xforms:upload/@incremental

> Erik Bruchez wrote:
>> Adrian Baker wrote:
>>> Yes exactly, thanks.
>>>
>>> Regarding
>>> http://forge.objectweb.org/tracker/index.php?func=detail&aid=304933&group_id=168&atid=350207: 
>>> I know this is always a difficult question, but do you see this
>>> fitting into any particular point on the development roadmap?
>>
>> 1. Supporting upload with replace="instance|none" would certainly be
>> very valuable for most applications that use upload, but so far we
>> have seen relatively little demand for it. So for now this remains
>> fairly low priority.
>>
>> 2. Supporting the incremental mode is even lower priority, as this
>> falls in the "fun to have" category ;-) But once #1 is implemented,
>> this should not bee *too* hard to do.
>>
>> I don't think that #1 should be very hard to implement by using the
>> appropriate YUI facilities:
>>
>>   http://developer.yahoo.com/yui/connection/
>>
>> It would be great if somebody did some preliminary investigations on
>> this. A good part of the work is pure JavaScript / YUI and should be
>> doable in xforms.js, and then we also have to make the XForms server
>> be able to handle upload data (see xforms-server-submit.xpl vs.
>> xforms-server.xpl).
>>
>> -Erik
>>
> I'd hoped to do some work on implementing (1), however this is now
> looking unlikely. Here are some notes I made regarding a possible
> implementation approach - these might be useful for someone, although I
> expect most of this would be self-evident to Erik & Alex :) I got as far
> as modifying the client to asynchronously trigger a file upload & invoke
> the xforms-server-upload.xpl pipeline mentioned below (easy enough), but
> did not start on the server side changes.
>
> (start)
>
> Orbeon's support for upload isn't complete: upload is only supported on
> replace="all", not replace="instance" - see
> http://forge.objectweb.org/tracker/index.php?func=detail&aid=304933&group_id=168&atid=350207^
> <http://forge.objectweb.org/tracker/index.php?func=detail&aid=304933&group_id=168&atid=350207>.
>
> The standard HTML 4 file upload & current OPS upload support works by
> declarding an input with type file:
>     <input type="file"/>
>
> This gets rendered as an input field with a Browse button immediately to
> the right. The user chooses a file using Browse... and the input field
> is populated with the filename which will be uploaded. When the parent
> html form is submitted the file is uploaded, page is blown away and
> replaced with response (effectively a replace="all").
>
> In XForms we need to support the concept of uploading a file *without*
> doing a replace="all", eg when
>
>     * instance with file is submitted with replace="instance"
>     * xf:upload/@incremental is true and the user chooses a file
>
> This gives rise to a some UI considerations which we don't face with
> replace="all".
>
> 1. how do we communicate that upload is occuring/upload has completed?
>
>     * initially just make do with standard throbber
>     * eventually during upload could the <input> box could be used
>       as/replaced with a progress bar?
>
> 2. what do we do when upload is complete/when xf:upload is bound to an
> uploaded file?
>     (a). leave <input> filled in with filename? will cause reupload on
> form.submit() though - can we prevent this? Won't leaving the filename
> there indicate that there is a pending upload?
>     (b). blank the input field. puts onus on form author to
> indicate/display uploaded file, which is more flexible. However controls
> are meant to reflect current instance data ("Form controls when rendered
> display the underlying data values to which they are bound" -
> http://www.w3.org/TR/xforms/slice8.html#ui-processing^ ). On the other
> hand, blanking gives an indication that there is no pending upload. Also
> when a blank <input> is submitted with a form.submit() OPS ignores this
> rather than clearing the uploaded file in the instance data.
>     (c) use some extra html elements alongside the <input file=""> to
> indicate that a binary is present (icon+filename etc). Convenient, but
> this behaviour can be more flexibly added by form author.
>
> Let's aim to start with the simplest solution of (b), blanking the input
> field, which is also closest to the current behaviour of OPS.
>
>
>     Implementation
>
> We can use YAHOO.util.Connect to upload a <form> containing an <input
> type="file"> asynchronously:
>
> // argument formId can be the id or name attribute value of the
> // HTML form, or an HTML form object.
> var formObject = document.getElementById('aForm');
>
> // the second argument is true to indicate file upload.
> YAHOO.util.Connect.setForm(formObject, true);
>
> var cObj = YAHOO.util.Connect.asyncRequest('POST', 'http://www.yahoo.com', callback);
>
> However this is different to the current way OPS does asynchronous
> requests, which involves manual construction of an event-request xml
> document which contains information about the interaction:
>
> requestDocumentString += '<!DOCTYPE xxforms:event-request [<!ENTITY nbsp "&#160;">]>\n';
> ...
