Nokogiri to_xml without carriage returns

Question

I'm currently using the Nokogiri::XML::Builder class to construct an XML document, then calling .to_xml on it. The resulting string always contains a bunch of spaces, linefeeds and carriage returns in between the nodes, and I can't for the life of me figure out how to get rid of them. Here's an example:

b = Nokogiri::XML::Builder.new do |xml|
  xml.root do
    xml.text("Value")
  end
end

b.to_xml

This results in the following:

<?xml version="1.0"?>
<root>Value</root>

What I want is this (notice the missing newline):

<?xml version="1.0"?><root>Value</root>

How can this be done? Thanks in advance!

Answer 1

Builder#to_xml by default outputs formatted (i.e. indented) XML. You can use the Nokogiri::XML::Node::SaveOptions to get an almost unformatted result.

b = Nokogiri::XML::Builder.new do |xml|
  xml.root do
    xml.foo do
      xml.text("Value")
    end
  end
end

b.to_xml
# => "<?xml version=\"1.0\"?>\n<root>\n  <foo>Value</foo>\n</root>\n"

b.to_xml(:save_with => Nokogiri::XML::Node::SaveOptions::AS_XML)
# => "<?xml version=\"1.0\"?>\n<root><foo>Value</foo></root>\n"

Now you could either just get rid of the XML header (which is optional anyway) and remove the last newline

b.to_xml(:save_with => Nokogiri::XML::Node::SaveOptions::AS_XML | Nokogiri::XML::Node::SaveOptions::NO_DECLARATION).strip
# => "<root><foo>Value</foo></root>"

Just removing all newlines in the XML is probably a bad idea as newlines can actually be significant (e.g. in <pre> blocks of XHTML). If that is not the case for you (and you are really sure of that) you could just do it.

Answer 2

This is not something that Nokogiri is designed to do. The closest you can get is to serialize the root of the document with no newlines or indentation, and then add the PI yourself (if you really need it):

require 'nokogiri'

b = Nokogiri::XML::Builder.new{ |xml| xml.root{ xml.foo "Value" } }
p b.to_xml
#=> "<?xml version=\"1.0\"?>\n<root>\n  <foo>Value</foo>\n</root>\n"

p b.doc.serialize(save_with:0)
#=> "<?xml version=\"1.0\"?>\n<root><foo>Value</foo></root>\n"

flat_root = b.doc.root.serialize(save_with:0)
p flat_root
#=> "<root><foo>Value</foo></root>"

puts %Q{<?xml version="1.0"?>#{flat_root}}
#=> <?xml version="1.0"?><root><foo>Value</foo></root>

Alternatively, you could simply cheat and do:

puts b.doc.serialize(save_with:0).sub("\n","")
#=> <?xml version="1.0"?><root><foo>Value</foo></root>

Note the usage of sub instead of gsub to only replace the first known-present newline.