VSO Programmatic Interface Authors: Igor Suárez Solá Joe Hourclé Alisdair Davey VSO Team

VSO Basics – VSO GUI and underlying XML correspondence VSO Programmatic interface – WSDL stub generation Java C – IDL VSO – Perl interface VSO Advance Querying The documentation on this talk can be found in:

Some Jargon Metadata: attributes that define a specific observation. – E.g. – Time,instrument,observable,spectral range,provider, fileid, etc Data: a reference to actual data, such as a url: – E.g. – bin/drms_test/drms_export.cgi?series=aia_lev1;compress=ric e;record=1700_ bin/drms_test/drms_export.cgi?series=aia_lev1;compress=ric e;record=1700_

The VSO only has two operations: Metadata Query GetData Query

Check box you want to sort by Select view type to display additional columns Sorts based on order the table column was ticked

VSO programmatic interface Why using the VSO in a programmatic way? Because you can: – Embed VSO calls in existing code – perform complex queries – Query on fields that the GUI might not implement. – Engage in querying providers that offer specific extended interfaces. E.g. XRT

What’s a WSDL? Web Service Description Language – A document that describes how the message interaction between client and server takes place. – It describes: The message structure Implemented operations Protocol Network connection (or end-point) – The client is your program or application – The server is a VSO Core implementation

How does a WSDL helps you? There are libraries / packages out there are able to generate code that allows you to manipulate the transaction client/server in a effective way. Axis2 JAVA and C JWS C#

Axis2 Generate java client stubs code: export JAVA_HOME=/usr/local/java export AXIS2_HOME=/usr/local/axis export PATH=$AXIS2_HOME/bin:$PATH wsdl2java.sh -s -S./src -uri VSOi_rpc_literal.wsdl Generate C client stubs code WSDL2C.sh -uri VSOi_rpc_literal.wsdl -d adb –u See client code in

Java sample code

IDL VSO SSW (SolarSoftWare) Just two IDL routines – vso_search To search on metadata E.g. aia_lev1 = vso_search( ' ', ' :00', inst='aia’) – vso_get To bring the urls for the data E.g. status = vso_get( aia_lev1 ) Download from

IDL VSO Further Documentation can be found at:

Perl interface The simplest one (Native interface) – Just needs SOAP::Lite – An end point – A perl structure Example: my $client = SOAP::Lite -> proxy(’ -> uri(' my $results = $client->Query( { version=>’1.0’, block => { provider=>’jsoc’, instrument=>’aia’, time=>{ start=>’ ’, end=> ’ ’ } });

Specific Querying Sampling: returns records per “sampling” period Sampling is in seconds E.g. Get records every hour – Xml: 3600 – IDL sample=3600 Near querying: returns records closest to specified time Specify the time you want the closest product to be: – XML: – IDL: near_time=“ ” – Last record You can get the last record by setting the start time a couple of hours in the past and the end time and near time to be now or slightly in the future. IDL: – This is achieve simply by setting the flag : /latest

Specific Querying Other filters – Requesting data by : Processing level: level Pixel resolution : pixels Resolution: resolution Pixel Scale: pscale Detector: dectector Layout : layout

Summary Programmatic interface in place Support for multiple programming languages Standardized interface