Re: Use of XML for config files

["Warren W. Gay VE3WWG" <ve3wwg@cogeco.ca>]

Stephen Leake wrote:

> "Tarjei T. Jensen" <tarjei.jensen@kvaerner.com> writes:
>>Stephen Leake wrote:
>>
>>>However, I think a sufficiently small subset of XML is ok. I'll be
>>>posting a complete example Real Soon Now :).
>>
>>Aaarrrggggghhhhhhhh!!!!!!!!!
>>
>>When will people learn that config files should be readable and
>>understandable.
> 
> Yes, that is one of the requirements for Config_Files.
> 
> You seem to be implying that XML is inherently _not_ readable, or
> _not_ understandable.
> 
> Many people here disagree.


If your goal is to provide a configuration file that is as simple
as a .ini file, then I think any subset of XML is a poor choice.
Here's one reason why:

It _does_ add complexity. As Ted mentioned in an earlier post, if
you had to describe to a person who barely can handle an editor
over the phone (the worst kind of support position), you would
have to ask many questions about whether a tag was properly closed
etc. You'd have to start by describing how tags open and close
for starters.. and they probably wouldn't really get it anyway.
Then going beyond that to nested tags - arg!

I for one, would hate to be in that sort a support role. But
even ignoring support roles, it is easier to describe an ini
file change, than a XML change in a document.


BUT, if your _goal_ is a hierarchical structure like the Windoze
registry, then I think you should be prepared to accept binary
and focus on it at the API and implementation level. The way
to make it user configurable, is to provide a regedit type of
tool that is general enough to handle most cases. Perhaps make
it type extendable that is supported by dynamic shared libraries.
Furthermore, it is then possible to layer some ACL type of security
on your values.


I personally would like to see this registry-like data in a
postgres database, with a smooth API to access/create/modify
values. The disadvantage of course, is that this would require
that Postgres be running on all hosts where your application
goes. There is a fellow that is attempting to put all Linux
configuration values into a Postgres database. I think I
saw this in a Linux publication last fall. This approach will
then make it easier to configure all aspects of the system
from a GUI.

So many have already said here: your implementation will depend
upon your design goals.


Warren.