All TAPIR operations can alternatively be invoked with a http GET URL. The operation name itself is specified in a parameter called "op". If not specified the default operation is metadata.

Global parameters (valid for all operations)

• op=[ping,metadata,capabilities,inventory,search]
• default=metadata
• cardinality=1..1

• xslt=[URI]
• default=null
• cardinality=0..1

• xslt-apply=[true,false,1,0]
• default=false
• cardinality=0..1

• log-only=[true,false,1,0]
• default=false
• cardinality=0..1

The accepted list of parameters for each operation

ping

• op=[ping,p]

metadata

• op=[metadata,m]

capabilities

• op=[capabilities,c]

inventory

• op=[inventory,i]

• count=[true,false,1,0]
• default=false
• cardinality=0..1

• start=>= 1?
• default=1
• cardinality=0..1

• limit=>=0, NONE?
• default=NONE
• cardinality=0..1

Then either a "template" parameter must be present:

• template=[URI]
• default=null
• cardinality=0..1

Or one or more concepts with an optional filter:

• concept=qualified or alias?
• default=(UNDEFINED which must be interpreted by implementation to mean no concepts and therefore empty response)
• cardinality=0..n

• filter=[expression]
• default=null
• cardinality=0..1

Parameter "template" takes precedence over "concept". So if both are present, "concept" (and the optional "filter") should be ignored.

search

• op=[search,s]

• count=[true,false,1,0]
• default=false
• cardinality=0..1

• start=>= 1?
• default=1
• cardinality=0..1

• limit=>=0, NONE?
• default=NONE
• cardinality=0..1

Then either a "template" parameter must be present:

• template=[URI]
• default=null
• cardinality=0..1

Or a "model" parameter with optional "partial", "filter" and "orderby":

• model=[URI]
• default=null
• cardinality=0..1

• partial=[XPath]
• default=null
• cardinality=0..n

• filter=[expression]
• default=null
• cardinality=0..1

• orderby=qualified or alias?
• default=null
• cardinality=0..n

Parameter "template" takes precedence over "model". So if both are are present, "model" (and the optionals "partial", "filter" and "orderby") should be ignored.

• envelope=[true,false,1,0]
• default=true
• cardinality=0..1

Filter encoding

Filter expressions in GET requests will be infix equivalents to their XML counterparts

Order of Operations

The precedence of operators follows these rules:

E: AOP, COP, LOP
AOP: Mul, Div, Add, Sub
COP: Equals
LOP: Not, And, Or

Blocks can be formed by using simple parenthesis ( )

BNF Grammar For GET Filter expressions

WikiPedia?:Backus-Naur_form

<expression>                    ::= <logical_operator> |
                                    <comparative_operator>

<comparative_operator>          ::= <unary_comparison_expression> |
                                    <binary_comparison_expression> | 
                                    <unbound_comparison_expression>

<logical_operator>              ::= <unary_logical_expression> | <binary_logical_expression>

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