Even though AVTs and <xforms:output>
elements may be placed before any XForms
model, they are still considered part of the XForms "view" of the XForms document and refer to data placed in
models.
XForms Reference: Extensions
- 1. Introduction
- 2. Placement of Controls and Models
- 3. XForms 1.1 Support
- 3.1. Media Type for xforms:output
- 3.1.1. Image Types
- 3.1.2. HTML Type
- 3.2. origin Attribute on xforms:insert Action
- 3.3. context Attribute on xforms:insert Action
- 3.4. validate and relevant Attributes on <xforms:submission>
- 3.5. serialization Attribute on <xforms:submission>
- 3.6. Preliminary support for asynchronous handling of <xforms:submission>
- 3.7. Conditional Execution and Iteration of XForms Actions
- 3.8. XForms 1.1 Functions
- 3.1. Media Type for xforms:output
- 4. Extensions
- 4.1. Read-Only Mode
- 4.2. Formatting
- 4.2.1. Rationale
- 4.2.2. xforms:input
- 4.2.3. xforms:output
- 4.2.4. Default Formatting
- 4.3. Iteration of XForms Actions over Sequences
- 4.4. Generalized context attribute
- 4.5. Enhanced event() Function Support
- 4.6. Enhanced <xforms:dispatch> Support
- 4.7. Enhanced Support for xforms-select and xforms-deselect
- 4.8. Targetting effective controls within repeat iterations
- 4.9. Validation Extensions
- 4.9.1. Extension Events
- 4.9.2. Extension Types
- 4.9.3. Controlling the XML Schema Validation Mode
- 4.10. JavaScript Integration
- 4.10.1. Rationale
- 4.10.2. Getting and Setting Controls Value
- 4.10.3. Dispatching Events
- 4.11. Attribute Value Templates
- 4.11.1. AVTs on XForms Elements
- 4.11.2. AVTs on XHTML Elements
- 4.12. Variables
- 4.13. Dialogs
- 4.13.1. The xxforms:dialog Control
- 4.13.2. The xxforms:show and xxforms:hide Actions
- 4.13.3. The xxforms-dialog-open Event
- 4.13.4. The xxforms-dialog-close Event
- 4.14. Submission Extensions
- 4.14.1. HTTP Authentication
- 4.14.2. HTTP Headers Forwarding
- 4.14.3. Loading Indicator
- 4.14.4. Target
- 4.14.5. xxforms:instance Attribute
- 4.14.6. xxforms:xinclude Attribute
- 4.14.7. Submitting Binary Content
- 4.15. Other Extensions
- 4.15.1. <xxforms:script> Action
- 4.15.2. Read-Only XForms Instances with xxforms:readonly
- 4.15.3. Sharing of Read-Only XForms Instances with xxforms:shared
- 4.15.4. Controlling Item Sets Refreshes with xxforms:refresh-items
- 4.15.5. xxforms:internal Appearance on <xforms:group>
- 4.15.6. Trees with the xxforms:tree Appearance
- 4.15.7. Menus with the xxforms:menu Appearance
- 4.15.8. Autocomplete box xxforms:tree Appearance
- 4.15.9. Multiple Event Names, Observers and Targets on Event Handlers
- 4.15.10. Modal Trigger / Submit Behavior
- 5. Configuration
- 5.1. State Handling
- 5.1.1. Rationale
- 5.1.2. Configuring State Handling
- 5.1.3. Session Heartbeat
- 5.2. JavaScript and CSS Resources
- 5.2.1. Minimal Resources
- 5.2.2. Combined Resources
- 5.2.3. Versioned Resources
- 5.2.4. Examples of Apache Configurations
- 5.3. Browser Navigation (Back and Forward) Handling
- 5.4. Encryption
- 5.5. Debugging XForms Pages
- 5.5.1. Enabling XForms Logging
- 5.5.2. The Instance Inspector
- 5.1. State Handling
1. Introduction
This part of the XForms reference documentation focuses on extensions over XForms provided by Orbeon Forms, as well as XForms engine configuration.
Please be sure to visit:
2. Placement of Controls and Models
XForms does not specify normatively where XForms controls and models must be placed within an HTML
document. The convention is to place
<xforms:model>
elements within <xhtml:head>
, and controls within
<xhtml:body>
. Orbeon Forms is more flexible on this:
-
<xforms:model>
can be placed within<xhtml:head>
as is usual, but also under<xhtml:body>
and even nested within other XForms elements. For example:<xxforms:dialog id="my-dialog" model="my-dialog-model"><xforms:label>My Dialog</xforms:label><xforms:group>...</xforms:group><xforms:model id="my-dialog-model"><!-- Model used by the dialog -->...</xforms:model></xxforms:dialog>In this particular case, this allows you to write your dialog as a module in a completely separate file and to XInclude that file within your main form.
At the moment, nested models behave exactly as if they were placed under
<xhtml:head>
. It is just a syntactic convenience to be able to place them within elements such as<xxforms:dialog>
. -
Attribute Value Templates (AVTs) can be placed on HTML elements outside
<xhtml:body>
.<xhtml:body lang="{instance('language')}">...</xhtml:body> -
A single
<xforms:output>
control may be placed within<xhtml:title>
. This allows dynamically changing the HTML document title using XForms.<xhtml:title><xforms:output value="instance('resources')/title"/></xhtml:title>
3. XForms 1.1 Support
3.1. Media Type for xforms:output
In XForms 1.0, xforms:output
is only used to display text. However, XForms 1.1 supports
a mediatype
attribute on that element allowing display of other media types.
3.1.1. Image Types
For the <xforms:output>
control to display an image, you
need to:
-
Have a
mediatype
attribute on the<xforms:output>
. That attribute must refer to an image mediatype, such asimage/*
orimage/jpeg
. -
Use the
value
attribute on<xforms:output>
or bind to the control to a node without type, with anxs:anyURI
type or with anxs:base64Binary
type.
The resulting value from the instance is interpreted either as a URI pointing to an image, or as
a base64-encoded binary representation of the image. The image will display in place of the
xforms:output
. It is possible to dynamically change the image pointed to. For
example:
The image URI may or may no be reachable from the client browser. Orbeon Forms hides this from the developer. For example, to upload and show an image:
In that example, the upload control stores a temporary URI pointing to a local
file:
resource. While this URI is not visible from the client web browser, the
output control automatically proxies it so that the end user can see the image.
3.1.2. HTML Type
When an xforms:output
control has a mediatype
attribute with value text/html
, the value of the node to which
the control is bound is interpreted as HTML content. Consider the following
XForms instance:
You bind an xforms:output
control to the
html-content
node as follows:
This will display the result as HTML, as expected: "This is in bold!". If the
mediatype
is not specified, the result would be instead: "This is in
<b>bold</b>!". In the XForms instance, the HTML content must be escaped as text. On
the other hand, the following content will not work as expected:
mediatype="text/html"
, an HTML
<div>
element will be generated by the XForms engine to hold
the HTML data. As in HTML a <div>
cannot
be embedded into a <p>
, if you have a
<xforms:output mediatype="text/html">
control, you should
not put that control into a <xhtml:p>
.
3.2. origin Attribute on xforms:insert Action
Orbeon Forms supports the XForms 1.1 origin
attribute on the
xforms:insert
action. This attribute allows specifying the source node to use as
template. This allows storing templates separately from the node-set specified by the
nodeset
attribute. For example:
The template copied in this case comes from an XForms instance:
3.3. context Attribute on xforms:insert Action
Orbeon Forms supports the XForms 1.1 context
attribute on the
xforms:insert
action. This attribute allows specifying a context for insertion,
which along with the origin
attribute allows inserting content into elements:
With original instances as follows:
The result of a first insertion is:
3.4. validate and relevant Attributes on <xforms:submission>
Orbeon Forms supports the XForms 1.1 validate
and relevant
attributes
on <xforms:submission>
. These boolean attributes disable processing of validation
and relevance respectively for a given submission:
For more information, please visit the XForms 1.1 specification.
