PANAXIOM

[panaxiom]

Announcing PXAlertView: a replacement for UIAlertView

While upgrading Meep to iOS 7 it became necessary to reimplement the standard UIAlertView provided by Apple because we wanted to specify a custom UIView underneath the title (an image) and also change the styling from the default colours.

Previously we were subclassing UIAlertView and overriding the drawRect method to differentiate from the default look and feel, but this was dangerous as Apple even mentioned in their docs that subclassing of UIAlertView was not supported.

PXAlertView now mimics the iOS 7 UIAlertView in every way but has a default dark style and an easier block based syntax for the API.

Released under the permissive MIT licence, you can do with it as you please, it makes a great alternative to the default UIAlertView and you have the power to customise it to your hearts content.

[panaxiom]

ReactiveMongo Slides from MongoDB London 2013

These are the slides from the talk I gave last week about ReactiveMongo - an Asynchronous and Non-blocking Scala driver for MongoDB.

Although it is a very technical talk, which the slides reflect, much of the detail is delivered along with the presentation and so I am looking forward to when 10gen publish the video as it will make it easier to digest and will also include the questions afterwards.

It was a pleasure to take part and I was especially pleased with all of the positive feedback, where people came up to me hours afterwards even.

Thanks to 10gen for putting on a great conference & an even bigger thank you to Stephane Godbillion for writing ReactiveMongo, you're awesome.

[panaxiom]

ReactiveMongo @ MongoDB London 2013

Next week I will be giving a talk about ReactiveMongo (a non-blocking Scala driver for MongoDB) at MongoDB London.

If you are evaluating MongoDB, or just want to learn faster and gain invaluable tips & insights then I would recommend attending as I did last Summer. You will get a feel for the community around the technology and can even speak to 10gen directly (the MongoDB company).

These are some of the highlighted talks:

Text Search in MongoDB 2.4 (Eliot Horowitz, CTO/Co-Founder of 10gen)

MongoDB and Hitman: Absolution (Tomas Jelinek, Senior Online Operations Administrator at Square Enix Europe)

Creating MongoDB Based Logging System in Webservice Heavy Environment (Arek Goralski, Head of Development at YouWin)

Python + MongoDB = really fast development (Pablo Enfedaque, R&D SW Engineer at Telefonica PDI)

Optimising for Performance, Scale & Analytics (David Mytton, founder of Server Density)

Best of all, you can use the discount code Speaker20 for 20% off tickets.

Hope to see you there!

Alex

[panaxiom]

Scala Benchmark comparison with JDK 6 and 7

This post attempts to determine if running Scala is more performant under the Java 6, or 7 virtual machines, using a [benchmark](http://markehammons.wordpress.com/2012/12/02/2-10-performance/) recently used to compare Scala versions 2.9.2 and 2.10-RC3. Recently I upgraded my Java version from 6 to 7 (1.6.0_37 to 1.7.0_09 Oracle JDK) and thought I noticed a performance increase when running my Scala applications, but was not sure. Since Scala runs on the JVM, it would be reasonable to expect it to use the same JVM as installed on a system and based on the bash script of the 'scala' command, it appears that it does run the 'java' command with Scala as a library. After reading about the increased performance in Scala 2.10 over 2.9.2 in this [performance benchmark](http://markehammons.wordpress.com/2012/12/02/2-10-performance/) I thought that it would be interesting to run the same benchmarks again in the different JVM versions and compare the results. So without further ado:  As expected, Scala 2.10-RC3 trumps 2.9.2 in all cases (lower is better). Rather unexpected however is that JDK 6 is faster than 7 for the Eratosthenes tests for Scala 2.9.2, but the difference is negligable for the warm mean in 2.10 and JDK 7 is only 1ms faster. In conclusion then, running Scala on a Java 7 virtual machine has proven to be more performant, but only for Scala 2.10 and only with this limited benchmark.

