qk/sadira

Qk/Sadira is aimed to be an ECMAScript(JS)/C++ scientific-oriented application framework running on Node.js servers and web-browsers. Its goal is to provide to existing data processing applications:

• a JavaScript object data model based on templates,
• an HTML graphical user interface engine,
• a peer to peer, dialog based JavaScript communication system and binary protocol for data exchange,
• serialization of objects in databases, files, web-storage.

##Introduction

The main 'inaccessible' goal of quarklib is to provide the scientific community with a magic tool automatically wrapping an interactive application (providing rich user-interface, data and process sharing via a peer to peer communication protocol, ...) on top of the everyday mess of the [astro]-physicist researcher : binary data files of any kind, numbers, vectors, functions, images, n-cubes, complex pipeline logic, database access, custom exotic algorithms in whatever language, etc...

ECMAScript has become a powerfull high-level language with its increasing just-in-time compilation and hardware-acceleration features on web browser's and server interpretors. The actual set of "JS-enabled" technologies available on the browser side provides a powerfull, theoretically platform-agnostic user-interface consisting in rich html dom content, hardware-accelerated WebGL/WebCL computations and new possibilities of client/server socket programming with websockets and webrtc.

From this renewed viewpoint, sadira is the latest implementation of the quarklib project, now using JS-based server and client code and the latest web technologies to create a lower codeline count, still providing a powerfull system, in comparison with a corresponding native c++/networked/ui-toolkit implementation.

A pure web application has the natural advantage to be installation-free, web-storage beeing used for serialization : for example, to recover the UI state. Furthermore, web applications are natively multi-platform, code needs ony be written once, the browser incompatibilities obscuring a little the things ont that matter.

This work is curently realised at the INAF, IASF-Bologna, in Italy, funded by the GLORIA project, a EU commission program.

#Communication

One of the core components of sadira is its binary communication protocol, permitting the exchange of arbitrarilly complex data between either Node.js servers or web browsers using WebSockets or the newer WebRTC datachanels. sadira allows browsers and node.js servers to communicate with each othertrough a simple yet powerfull binary protocol. Using WebRTC datachannels, sadira can be used as the core of peer to peer applications running between web browsers and/or node.js servers.

The actual support of webRTC and particulary the datachannel part is still very limited right now in curent web browsers, but this technology will surely be broadly available in a near future.

For performance and bandwidth usage reasons, data need to be exchanged in binary form. ArrayBuffer support in web browser opened the way to custom binary handling of data. Sadira uses the BSON format to encode the data of JavaScript objects transfered within dialogs in a binary efficient way. Large binary messages need to be serialized in packets, sometimes asynchronously, to avoid congestionning, which is also a feature of the sadira dialogs.

##Grammar and Vocabulary: Templates

Templates are stuctured data field assemblies describing a project's data, processing pipelines, and user interfaces. From the user point of view, they are simple JavaScript objects like the minimal, empty template

  var example_template = {};

Some properties have a special meaning. To specify child objects, the elements object property must be used :

  var example_template = {
      elements : {
      	       child1 : {},
	       child2 : {}
      }

  };

  

##Talking : Dialogs

###Wave packets : Datagrams

One of the core sadira class exists for the purpose of encoding metadata and binary data into a single 'datagram' binary buffer :

https://github.com/Nunkiii/sadira/blob/master/www/js/datagram.js

The file can be included in node.js and browsers. The datagram embed a BSON encoded header + an arbitrary binary data packet into a 'datagram' binary buffer, received in the browser as an ArrayBuffer. Datagrams are the 'words' transmitted inside 'dialogs' :

https://github.com/Nunkiii/sadira/blob/master/www/js/dialog.js

, dialogs ocuring within a websocket or a webrtc datachanel connexion.

The datagrams can also be used for binary AJAX GET requests. In the Gloria 'get' server case, it can also be used to encode the binary replies of the gloria image data GET requests, allowing to pass image name, width, height,... in a BSON encoded header, along with the pixel binary float32 ArrayBuffer data.

###Long data : Serializers

Big binary buffers cannot be transfered in one piece, they need to be sliced in packets and reconstructed server side before beeing used. This is the scope of the serializer classes in sadira. It manages a stream of datagrams containing pieces of the final object. When done with datagram grabbing, the serializer notifies the client application with the reconstructed object data.

##HTML user interface builder ##Data storage

##Installation

Git clone or download the zip project's file.

##Examples

To do.