3.5. serialization Attribute on <xforms:submission>
Orbeon Forms supports the XForms 1.1 serialization
on
<xforms:submission>
. This is particularly useful to specify the value
none
with a get
method:
For more information, please visit the XForms 1.1 specification.
3.6. Preliminary support for asynchronous handling of <xforms:submission>
Orbeon Forms partially supports the XForms 1.1 mode="asynchronous"
attribute on
<xforms:submission>
. The limitations are:
-
Asynchronous submissions in an Ajax request are delayed until after everything else in the request has run (including other submissions).
-
Asynchronous submissions are "fire and forget": they only work with
replace="none"
and noxforms-submit-done
/xforms-submit-error
events are dispatched. -
All asynchronous submissions started during a given Ajax request run serially.
For more information, please visit the XForms 1.1 specification.
XForms 1.1 specifies that mode="asynchronous"
should be the default, but due to the
client-server nature of the Orbeon Forms XForms engine, Orbeon Forms still defaults to
mode="synchronous"
.
3.7. Conditional Execution and Iteration of XForms Actions
Orbeon Forms supports the XForms 1.1 if
and while
attributes on XForms
action elements. For more information, please visit the XForms 1.1 specification.
3.8. XForms 1.1 Functions
[TODO: List all XForms 1.1 functions implemented]
4. Extensions
4.1. Read-Only Mode
4.1.1. Making an Entire Instance Read-Only
You often want to present a form without allowing the user to enter data. An easy solution is to use
the readonly
MIP in the model. By making for example the root element of an instance
read-only, all the controls bound to any node of that instance will appear read-only (because the
read-only property is inherited in an instance):
4.1.2. Static Appearance for Read-Only Mode
Sometimes, read-only controls don't appear very nicely in web browsers. For example, a combo box will appear grayed out. It maybe be hard to read, and there is not much point showing a combo box since the user can't interact with it. Furthermore, with some browsers, like IE 6 and earlier, it is not even possible to make disabled controls appear nicer with CSS. In order to make read-only versions of forms look nicer, Orbeon Forms supports a special extention attribute that allows you to produce a "static" appearance for read-only controls. You enable this on your first XForms model:
The attribute takes one of two vales: static
or dynamic
(the default).
When using the value static
, read-only controls do not produce disabled HTML form
controls. This has one major limitation: you can't switch a control back to being read-write once
it is displayed as read-only.
You can also set the xxforms:readonly-appearance
attribute directly on individual
XForms controls.
See the Government Forms sample application's View Read-Only option for an example of this feature in action.
4.2. Formatting
4.2.1. Rationale
It is usually recommended to use native XML types within XForms instances, as this guarantees
interoperability and maintainability. For example, a date of January 10, 2005 is stored in ISO
format as: 2005-10-01
. However it is often necessary to format such values on screen
in a user-readable format, like "January 10, 2005", "10 janvier 2005", or "10. Januar 2005".
Orbeon Forms provides an extension attribute, xxforms:format
, for that purpose.
xxforms:format
must contain an XPath 2.0 expression. In your XPath expression you can
use all the XPath 2.0 functions, including those for date manipulation (external
documentation). However since XPath 2.0 functions don't provide any facility for date and time
formatting, you can in this attribute also use the following XSLT 2.0 functions:
-
format-date()
(external documentation) -
format-dateTime()
(external documentation) -
format-time()
(external documentation) -
format-number()
(external documentation)
The XPath expression is evaluated by the XForms engine whenever the value bound to the
xforms:input
control changes and needs to be updated on screen. It is evaluated in the
context of the instance node bound to the control. This means that the current value of the control
can be accessed with ".
". Often the value must be converted (for example to a date) in
which case the conversion can be done with a XPath 2.0 constructor such as xs:date(.)
or with as cast such as (. cast as xs:date?)
.
4.2.2. xforms:input
When using xforms:input
and a bound xs:date
type, you can control the
formatting of the date using the xxforms:format
extension attribute on the
xforms:input
control. For example:
This only controls the appearance of the date as shown to the user. It does not control the format of the date captured in the XML document, or determines the format into which the user can type the date.
4.2.3. xforms:output
When using xforms:output
, you can control the formatting of the date using the
xxforms:format
extension attribute on the xforms:output
control.
4.2.4. Default Formatting
For both xforms:input
and xforms:output
, if the bound node is of one of
the following types: xs:date
, xs:dateTime
, xs:time
,
xs:decimal
, xs:integer
, xs:float
, and xs:double
,
and if no xxforms:format
attribute is present on the control, formatting is based on
properties. If the properties are missing, a built-in default
formatting is used. The default properties, as well as the built-in defaults, are as follows:
They produce results as follows:
-
2004-01-07
asxs:date
is displayed asWednesday January 7, 2004
-
2004-01-07T04:38:35.123
asxs:dateTime
is displayed asWednesday January 7, 2004 04:38:35 UTC
-
04:38:35.123
asxs:time
is displayed as04:38:35 UTC
-
123456.789
asxs:decimal
is displayed as123,456.79
-
123456.789
asxs:integer
is displayed as123,456
-
123456.789
asxs:float
orxs:double
is displayed as123,456.789
Note:
- With the "if" condition in the XPath expressions, a value which cannot be converted to the appropriate type is simply displayed as is.
- For values of type xs:time or xs:dateTime, if you wish the time to be displayed using the current timezone instead of UTC, replace in the value attribute UTC by [ZN].
4.3. Iteration of XForms Actions over Sequences
Orbeon Forms supports the exforms:iterate
attribute, also available as
xxforms:iterate
attribute, on XForms action elements. Consider the following
instances:
The following action iterates over the <title>
elements of
source-instance
. For each of those, a new <book>
element, copied from
the template stored in template-instance
, is inserted into main-instance
.
Then values from the <title>
and <author>
elements are copied over
to the new structure. The XForms 1.1 context()
function provides access to each of the
iterated nodes:
The resulting main-instance
is as follows:
Note that because Orbeon Forms uses XPath 2.0, xxforms:iterate
is not limited to
returning node-sets, but can return sequences of items such as strings.
For more information about eXforms extensions, please visit the eXforms site.
4.4. Generalized context attribute
XForms 1.1 introduces the context
attribute on <xforms:insert>
and
<xforms:delete>
. Orbeon Forms supports this convenient attribute on all XForms
elements changing the XPath evaluation context, including controls, actions, binds, and
submissions.
The context
attribute overrides the in-scope XPath evaluation context for an action. It
applies before the ref
and context
attributes, but after the
model
attribute.
One convenient use is to just change the context within a group:
Note that it is also possible to use ref
in this case, but doing so has the side effect
of binding the group to an instance data node, which may affect group relevance, for example.
4.5. Enhanced event() Function Support
Orbeon Forms enhances the XML Events event()
function to take a qualified name as
parameter:
This allows namespacing attribute names, therefore better allowing for extension attributes.
The following standard event attributes are implemented:
[TODO: describe standard Orbeon Forms support for event() function]
On all events, the following extension attributes are supported:
-
event('xxforms:type') as xs:string
Return the event type (also known as event name), for example
"DOMActivate"
. -
event('xxforms:target') as xs:string
Return the id of the event target.
-
event('xxforms:bubbles') as xs:boolean
Return whether the event is allowed to bubble or not.
-
event('xxforms:cancelable') as xs:boolean
Return whether the event is cancelable or not.
On all UI events (DOMActivate
, DOMFocusIn
, DOMFocusOut
,
xforms-select
, xforms-deselect
, xforms-enabled
,
xforms-disabled
, xforms-help
, xforms-hint
,
xforms-valid
, xforms-invalid
, xforms-required
,
xforms-optional
, xforms-readonly
, xforms-readwrite
,
xforms-value-change
), the following extension attributes are supported:
-
event('xxforms:binding') as node()?
