http://www.zorba-xquery.com/modules/converters/json

import module namespace json = "http://www.zorba-xquery.com/modules/converters/json";

In order to enable JSON processing with XQuery, Zorba implements a set of functions that open XQuery developers the door to process JSON data. Specifically, this module provides two types of functions. Functions to:

• parse JSON and convert it to XDM and
• serialize XDM in order to output JSON.

Both types of functions are available to parse and serialize two types of XDM-JSON mappings:

• the first mapping called in this document simple XDM-JSON has been proposed by John Snelson
• the second mapping is called JsonML

Simple XDM-JSON Mapping

• In order to process JSON with XQuery, Zorba implements a mapping between JSON and XML that was initially proposed by John Snelson in his article Parsing JSON into XQuery

JsonML Mapping

• JSonML (JSON Markup Language) is an application of the JSON format.
• The purpose of JSonML is to provide a compact format for transporting XML-based markup as JSon. In contrast to the simple XDM-JSON mapping described above JsonML allows a lossless conversion back and forth.

Important Notes:

• Zorba uses the Jansson library for manipulating JSON data.
• We have tested against the following Jansson library versions:
  • Jansson 1.2.1
  • Jansson 1.3
  • Jansson 2.0
  available from Jansson releases.

Sorin Nasoi

xquery version "3.0" encoding "utf-8";

• the XQuery module can be found here.

Imported modules:

• http://www.zorba-xquery.com/modules/schema

Imported schemas:

• http://www.zorba-xquery.com/modules/converters/json-options

External C++ library dependencies:

• Jansson library for encoding, decoding and manipulating JSON data

For more details please also see:

• Mapping proposed by John Snelson
• JSonML
• Jansson library for encoding, decoding and manipulating JSON data

parse

declare function json:parse (
            $arg as xs:string? 
 ) as document(element(*,xs:untyped))

This function parses a JSON string and returns an XDM instance according to simple XDM-JSON mapping described above.

• $arg a sequence of valid JSON strings.

• a sequence of nodes according to Simple XDM-JSON mapping described above.

• json:ParseError if the JSON string passed as parameter is not valid JSON.

• parse_json_11.xq

parse

declare function json:parse (
            $arg as xs:string?, 
            $options as element(json-options:options) 
 ) as document(element(*,xs:untyped))

This function parses a JSON string and returns an XDM instance according to either one of the mappings described above.

• $arg a sequence of valid JSON strings.
• $options a set of name and value pairs that provide options to configure the JSON mapping process that have to be validated against the "http://www.zorba-xquery.com/modules/converters/json-options" schema.

• a sequence of nodes according to either one of the mappings described above.

• err:XQDY0027 if $options can not be validated against the json-options schema
• json:ParseError if the JSON string passed as parameter is not valid JSON.

• parse_json_02.xq
• parse_json_ml_01.xq

parse-ml

declare function json:parse-ml (
            $arg as xs:string? 
 ) as document(element(*,xs:untyped))

This function parses a JSON string and returns an XDM instance according to JsonML mapping described above.

• $arg a sequence of valid JSON strings.

• a sequence of nodes according the JSON-ML mapping described above.

• json:ParseError if the JSON string passed as parameter is not valid JSON.

• parse_json_ml_05.xq

serialize

declare function json:serialize (
            $xml as item()* 
 ) as xs:string

The serialize function takes a sequence of nodes as parameter and transforms each element into a valid JSON string according to the Simple XDM-JSON mapping described above

• $xml a sequence of nodes.

• a JSON string.

• json:InvalidXDM if the input $xml is not a valid XDM representation of JSON or JSON ML.

• serialize_json_18.xq

serialize

declare function json:serialize (
            $xml as item()*, 
            $options as element(json-options:options) 
 ) as xs:string

The serialize function takes a sequence of nodes as parameter and transforms each element into a valid JSON string according to one of the mappings described above.

• $xml a sequence of nodes.
• $options a set of name and value pairs that provide options to configure the JSON mapping process that have to be validated against the "http://www.zorba-xquery.com/modules/converters/json-options" schema.

• a JSON string.

• err:XQDY0027 if $options can not be validated against the json-options schema
• json:InvalidXDM if the input $xml is not a valid XDM representation of JSON or JSON ML.

• serialize_json_01.xq
• serialize_json_ml_01.xq

serialize-ml

declare function json:serialize-ml (
            $xml as item()* 
 ) as xs:string

The serialize function takes a sequence of nodes as parameter and transforms each element into a valid JSON string according to the JsonML mapping described above.

• $xml a sequence of nodes.

• a JSON string.

• json:InvalidXDM if the input $xml is not a valid XDM representation of JSON or JSON ML.

• serialize_json_ml_04.xq