Action syntax

Availability

This feature is available since Orbeon Forms 2018.2.

Rationale

Orbeon Forms supports services and actions. With Orbeon Forms 2018.2, a first step towards more powerful actions is introduced. There is no interface for it yet, but instead an XML configuration which you can paste into the form definition via the "Edit Source" dialog.

Enhancements

In addition to the features available through the "Actions" dialog, the following enhancements are available:

• Call an action in response to multiple events.

• Support more event types.

• Call an arbitrary number of services.

• Run actions without calling services.

• Clear repeated grid or repeated section repetitions.

• Add repeated grid or repeated section repetitions.

• Repeatedly run parts of an action. [SINCE Orbeon Forms 2019.1]

• Conditionally run parts of an action. [SINCE Orbeon Forms 2019.1]

Updating the form definition

You place listeners and actions within the source code, preferably before the end of the main <xf:model> content. For example:

    <!-- other Form Builder code here -->

    <fr:listener
        version="2018.2"
        .../>
        
    <fr:action name="my-action" version="2018.2">
        ...
    </fr:action>
    
    <!-- Put `<fr:listener>` and `<fr:action>` just above this. -->
</xf:model>

Example

The following example:

• listens to an activation event on the button my-button

• in response, calls the my-action action, which

  • sets values from controls into the my-service service request

  • calls the my-service service

• when the service call completes

  • the my-table repeated grid is cleared

  • iterating over the XML response, for each iteration

    • adds a repetition at the end of the my-table repeated grid

    • sets the value of controls on the new repetition

  • finally, all the result-dropdown dropdown control items are updated

    <!-- other Form Builder code here -->
    
    <fr:listener
        version="2018.2"
        events="activated"
        controls="my-button"
        actions="my-action"/>
    
    <fr:action name="my-action" version="2018.2">
    
        <fr:service-call service="my-service">
            <fr:value control="foo" ref="/*/foo"/>
            <fr:value control="bar" ref="/*/bar"/>
        </fr:service-call>
    
        <fr:repeat-clear repeat="my-table"/>
    
        <fr:data-iterate ref="/*/row">
            <fr:repeat-add-iteration repeat="my-table" at="end"/>
            <fr:control-setvalue value="@field" control="result-field" at="end"/>
            <fr:control-setvalue value="@dropdown" control="result-dropdown" at="end"/>
        </fr:data-iterate>
    
        <fr:control-setitems
            items="/*/response/item"
            label="@label"
            value="@value"
            control="result-dropdown"/>
    
    </fr:action>

    <!-- Put `<fr:listener>` and `<fr:action>` just above this. -->
</xf:model>

Listeners

Basic syntax

A listener looks like this:

<fr:listener
    version="2018.2"
    modes="..."
    events="..."
    controls="..."
    actions="..."
>

Attribute	Mandatory	Value	Comment
version	Yes	format version	always 2018.2
modes	No	space-separated list of modes	The listener is enabled for each mode listed only. If absent, the listener is enabled for all modes.
events	Yes	space-separated list of event names	When more than one event name is present, the listener reacts if any of the listed events is present.
controls	Yes for events which relate to a particular control, like enabled or value-changed	space-separated list of control names	When more than one control name is present, the listener reacts if an event is dispatched to any of the listed controls.
actions	No, but nothing will happen if there is not at least one action referenced	space-separated list of action names	When more than one action name is present, all the specified actions are called when the listener reacts to an event.

NOTE: It is disallowed to mix and match, in a single listener, events for which a control name is required and events for which a control name is not required. Instead, use multiple listeners.

Modes supported

• new

• edit

• view

• pdf

xxx link to new modes page with explanations

Events supported

Controls:

• enabled: the control has become enabled

• disabled: the control has become disabled

• visible: the control has become visible (for example in a wizard page)

• hidden: the control has become hidden (for example in a wizard page)

• value-changed: the value of an enabled control has changed

• activated: the control has been activated (clicked, or enter in text field)

• item-selected: an item of an enabled control has been selected

• item-deselected: an item of an enabled control has been deselected

Form load:

• form-load-before-data: run before the data's initial values are calculated

• form-load-after-data: run when the data is ready

• form-load-after-controls: run after the controls are ready

See also Running processes upon page load for the detail of the form load events.

