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RE: How can a text file be uploaded by XForms?

From: Ogbuji, Chimezie <OGBUJIC@ccf.org>
Date: Fri, 22 Apr 2005 12:45:06 -0400
Message-ID: <E9B52E50D32640449D84BD2A85F9CADF12A6D2@CCHSCLEXMB60.cc.ad.cchs.net>
To: www-forms@w3.org

The approach that I have found to work for this specific scenario (where
I need to submit XML content to an endpoint as instance data), is to
base64 encode/decode the XML content within the Forms using a javascript
encoding library.  Some examples:


There is another one in the Orielly Javascript and DHTML Cookbook

The advantage of this is that you can have your content automatically
encoded by the XForms processor by associating an xf:upload with the
instance.  Where you prefer the data is entered as text, I use a binding
from the entered text to a node with the base64 encoded content via an
XPath expression that makes use of an encoding function (formsPlayer
allows you to use user-specified javascript functions within your XPath

For example:

  nodeset='.. path to node where base64 encoded content will lie..'
type='xsd:base64Binary' calculate='inline:encodeBase64(string(.. path to
node containing XML text ..))'>

-----Original Message-----
From: www-forms-request@w3.org [mailto:www-forms-request@w3.org] On
Behalf Of Victor Engmark
Sent: Friday, April 22, 2005 3:23 AM
To: Mark Birbeck
Cc: 'Kianoush Eshaghi'; www-forms@w3.org
Subject: Re: How can a text file be uploaded by XForms?

Mark Birbeck wrote:

>Can I just check that I understand the issue? Are you saying that you
>to upload the file 'as is'? That is, you don't want to see it to be
>in a binary or hex format?
>If so, then I am afraid that can't be done in XForms 1.0, although it
>certainly wouldn't be difficult to do. At the moment the specification
>that you must bind to an element with a schema type of one of the
>types -- which is why formsPlayer correctly "cries" if you use a type
>xsd:string ;).
>However, just having the raw text is certainly a good suggestion for
I'd expect that you still would have to escape characters in /some/ way,

unless you have specialized parsers which know to treat XForms instance 
data. With this in mind, the most obvious encodings which come to mind

    * Just escaping <, &, and > as &lt;, &amp;, and &gt; (this is not
      complete enough to handle all data, but should be enough for most
      non-binary stuff)
    * The above generalized to XHTML - That is, including entities like
      &copy; without messing up the parsing of the XML (can this be done
      with a DTD?)
    * Generalized even further to escape other non-valid characters,
      such as mentioned in message-ID <4267FF98.8030803@bruchez.org> (is
      this sufficient to handle any binary data?)

Frankly, these encodings are IMNSHO so obvious that I'm starting to 
suspect that my understanding of the concept of "encoding" is 
fundamentally flawed. If this is not the case, how come these encodings 
have not been included in XForms 1.0? They would be very useful to be 
able to display the raw data that is sent with a form, and for e.g. web 
authoring XForms (preview of result).

Chimezie Thomas-Ogbuji
Lead Systems Analyst
Department of Cardiovascular Surgery
Cleveland Clinic Foundation
E: ogbujic@ccf.org
P: (216)444-8593

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Received on Friday, 22 April 2005 17:41:09 UTC

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