Actions

Introduction
The Form Builder Actions Editor is an Orbeon Forms PE feature and allows you to implement simple actions in your form. The basic philosophy goes as follows:
React to an event occurring on the form, such as the form being loaded or a user action.
Call an HTTP or database service:
passing in parameters from the form,
receiving parameters back from the service.
Use the returned parameters to update the form
Actions are tightly coupled with services. In the future, support might be added for actions which do not require services.
Basic action configuration
Creating or updating an action
You create a new action or update an existing action in the "Advanced" tab of the toolbox. This opens the Actions Editor.
Reordering actions
[SINCE Orbeon Forms 2018.2]
You can reorder actions by drag and drop in the toolbox. Sometimes, the specific order of actions is important, or you might just want to organize them in a way that makes sense for your form.
List of actions in the toolbox
With Orbeon Forms 2017.1 or newer
[SINCE Orbeon Forms 2017.1]
Actions Editor General Settings
This is the meaning of the fields of the dialog:
Action Name
This is the name of the action, as seen by Form Builder.
Must start with a letter, and may not contain spaces.
Condition
Run always: Run the action independently from the form mode.
Run on creation only: Run the action only in creation mode, that is when the user creates new data, as opposed to editing, viewing, emailing, or generating a PDF.
Run action when
Specifies a phrase built of the following parts:
"the control"
label / name of the control
"changes its value"
or "appears or changes its value"
or "is activated" (a button is activated or the "Enter" key is pressed in a text line)
or "the form loads"
"after the controls are ready"
This is the default.
The action runs when controls are "live", which means you can set their values and list of choices.
"after the data is ready"
The action runs when the data is ready:
It has been loaded from the database if needed.
Its initial values and calculations are up to date.
You cannot set control values and list of choices as a result.
You can store datasets as a result.
"before the data's initial values are calculated"
The action runs before the data is ready.
You cannot set control values and list of choices as a result.
You can store datasets as a result.
Service to Call.
The service to call as once the action is triggered.
Like for services, once your action is defined, the Save buttons saves it to the form. You can come back to it and modify it later by clicking on the Edit icon next to the action name. You can also delete the action using the Remove button.
With Orbeon Forms 2016.3 or earlier
[UNTIL Orbeon Forms 2016.3]
Actions Editor
This is the meaning of the fields of the dialog:
Action Name. This is the name of the action, as seen by Form Builder. Must start with a letter, and may not contain spaces.
React to. The event which starts the action. Can be one of the following:
Value Change. The control's value has changed.
Value Change or Form Load. The control's value has changed OR the control has just become visible.
NOTE: The field description in the user interface does not accurately describe the behavior, which is that the action will run upon the control becoming visible, whether upon form load or at a later time. The action can happen multiple times for the control if the control hides and shows multiple times.  
Activation. The button has been clicked, or the "Enter" key has been pressed in a text line.
Form Load. The form just finished loading.
Condition.
Run always. Run the action independently from the form mode.
Run on creation only. Run the action only in creation mode, that is when the user creates new data, as opposed to editing, viewing, emailing, or generating a PDF.
Control. Except for the Form Load event which does not depend on a particular control, this specifies which control the action reacts to.
Service to Call. The service to call as a response to the action.
Like for services, once your action is defined, the Save buttons saves it to the form. You can come back to it and modify it later by clicking on the Edit icon next to the action name. You can also delete the action using the Remove button.
Handling the service request
Passing parameters to the service's XML request
With HTTP services
Use "Set Service Request Values".
Actions Editor Service Request Actions
Each row instructs the action to take the value of a form control and store it into the body of the XML service request.
Source Control. See the relevant section below.
Destination XPath Expression. The XPath expression, which must point to an element or attribute node of the request body defined in the HTTP service under "XML Request Body".
You can add as many such rows as you want using the "+" button, and remove existing entries with the dropdown menu.
Passing URL parameters to GET and DELETE methods
[SINCE Orbeon Forms 2016.1]
The HTTP Service Editor allows you to define URL parameters when using the GET and DELETE HTTP methods. In this case, the HTTP Service Editor implicitly creates an XML document representing these parameters, for example:
<params>
    <userId>1</userId>
    <userName>test</userName>
</params>
The Actions Editor doesn't yet support specifying URL parameters directly by name in this case. Instead, you use XPath expressions under "Set Service Request Values". For example:
to set the userId parameter: /*/userId
to set the userName parameter: /*/userName
With Database services
Use "Set Database Service Parameters".
Each row instructs the action to take the value of a control and set that value as the Nth query parameter of the database service.
Source Control. See the relevant section below.
Parameter Number. To set the first query parameter, use the value "1" (without the quotes), the second, "2", etc.
You can add as many such rows as you want using the "+" button, and remove existing entries with the dropdown menu.
Source control
Specifies the control whose value must be used. If the control is repeated, because it occurs in a repeated grid or repeated section, then the value of the first "instance" of that control is used and passed to the service.
Handling the service response
User interface
[SINCE Orbeon Forms 2017.1]
You access the response in the Service Response Actions tab. This allows adding, removing, and moving response actions:
Actions Editor Service Response Actions
Setting the value of a control
As a result of running an action, you can set a form control's value from data returned by a service using:
[SINCE Orbeon Forms 2017.1] the "Set Control Value" action
[UNTIL Orbeon Forms 2016.3] the "Set Response Control Values" section 
Parameters:
Destination Control.
Specifies the control whose value must be set.
A single "closest" control will be selected.
If the destination selection control is not within a repeated grid or section, then the single destination control is updated.
Otherwise the control which is the closest by following repeat iterations and repeat indexes is chosen.
