Overview

This component provides a Common Execution Connector web-service for HTTP applications (HTTP-CEC for short). The HTTP-CEC makes astronomy applications available to the virtual observatory; notably, it makes them visible to AstroGrid's web portal, desktop UI and workflow system.

Suitable applications for this kind of CEC (there are other kinds) run on external web-servers (i.e. they need not be co-located with the CEC) and can be invoked using the HTTP-get protocol; the CEC does not work with HTTP-post services. The HTTP-CEC acts as a proxy for the HTTP application, translating between the standards CEA protocols and the application's own protocol. This has two advantages.

  • Non-standard applications become accessible to the IVO.
  • IVO-standard HTTP-get services (e.g. SIAP), which are already accessible to the IVO in a basic form, become accessible as CEA applications and can be used from all AstroGrid UIs.

One HTTP-CEC can stand as proxy for any number of HTTP applications. Therefore, if you have an HTTP application on your web-server you can use associate it with an HTTP-CEC in two ways.

  1. Run your own HTTP-CEC.
  2. Have your application configured onto someone else's HTTP-CEC.

If your application has a command-line interface instead of a web interface you should run the command-line CEC (CL-CEC) instead.

If your application is to serve archive data then this may not be the ideal component. You should look first at the Data Set Access (DSA) component of AstroGrid. It is possible to use the HTTP-CEC as an archive interface, but the DSA component provides better support for archive queries.

Internal web-pages and local controls

The CEC web-application contains a copy of these web-pages. If you install the web application as, say, CEC-1 on server my.cea.server on port 8081, then the internal web pages are at

					http://my.cea.server:8081/CEC-1/
				

The internal copy of the pages has, in its sidebar, extra links leading to local controls for configuration, testing and registration. Therefore, while setting up the CEC, you should look at the internal pages. If you can't find the controls, you're probably reading the web pages on software.astrogrid.org instead.