Actions

Basic syntax

An action looks like this:

<fr:action
    version="2018.2" 
    name="my-action" 
>

Attribute	Mandatory	Value	Comment
version	Yes	format version	always 2018.2
name	Yes	action name	must be unique in the form definition

Control structures

Iterating over data

[SINCE Orbeon Forms 2019.1]

Basic usage

<fr:data-iterate ref="...expression...">
    ...
</fr:data-iterate>

<fr:data-iterate> allows you to iterate over data. The contained actions are executed once for each value returned by the expression.

Containing actions can include one or more calls to services.

Attribute	Mandatory	Value	Comment
ref	Yes	sequence XPath expression	runs in the current XPath evaluation context

In the following example, each repetition adds a row to the grid, calls a service, passing the attachment id, and sets the attachment value on the last row.

<fr:action name="populate-attachments" version="2018.2">

    <fr:service-call service="get-attachments-list"/>
    <fr:repeat-clear repeat="my-grid"/>

    <fr:data-iterate ref="/*/row">
        <fr:repeat-add-iteration repeat="my-grid" at="end"/>
        <fr:service-call service="get-attachment">
            <fr:url-param name="text" value="attachment-id"/>
        </fr:service-call>
        <fr:control-setattachment control="my-attachment" at="end"/>
    </fr:data-iterate>

</fr:action>

Nesting of iterations

[SINCE Orbeon Forms 2019.2]

Calls to <fr:data-iterate> can be nested. This allows, for example, filling nested repeated sections and/or grids with the result of a service call that returns hierarchical data.

Example:

<fr:action name="my-action" version="2018.2">
    <fr:service-call service="get-nobel-prizes"/>
    <fr:repeat-clear repeat="prizes"/>
    <fr:data-iterate ref="/*/prizes/_">
        <fr:repeat-add-iteration repeat="prizes"/>
        <fr:control-setvalue value="year"     control="year"     at="end"/>
        <fr:control-setvalue value="category" control="category" at="end"/>
        <fr:repeat-clear repeat="laureates"/>
        <fr:data-iterate ref="laureates/_">
            <fr:repeat-add-iteration repeat="laureates"/>
            <fr:control-setvalue value="firstname"  control="firstname"  at="end"/>
            <fr:control-setvalue value="surname"    control="surname"    at="end"/>
            <fr:control-setvalue value="motivation" control="motivation" at="end"/>
        </fr:data-iterate>
    </fr:data-iterate>
</fr:action>

Conditions

[SINCE Orbeon Forms 2019.1]

<fr:if condition="...boolean expression...">
    ...
</fr:if>

<fr:if> allows you to conditionally run a block of actions.

Attribute	Mandatory	Value	Comment
condition	Yes	boolean XPath expression	runs in the current XPath evaluation context

In the following example, with the repetition performed by <fr:data-iterate>, the call to the service that retrieves an attachment depends on whether there is a non-blank attachment id provided.

<fr:action name="populate-attachments" version="2018.2">

    <fr:service-call service="get-attachments-list"/>
    <fr:repeat-clear repeat="my-grid"/>

    <fr:data-iterate ref="/*/row">
        <fr:repeat-add-iteration repeat="my-grid" at="end"/>
        <fr:if condition="xxf:non-blank(attachment-id)">
            <fr:service-call service="get-attachment">
                <fr:url-param name="text" value="attachment-id"/>
            </fr:service-call>
            <fr:control-setattachment control="my-attachment" at="end"/>
        </fr:if>
    </fr:data-iterate>

</fr:action>

Asynchronous actions

[SINCE Orbeon Forms 2023.1]

Previously, actions were run synchronously. That is, they were blocking any other form processing until completed. It is now possible to run actions asynchronously. This means that the form processing can continue while the actions are running in the background. This is particularly useful when the actions call services.

You can enable asynchronous actions:

• at the action level, using the async="true attribute

• at the form level, using the oxf.fr.detail.actions.async.*.* property

Example of configuration property:

<property 
    as="xs:boolean" 
    name="oxf.fr.detail.actions.async.*.*"                            
    value="true"/>

It is currently not possible to mix and match synchronous and asynchronous service calls within a given action.

An asynchronous action, by default, causes a response to the client (web browser) to wait forever for its completion. This is done to enhance the backward-compatibility of asynchronous actions. This can be disabled:

• at the action level, using the response-must-await="0ms" attribute (or 0 followed by any other unit allowed as shown below)

• at the form level, using the oxf.fr.detail.actions.response-must-await.*.* property

Example of configuration property:

<property 
    as="xs:string" 
    name="oxf.fr.detail.actions.response-must-await.*.*"              
    value="0ms"/>

If response-must-await is set to 0ms, a response to the client doesn't wait for the completion of asynchronous actions. Instead, the response is sent immediately, and the pending action's service calls continue to wait in the background. The client polls the server at regular intervals to check for the completion of such pending services, and then resumes the processing of the actions. This is useful when an action calls long-running services, and you don't want to keep the client waiting for its completion.