Source XPath Expression.
The expression is evaluated in the context of root element of the XML data returned by the service.
The expression can point to an element or attribute node of the response body, but can also be a more complex expression. Its result is converted to a string.
Setting the choices of a selection control
Basics
As a result of running an action, you can set a selection control's set of items (AKA "itemset") using:
[SINCE Orbeon Forms 2017.1] the "Set Control Choices" action
[UNTIL Orbeon Forms 2016.3] the "Set response Selection Control Items" section
Selection controls include dropdown menus, checkboxes, and more.
Destination Selection Control.
Specifies the selection control whose items must be set. Only selection controls appear in this list.
Depending on the relative position of the source of the action and the target selection controls, one or more "closest" controls can be selected (see the detailed explanation of the behavior below).
Choices XPath expression.
The XPath expression must point to a set of element or attribute nodes of the response body returned by the service.
For each node returned, an item is created.
Label XPath expression. The XPath expression must return the text of the label for an item. It is relative to the current item node.
Value XPath expression. The XPath expression must return the text of the value for an item. It is relative to the current item node.
Adjustment of control values
[SINCE Orbeon Forms 4.3]
Each selection control's selected value(s) are updated to be in range following the new itemset:
For single-selection controls: if the item value currently stored in the instance data is not part of the returned set of items, the value is cleared.
For multiple-selection controls: any of the space-separated values currently stored in the instance data that are not part of the returned set of item values are removed.
Behavior starting with Orbeon Forms 2016.1
In the presence of repeated grids or sections, the destination selection control can resolve to zero, one or more concrete controls.
The way this works is that the "closest" controls are searched. This means:
If the destination selection control is not within a repeated grid or section, then the single destination control is updated.
If the source of the action is within the same repeated iteration as the destination selection control, then that single destination control is updated. Occurrences of the selection control on other repeat iterations are not updated.
If the source of the action is at a higher level compared to the destination selection control, then all iterations of the selection control are updated, and subsequent new iterations added will also use the new itemset.
Behavior up to Orbeon Forms 4.10 included
All the previously available items of the selection control(s) identified are replaced with the items specified. In other words, the itemset for the given control is global. This is the case even in the presence of repeated grids or sections.
Internationalization
[SINCE Orbeon Forms 4.7]
Your service should return localized labels for all the languages supported by your form. For instance, if your form is available in English and French, a service you use to populate a dropdown with a list of countries might return:
<response>
    <row>
        <value>us</value>
        <lang>en</lang>
        <label>United States</label>
    </row>
    <row>
        <value>us</value>
        <lang>fr</lang>
        <label>États-Unis</label>
    </row>
    <row>
        <value>ch</value>
        <lang>en</lang>
        <label>Switzerland</label>
    </row>
    <row>
        <value>ch</value>
        <lang>fr</lang>
        <label>Suisse</label>
    </row>
</response>
After the service is called, the items, label, and value XPath expressions you wrote when defining the action are executed once per language supported by the form, and for each execution the $fr-lang variable is set to current language. So in the case of our hypothetical service returning a list of countries, you will define the items as /response/row[lang = $fr-lang], the value simply as value, and label as label.
While in theory this allows you to have the values depend on the language, to avoid unexpected behavior when users switch languages or different users look at the same data using a different language, you should make sure that values are the same for all languages, and only the labels differ between languages.
Storing the response to a dataset
[SINCE Orbeon Forms 2017.1]
As a result of running an action, you can store the entire set of data returned by the service into a dataset:
use the "Save to Dataset" action
enter a dataset name
Each dataset name identifies a unique dataset for the form. Depending on the use case, dataset names can be reused or be unique.
A dataset name must:
start with a letter or _
continue with letters, digits, ., - or _ (if the name has more than one character)
You access data from a dataset using the fr:dataset() function.
For more on datasets, see Datasets.
NOTE: Section templates keep their own local datasets, separate from the main form.
Namespace handling
At this point, you can't declare custom namespace mappings in the Actions Editor. So say you have a response looking like this:
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
    <soap:Body>
        <my:items xmlns:my="http://example.org/my">
            <my:item>
                <my:label>Cat</my:label>
                <my:value>cat</my:value>
            </my:item>
            <my:item>
                <my:label>Dog</my:label>
                <my:value>dog</my:value>
            </my:item>
            <my:item>
                <my:label>Bird</my:label>
                <my:value>bird</my:value>
            </my:item>
        </my:items>
    </soap:Body>
</soap:Envelope>
or, using the default namespace mechanism:
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
    <soap:Body>
        <items xmlns="http://example.org/my">
            <item>
                <label>Cat</label>
                <value>cat</value>
            </item>
            <item>
                <label>Dog</label>
                <value>dog</value>
            </item>
            <item>
                <label>Bird</label>
                <value>bird</value>
            </item>
        </items>
    </soap:Body>
</soap:Envelope>
In both these cases, <my:item> (or <item>) and nested elements are in the http://example.org/my namespace. This means that your XPath expression must match elements in a namespace and that, in theory, you need a custom namespace mapping in form builder. Since this is not supported yet, you can work around the issue by using XPath expressions with wildcards:
Items: /soap:Envelope/soap:Body/*:items/*:item
Label: *:label
Value: *:value
You can even use shorter variations if element names are use consistently, for example:
Items: //*:item
Label: *:label
Value: *:value
These expressions with wildcards ignore namespace information completely, so you have to be careful if your XML document contains elements with the same name but in different namespaces.
See also
​HTTP services​
​Database services​
​Synchronizing repeated content​
Database services
Action syntax
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