is sponsoring the development of CocoaPods through a Travis Foundation grant. CocoaPods is an open-source dependency manager for Objective-C projects. Travis Foundation is a non-profit that pairs corporate sponsors with open-source projects to make open source even better.

At SoundCloud, our iOS team uses CocoaPods every day to manage the dependencies of our mobile apps. We hope that this sponsorship will lead to improvements that benefit the entire Mac…

• JavaScript

The site soundcloud.com is a single-page application that displays a multitude of users’ images. At SoundCloud, we use a technique to make the loading of an image appear smooth and fast. When displaying an image on screen, we want it to display to the user as fast as possible. The images display in multiple locations from a tiny avatar on a waveform to a large profile image. For this reason, we create each image in several sizes. If you are using Gravatar, this technique also applies because you can fetch…

• Android

Both our Android and iOS teams use the reactive programming paradigm to simplify asynchronous, concurrent code in our native mobile apps. For Android, we use Netflix’s RxJava. Matthias Käppler—a SoundCloud engineer and a contributor to the RxJava Android library—blogs about the HOWs and WHYs of RxJava on Android.

Tomorrow in London, Matthias will be talking about RxJava at Droidcon. You can grab a drink with him and other members of our Android Team at the SoundCloud Droidcon Drinkup.

• Open Source

Sketchy is a spam-fighting, open-source software framework developed by SoundCloud engineers Matt Weiden, Rany Keddo, and Michael Brückner. Sketchy reduces malicious user activity on web applications. You can use it to address several common issues:

• Detect when a user submits text that contains spam content.
• Detect when a user submits multiple texts that are nearly identical.
• Rate-limit malicious actions that users perform repeatedly.
• Check user signatures such as IP addresses against external blacklist APIs.
• Collect and consolidate reports of spam from users.
…

• Architecture
• Clojure

SoundCloud has a service-oriented architecture, which allows us to use different languages for different services. With concurrency and scaling in mind, we started to build some services in Clojure due to its interoperability with the JVM, the availability of good quality libraries, and we just plain like it as a language.

How do you build distributed, robust, and scalable micro-services in Clojure? Read what Joseph Wilk, an engineer and Clojure enthusiast at SoundCloud, has to say.

• JavaScript

Background

When we started to work on the new version of our mobile web app, we knew we wanted to run unit tests on a wide variety of clients, mobile devices, PhantomJS, and on Chrome when running locally. Because we practice continuous integration, we knew we also wanted Git hooks and proper results formatting.

We chose Karma runner, which is a project from the Angular JS team that provides developers with a “productive testing environment”. One of the advantages that Karma runner offers over other similar projects is its ability to use any testing framework. At SoundCloud, we aim to have the same toolset across various JavaScript projects, and our unit test framework of choice is Tyrtle…

• Android
• Mobile

A common problem in Android development is that you need to jump off the main UI thread to retrieve data from an IO-based source. At SoundCloud, we use Netflix’s RxJava to simplify asynchronous flows in Android. In an interview given for the Google Developers series “root access Berlin”,  Mustafa Sezgin—who heads up our Mobile Team—explains why we chose RxJava, what it gives us, and he walks through an example-usage pattern:

If you are interested in more details, be sure to catch Matthias Käppler—from our Android Team—give an in-depth talk at Droidcon London…

• Contests
• Open Source
• Ruby
• Events

The lineup for BaRuCo 2013 looks amazing, with speakers such as Aaron Patterson, Katrina Owen, Sandi Metz, and Ruby’s inventor Yukihiro Matsumoto. The conference is currently SOLD OUT, but we have one extra ticket… and it could be yours!

If you win the ticket, SoundCloud will fly you from anywhere in the world to Barcelona, Spain and put you up in a nice Catalonian hotel.

How do you enter to win?

It’s simple. Just create a command-line interface in Ruby that uses the SoundCloud API. You can use the SoundCloud Ruby SDK, but this is not a requirement. The only…

• Events
• Hacks

The first Music Hack Day — organized by our very own Dave Haynes — was held in July 2009 in London, UK. Since then there have been over 30 Music Hack Day events all over the world in cities like San Francisco, New York, Paris, Barcelona and Reykjavik.

Music Hack Day events gather programmers, designers and artists to conceptualize, build and demo the future of music. Software, hardware, mobile, web, instruments, art — anything goes as long as it’s music related.

I’m happy to announce that SoundCloud is teaming up with Rdio, Unspace and The Echo Nest to organize the first ever Music Hack Day in Toronto. MHD Toronto…