Return the event target's single-node binding if any.
-
event('xxforms:label') as xs:string?
Return the event target's label value if any.
-
event('xxforms:hint') as xs:string?
Return the event target's hint value if any.
-
event('xxforms:help') as xs:string?
Return the event target's help value if any.
-
event('xxforms:alert') as xs:string?
Return the event target's alert value if any.
-
event('xxforms:repeat-indexes') as xs:string*
Return the event target's current repeat indexes, if any, starting from the ancestor repeat.
On xforms-select
, the following extension attributes are supported:
-
event('xxforms:item-value')
When this event is dispatched to in response to a selection control item being selected, returns the value of the selected item.
On xforms-submit-serialize
, the following extension attributes are supported:
-
event('xxforms:binding') as node()?
Return the submission's single-node binding if any.
-
event('xxforms:serialization') as xs:string
Return the submission's requested serialization, e.g.
application/xml
,application/x-www-form-urlencoded
, etc..
4.6. Enhanced <xforms:dispatch> Support
Orbeon Forms supports passing event context attributes with the <xxforms:context>
child element. The actions supported are actions which directly cause an event to be dispatched:
-
<xforms:dispatch>
-
<xforms:send>
-
<xxforms:show>
-
<xxforms:hide>
Here is how you pass context attributes when executing an action:
<xxforms:context>
supports the following two attributes:
name |
Mandatory | Name of the context attribute. In order to avoid confusion with standard XForms names, we recommend you use qualified names. |
---|---|---|
select |
Mandatory | XPath 2.0 expression determining the value of the context attribute. |
Context attribute passed this way can be retrieved using the event()
function:
At the moment, with, <xforms:dispatch>
, only custom events support passing
context attributes this way. Built-in events, such as xforms-value-changed
, or
DOMActivate
, ignore nested <xxforms:context>
elements.
4.7. Enhanced Support for xforms-select and xforms-deselect
[TODO: describe support for these events on xforms:upload]
4.8. Targetting effective controls within repeat iterations
The following actions all support attributes resolving to a particular control:
-
<xforms:dispatch>
(target
attribute) -
<xforms:setfocus>
(control
attribute) -
<xforms:toggle>
(case
attribute) -
<xxforms:show>
(neighbor
attribute)
When that control is within a repeat iteration, the actual control targetted is chosen based on the
current set of repeat indexes. However, in some cases, it is useful to be able to target the control
within a particular iteration. This is achieved with the xxforms:repeat-indexes
extension attribute on these actions. This attribute takes a space-separated list of repeat
indexes, starting with the outermost repeat. Example:
4.9. Validation Extensions
4.9.1. Extension Events
Orbeon Forms supports extensions events dispatched to an instance when it becomes valid or
invalid: xxforms-valid
and xxforms-invalid
. These events are
dispatched just before xforms-revalidate
completes, to all instances of the model
being revalidated. For a given instance, either xxforms-valid
or
xxforms-invalid
is dispatched for a given revalidation.
These events can be used, for example, to toggle the appearance of icons indicating that a form is valid or invalid:
4.9.2. Extension Types
Orbeon Forms supports the built-in xxforms:xml
extension type. This types checks
that the value is well-formed XML:
Note that this checks the string value of the node, which means that the node must contain escaped XML.
Orbeon Forms supports the built-in xxforms:xpath2
extension type. This types
checks that the value is well-formed XPath 2.0. Any variable used by the expression is assumed
to be in scope:
In both these cases, Orbeon Forms checks for the required
MIP: if it evaluates
to false()
and the value is the empty string, then the instance data node is
considered valid. This is contrary to XForms 1.1 as of August 2008.
4.9.3. Controlling the XML Schema Validation Mode
When an XML Schema is provided, Orbeon Forms supports controlling whether a particular instance is validated in "lax" mode, "strict" mode, or not validated at all.
Orbeon Forms implements a "lax" validation mode by default, where only elements that have definitions in the imported schemas are validated. Other elements are not considered for validation. This is in line with XML Schema and XSLT 2.0 lax validation modes, and with the default validation mode as specified in XForms 1.1
In addition, the author can specify the validation mode directly on each instance with the
extension xxforms:validation
attribute, which takes values lax
(the default), strict
(the root element has to have a definition in the schema
and must be valid), or skip
(no validation at all for that instance).
Nodes validated through a schema receive datatype annotations, which means that if an element
or attribute is validated against xs:date
in a schema, an XForms control bound to
that node will display a date picker.
4.10. JavaScript Integration
4.10.1. Rationale
While XForms gets you a long way towards creating a dynamic user-friendly user interface, there are some dynamic behaviors of the user interface that cannot be implemented easily or at all with XForms, or you might already have some JavaScript code that you would like to reused. A JavaScript API is provided to handle those cases, or other use cases involving JavaScript that you might have.
4.10.2. Getting and Setting Controls Value
In JavaScript, you get the current value of an XForms control var value =
ORBEON.xforms.Document.getValue("myControl")
where myControl
is the id of
the XForms control, for instance: <xforms:input id="myControl">
.
You set the value of an XForms control with ORBEON.xforms.Document.setValue("myControl",
"42")
where myControl
is the id of the XForms control, and 42
the new value. Setting the value with JavaScript is equivalent to changing the value of the
control in the browser. This will trigger the recalculation of the instances, and the dispatch
of the xforms-value-changed
event. More formally, the Value Change sequence of
events occurs.
As an example, consider you have the model below. It declares an instance with two elements
foo
and bar
, where bar
is a copy of foo
,
implemented with a calculate
MIP.
The input control below is bound to foo
, and the output control is bound to
bar
. When activated, the trigger executes JavaScript with the
<xxforms:script>
action. It increments the value of the input control bound to
foo
. When this happens the value displayed by the output control bound to
bar
is incremented as well, as bar
is a copy of foo
.
4.10.3. Dispatching Events
You can dispatch your own events from JavaScript by calling the function
ORBEON.xforms.Document.dispatchEvent()
. The parameters to this function are:
targetId | Mandatory |
Id of the target element. The element must be an element in the XForms namespace: you
cannot dispatch events to HTML elements. In addition, the id must identify either a
relevant and non-readonly XForms control, or a model object that supports event handlers
such as <xforms:model> , <xforms:instance> , or
<xforms:submission> .
|
---|---|---|
eventName | Mandatory |
Name of the event. Warning
For security reasons, by default Orbeon Forms prohibits client-side JavaScript
from dispatching any external events except <xforms:model xxforms:external-events="acme-super-event acme-famous-event">...</xforms:model>
This attribute contains a space-separated list of event name. In this example,
you explicitly enable your JavaScript code to fire the two events
Since the event handlers for custom events can be called by JavaScript code that runs on the client, you need to be aware that these handlers can potentially be activated by anybody able to load the form in his browser. |
form | Optional |
The form object that corresponds to the XForms form you want to dispatch the event to.
This argument is only needed when you have multiple "XForms forms" on the same HTML
page. Typically, this would only happens if you are running your form in a portal and
you have multiple portlets using XForms on the same page. When the parameter is not
present or null , the first form on the HTML page with the class
xforms-form is used.
|
bubbles | Optional | Optional boolean indicating if this event bubbles, as defined in DOM2 Events. The default value depends on the definition of the custom event. |
cancelable | Optional | Optional boolean indicating if this event bubbles, as defined in DOM2 Events. The default value depends on the definition of the custom event. |
incremental | Optional |
When false the event is sent to the XForms server right away. When
true the event is sent after a small delay, giving the opportinuty for other
events that would occur during that timespan to be aggregated with the current event.
|
ignoreErrors | Optional |
When set to true , errors happening while the event is dispatched to the
server are ignored. This is in particular useful when you are using a JavaScript timer
(e.g. window.setInterval() ) that runs a JavaScript function on a regular
interval to dispatch an event to the server, maybe to have part of the UI updated. In
some cases, you might not want to alert the user when a there is a maybe temporary
communication error while the event is being dispatched to the server. In those cases,
you call call dispatchEvent with ignoreErrors set to true.
|
In most cases, you only need to call dispatchEvent()
with a target id and event name,
as in:
ORBEON.xforms.Document.dispatchEvent("main-model", "do-something");
An event handler for the custom event can be in an XForms model or control, and can execute any
valid XForms action. Here an action is explicatly declared to handle the
do-something
even on the XForms model:
4.11. Attribute Value Templates
Certain attributes in XForms are literal values defined by the form author at the time the form is
written, as opposed to being evaluated at runtime. Examples include the action
attribute on <xforms:submission>
, or the resource
attribute on
<xforms:load>
.