Possible values for this property and attribute are:

• forever

• "$length$unit" (whitespace allowed around and between tokens)

  • $length is a positive long integer value

  • $unit is as described below

Unit	Description
h	hours
m	minutes
s	seconds
ms	milliseconds

Practically, units in the ms and s ranges are the most useful.

Examples:

• response-must-await="0ms": don't wait

• response-must-await="200ms": wait up to 200 milliseconds

• response-must-await="5s": wait up to 5 seconds

• response-must-await="forever"`: wait indefinitely

For example, the Form Runner Landing page runs multiple background services to load lists of published forms. The page waits a few hundreds of milliseconds for the completion of those services, and if they take longer, for example due to a slow database, the page is shown to the user, and the services continue to run in the background.

In the future, asynchronous actions will likely be enabled by default.

Resolution of form controls

Many individual actions refer to form controls. When form controls are present in a repeated section or repeated grid, there can be ambiguity as to which control is being referred to.

For this reason, an optional at attribute can be specified. That attribute is a space-separated list of tokens, one for each repetition level.

A token can take the following values:

• start: the first repetition

• end: the last repetition

• a strictly positive integer: the repetition at that specific position

• all: all controls [SINCE Orbeon Forms 2023.1]

When the at attribute is not present, it defaults to being relative to the action source. This usually means targeting the first repetition.

The following example sets the value of the control my-repeated-value in all repetitions of the my-repeated-value repeated grid to 42

<fr:control-setvalue 
    value="'42'" 
    control="my-repeated-value" 
    at="all"/>

Assume now that the control my-repeated-value is within a repeated grid, itself nested within two levels of repeated sections. The following example sets the value of the control my-repeated-value in the third repetition of the last repetition of the first repetition to 42:

<fr:control-setvalue 
    value="'42'" 
    control="my-repeated-value" 
    at="start end 3"/>

Individual actions

Calling a service

<fr:service-call service="...service name...">
    <fr:value value="..." ref="..."/>
</fr:service-call>

<fr:service-call> calls a service by name.

Attribute	Mandatory	Value	Comment
service	Yes	name of the service to call	must be an existing service

Passing a value

<fr:value value="..." ref="..."/>

or:

<fr:value control="..." ref="..."/>

When calling an HTTP service, you can set XML request body values using nested <fr:value> elements.

Attribute	Mandatory	Value	Comment
control	No	control name	either this or value must be specified
value	No	value expression	either this or control must be specified
ref	Yes	destination expression	points to an element or attribute in the request XML

Passing a URL parameter

<fr:url-param name="..." value="..."/>

When calling an HTTP service, you can pass URL parameters using nested <fr:url-param> elements.

Attribute	Mandatory	Value	Comment
control	No	control name	either this or value must be specified
value	No	value expression	either this or control must be specified
name	Yes	parameter name	URL parameter name

Passing a SQL parameter

<fr:sql-param index="..." value="..."/>

When calling a database service, you can pass parameters using nested <fr:sql-param> elements.

Attribute	Mandatory	Value	Comment
control	No	control name	either this or value must be specified
value	No	value expression	either this or control must be specified
index	Yes	positive integer	SQL query parameter index

Removing all repetitions of a repeat

<fr:repeat-clear
    repeat="..."
    at="..."/>

Attribute	Mandatory	Value	Comment
repeat	Yes	repeated grid or repeated section name
at	No	space-delimited position tokens: start, end, or a positive integer	missing leading tokens default to end

This action starts by identifying a single repeated grid or section with the repeat attribute. See <fr:repeat-add-iteration> for details. The only difference is that with this action, at is only used to identify the ancestor repeated sections if any.

With my-repeated-grid nested within my-repeated-section:

• Remove all repetitions of my-repeated-section:

  <fr:repeat-clear repeat="my-repeated-section"/>

• Remove all repetitions of the last my-repeated-grid:

  <fr:repeat-clear repeat="my-repeated-grid" at="end"/>

• Remove all repetitions of the first my-repeated-grid:

  <fr:repeat-clear repeat="my-repeated-grid" at="start"/>

• Remove all repetitions of the second my-repeated-grid:

  <fr:repeat-clear repeat="my-repeated-grid" at="2"/>

Adding repetitions to a repeat

<fr:repeat-add-iteration
    repeat="..."
    at="..."/>

Attribute	Mandatory	Value	Comment
repeat	Yes	repeated grid or repeated section name
at	No	space-delimited position tokens: start, end, or a positive integer	missing leading tokens default to end

This action starts by identifying a single repeated grid or section with the repeat attribute. If the repeated grid or section is at the top-level, there is only one possible match. If the repeated grid or section is nested within one or more repeated sections, then a single repetition of the ancestor repeated sections is determined using the optional at attribute.

