Expressions in Axiom Query

Last modified 15 Mar 2022 12:42 +01:00

Since 4.5

This functionality is available since version 4.5.

Table of Contents

Path Expression
Script
- Other Scripting languages
Other expression types

Axiom Query language also provides special syntax support for most common expression types.

Expressions are not executed / supported for user entered queries in search box in midPoint GUI, since that would allow users to execute code and may pose additional security risks.

Script expressions are supported for following filters:

Value comparison filters
- =, <, >, <=, >=
- equal, less, greater, lessOrEqual, greaterOrEqual
String filters
- contains, startsWith, endsWith

Path Expression

The syntax for path expression is pretty straight-forward, since most path expression references variable.

Variables starts with dollar $ symbol. Note that variables are only supported as right-hand side value.

Path Expression in Equals filter

name = $c:account/c:attributes/ri:uid

XML equivalent

<q:equal>
    <q:path>name</q:path>
    <c:expression>
       <c:path>$c:account/c:attributes/ri:uid</c:path>
    </c:expression>
</q:equal>

Script

There are two syntaxes for script expression: single-line scripts and multi-line scripts. By default scripts are Groovy scripts unless other scripting language is specified.

Single-line Groovy expression

metadata/createTimestamp > `basic.fromNow("-P30D")`

Single-line expressions are written as strings surrounded with single ` (backtick) character. This allows you to use quotes inside script without need to escape them.

Multi-line Groovy expression

metadata/createTimestamp > ```
    now = basic.currentDateTime();
    ret = basic.addDuration(now, "-P30D");
    return ret
    ```

The syntax for multi-line expressions is bit more elaborated, multi-line script starts with triple backticks (```), followed by new-line. Script body is closed by triple backticks (```). This minimizes need for escaping most of the qoutes or sequences inside the script body.

Other Scripting languages

You can use other supported scripting language for expressions, by prefixing quotes with language name e.g.:

metadata/createTimestamp > groovy`basic.fromNow("-P30D")`

The language name is same as you would use in XML filter script expressions.

Other expression types

If you plan to use expression type, which does not have simplified syntax, you can use yaml script expression (yaml as scripting language is only available in Axiom Queries)

yaml expression allows you to pass-thru standard expression element serialized in YAML format.

This is useful, if you need to define additional properties of expression, or use other expression types, which does not built-in syntax support.

metadata/createTimestamp > yaml```
    language: groovy
    code: |
        now = basic.currentDateTime();
        ret = basic.addDuration(now, "-P30D");
        return ret
    ```

XML Equivalent

<filter>
  <gt>
    <path>metadata/createTimestamp</path>
    <expression>
      <language>groovy</language>
      <code>
        ret = basic.addDuration(now, "-P30D");
        now = basic.currentDateTime();
        return ret
      </code>
    </expression>
  </gt>
</filter>