To improve this, Orbeon Form supports a notation called Attribute Value Templates (AVTs),
borrowed from XSLT, which allows including XPath
expressions within attributes. You include XPath expressions in attributes by enclosing them within
curly brackets ({
and }
).
4.11.1. AVTs on XForms Elements
Consider this example:
When <xforms:load>
is executed, the resource
attribute is
evaluated. The results is the concatenation of /forms/detail/
and of the result of
the expression within brackets:
If the id
element pointed to contains the string
C728595E0E43A8BF50D8DED9F196A582
, the resource
attribute takes the
value:
Note the following:
-
If you need curly brackets as literal values instead of enclosing an XPath expression, escape them using double brackets (
{{
and}}
). -
You can use as many XPath expressions as you want within a single attributes, each of them enclosed by curly brackets.
AVTs are currently supported only within certain attributes:
-
<xforms:submission>
attributes:-
method
-
action
andresource
-
serialization
-
mediatype
-
version
-
encoding
-
separator
-
indent
-
omit-xml-declaration
-
standalone
-
validate
-
relevant
-
mode
-
xxforms:target
-
xxforms:username
-
xxforms:password
-
xxforms:readonly
-
xxforms:shared
-
xxforms:xinclude
-
-
<xforms:dispatch>
attributes:-
name
-
target
-
bubbles
-
cancelable
-
-
<xforms:load>
attributes:-
resource
-
replace
-
xxforms:target
-
xxforms:show-progress
-
f:url-type
-
-
<xforms:setfocus>
:control
attribute. -
<xforms:toggle>
:case
attribute. -
<xxforms:show>
attributes:-
dialog
-
neighbor
-
constrain
-
-
<xxforms:hide>
:dialog
attribute.
There are plans to support AVTs in more places in the future. Please send your suggestions!
4.11.2. AVTs on XHTML Elements
AVTs are also supported on XHTML elements. You must first enable this feature in
properties.xml
:
For example:
In the above example, the value of the class
attribute on
<xhtml:tr>
is determined dynamically through XPath and XForms. Even table rows
get the class zebra-row-even
and odd table rows get the class
zebra-row-odd
.
The values of XHTML attributes built using AVTs update as you interact with the XForms page. In
the example above, inserting or deleting table rows after the page is loaded will still
correctly update the class
attribute.
It is also possible to use AVTs outside <xhtml:body>
, for example:
AVTs are also usable on HTML elements within <xforms:label>
,
<xforms:hint>
, <xforms:help>
, <xforms:alert>
:
It is not possible to use AVTs within the id
attribute of XHTML elements.
4.12. Variables
Orbeon Forms supports declaring variables which look and behave very much like XSLT variables.
Variables are extremely useful, for example to avoid repeating long XPath expressions, or to give an
XPath expression unambiguous access to data computed in enclosing <xforms:group>
or
<xforms:repeat>
elements.
You define variables with the extension element <xxforms:variable>
. You can also use
<exforms:variable>
in the eXforms namespace. Either element supports the
following attributes:
name |
Mandatory | Name of the variable. |
---|---|---|
select |
Mandatory | XPath 2.0 expression determining the value of the variable. |
Once a variable is declared, you can use it from XPath expressions for which the variable is visible:
Under the <xhtml:body>
element, the following rules apply:
-
You can declare XPath variables anywhere an XForms control can be declared, as well as within
<xforms:action>
. -
A variable is visible to any XPath expression on a following sibling element or on a following sibling element's descendant element.
In addition, variables are supported within <xforms:model>
, as well as within
<xforms:action>
in a model. Under the <xforms:model>
element, the
following rules apply:
-
Variables have to be declared as direct children of an
<xforms:model>
element. -
Variables defined within a given model are also visible from XPath expression under the
<xhtml:body>
element whenever that model is in scope:
Currently you cannot declare variables in these locations:
-
Within XForms core controls such as
<xforms:input>
, including within nested items or itemsets (except within<xforms:action>
elements, where they are allowed). -
Within nested model elements, including
<xforms:bind>
or<xforms:submission>
(except within<xforms:action>
elements, where they are allowed).
4.13. Dialogs
4.13.1. The xxforms:dialog Control
You declare dialogs directly under the <xhtml:body>
element with:
-
When you have
appearance="full"
on the dialog, you define the title of the dialog with the embedded<xforms:label>
element. -
Inside an
<xxforms:dialog>
you can use all the XHTML and XForms elements you can normally use elsewhere on the page. You can have other XForms controls, or show anything you would like to with HTML. -
The attributes on the
<xxforms:dialog>
are as follows:
id |
Mandatory |
The ID of the dialog. You reference this ID when opening the dialog with
<xxforms:show dialog="my-dialog-id"> .
|
---|---|---|
appearance |
Optional. Possible values are:
|
You can set the appearance to either full or minimal :
|
level |
Optional. Can only be used appearance is set to full . Possible values are:
|
When set to modal the rest the page is grayed out and you can't interact
with any ontrol on the page outside of the dialog. When set to modeless you
can still use other controls on the page.
|
close |
Optional. Can only be used appearance is set to full . Possible values are:
|
A "x" is shown in the dialog title bar when close is set to
true . If you specify close="false" , then you should provide a
way to close the dialog, for instance by having you own "Close" button inside the
dialog. This is typically useful when you want to force users to enter some data before
proceeding and you don't want them to cancel the current operation by closing the
dialog.
|
draggable |
Optional. Can only be used appearance is set to full . Possible values are:
|
When set to false , you won't be able to move dialog on the page by using
drag and drop in the dialog title bar.
|
visible |
Optional. Whether the dialog is initially visible when the page loads. Possible values
are:
|
When set to true , the dialog appears immediately when the page loads.
|
neighbor |
Optional |
Optional. Use only with minimal appearance. The id of the control next to
which the dialog should display when opening.
|
4.13.2. The xxforms:show and xxforms:hide Actions
You open a dialog by using the xxforms:show
action:
If the dialog is already open, no action takes place.
xxforms:show
supports the following attributes:
dialog |
Mandatory | The id of an existing dialog to open. |
---|---|---|
neighbor |
Optional |
Optional. Use only with minimal appearance. The id of the control next to
which the dialog should display when opening.
|
constrain |
Optional |
Whether to constrain the dialog to the viewport. Possible values
are:
|
You close a dialog by using the xxforms:hide
action:
If the dialog is already closed, no action takes place.
xxforms:hide
supports the following attributes:
dialog |
Mandatory | The id of an existing dialog to close. |
---|
4.13.3. The xxforms-dialog-open Event
Dispatched in response to: xxforms:show
action executed with an existing dialog id.
Target: dialog
Bubbles: Yes
Cancelable: Yes
Context Info: none
Default Action: Open the dialog.
You can respond to this event before the dialog opens, for example to perform initialization of data:
4.13.4. The xxforms-dialog-close Event
Dispatched in response to: xxforms:hide
action executed with an existing dialog id.
Target: dialog
Bubbles: Yes
Cancelable: Yes
Context Info: none
Default Action: Close the dialog.