With my-repeated-grid nested within my-repeated-section:

• Insert a new repetition at the end of the last my-repeated-grid:

  <fr:repeat-add-iteration repeat="my-repeated-grid" at="end end"/>

  or:

  <fr:repeat-add-iteration repeat="my-repeated-grid" at="end"/>

  or:

  <fr:repeat-add-iteration repeat="my-repeated-grid"/>

• Insert a new repetition at the end of the first my-repeated-grid:

  <fr:repeat-add-iteration repeat="my-repeated-grid" at="start end"/>

• Insert a new repetition at the start of the first my-repeated-grid:

  <fr:repeat-add-iteration repeat="my-repeated-grid" at="start start"/>

• Insert a new repetition after repetition 2 of the third my-repeated-grid:

  <fr:repeat-add-iteration repeat="my-repeated-grid" at="3 2"/>

• Insert a new repetition at the end of my-repeated-section:

  <fr:repeat-add-iteration repeat="my-repeated-section" at="end"/>

  or:

  <fr:repeat-add-iteration repeat="my-repeated-section"/>

Removing repetitions from a repeat

<fr:repeat-remove-iteration
    repeat="..."
    at="..."/>

Attribute	Mandatory	Value	Comment
repeat	Yes	repeated grid or repeated section name
at	No	space-delimited position tokens: start, end, or a positive integer	missing leading tokens default to end

This action starts by identifying a single repeated grid or section with the repeat attribute. See <fr:repeat-add-iteration> for details.

With my-repeated-grid nested within my-repeated-section:

• Remove the last repetition of the last my-repeated-grid:

  <fr:repeat-remove-iteration repeat="my-repeated-grid" at="end end"/>

  or:

  <fr:repeat-remove-iteration repeat="my-repeated-grid" at="end"/>

  or:

  <fr:repeat-remove-iteration repeat="my-repeated-grid"/>

• Remove the last repetition of the first my-repeated-grid:

  <fr:repeat-remove-iteration repeat="my-repeated-grid" at="start end"/>

• Remove repetition 2 of the third my-repeated-grid:

  <fr:repeat-remove-iteration repeat="my-repeated-grid" at="3 2"/>

Setting the value of a control

<fr:control-setvalue/>

<fr:control-setvalue/> sets the value of a form control.

Attribute	Mandatory	Value	Comment
control	Yes	control name
value	Yes	value expression	value to set
at	No	space-delimited position tokens: start, end, or a positive integer	missing leading tokens default to end

<fr:control-setvalue
    control="my-control"
    value="current-date()"/>

Clearing the value of a control

[SINCE Orbeon Forms 2020.1]

<fr:control-clear/>

<fr:control-clear/> clears the value of a control. For attachment controls, this clears the file but also the file metadata (filename, mediatype, and size).

Attribute	Mandatory	Value	Comment
control	Yes	control name
at	No	space-delimited position tokens: start, end, or a positive integer	missing leading tokens default to end

Example:

<fr:control-clear control="my-control"/>

Setting the choices of a selection control

<fr:control-setitems/>

<fr:control-setitems/> sets the choices (or "itemset") of a selection control such as a dropdown or radio buttons.

Attribute	Mandatory	Value	Comment
control	Yes	control name
items	Yes	XPath expression returning one XPath item for each choice
label	Yes	relative XPath expression returning the label for the current choice
hint	No	relative XPath expression returning the hint for the current choice	[SINCE Orbeon Forms 2020.1]
value	Yes	relative XPath expression returning the value for the current choice
at	No	space-delimited position tokens: start, end, or a positive integer	missing leading tokens default to end

NOTE: Hints are only supported for checkboxes and radio buttons as of Orbeon Forms 2020.1.

