Ruby newbie & XML - What's the simplest way to get XML data into a hash?

[darenbell]

Sorry for having such a specific question, but is there a simple way to
take the XML document below and put it into some sort of organized hash
value without first knowing anything about it?

This is an easy job using something like XML::Simple in Perl, but for
the life of me, I can't figure out an easy way to do this in Ruby.

I'm thinking of some sort of data structure like so:

environment=>authentication=>adminGroup=>description=>'NULL'
environment=>authentication=>adminGroup=>dataType=>'NULL'
environment=>authentication=>adminGroup=>value=>'NULL'
etc...
environment=>database=>databaseHost=>description=>'NULL'
environment=>database=>databaseHost=>dataType=>'NULL'
etc...


XML document:
<environment>
<authentication>
<adminGroup>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</adminGroup>
<bindUserID>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</bindUserID>
<bindUserPassword>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</bindUserPassword>
<ldapServer>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</ldapServer>
</authentication>
<database>
<databaseHost>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</databaseHost>
<databaseSchema>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</databaseSchema>
<databasePort>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</databasePort>
<databaseUser>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</databaseUser>
<databasePassword>
<description>NULL</description>
<dataType>NULL</dataType>
<value>NULL</value>
</databasePassword>
</database>
</environment>


TIA

 

[David Roberts]

Sorry for having such a specific question, but is there a simple way to
take the XML document below and put it into some sort of organized hash
value without first knowing anything about it?

This is an easy job using something like XML::Simple in Perl, but for
the life of me, I can't figure out an easy way to do this in Ruby.

I think most people would think a specific question something to be
admired, not something to be apologised for!

Are you aware of the Ruby library xml-simple, which is a translation of
the Perl XML::Simple

Details at: http://xml-simple.rubyforge.org/

dj

 

[Robert Klemme]

Sorry for having such a specific question, but is there a simple way to
take the XML document below and put it into some sort of organized hash
value without first knowing anything about it?

This is an easy job using something like XML::Simple in Perl, but for
the life of me, I can't figure out an easy way to do this in Ruby.

I'm thinking of some sort of data structure like so:

environment=>authentication=>adminGroup=>description=>'NULL'
environment=>authentication=>adminGroup=>dataType=>'NULL'
environment=>authentication=>adminGroup=>value=>'NULL'
etc...
environment=>database=>databaseHost=>description=>'NULL'
environment=>database=>databaseHost=>dataType=>'NULL'
etc...

You can easily create nested Hashes with the typical idiom:

irb(main):001:0> miss = lambda {|h,k| h[k] = Hash.new(&miss)}
=> #<Proc:0x003cbaa8@(irb):1>
irb(main):002:0> root = Hash.new(&miss)
=> {}
irb(main):003:0> root[:foo][:bar][:baz] = 10
=> 10
irb(main):004:0> root
=> {:foo=>{:bar=>{:baz=>10}}}

Now you just need a XML stream parser (REXML has one) and fill the Hash
while you go.

But my question to this is, why do you want it in a Hash of Hashes when
there is REXML with an equally easy accessible DOM and which knows more
about the data than nested hashes (order for example)? Also, you can
access nested elements with XPath which is a powerful query language.
Granted, accesses are likely less efficient than with the nested Hash
approach but do you need the speed?

Kind regards

robert

 

[Joel VanderWerf]

Try this:

The Zen of XML