4.14. Submission Extensions
4.14.1. HTTP Authentication
The <xforms:submission>
element supports optional xxforms:username
and
xxforms:password
attributes that allow specifying HTTP authentication credentials.
You can specify either both attributes, or only the xxforms:username
attribute. The
latter case is equivalent to setting the value of xxforms:password
to an empty
string.
4.14.2. HTTP Headers Forwarding
The <xforms:submission>
automatically forwards current HTTP headers specified by the
oxf.xforms.forward-submission-headers
property. This property contains a
space-separated list of header names to forward:
It can also be set on a per-page basis on your first model element:
Whenever <xforms:submission>
performs an HTTP request, it looks at this list of
header names and it forwards the header value if the following conditions are met:
- There is an incoming header with that name, i.e. either the HTTP request causing the XForms page to load or the XForms Ajax request to run contains that header.
-
There is no author-specifed header with the same name in an
<xforms:header>
element within<xforms:submission>
.
Forwarding the Authorization
or other authentication-related headers can be useful
to propagate authentication credentials to other services.
The Authorization
is treated specially: if a username is specified on the
submission with xxforms:username
, then this header is never forward.
Forwarding authentication-related headers may cause a security risks when communicated with non-trusted servers. Use carefully!
4.14.3. Loading Indicator
When an <xforms:submission>
with replace="all"
is executed, in general,
the browser will load another page. While this happens, the loading indicator, by default shown
in red at the top right of the window, is displayed. However, when the browser is served not a
web page but say a ZIP file, the browser might ask you in you want to download it, and then stay
in the current page. When this happens, the loading indicator does not go away.
In those cases where you know that the target page does not replace the current page, you can
prevent the loading indicator from being displayed by adding the
xxforms:show-progress="false"
attribute:
Similarly the xxforms:show-progress="false"
attribute can be used with the
xforms:load
action:
4.14.4. Target
You can use the xxforms:target
attribute on both <xforms:submission>
and
xforms:load
. It behaves just like the HTML target attribute.
When used on <xforms:submission>
, it makes sense to use this attribute only when you
have a replace="all"
, as the replace="instance"
doesn't load another
page.
4.14.5. xxforms:instance Attribute
On an <xforms:submission>
element with replace="instance"
, the
optional instance
attribute specifies a destination instance for the result. That
attribute is processed like the instance()
function, which means that the instance
specified must be in the current model.
The xxforms:instance
extension attribute can be use instead of the standard
instance
attribute. It works like instance
, except that the instance
is searched globally among all models. xxforms:instance
is to the
instance
attribute what the xxforms:instance()
function is to the standard
instance()
function.
4.14.6. xxforms:xinclude Attribute
On an <xforms:submission>
element with replace="instance"
, the
optional xxforms:xinclude
attribute specifies whether XInclude processing should be
performed on the XML document returned, before storing it into the destination instance. The
default is false
.
4.14.7. Submitting Binary Content
XForms 1.1 does not explicitly support submitting binary content, but does not prohibit it
either. Orbeon Forms supports sending the content of a binary resource specified by a URI. Such
resources are easily obtained with <xforms:upload>
, for example. To perform a
binary submission:
-
The
post
orput
method is required. -
You must use a binary
serialization
attribute. This includes all mediatypes which are not XML or text, includingapplication/octet-stream
,image/*
, etc. -
The node referred to by the submission must be of type
xs:anyURI
.
Alternatively, you can set the type information using the xsi:type
attribute:
4.15. Other Extensions
4.15.1. <xxforms:script> Action
The <xxforms:script>
action allows you to call client-side JavaScript as a
result of XForms events:
Scripts run with <xxforms:script>
have access to the following JavaScript
variables:
-
this. The element observing the event causing
<xxforms:script>
to run. -
event. Object containing a "target" propeterty.
event.target
returns the element which is the target of the event causing<xxforms:script>
to run.
<xxforms:script>
actions are currently always executed last in a
sequence of XForms actions, even if they appear before other XForms actions.
4.15.2. Read-Only XForms Instances with xxforms:readonly
Orbeon Forms supports an extension attribute, xxforms:readonly
, on the
<xforms:instance>
and <xforms:submission>
elements. When set to
true
, this attribute signals that once loaded, the instance is read-only, with the
following consequences:
-
The instance is loaded into a smaller, more efficient, read-only data structure in memory.
-
Instance values cannot be updated, and no Model Item Properties (MIPs) can be assigned with
<xforms:bind>
to the instance. But a read-only instance can be replaced entirely by an<xforms:submission replace="instance">
-
When using client-side state handling, less data may be transmitted between server and client.
Read-only instances are particularly appropriate for loading internationalization resources, which can be large but don't change. Example:
The xxforms:readonly
attribute on <xforms:instance>
determines if
the instance is read-only until that instance is being replaced. After an instance is replaced,
it can be read-only or not irrelevant of the of xxforms:readonly
on
<xforms:instance>
. When the instance is replaced, the replaced instance is
read-only if and only if the <xforms:submission>
that does the replacement has a
attribute xxforms:readonly="true"
.
4.15.3. Sharing of Read-Only XForms Instances with xxforms:shared
Orbeon Forms supports an extension attribute, xxforms:shared
, on the
<xforms:instance>
and <xforms:submission>
elements. This
attribute can be used only when an XForms instance is marked as read-only with
xxforms:readonly="true"
. xxforms:shared
can take two values:
document
(the default if the attribute is not specified) and
application
. When application
is specified:
-
The instance can be shared at the application level identified just by its source URL.
-
The instance is not stored into the XForms document's state, but in a global cache, therefore potentially saving memory. If, upon loading an XForms document, the instance is found in the cache, it is directly retrieved from the cache. This can save time especially if the URL can take significant time to load.
-
The URL must refer to a constant XML document and authorization credentials such as username and password should not cause different data to be loaded.
Here is how you use the attribute on <xforms:instance>
:
When used on <xforms:submission>
, the submission has to use
method="get"
method and replace="instance"
:
You set the size of the shared instances cache using a property in properties.xml
:
You can force the XForms engine to remove a shared instance from the cache by dispatching the
xxforms-instance-invalidate
event to it. The next time an XForms document requires
this instance, it will not be found in the cache and therefore reloaded. Example:
It is also possible to remove all shared instances from the cache by using the
xxforms:invalidate-instances
action, for example:
When using xxforms:readonly="true"
, another attribute, xxforms:ttl
,
can be used to set a time to live for the instance in cache. This duration is expressed
in milliseconds and has to be greater than zero. When a shared instance if found in cache but
has an associated time to live, if it was put in the cache more than time to live milliseconds
in the past, then the instance is discarded from the cache and retrieved again by URI as if it
had not been found in cache at all. The following example expires the shared instance after one
hour:
xxforms:shared="application"
, be sure that the data contained in the
instance does not contain information that could be inadvertently shared with other XForms
documents. It is recommended to use it to load localized resources or similar types of data.
4.15.4. Controlling Item Sets Refreshes with xxforms:refresh-items
XForms specifies that items and itemsets are re-evaluated when processing
xforms-refresh
. This may happen quite often, and may lead to time-consuming
re-evaluations especially when there are many or large itemsets.
Orbeon Forms supports an extension attribute, xxforms:refresh-items
, on the
<xforms:select>
and <xforms:select1>
elements. When set to
true
(the default), items and itemsets are re-computed upon
xforms-refresh
event processing. When set to false
, this attribute
signals that once computed, the set of items for the control will not be recomputed upon
xforms-refresh
event processing.
If you know that itemsets do not change over time, setting xxforms:refresh-items
to
false
disables refreshing of the items during xforms-refresh
and may
yield significant performance improvements. For example:
4.15.5. xxforms:internal Appearance on <xforms:group>
<xforms:group>
supports the xxforms:internal
appearance, which
causes the group to have no representation at all on the client:
In general you won't have a need for this appearance, but it is useful as an optimization, as it leads to less HTML sent to the client. You may use it when a group is used only to change the in-scope evaluation context for nested controls and when you don't need changes to relevance which apply directly to the group to be reflected in the client.