Writing to a dataset

<fr:dataset-write
    name="..."/>

Attribute	Mandatory	Value	Comment
name	Yes	dataset name

This action takes the latest service result and saves it to the dataset specified by name. Example:

<fr:dataset-write
    name="my-dataset"/>

Clearing a dataset

[SINCE Orbeon Forms 2022.1.2]

<fr:dataset-clear
    name="..."/>

Attribute	Mandatory	Value	Comment
name	Yes	dataset name

This action clears the content of the dataset with the given name. Specifically, it replaces it with a single anonymous root element (<_/>). Example:

<fr:dataset-clear
    name="my-dataset"/>

Calling a process

[SINCE Orbeon Forms 2019.1]

<fr:process-call
    scope="oxf.fr.detail.process"
    name="send"/>

Attribute	Mandatory	Value	Comment
scope	Yes	property scope
name	Yes	process name

Navigating to a page or URL

[SINCE Orbeon Forms 2019.1]

<fr:navigate
    location="https://www.bbc.com/news"/>

Attribute	Mandatory	Value	Comment
location	Yes	path or URL
target	No	_self or _blank or name of the browsing context	where to display the location

Setting the value of an attachment control

[SINCE Orbeon Forms 2019.1]

<fr:control-setattachment
    control="..."/>

Attribute	Mandatory	Value	Comment
control	Yes	control name

When the response of a service is binary, this action allows setting the value of an attachment control to the content of the service response:

<fr:control-setattachment
    control="my-attachment"/>

This supports the following controls:

• <fr:attachment>

• <fr:image-attachment>

The mediatype and received by the service and the actual size of the attachment are automatically set. However, the filename is not set automatically.

See also the following actions:

• <fr:control-setfilename>

• <fr:control-setmediatype>

• <fr:control-setsize>

Setting the filename of an attachment control

[SINCE Orbeon Forms 2019.1]

<fr:control-setfilename
    control="..."
    value="..."/>

Attribute	Mandatory	Value	Comment
control	Yes	control name
value	Yes	value expression	value of the filename to set

This action allows setting the filename of an attachment control. Example:

<fr:control-setfilename
    control="my-attachment"
    value="'My Image.png'"/>

This supports the following controls:

• <fr:attachment>

• <fr:image-attachment>

Setting the mediatype of an attachment control

[SINCE Orbeon Forms 2019.1]

<fr:control-setmediatype
    control="..."
    value="..."/>

Attribute	Mandatory	Value	Comment
control	Yes	control name
value	Yes	value expression	value of the mediatype to set

This action allows setting the mediatype of an attachment control. Example:

<fr:control-setmediatype
    control="my-attachment"
    value="'image/png'"/>

This supports the following controls:

• <fr:attachment>

• <fr:image-attachment>

Note that the <fr:control-setattachment> action automatically sets a mediatype.

Setting the size of an attachment control

[SINCE Orbeon Forms 2023.1]

<fr:control-setsize
    control="..."
    value="..."/>

Attribute	Mandatory	Value	Comment
control	Yes	control name
value	Yes	value expression	value of the size to set

This action allows setting the mediatype of an attachment control. Example:

<fr:control-setsize
    control="my-attachment"
    value="123"/>

This supports the following controls:

• <fr:attachment>

• <fr:image-attachment>

Note that the <fr:control-setattachment> action automatically sets a size.

Setting the focus on a form control

[SINCE Orbeon Forms 2022.1.2]

<fr:control-setfocus
    control="..."/>

Attribute	Mandatory	Value	Comment
control	Yes	control name

This action allows setting the focus on a form control. Example:

<fr:control-setfocus
    control="my-text-field"/>

Marking a form control visited or unvisited

[SINCE Orbeon Forms 2022.1.2]

<fr:control-setvisited
    control="..."
    visited=""/>

Attribute	Mandatory	Value	Comment
control	Yes	control name
visited	No	true or false	defaults to true

This action allows setting whether a form control is visited or not. Example:

<fr:control-setvisited
    control="my-text-field"
    visited="false"/>

In Orbeon Forms, a form control can be visited or not. Visited controls have been visited by the user, which means that the user navigated through the form control, possibly without changing its value. One way to visit form controls is to navigate using the "Tab" key, or to click on the form control and then click outside of it. Another way is to use the default "Save" or "Send" buttons, which by default visit all the form controls before proceeding. The notion is used to determine whether to show validation errors associated with that form control. [SINCE Orbeon Forms 2023.1] Form controls can also be visited when they are calculated, visible, and their value changes.

When working with actions, some form controls can benefit from having their "visited" status reset so that the user doesn't see extra errors appear. The <fr:control-setvisited> action allows doing that.

