Which web apps actually validate?

[J David Eisenberg]

One of the students in my XML class is asking what the purpose of
validating is in the context of a web application. He's trying to
figure out how he would use XML Schema or Relax NG and associated tools
to validate input from a web form. This is the wrong approach, since
that input isn't XML at all.

I've told him that any XML validation would most likely occur at the
server side, when servers have to transfer data that is in XML format
and make sure that everything is OK. Does anyone know examples of
XML-based content management systems, or web applications, that do
validation on the server side? I'd like to be able to point this
student to some examples in actual use.

(If this is already covered in the FAQ, sorry; I must have missed it on
first reading.)

 

[Tjerk Wolterink]

One of the students in my XML class is asking what the purpose of
validating is in the context of a web application. He's trying to
figure out how he would use XML Schema or Relax NG and associated tools
to validate input from a web form. This is the wrong approach, since
that input isn't XML at all.

The w3c is creating a new standard for the forms in the old html:

XForms,

in XForms the input is send as a xml model to the server,
and can also be bound to a XSchema.

I've told him that any XML validation would most likely occur at the
server side, when servers have to transfer data that is in XML format
and make sure that everything is OK. Does anyone know examples of
XML-based content management systems, or web applications, that do
validation on the server side?

I use XSchema documents to validate my config files in
my content management system.
My content management system is also almost completely XML based,
but it relies on a relational database ( there is data abstraction
so in the future i can move to a xml database)

I'd like to be able to point this
student to some examples in actual use.

Well, on tomcat there are a lot of config files and
they have an XML Schema.

 

[Peter Flynn]

One of the students in my XML class is asking what the purpose of
validating is in the context of a web application. He's trying to
figure out how he would use XML Schema or Relax NG and associated tools
to validate input from a web form. This is the wrong approach, since
that input isn't XML at all.

I've told him that any XML validation would most likely occur at the
server side, when servers have to transfer data that is in XML format
and make sure that everything is OK. Does anyone know examples of
XML-based content management systems, or web applications, that do
validation on the server side? I'd like to be able to point this
student to some examples in actual use.

Probably Lenya (lenya.apache.org) but I haven't tried it yet. Cocoon
certainly does.

(If this is already covered in the FAQ, sorry; I must have missed it on
first reading.)

Validation is covered, but not the reasons why you might want to validate
(or not). Your example is correct. The most widespread occurrence of
validation is probably in XML editors, where the software is checking
that what you have done (or are trying to do) is within the rules of
the DTD or Schema you have specified. Once a file is known to be valid,
there is little point in validating it again and again, unless you are
exporting it to another application which may have no way to know if
its input (your output) is valid or not.

///Peter

 

[Andy Dingley]

Does anyone know examples of
XML-based content management systems, or web applications, that do
validation on the server side?

Not obvious ones offhand.

The only popular application I can think of for bulk validation against
a schema or DTD is with HTML/XHTML authoring. Authors are finally
getting the message here and validation is this month's fashionable
thing. It's also one of the few cases where there's a lot of hand-edit
of documents where validity is far from an assumption. In most of the
web services or database query tasks there might be a lot of validation
in the development phase, but the assumption is by-and-large that valid
tools accepting valid inputs will continue to generate valid documents.

As to user input validation, then I've never seen schema used as a major
part of that - it's just too poorly descriptive, particularly in how to
react after invalid input. Like compilers, a good user-input tool is
mainly a device for generating really helpful error messages after bad
input, then just occasionally getting to process a valid set.

Some of the ontology tools (sniff around the Protege project) also do
validation against schema or OWL.

 

[Rob Tweed]

You might want to have a look at
http://www.mgateway.com/ewd/XMLForms1.2.pdf

This automatically performs back-end validation based on the XML
Schema from which the web form is automatically derived.

I'm sure your XML class in general will find this totally XML-based
tool interesting in its own right

One of the students in my XML class is asking what the purpose of
validating is in the context of a web application. He's trying to
figure out how he would use XML Schema or Relax NG and associated tools
to validate input from a web form. This is the wrong approach, since
that input isn't XML at all.

I've told him that any XML validation would most likely occur at the
server side, when servers have to transfer data that is in XML format
and make sure that everything is OK. Does anyone know examples of
XML-based content management systems, or web applications, that do
validation on the server side? I'd like to be able to point this
student to some examples in actual use.

(If this is already covered in the FAQ, sorry; I must have missed it on
first reading.)

---
Rob Tweed
M/Gateway Developments Ltd

The Pursuit of Productivity : http://www.mgateway.com
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