4.15.6. Trees with the xxforms:tree Appearance
[TODO: describe the Orbeon Forms xxforms:tree
appearance on
xforms:select
and xforms:select1
]
4.15.7. Menus with the xxforms:menu Appearance
[TODO: describe the Orbeon Forms xxforms:tree
appearance on
xforms:select1
]
4.15.8. Autocomplete box xxforms:tree Appearance
[TODO: describe the Orbeon Forms xxforms:autocomplete
appearance on
xforms:select
and xforms:select1
]
4.15.9. Multiple Event Names, Observers and Targets on Event Handlers
The ev:event
, ev:observer
and ev:target
attributes,
defined by the XML Events specification, only
support one event name, observer, or target respectively. Orbeon Forms supports as an extension
a list of space-separated values. The behavior is as follows:
-
For
ev:event
: the handler is called if any of the specified events matches.<xforms:action ev:event="DOMFocusIn DOMFocusOut"><!-- Reacting to either the "DOMFocusIn" and "DOMFocusOut" events -->...</xforms:action> -
For
ev:observer
: the event handler is attached to all the observers specified.<xforms:action ev:event="DOMActivate" ev:observer="my-input my-trigger"><!-- Observing both the "my-input" and "my-trigger" controls -->...</xforms:action> -
For
ev:target
: the handler is called if any of the specified targets matches.<xforms:action ev:event="xforms-submit-done" ev:target="create-submission update-submission"><!-- Checking that either the "create-submission" and "update-submission" controls is a target -->...</xforms:action>
This feature has been requested for inclusion in XML Events 2.
4.15.10. Modal Trigger / Submit Behavior
Usually, activating a trigger or submit button on the client doesn't prevent further actions in the user interface. Sometimes however it is useful to block such actions until further processing is complete, for example calling a submission that saves a document.
You can obtain this behavior by using the xxforms:modal="true"
attribute on
<xforms:trigger>
and <xforms:submit>
:
With this attribute set to true
, user input is blocked until all the events
triggered by DOMActivate
are processed. In the meanwhile, the page is grayed out
and an icon appears indicating that background processing is taking place.
5. Configuration
5.1. State Handling
5.1.1. Rationale
The Orbeon Forms XForms engine requires keeping processing state while operating on an XForms page. Such state includes the current values of XForms instances, selected repeated elements, and more. With Orbeon Forms, XForms state information can be handled in one of two ways:
-
Server-side: in this case, state information is stored on the server. Only very little state information circulates between client and server. The most frequently used state information is stored in memory. Less frequently used state information is stored on disk in a local database.
Benefits of the approach:
-
Resulting HTML page are smaller. HTML pages increase in size as more XForms controls are used, but they don't increase in size proportionally to the size of XForms instances.
-
Small amounts of data circulate between the client browser and the Orbeon Forms XForms server.
-
This means that very large XForms instances can be processed without any impact on the amount of data that is transmitted between the client and the server.
Drawbacks of the approach:
-
The Orbeon Forms XForms server needs to be stateful. It uses server memory to store state information even when no request is being processed. This creates additional demand for resources on the server and slightly complicates the task of tuning the server.
-
State information can become unavailable when sessions expire or when the server is restarted. When state information becomes unavailable for a page, that page will no longer function unless it is reloaded.
NoteOrbeon Forms ensures that it is possible to open multiple client browser windows showing the same page within the same session. -
-
Client-side: in this case, static initial state information is sent along with the initial HTML page, and dynamic state is exchanged over the wire between the client browser and the Orbeon Forms XForms server when necessary.
Benefits of the approach:
-
The Orbeon Forms server is entirely stateless. It only requires memory while processing a client request. It can be restarted without consequence for the XForms engine.
-
State information does not expire as long as the user keeps the application page open in the web browser.
Drawbacks of the approach:
-
Resulting HTML pages are larger. In particular, the size of state data grows when XForms instances grow, regardless of whether many XForms controls are bound to instance data.
-
More data circulates between the client browser and the Orbeon Forms XForms server.
NoteOrbeon Forms compresses and encrypts XForms state information sent to the client. -
By default, Orbeon forms store XForms state information on the server. Please change this default to client-side only if you have well understood the tradeoffs explained above.
5.1.2. Configuring State Handling
State handling can be configured globally for all pages, or locally for each individual page
served. Global configuration is performed in properties.xml
with the
oxf.xforms.state-handling
property. When missing or set to client
,
state is stored client-side. When set to server
, state is stored server-side. For
example:
The global configuration can be overridden for each page by setting the
xxforms:state-handling
attribute in the page. This attribute can be set on the
root element of the XHTML page, or on the first xforms:model
element. Only the
first such attribute encountered by the XForms engine is used:
When storing state on the server, the maximum size of the data to be stored globally in memory
can be selected using the oxf.xforms.store.application.size
property. The size is
specified in bytes:
When the allowed memory space for state information is full, Orbeon passivates state information to a local eXist database. Configuration parameters for the connection to the eXist database can be changed. The defaults are as follows:
Whether state information is kept client-side or server-side, a property controls whether the XForms
engine should try to optimize state reconstruction by using a cache. This property should usually
be set to true
:
If the above property is set to true
, the number of XForms documents that can be
held in that document cache at a given time is configured with the following property:
Note that this represents XForms documents in a particular state of interaction with a user, which means that if to users load the same XForms page two entries will be needed in the cache.
5.1.3. Session Heartbeat
If you happen to leave a browser window open on your computer, chances are that you will get back to that window and keep using the application. The last thing you want to happen when you come back is lose your session and therefore your data.
This is not always a correct guess of course: you may just happen to leave a window or tab open without planning to use it again. Conversely you may have a page which is not actually visible, for example in your browser history, yet you will come back to it. This approach wouldn???t be good for banking applications either. Still, in many situations, such as filling-out large forms, it sounds like a good idea to keep your session alive for open pages.
To achieve this goal you could make all server sessions longer. However this is harder to configure for the application developer, and this won???t discriminate between pages that are actually open on a client and the ones that are not. And while it may be ideal to have infinitely long sessions, unfortunately many applications are not ready for this kind of approach.
So Orbeon Forms supports a "session heartbeat" feature. Here is how this works:
-
When this feature is enabled (the default), an open XForms page in a client browser regularly pings the server through Ajax to keep the current server session alive.
-
The ping delay is automatically computed based on the server???s session timeout. The client pings the server at 80% of the session expiration time after the last interaction with the server.
-
We are careful not to hit the XForms engine too much, in fact we do a very limited amount of work on the server for each ping, so they should run fast.
-
XForms state information for pages hit with the heartbeat just migrates to the disk store over time if RAM is used by other pages, so keeping even large numbers of pages open should not have any negative impact on server RAM.
-
When a user gets back to using the page, state information migrates back from disk to RAM, and the page will be live again.
-
Sessions do eventually expire as nobody keeps a browser open forever.
Note that whenever an application keeps sessions alive for a long time, it is a good idea to keep as little data as possible in the session. The Orbeon Forms XForms engine itself uses a global state store and does not use session objects for storage, but do remember to keep your sessions small!
The session heartbeat should help prevent many occurrences of "session expired" error messages.
As an Orbeon Forms application developer you don???t have to worry about anything: the session
heartbeat is enabled by default. You can configure it globally in properties.xml
:
You can also override the global default by specifying a property on the first XForms model of a page:
5.2. JavaScript and CSS Resources
5.2.1. Minimal Resources
Most JavaScript and CSS files used by the XForms engine are available in two versions:
-
A full version, which may contain comments, spaces, longer identifiers, etc.
