Handling Binary Data in Foxx

00Foxx, JavascriptTags:

Handling binary data in JavaScript applications is a bit tricky because JavaScript does not provide a data type for binary data. This post explains how to use binary data in JavaScript actions written using ArangoDB’s Foxx.

String vs. binary data

Internally, JavaScript strings are sequences of 16 bit integer values. Furthermore, the ECMAScript standard requires that a JavaScript implementation should interpret characters in conformance with the Unicode standard, using either UCS-2 or UTF-16 encoding.

While this is fine for handling natural language, it becomes problematic when trying to work with arbitrary binary data. Binary data cannot be used safely in a JavaScript string because it may not be valid UTF-16 data.

Read more on Jan’s Blog

If you want to continue with other JavaScript related resources, you should start with ArangoDB NoSQL and JavaScript.

Cheerio, Node and Coffee-Script

02Foxx, General, JavascriptTags: ,

Foxx’ main purpose is to create a beautiful API for your AngularJS, EmberJS or Backbone.js front-end. However, sometimes you want to do more. We, for example, needed to parse some HTML files. ArangoDB is capable of using some Node.js modules, but unfortunately Cheerio was not one of those. One problem was that we did not support loading of JSON data modules. So, this was a good excuse to rewrite the module loader in ArangoDB to make it even more Node.js-friendly.

With those improvements, that are currently available in ArangoDB’s devel branch. You can now also “require” a JSON data file. These files must have a filename ending with “.json”. If the filename ends with “.coffee” it is treated as coffee-script file and automatically compiled into JavaScript.

A Foxx app can now contain its own “node_modules” directory to include Node modules which it requires. This makes it much easier to deploy a Foxx app.

Ideas and Facts from scotland.js in Edinburgh

00Community, Foxx, General, JavascriptTags:

Test Driven Development

I have been one of the lucky attendants of scotland.js in Edinburgh recently.
It was a really nice & informative conference, thanks to all people that made it possible.
I did really like to see that TDD is reaching the front-end developers finally.
A lot of useful tools for this have been presented by James Shore, Bernard Kobos and Sebastian Golasch.
In ArangoDB, TDD is in action all day and I am looking forward to improving our front-end testing even further using these awesome tools.

 

Front-end Development meets NoSQL

Furthermore several talks focussing on front-end development have been given, e.g. by Gregor Martynus presenting Hoodie.js.
These front-end talks and my discussions with other attendees gave me the impression that front-end developers spend a lot of time deciding which database they should use. More info

Feature Preview: Using CoffeeScript in ArangoDB

02General, JavascriptTags: ,

In my blog post about npm packages, I tried to use underscore for ArangoDB. I found that the easiest way to archive this, is using the nodes package manager NPM. Node packages and modules follow the Common.JS specification, so they can be used by ArangoDB.

Why not try to use the package coffee-script as well? Install it using

and that’s it. Unfortunately, CoffeeScript use a module “path”, which is not a CommonJS module. I assume that most of the functionality is part or will be part of the module “fs”. The “path.js” from node.js is simple JavaScript code with some references like

Being brave, I simply copied the file into my module path and tried again. The next obstacle is node’s global variable “process”. Luckily, this is only used to check for Windows in the module “path”. Also ignoring the module “vm” used to execute JavaScript code, this allows one to actually load CoffeScript into ArangoDB.

So, I can now use CoffeeScript definition within ArangoDB. Some of the loaders must be adjusted to check for both “.js” and “.coffee” files. Afterwards it should be possible, to define an action in CoffeeScript as well as JavaScript.

Feature Preview: Using NPM packages for ArangoDB

04Javascript, nodejsTags:

ArangoDB follows the Common.JS specification for modules. However, it would be very convenient, if there was an easy way to install a package like “underscore.js”. These package are, for instance, available using NPM. There is a draft for packages on Common.JS which seems to be compatible with NPM.

NPM has a neat way of dealing with version conflicts. Basically, it allows multiple versions to exists simultaneously. For example, assume you have 4 packages A, B, C, D. A requires B and C and D, B requires C. Then directory layout might be as follows.

Package B will see package C in version 1.0.0, while package A sees package C in version 2.0.0.

This behaviour is easy to implement in ArangoDB. In addition to “Module” there is now a “Package”. Each package has it own module cache. When a package requires a module, the package hierarchy is traversed from the current package to the root (or global) package, until the module is found.

In order to use underscore, switch into the package directory and use NPM to install it

Now start arangosh with the new “–javascript.package-path” option and enjoy underscore.