[panaxiom]

Mongo Base64Id Shell Enhancement

This post describes a Base64 alternative to working with hexadecimal representations of ObjectId's in mongo. This: UKZBAooUfVcAYOfa Instead of: 50a641028a147d570060e7da That is 16 characters instead of 24 and depending on your style, you may prefer it. ## Motivation After designing an API that looks something like this: GET http://example.com/resource/50a641028a147d570060e7da I wondered if there was a more elegant alternative - surely a hexadecimal string is not the most compact form. MongoDB is a great database and provides a default index field "_id" which is comprised of 12 bytes of data in a type called [ObjectID](http://www.mongodb.org/display/DOCS/Object+IDs), usually represented in hexadecimal format as above. There are advantages to sticking with ObjectID, for example: 1. A high chance of being unique when created. 2. It includes a timestamp, so no need to create a date created field. ## Solution Encoding the 12 ObjectId bytes into URL safe Base64 is simple and effective, meaning you can indeed write an API like this without losing the benefits of ObjectID and all without declaring another field on your document. GET http://example.com/resource/UKZBAooUfVcAYOfa But what about the mongo shell? There's clearly no point of having all this indirection if the tools we have refuse to work for us. ## Usage Clone the repoistory on [GitHub](https://github.com/alexanderjarvis/mongo-base64id) git clone https://github.com/alexanderjarvis/mongo-base64id Link ```mongo-base64id.js``` to ```.mongorc.js``` in your home directory. ln -sf /mongo-base64id.js ~/.mongorc.js Data is now returned in Base64Id format: $ mongo > db.users.find() { "_id" : Base64Id("UKZBAooUfVcAYOfa"), "email" : "[email protected]" } You can also query by Base64Id: > db.users.find(Base64Id("UKZBAooUfVcAYOfa")) { "_id" : Base64Id("UKZBAooUfVcAYOfa"), "email" : "[email protected]" } What if I want to use ObjectId again? Easy: > setBase64Id(false)

[panaxiom]

About this blog (how meta!)

Since this is a technical blog, you may be interested to know that you can and will be able to also browse the archive of the posts at [GitHub](https://github.com/panaxiom/engineering.panaxiom.co.uk). It is currently hosted for free by Tumblr, which allows for posts to be written in Markdown. A similar solution is also probably possible using GitHub Pages, but this was the easiest to get working for now. Comments welcome.

[panaxiom]

Sublime Text 2 with SBT and Play 2

Documentation for getting a [Play 2](http://playframework.org) project working with [Sublime Text 2](http://www.sublimetext.com/) is available, but sparse, so this post aims to consolidate the steps necessary to get you up and running quickly. Once done, you should have a more semantically aware Sublime Text installation which highlights errors just like a regular IDE, but without all the hassle and lockups.  ## Part 1: Install the ensime-sbt-cmd plugin for sbt $ mkdir ~/.sbt/plugins $ echo "addSbtPlugin(\"org.ensime\" % \"ensime-sbt-cmd\" % \"0.1.0\")" >> ~/.sbt/plugins/plugins.sbt Make sure to obtain the correct version number from [https://github.com/aemoncannon/ensime-sbt-cmd](https://github.com/aemoncannon/ensime-sbt-cmd) ## Part 2: Use sbt to generate an ensime config file From the sbt/play console of your project: $ ensime generate ## Part 3: Install sublime-ensime Mac $ cd ~/Library/Application\ Support/Sublime\ Text\ 2/Packages/ $ git clone git://github.com/sublimescala/sublime-ensime.git Ensime Linux $ cd ~/.config/sublime-text-2/ $ git clone git://github.com/sublimescala/sublime-ensime.git Ensime ## Part 4: Install ensime Download Ensime package from http://download.sublimescala.org/ Extract the contents of this package into the **server** subdirectory of just created Ensime directory. You may need to create this directory Mac $ cd ~/Library/Application\ Support/Sublime\ Text\ 2/Packages/Ensime $ mkdir server Linux $ cd ~/.config/sublime-text-2/Ensime $ mkdir server ## Finally * Restart Sublime Text 2 * In Sublime Text 2, right click, Ensime > Maintenance > Startup I would recommend the [play2-sublimetext2](https://github.com/guillaumebort/play2-sublimetext2) bundle for syntax highlighting and code snippets if you are using Play.