-
A minimal version, which is usually much smaller
Both versions work exactly the same. For development and debugging of the XForms engine itself, the full
version is easier to work with. But if you never work directly with these JavaScript and CSS files, as
well as for deployment, the minimal versions are recommended as they will load faster in the user's web
browser. You enable minimal resources in properties.xml
as follows:
5.2.2. Combined Resources
Serving CSS and JavaScript can have a high performance cost on page loads. This is particularly important with the intensive use of JavaScript in Orbeon Forms. In particular, it can be shown that serving many small files is slower than serving a single large file. In theory, HTTP pipelining can improve very much on this, but this is (very unfortunately) useless in practice at the time of writing because Internet Explorer doesn't implement it at all and Firefox / Mozilla do implemente it but do not enable it by default. This is why Orbeon Forms supports the option of combining the multiple JavaScript and CSS files required for a given XForms page into a single JavaScript file and a single CSS file.
You enable this feature in properties.xml
as follows
When this is enabled, Orbeon Forms refers to a single JavaScript file and a single CSS file for XForms-related functionality. The URL identifies special resources needed by the page, for example:
This in short tells the XForms server to produce the minimal CSS and JavaScript for the XForms engine including support for the "range" and "autocomplete" features. Note that you don't have to write these URLs yourself: the Orbeon Forms XForms engine adds them automatically to your page.
When the Orbeon Forms XForms server receives a request for a combined resource, it determine what files
need to be combined and outputs them all together. Furthmore, for CSS files, all URLs referred to with
url()
are rewritten, so that links to images, in particular, remain correct.
In addition, you can enable caching of combined resources with:
This cache works differently from other Orbeon Forms caches, as the result is stored in the resources, typically under:
One benefit of this mechanism is that it allows making such combined files to be served by an Apache front-end.
5.2.3. Versioned Resources
To further improve caching efficiency, Orbeon Forms supports enabling versioned resources. Usually, a resource such as a CSS, JavaScript or image file, is served through URLs like this one:
When configuring caching on the server, for example by using an Apache front-end, you may face a dilemma:
-
Caching aggressively (with an expiration date far in the future and no revalidation) so that the client asks for the resource as rarely as possible. Doing so may cause resources on the client to be out of date.
-
Caching for a shorter period of time or by forcing revalidation so that your client always has a fresh version of the resources. Doing so may cause longer page loads and more load on the server.
Orbeon Forms solves this by providing the option of using versioned resources, that is inserting
automatically a version number within resource URLs. You enable versioned resources in
properties.xml
:
With this, the resource above is served as follows:
The XForms Server component, which serves the resource in this case, sets an expiration date far
in the future. For example, this is the description of the cache entry in the Firefox
about:cache
page:
Key: http://localhost:8080/orbeon/xforms-server/3.6.0.200803010236/xforms-dialog-min.css Data size: 22524 bytes Fetch count: 2 Last modified: 2008-03-01 17:04:25 Expires: 2011-12-25 17:10:42
This means that the resource can effectively be cached "for ever" by a client. In case the client visits Orbeon Forms pages often, the resources will be availabe from cache, therefore reducing page loading times and server load as well.
When Orbeon Forms is upgraded on the server, the version number changes as well. An XForms page will refer to resources with the new version number, so the cached resource is not used by the browser and a new resource is loaded from the server, before being cached. This "magic" is enabled simply with the inclusion of the Orbeon Forms version number in the URL.
Only CSS and JavaScript resources used by the XForms engine are loaded through the XForms Server component. Other resources like images referred by XForms stylesheets are served by the Page Flow Controller, through URLs like this one:
With resource versioning enabled, the URL becomes:
When resource versioning is enabled, the Page Flow Controller by default serves all the
resources defined in <files>
elements by first checking the
oxf.resources.versioned
property. If versioning is enabled, the PFC removes the
version number from the URL before searching for the resource on disk. It is possible to turn
this behavior on and off selectively with the versioned
attribute. Here is how to
turn off versioning for PDF files in page-flow.xml
:
Conversely, resource URLs produced by an XForms page are automatically rewritten following the
Page Flow's <files>
definitions.
The versioning mechanism is made available to your own application resources as well. Any
resource whose path doesn't start with /ops/
or /config/
is considered
part of your application, not of Orbeon Forms. In that case, the Orbeon Forms version number is
not used, but you specify instead an application version number in properties.xml
:
Note that if this property is commented out or missing, no versioning takes place for your
application resources even if oxf.resources.versioned
is set to true
.
For deployed application, you should upgrade the application version number whenever you modify application resources so that clients retrieve the proper resources.
The following scenario shows the entire lifecycle for application resources:
-
You an image as
RESOURCES/apps/foo/bar.png
-
You refer to it as:
<xhtml:body><xhtml:img src="/apps/foo/bar.png" alt="My Image"/></xhtml:body> -
With versioning enabled, the image path is rewritten automatically as follows:
/1.6.3/apps/foo/bar.pngNote that the application resource number is used because the resource is not part of Orbeon Forms.
-
Your browser sees a URL like:
http://localhost:8080/orbeon/1.6.3/apps/foo/bar.png -
When the browser loads the image, the PFC receives back:
/1.6.3/apps/foo/bar.png -
The PFC knows that PNG files are versioned, so removes the version number and sends this resource to the browser:
RESOURCES/apps/foo/bar.png
From client-side JavaScript, you can access the application version number as follow:
At the moment, the resources served by the PFC (that is all the resources except the XForms engine's CSS and JavaScript resources) do not automatically get a special expiration date. If you want to fully leverage client-side caching capabilities, you may want to use an Apache front-end or a Servlet filter to modify the Expires header of those resources. With Apache, you can use mod_expires.
In case you use Apache, you can in addition configure a rewriting rule with mod_rewrite to allow Apache to directly load resources containing a version number, as shown below.
We recommend restarting Orbeon Forms after changing the oxf.resources.versioned
property, as data in Orbeon Forms caches may not be made aware of the change until the next
restart.