Alert for debugging

[SINCE Orbeon Forms 2022.1, 2021.1.2, 2020.1.7] The <fr:alert> action is intended to be used for debugging, allowing you to get some visibility on the value of intermediary results, or more generally the value of any expression is at a given point. The value of the message attribute uses the AVT syntax, so the example below would show a dialog with the message "The answer is 42".

<fr:alert message="The answer is {40+2}"/>

Copying control content

[SINCE Orbeon Forms 2023.1]

Description

The <fr:copy-content> action allows you to copy form content:

• from non-repeated form controls to other non-repeated form controls

• from non-repeated form controls to repeated form controls

• from repeated form controls to other repeated form controls

See also Synchronizing repeated content.

Example

Assuming that:

• control-1, control-2, control-3, and control-4 are all within repeated grids or repeated sections

• non-repeated-control is non-repeated, and control-5 is repeated

Then, in the following example, each <fr:map> expresses that all repeated controls denoted by the left attribute (source) are copied to the corresponding repeated controls denoted by the right attribute (destination).

<fr:copy-content warn="true">
    <fr:map left="control-1"            right="control-3"/>
    <fr:map left="control-2"            right="control-4"/>
    <fr:map left="non-repeated-control" right="control-5" right-at="all"/>
</fr:copy-content>

Example form showing copied content

Repeated source and destination

When both the source and destination are repeated, the destination repeat's iterations are enforced, which means:

• Extra iterations in the destination are removed from the end if needed, to match the number of iterations in the source.

• New iterations in the destination are added at the end if needed, to match the number of iterations in the source.

• For each iteration, the values of controls specified with <fr:map> are copied over.

Each <fr:map> element can individually refer to separate repeated grids and sections. In other words, not all left need to be in the same repeated grid or section, and not all right need to be in the same repeated grid or section.

Non-repeated source and destination

When the source is non-repeated and the destination is also non-repeated, the value of the control is simply copied.

Non-repeated source and repeated destination

When the source is non-repeated and the destination is repeated, the value of the control is copied to one or more of the destination controls. The right-at attribute can be used to control this behavior:

• start: first control only

• end: last control only

• strictly positive integer: specific position

• all: all controls

Repeated source and non-repeated destination

This scenario is not supported yet.

Warning the user

When the warn attribute is set to true, the action will show a warning dialog if the action will overwrite existing content in the destination. An overwrite is considered when:

• The destination has more iterations than the source.

• The destination has the same number of iterations as the source or less, but the action would overwrite a non-blank destination value.

The default is false.

Error handling

With Orbeon Forms 2018.2, errors when running services are silently ignored and the action continues.

With Orbeon Forms 2019.1, errors:

1. cause the entire action to stop.

2. run the oxf.fr.detail.process.action-service-error process

The default implementation of the service error process is as follows:

<property as="xs:string"  name="oxf.fr.detail.process.action-service-error.*.*">
    error-message("service-error")
</property>

You can provide your own service error process in properties-local.xml.

Evaluation context of XPath expressions

The context item used for XPath evaluations is set as follows:

• At the beginning of an action, it is the root element of the form data.

• Within an <fr:data-iterate>, and until a service response is available, it is the current iteration item.

• After a service call, whether at the top-level or within an <fr:data-iterate>, it is the root element of the preceding action response.

[SINCE Orbeon Forms 2019.1]

You can explicitly set the XPath evaluation context to the current iteration item within a <fr:data-iterate> with the expression-context attribute set to current-iteration.

In the following example, without the expression-context="current-iteration" attribute, the second <fr:value> would evaluate within the context of the first service call's response.

<fr:data-iterate ref="/*/row">
    <fr:service-call service="my-first-service">
        <fr:value
            value="foo"
            ref="/some/path"/>
    </fr:service-call>
    <fr:service-call service="my-second-service">
        <fr:value
            expression-context="current-iteration"
            value="bar"
            ref="/some/other/path"/>
    </fr:service-call>
</fr:data-iterate>

To be more explicit, the attribute can also be set on the first <fr:value>:

<fr:data-iterate ref="/*/row">
    <fr:service-call service="my-first-service">
        <fr:value
            expression-context="current-iteration"
            value="foo"
            ref="/some/path"/>
    </fr:service-call>
    <fr:service-call service="my-second-service">
        <fr:value
            expression-context="current-iteration"
            value="bar"
            ref="/some/other/path"/>
    </fr:service-call>
</fr:data-iterate>

See also

• Editing the source code of the form definition

• Synchronizing repeated content

• Actions

• HTTP services

• Database services