> YAHOO.util.Connect.initHeader("Content-Type", "application/xml");
> YAHOO.util.Connect.asyncRequest("POST", XFORMS_SERVER_URL, { success: xformsHandleResponse }, requestDocumentString);
>
> Orbeon also does regular synchronous form submissions when replace="all":
>
> // Submit form
> case "submission": {
> if (xformsGetLocalName(actionElement.childNodes[actionIndex]) == "submission") {
> newDynamicStateTriggersPost = true;
> ORBEON.xforms.Globals.formDynamicState[formIndex].value = newDynamicState;
> ORBEON.xforms.Globals.requestForm.submit();
>
> The submitted form here contains the entire state of the instance data
> in hidden inputs, along with the visible inputs - including any <input
> type="file">. This how OPS supports synchronous file uploads with
> replace="all". OPS uses xforms-server-submit.xpl to extract the hidden
> inputs and constructs the event request xml document server side, which
> is then processed normally by XFormsServer.java:
>
> *xforms-server-submit.xpl*
>
> <p:config xmlns:p="http://www.orbeon.com/oxf/pipeline"
>     xmlns:oxf="http://www.orbeon.com/oxf/processors"
>     xmlns:xs="http://www.w3.org/2001/XMLSchema"
>     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
>     <!-- Extract parameters -->
>     <p:processor name="oxf:request">
>         <p:input name="config">
>             <config stream-type="xs:anyURI">
>                 <include>/request/parameters</include>
>             </config>
>         </p:input>
>         <p:output name="data" id="request-params" debug="xxxrequest-params"/>
>     </p:processor>
>
>     <!-- Create XForms Server request -->
>     <p:processor name="oxf:xslt">
>         <p:input name="data" href="#request-params"/>
>         <p:input name="config">
>             <xxforms:event-request xsl:version="2.0" xmlns:xxforms="http://orbeon.org/oxf/xml/xforms">
>                 <xxforms:static-state>
>                     <xsl:value-of select="/*/parameters/parameter[name = '$static-state']/value"/>
>                 </xxforms:static-state>
>                 <xxforms:dynamic-state>
>                     <xsl:value-of select="/*/parameters/parameter[name = '$dynamic-state']/value"/>
>                 </xxforms:dynamic-state>
>                 <xsl:variable name="files" select="/*/parameters/parameter[filename]"/>
>                 <xsl:if test="$files">
>                     <xxforms:files>
>                         <xsl:copy-of select="$files"/>
>                     </xxforms:files>
>                 </xsl:if>
>                 <xxforms:action/>
>             </xxforms:event-request>
>         </p:input>
>         <p:output name="data" id="xml-request"/>
>     </p:processor>
>
>     <!-- Run XForms Server -->
>     <p:processor name="oxf:xforms-server">
>         <p:input name="request" href="#xml-request" schema-href="xforms-server-request.rng"/>
>     </p:processor>
>
> </p:config>
>
> We could extend this submit behaviour to run asynchronously to perform
> uploads. Instead of calling requestForm.submit(), we would use the
> YAHOO.util.Connect library to asynchronously POST the form. To handle
> the POST server side, we'd need an extended version of
> xforms-server-submit.xpl which responded with the standard xml event
> response (which xforms-server-submit.xpl does not do). This logic is
> already present in xforms-server.xpl:
>
> *xforms-server.xpl*
>
> <p:config xmlns:p="http://www.orbeon.com/oxf/pipeline"
>     xmlns:oxf="http://www.orbeon.com/oxf/processors"
>     xmlns:xs="http://www.w3.org/2001/XMLSchema"
>     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
>     <!-- Extract request body -->
>     <p:processor name="oxf:request">
>         <p:input name="config">
>             <config stream-type="xs:anyURI">
>                 <include>/request/body</include>
>             </config>
>         </p:input>
>         <p:output name="data" id="request-body"/>
>     </p:processor>
>
>     <!-- Dereference URI and return XML -->
>     <p:processor name="oxf:url-generator">
>         <p:input name="config" href="aggregate('config', aggregate('url', #request-body#xpointer(string(/request/body))))"/>
>         <p:output name="data" id="xml-request"/>
>     </p:processor>
>
>     <!-- Run XForms Server -->
>     <p:processor name="oxf:xforms-server">
>         <p:input name="request" href="#xml-request" schema-href="xforms-server-request.rng"/>
>         <p:output name="response" id="xml-response" schema-href="xforms-server-response.rng"/>
>     </p:processor>
>
>     <!-- Generate response -->
>     <p:processor name="oxf:xml-serializer">
>         <p:input name="data" href="#xml-response"/>
>         <p:input name="config">
>             <config>
>                 <content-type>application/xml</content-type>
>             </config>
>         </p:input>
>     </p:processor>
>
> </p:config>
>
> So a first attempt at the resulting xpl might look like:
>
> *xforms-server-upload.xpl*
>
> <p:config xmlns:p="http://www.orbeon.com/oxf/pipeline"
>     xmlns:oxf="http://www.orbeon.com/oxf/processors"
>     xmlns:xs="http://www.w3.org/2001/XMLSchema"
>     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
>
>     <!-- Extract parameters -->
>     <p:processor name="oxf:request">
>         <p:input name="config">
>             <config stream-type="xs:anyURI">