5.2.4. Examples of Apache Configurations
Here is how you can configure Apache to serve Orbeon Forms resources. This assumes the following:
-
Orbeon Forms deployed under the
/orbeon
context -
Orbeon Forms exploded WAR file under
/home/orbeon/war/
-
orbeon-resources-public.jar
unziped under/home/orbeon/war/WEB-INF/orbeon-resources-public/
-
oxf.xforms.cache-combined-resources
set totrue
inproperties.xml
Without resources versioning:
RewriteEngine on # Rewrite CSS and JavaScript resources served by the XForms Server # -> make sure "oxf.xforms.cache-combined-resources" is set to "true" in properties.xml RewriteRule ^/orbeon/(xforms-server/.*\.(css|js))$ /home/orbeon/war/WEB-INF/resources/$1 [L] # Serve /config/theme resources # -> make sure orbeon-resources-public.jar is unzipped under "orbeon-resources-public" RewriteRule ^/orbeon/(config/theme/.*\.(css|png|gif))$ /home/orbeon/war/WEB-INF/orbeon-resources-public/$1 [L] # Special handling of PNG images for IE 6 RewriteCond %{HTTP_USER_AGENT} .*MSIE\ 6.* # Make sure the corresponding GIF image exists RewriteCond /home/orbeon/war/WEB-INF/orbeon-resources-public/$1.gif -f # Match on PNG images only and rewrite to GIF RewriteRule ^/orbeon/(ops/.*)\.png$ /home/orbeon/war/WEB-INF/orbeon-resources-public/$1.gif [L] # Serve /ops resources # -> make sure orbeon-resources-public.jar is unzipped under "orbeon-resources-public" RewriteRule ^/orbeon/(ops/.*\.(gif|css|pdf|json|js|png|jpg|xsd|htc|ico|swf))$ /home/orbeon/war/WEB-INF/orbeon-resources-public/$1 [L] # Special handling of PNG images for IE 6 RewriteCond %{HTTP_USER_AGENT} .*MSIE\ 6.* # Make sure the corresponding GIF image exists RewriteCond /home/orbeon/war/WEB-INF/resources/$1.gif -f # Match on PNG images only and rewrite to GIF RewriteRule ^/orbeon/(.*)\.png$ /home/orbeon/war/WEB-INF/resources/$1.gif [L] # Serve remaining resources RewriteRule ^/orbeon/(.*\.(gif|css|pdf|json|js|png|jpg|xsd|htc|ico|swf))$ /home/orbeon/war/WEB-INF/resources/$1 [L]
With resources versioning:
RewriteEngine on # Rewrite CSS and JavaScript resources served by the XForms Server # -> make sure "oxf.xforms.cache-combined-resources" is set to "true" in properties.xml RewriteRule ^/orbeon/xforms-server/[^/]+/(.*\.(css|js))$ /home/orbeon/war/WEB-INF/resources/xforms-server/$1 [L] # Serve /config/theme resources # -> make sure orbeon-resources-public.jar is unzipped under "orbeon-resources-public" RewriteRule ^/orbeon/[^/]+/(config/theme/.*\.(css|png|gif))$ /home/orbeon/war/WEB-INF/orbeon-resources-public/$1 [L] # Special handling of PNG images for IE 6 RewriteCond %{HTTP_USER_AGENT} .*MSIE\ 6.* # Make sure the corresponding GIF image exists RewriteCond /home/orbeon/war/WEB-INF/orbeon-resources-public/$1.gif -f # Match on PNG images only and rewrite to GIF RewriteRule ^/orbeon/[^/]+/(ops/.*)\.png$ /home/orbeon/war/WEB-INF/orbeon-resources-public/$1.gif [L] # Serve /ops resources # -> make sure orbeon-resources-public.jar is unzipped under "orbeon-resources-public" RewriteRule ^/orbeon/[^/]+/(ops/.*\.(gif|css|pdf|json|js|png|jpg|xsd|htc|ico|swf))$ /home/orbeon/war/WEB-INF/orbeon-resources-public/$1 [L] # Special handling of PNG images for IE 6 RewriteCond %{HTTP_USER_AGENT} .*MSIE\ 6.* # Make sure the corresponding GIF image exists RewriteCond /home/orbeon/war/WEB-INF/resources/$1.gif -f # Match on PNG images only and rewrite to GIF RewriteRule ^/orbeon/[^/]+/(.*)\.png$ /home/orbeon/war/WEB-INF/resources/$1.gif [L] # Serve remaining resources RewriteRule ^/orbeon/[^/]+/(.*\.(gif|css|pdf|json|js|png|jpg|xsd|htc|ico|swf))$ /home/orbeon/war/WEB-INF/resources/$1 [L]
The rewriting rules above have special handling of PNG images for IE 6: when that browser is detected, any request for PNG image having a corresponding GIF image serves the GIF images instead. If you don't need that behavior, remove the corresponding lines in the rules above.
All in all, the rules above perform the following:
- Special handling for XForms JavaScript and CSS files (using the cached/combined/minimized resources)
- Serving of
/config/theme
resources originally inorbeon-resources-public.jar
- Special handling of PNG images for IE 6 for
/ops
resources originally inorbeon-resources-public.jar
- Serving of other
/ops
resources originally inorbeon-resources-public.jar
- Special handling of PNG images for IE 6 for resources under
RESOURCES
- Serving of other resources under
RESOURCES
5.3. Browser Navigation (Back and Forward) Handling
When visiting an XForms page by using your browser's Back and Forward buttons, or other browser-history mechanisms, Orbeon Forms by default restores the appearance of that page as it was when you left it. (Browsers don't automatically handle this behavior with Ajax applications!) This behavior best matches the usual user experience obtained when navigating regular web pages.
In certain situations, it can be useful instead to ask the XForms page to reload entirely. You
control this by using the xxforms:revisit-handling
attribute on the first XForms model
of the page you want to reload. This attribute supports two values: restore
(the
default) and reload
. Example:
reload
value carefully, as reloading pages upon browser
navigation often does not match the expectation of the user.
5.4. Encryption
Orbeon Forms encrypt some information sent to the client (for example when using client-side state
state handling). This is done through the following property in properties.xml
:
It is strongly advised to change the default password in the property above.
In addition, Orbeon Forms by default encrypts the value of selection controls before sending them to the client. This can be controlled with this property:
In general, this should be set to true
, but you can set it to false
if you
need to access the value of selection controls through JavaScript on the client, or through offline
binds.
5.5. Debugging XForms Pages
5.5.1. Enabling XForms Logging
When a fatal error occurs, the XForms engine throws a Java exception which either results in an error page in your web browser (when the error occurrs during page initialization) or in an error message at the top of the displayed XForms page (when the error occurs during an Ajax request after the page is loaded). The main Java exception is also logged on the server.
Sometimes, this provides enough information to the developer to figure out what went wrong. But
often this is not sufficient. The best tool available is the XForms engine logging facility. To
enable it, make sure you uncomment the following lines in config/log4j.xml
:
You must restart your Servlet container for those changes to be taken into account.
These settings enable verbose logging of the XForms engine's operations, in particular:
-
Dispatching of events.
-
Execution of actions.
-
Loading of instances.
-
Execution of submissions.
-
Resulting XForms instances.
-
XForms cache-related operations.
The following shows a sample XForms logging session:
event - dispatching {name: "DOMFocusIn", id: "xforms-element-222", location: "line 28 of XFormsDOMFocusInEvent.java"} action - executing {action name: "setvalue"} setvalue - setting instance value {value: "4", instance: "fr-form-instance"} event - dispatching {name: "xforms-recalculate", id: "fr-form-model", location: "line 1895 of XFormsModel.java"} model - performing recalculate {model id: "fr-form-model"} model - done recalculating {time: "4"} event - dispatching {name: "xforms-revalidate", id: "fr-form-model", location: "line 1900 of XFormsModel.java"} model - performing revalidate {model id: "fr-form-model"} model - done rebuilding {model id: "fr-form-model", time: "1"} event - dispatching {name: "xforms-refresh", id: "fr-form-model", location: "line 1905 of XFormsModel.java"} model - performing refresh {model id: "fr-form-model"} controls - start building model - evaluated variables {count: "1"} controls - end building {time (ms): "22"} event - dispatching {name: "xforms-value-changed", id: "xforms-element-222", location: "line 27 of XFormsValueChangeEvent.java"} action - executing {action name: "setvalue"} setvalue - setting instance value {value: "dirty", instance: "fr-persistence-instance"} event - dispatching {name: "xforms-valid", id: "xforms-element-222", location: "line 27 of XFormsValidEvent.java"} event - dispatching {name: "xforms-recalculate", id: "fr-persistence-model", location: "line 1895 of XFormsModel.java"} model - performing recalculate {model id: "fr-persistence-model"} model - done recalculating {time: "5"} event - dispatching {name: "xforms-revalidate", id: "fr-persistence-model", location: "line 1900 of XFormsModel.java"} model - performing revalidate {model id: "fr-persistence-model"} model - done rebuilding {model id: "fr-persistence-model", time: "5"} event - dispatching {name: "xforms-refresh", id: "fr-persistence-model", location: "line 1905 of XFormsModel.java"} model - performing refresh {model id: "fr-persistence-model"} controls - start building model - evaluated variables {count: "1"} controls - end building {time (ms): "9"} event - dispatching {name: "xforms-value-changed", id: "fr-data-status-input", location: "line 27 of XFormsValueChangeEvent.java"} event - dispatching {name: "xforms-valid", id: "fr-data-status-input", location: "line 27 of XFormsValidEvent.java"} controls - evaluating controls controls - done evaluating controls {time (ms): "4"}
5.5.2. The Instance Inspector
The Instance Inspector allows you to visualize all the instances of your XForms page. You enable
it by adding the following within your XForms page's xhtml:body
element, typically
just before closing that element:
This is an example of how the Instance Inspector looks like in your page:
You can select which model and instand to view, and decide whether to see plain XML or formatted XML.