DEWS project page

• DEWS_NCOF_18-01-2007.ppt: Introductory presentation on DEWS to NCOF
• DEWSTechnicalWorkshop6Feb07 Information about the DEWS technical workshop, 6-7 Feb 2007 at ESSC

Introduction

The ReSC's contribution to the DEWS project is to deliver a new version of the GridAccessDataService software. This new version (known as GADS-WCS) will be compliant as far as possible with the Open Geospatial Consortium's Web Coverage Server specification. It will extend WCS by allowing downloads of very large amounts of data in a secure fashion. Data will only be available for download in NetCDF format.

Project plan

According to the overall DEWS project plan, GADS-WCS must be delivered, ready for integration testing by the end of Feb 2007. These are the tasks and sub-tasks that must be completed in order to achieve this:

Implementation of getCoverage() according to OGC spec

Will implement getCoverage() only and will not be secured or allow for large data downloads. Will be deployed in WebSphere and linked to Lost Wax's Oracle database. Data will be returned synchronously as a direct response to the POSTing of an XML document representing the data request.

Implement asynchronous delivery mechanism

Will allow the client to specify whether the data should be provided synchronously (as a direct response to the request) or asynchronously (in which case the server will respond with some kind of ticket). If the client chooses synchronous delivery and the request is "too large" the server will respond with an error. Client chooses asynchronous delivery by setting the input parameter store=true. Default behaviour is for synchronous delivery in line with WCS spec.

Subtasks:

1. Design async delivery mechanism (possibly based around Web Processing Server spec)
2. Implement server behaviour
3. Implement means for the client to poll the service for latest progress and completion
   • At minimum, the server should respond with "complete" or "in progress". If possible and if time allows, server should respond with more details such as estimated time to completion.
4. Implement means for the client to retrieve the data once ready

Implement security

Currently assuming that we will use message-level security in which clients must sign their XML requests for data to prove they are entitled to see the dataset(s) in question.

Implement getCapabilities() and describeCoverage()

These are not very important for DEWS but would be useful to other clients especially for testing

Implement change to allow WSDL/SOAP messaging

Not sure when we should do this task. Currently it's only a proposed change (put reference here!) but by this stage of the project it might be approved. Does this affect security requirements?

-- JonBlower - 17 Feb 2006