>                 <include>/request/parameters</include>
>             </config>
>         </p:input>
>         <p:output name="data" id="request-params"/>
>     </p:processor>
>
>     <!-- Create XForms Server request -->
>     <p:processor name="oxf:xslt">
>         <p:input name="data" href="#request-params"/>
>         <p:input name="config">
>             <xxforms:event-request xsl:version= class="code-quote">"2.0" xmlns:xxforms="http://orbeon.org/oxf/xml/xforms">
>                 <xxforms:static-state>
>                     <xsl:value-of select="/*/parameters/parameter[name = '$static-state']/value"/>
>                 </xxforms:static-state>
>                 <xxforms:dynamic-state>
>                     <xsl:value-of select="/*/parameters/parameter[name = '$dynamic-state']/value"/>
>                 </xxforms:dynamic-state>
>                 <xsl:variable name="files" select="/*/parameters/parameter[filename]"/>
>                 <xsl:if test="$files">
>                     <xxforms:files>
>                         <xsl:copy-of select="$files"/>
>                     </xxforms:files>
>                 </xsl:if>
>                 <xxforms:action/>
>             </xxforms:event-request>
>         </p:input>
>         <p:output name="data" id="xml-request"/>
>     </p:processor>
>
>     <!-- Run XForms Server -->
>     <p:processor name="oxf:xforms-server">
>         <p:input name="request" href="#xml-request" schema-href="xforms-server-request.rng"/>
>         <p:output name="response" id="xml-response" schema-href="xforms-server-response.rng"/>
>     </p:processor>
>
>     <!-- Generate response -->
>     <p:processor name="oxf:xml-serializer">
>         <p:input name="data" href="#xml-response"/>
>         <p:input name="config">
>             <config>
>                 <content-type>application/xml</content-type>
>             </config>
>         </p:input>
>     </p:processor>
>
> </p:config>
>
> Invoking the new pipeline from the xforms.js client is straightforward
> enough (note that at least version 0.11.3 of the YUI library is needed
> for the upload to return a responseXML document - OPS currently runs
> against 0.11.1 so would need to be upgraded):
>
> YAHOO.util.Connect.setForm(ORBEON.xforms.Globals.requestForm, true);
> YAHOO.util.Connect.asyncRequest('POST', BASE_URL + "/xforms-server-upload", {upload: xformsHandleResponse});
>
> The remaining work is in modifying the server side code to accept file
> uploads outside of a submit with replace="all". The pipeline above
> results in the following event request:
>
> <xxforms:event-request xmlns:xxforms="http://orbeon.org/oxf/xml/xforms"
> xmlns:xs="http://www.w3.org/2001/XMLSchema"
> xmlns:oxf="http://www.orbeon.com/oxf/processors"
> xmlns:p="http://www.orbeon.com/oxf/pipeline">
>     <xxforms:static-state>session:7C457098-A8A9-FE08-E17E-83D8ED165739</xxforms:static-state>
>     <xxforms:dynamic-state>session:544FF17D-A43A-4A3B-5715-0CE457CF1DD4</xxforms:dynamic-state>
>     <xxforms:files>
>         <parameter>
>             <name>fu</name>
>             <filename>C:\Documents and Settings\adrianb\Desktop\backup.jpg</filename>
>             <content-type>image/pjpeg</content-type>
>             <content-length>3237</content-length>
>             <value>file:/C:/dev/Venice/Common/CommonService/build/main/catalina-base/temp/upload_00000149.tmp</value>
>         </parameter>
>     </xxforms:files>
>     <xxforms:action/>
> </xxforms:event-request>
>
> Currently OPS' server side logic will ignore the uploaded files, because
> interprets the <xxforms:files> element in
> org.orbeon.oxf.xforms.XFormsModelSubmission upon receiving a final
> replace="all" submission (indicated here by the
> isDeferredSubmissionSecondPass flag):
>
> if (isDeferredSubmissionSecondPass) {
> // Handle uploaded files if any
> final Element filesElement = (event instanceof XXFormsSubmitEvent) ? ((XXFormsSubmitEvent) event).getFilesElement() : null;
> if (filesElement != null) {
> for (Iterator i = filesElement.elements().iterator(); i.hasNext();) {
>
> // (update instance document with uploaded files)
>
> This logic would need to be factored out so it can be invoked from the
> standard event handling in
> org.orbeon.oxf.xforms.XFormsContainingDocument. To trigger the
> inspection of the file uploads & subsequent update of the instance data,
> an xforms-value-changed event could be raised by the new
> xforms-server-upload.xpl pipeline. This would also cover off something
> the above pipeline is missing: something identifying the upload control
> triggering the upload, because the <xxforms:files> section contains
> entries for *all* upload controls on the page (although they should be
> empty for already uploaded files) so this isn't enough.
>
> To make the filesElement available the XFormsValueChanged event could
> need to be modified or subclassed to store a reference to this. This
> contains a reference to the collection of <xxforms:files> elements
> provided by the client - the target of the value changed event (the
> upload control) would then be used to extract the appropriate file.
> Alternatively the pipeline could filter out files which do not originate
> from the target control, and only attach the correct uploaded file to
> the value changed event.
>
> (end)
>
> Adrian