How can I get multiple attributes from XML file? - ruby

Question

I have an XML file:
<One>
<Document Count="1">
<Customer Id="1" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="13" Name="Test Name"/>
<Passenger Seq="2" Id="14" Name="Test Name4"/>
</Passengers>
</Document>
<Document Count="2">
<Customer Id="2" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="16" Name="Test Name10"/>
<Passenger Seq="2" Id="18" Name="Test Name30"/>
</Passengers>
</Document>
</One>
...
<Two>
<Document Count="1">
<User Id="1" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="123" Name="Test Name"/>
<Passenger Seq="2" Id="124" Name="Test Name2"/>
</Passengers>
</Document>
<Document Count="2">
<Customer Id="2" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="1130" Name="Test Name123"/>
<Passenger Seq="2" Id="1131" Name="Test Name34342"/>
</Passengers>
</Document>
</Two>
My steps:
array = []
doc = Nokogiri::XML(File.open(file.xml))
doc_pass = doc.xpath("//Document//Passengers//Passenger")
doc_pass.each do |pass|
hash = {}
hash[:id] = pass['Name'] #???
array << hash
end
I want to get all attributes like Id, Name from Passengers, and create a hash with all passengers.
Example:
[{ :id => '13', :name => "Test Name"}, { :id => '14', :name => "Test Name4"}, { :id => '16', :name => "Test Name10"}, { :id => '18', :name => "Test Name30"}, { :id => '123', :name => "Test Name"} ... ]
How can I do that?

Answer 1

Just replace the line
hash[:id] = pass['Name'] #???
with
hash[:id] = pass['Id']
hash[:name] = pass['Name']
and it will work, as long as you have a valid XML file.
The XML fragment in your question is not valid for two reasons:
The ... between <One> and <Two> (I guess that's intentional and not a problem with your real data)
Your XML does not have a root element. Currently you have two "roots", the elements <One> and <Two>. If that's how your real XML file is composed, I think Nokogiri will only read the first node.

Answer 2

I'm seeing that you specify the attributes manually in your code. In case you want to get ALL of the attributes in the format you specified, try this:
array = []
Nokogiri::XML(File.open(file.xml)).xpath("//Document//Passengers//Passenger").each do |x|
hash = {}
x.attributes.each do |attribute| # loop through all attributes in the matches found
hash[attribute[1].name.to_sym] = attribute[1].value
end
array << hash
end
array should have this value:
[{:Seq=>"1", :Id=>"13", :Name=>"Test Name"}, {:Seq=>"2", :Id=>"14", :Name=>"Test Name4"}, {:Seq=>"1", :Id=>"16", :Name=>"Test Name10"}, {:Seq=>"2", :Id=>"18", :Name=>"Test Name30"}]

Answer 3

I'd do it like this:
require 'nokogiri'
doc = Nokogiri::XML(<<EOT)
<xml>
<One>
<Document Count="1">
<Customer Id="1" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="13" Name="Test Name"/>
<Passenger Seq="2" Id="14" Name="Test Name4"/>
</Passengers>
</Document>
<Document Count="2">
<Customer Id="2" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="16" Name="Test Name10"/>
<Passenger Seq="2" Id="18" Name="Test Name30"/>
</Passengers>
</Document>
</One>
<Two>
<Document Count="1">
<User Id="1" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="123" Name="Test Name"/>
<Passenger Seq="2" Id="124" Name="Test Name2"/>
</Passengers>
</Document>
<Document Count="2">
<Customer Id="2" Type="0"/>
<Passengers>
<Passenger Seq="1" Id="1130" Name="Test Name123"/>
<Passenger Seq="2" Id="1131" Name="Test Name34342"/>
</Passengers>
</Document>
</Two>
</xml>
EOT
Here's how to find all <Passenger> nodes and grab their data:
array = doc.search('Passenger').map{ |node|
{
id: node['Id'],
name: node['Name']
}
}
Here's what array looks like:
array
# => [{:id=>"13", :name=>"Test Name"},
# {:id=>"14", :name=>"Test Name4"},
# {:id=>"16", :name=>"Test Name10"},
# {:id=>"18", :name=>"Test Name30"},
# {:id=>"123", :name=>"Test Name"},
# {:id=>"124", :name=>"Test Name2"},
# {:id=>"1130", :name=>"Test Name123"},
# {:id=>"1131", :name=>"Test Name34342"}]
I'm using a CSS selector. Because I wanted all the "Passenger" nodes, then search becomes easy and doesn't require drilling down through the chain of parent nodes.
An array of hashes is awkward to use/reuse though. I'd recommend using a regular hash if there is no chance of collisions in :id:
hash = doc.search('Passenger').map{ |node| [node['Id'], node['Name']] }.to_h
hash
# => {"13"=>"Test Name",
# "14"=>"Test Name4",
# "16"=>"Test Name10",
# "18"=>"Test Name30",
# "123"=>"Test Name",
# "124"=>"Test Name2",
# "1130"=>"Test Name123",
# "1131"=>"Test Name34342"}
If you need to dynamically track all the parameters for Passenger nodes, whenever new ones are added or old ones deleted:
hash = doc.search('Passenger').map{ |node|
[
node['Id'],
node.attribute_nodes.map{ |a|
[a.name, a.value]
}.to_h
]
}.to_h
hash
# => {"13"=>{"Seq"=>"1", "Id"=>"13", "Name"=>"Test Name"},
# "14"=>{"Seq"=>"2", "Id"=>"14", "Name"=>"Test Name4"},
# "16"=>{"Seq"=>"1", "Id"=>"16", "Name"=>"Test Name10"},
# "18"=>{"Seq"=>"2", "Id"=>"18", "Name"=>"Test Name30"},
# "123"=>{"Seq"=>"1", "Id"=>"123", "Name"=>"Test Name"},
# "124"=>{"Seq"=>"2", "Id"=>"124", "Name"=>"Test Name2"},
# "1130"=>{"Seq"=>"1", "Id"=>"1130", "Name"=>"Test Name123"},
# "1131"=>{"Seq"=>"2", "Id"=>"1131", "Name"=>"Test Name34342"}}
Basically that'll create a hash representation of the node, which can be good or bad, depending on what you're trying to do with the data.