== Semantic Query Interface ==

The web interface leverages the Freemarker template engine and allows users to access the SQR main functionalities. 

[[PageOutline(3-4,Table of Contents,inline)]]

=== Index Page ===

From the index page at http://host:port/sqr/, you can select the functionality you want to access from the top menu.

[[Image(SQRIndex_new.jpg)]]

=== Request Resource Descriptions ===

From this page you can lookup resource descriptions either directly from the RD interface or through selector queries.

[[Image(SQRRequestRes_new.jpg)]]

=== Request Information ===

From this page you can request a piece of information using a selector query.

[[Image(SQRRequestInf_new.jpg)]]

=== Subscribe Information ===

From this page, using a selector, you can subscribe for a piece of information to be delivered periodically, on change or whenever it reaches a threshold

[[Image(SQRSubscribe_new.jpg)]]

=== Actuate ===

From this page you can excute an actuation task.

[[Image(SQRActuate_new.jpg)]]

=== Lookup Bindings === 

From this page you can lookup the entries within the ED. You can do so either by using the form for simple queries or an XML Stream for complex ones.

For a simple query, a validation process takes place on the server side to verify that the following set of rules is satisfied.

The four first fields i.e. ID, ResourceID, Operation, !ObservationArea do not have any specific requirements.

When one of the fields is EoI, Attribute, !EntityType, Value, QoA, QoI, Cost, an IOPEType has to be specified. As a matter of fact this part of the lookup will try to identify tuples of parameters e.g. (EoI, !EntityType) when an EoI and an !EntityType are specified that belongs to the same type of IOPE, for instance Input. The IOPEType parameter can take a value in the set {Input, Output, !PreCondition, !PostCondition, any}. The GUI returns a set of bindings matching the request.

For a complex query, the Template has to match the schema specified at [https://ncit-cluster.grid.pub.ro/trac/Sensei-Cookbook/attachment/wiki/ED/binding.xsd], the server returns an error otherwise. 

[[Image(SQRLookupBindings_new.jpg)]]

----