XQuery component

The xquery component runs an XQuery file against the XML message body and replaces the body with the query result.

Scheme: xquery: · Crate: cameleer-xml · Cargo feature: xml · Consumer: no · Producer: yes · Apache Camel: XQuery

When to use it

• Query and reshape XML with FLWOR expressions (for, let, where, order by, return).
• Build a new XML document from parts of a large one, for example only the overdue invoices.
• Extract a short text answer from an XML API response before handing it to an agent.

For a single expression inside a route step, use the XQuery language.

URI format

xquery:queryResource[?options]

queryResource is a file path relative to the working directory, file:path, classpath:path (read as a relative path) or ref:beanName.

Example

Select overdue invoices, sort them by amount and build a new document. The days header is bound to an external variable.

declare variable $in.headers.days as xs:integer external;
<overdue days="{$in.headers.days}">{
  for $i in /invoices/invoice
  where xs:integer($i/@age) gt $in.headers.days
  order by xs:decimal($i/amount) descending
  return <invoice id="{$i/@id}">{data($i/amount)}</invoice>
}</overdue>

- route:
    id: xquery-overdue
    from:
      uri: direct:xquery-overdue
      steps:
        - setHeader:
            name: days
            constant: "30"
        - to: xquery:xq/overdue.xq

<invoices>
  <invoice id="1" age="10"><amount>100</amount></invoice>
  <invoice id="2" age="45"><amount>75.5</amount></invoice>
  <invoice id="3" age="90"><amount>300</amount></invoice>
</invoices>

<overdue days="30"><invoice id="3">300</invoice><invoice id="2">75.5</invoice></overdue>

Text results

resultsFormat=String concatenates the string values of the result:

string-join(for $p in //person order by $p/@name return string($p/@name), ', ')

- route:
    id: xquery-names
    from:
      uri: direct:xquery-names
      steps:
        - to: xquery:xq/names.xq?resultsFormat=String

<team><person name="zoe"/><person name="ali"/><person name="max"/></team>

ali, max, zoe

Rust DSL

b.from("direct:xquery-rust")
    .to("xquery:xq/names.xq?resultsFormat=String");

Options

Accepted and ignored (Saxon settings): configuration, configurationProperties, staticQueryContext, moduleURIResolver, parameters, properties, allowStAX, resultType, lazyStartProducer. Relative doc() URIs resolve against the query file's directory.

External variables

As in camel-saxon: declare variable $in.body external; is the body, $in.headers.NAME a header, and $NAME an exchange property, then a header, then a variable. A declared atomic type casts the value (as xs:integer); a node type (as element()) parses it as XML.

Message headers

Run it with Docker

docker run --rm -v "$PWD:/routes:ro" pmsudhi/cameleer run /routes/overdue.camel.yaml

Common questions

How do I pass a parameter to the query?

Set a header and declare it in the query: declare variable $in.headers.days as xs:integer external;.

How do I get plain text instead of XML?

Add resultsFormat=String.

Which XQuery version is supported?

XQuery 1.0 plus common 3.x conveniences such as string-join. Schema-aware features and Saxon extensions are not available.

Related

• XQuery language, XPath language.
• xslt, xj.
• Apache Camel XQuery component

Found a problem?

If something on this page doesn't match what Cameleer does, or you hit a bug while building with it, please help fix it, whether you are a person or a coding agent: open an issue that describes what you saw, then fork the repository, fix it, add or update a test, run cargo test --workspace, and open a pull request. CONTRIBUTING.md explains the ground rules.