How to iterate XML nested elements using Nokogiri in Ruby

Question

I'm trying to iterate over the folder structure in XML using Nokogiri, but I'm stuck with this:

<test>
   <folder name="Folder A">
      <folder name="Folder A1">
         <file name="a.txt">Cool file</file>
      </folder>
      <folder name="Folder A2"></folder>
   </folder>
   <folder name="Folder B">
      <folder name="Folder B1"></folder>
      <folder name="Folder B2">
         <folder name="Folder B21">
            <file name="b.txt"></file>
         </folder>
   </folder>
</test>

So, I want to go over this in order to be able to create a tree of folders and files (folders A1 and A2 are inside folder A, folders B1 and B2 are inside folder B, and folder B21 is inside folder B2).

So, I am doing this:

nodes = allnodes.xpath('//folder')
nodes.each do |node|
  puts "name => #{node.attributes['name']}"
end

but it lists me all the folders (A, A1, A2, B, B1, B2, B21). How can I do this so that I do not check inside the previous folders for more folders and then send it to the same recursive function?

Thank you very much for your help:)

Answer 1

XPath //foo, foo . ./foo foo, . :

# Given an XML node, yields the node and all <file> children
# Then recursively does the same with every <folder> child
def process_files_and_folders(node,&blk)   
  yield node, node.xpath('file')
  node.xpath('folder').each{ |folder| process_files_and_folders(folder,&blk) }
end

() ( ) () , &blk, .

:

require 'nokogiri'
doc = Nokogiri.XML(my_xml)
process_files_and_folders( doc.root ) do |folder,files|
  depth  = folder.ancestors.length-1  # Just for pretty text output indenting
  indent = "  "*depth                 # Just for pretty text output indenting
  if folder['name']
    puts "#{indent}Processing the folder named #{folder['name']}"
  else
    puts "#{indent}No folder name; probably the root element."
  end
  unless files.empty?
    puts "#{indent}There are #{files.length} files in '#{folder['name']}':"
    files.each{ |file| print indent, file['name'], "\n" }
  end
end

:

No folder name; probably the root element.
  Processing the folder named Folder A
    Processing the folder named Folder A1
    There are 1 files in 'Folder A1':
    a.txt
    Processing the folder named Folder A2
  Processing the folder named Folder B
    Processing the folder named Folder B1
    Processing the folder named Folder B2
      Processing the folder named Folder B21
      There are 1 files in 'Folder B21':
      b.txt

Answer 2

, :

require 'nokogiri'

doc = Nokogiri::XML(<<-xml)
<test>
   <folder name="Folder A">
      <folder name="Folder A1">
         <file name="a.txt">Cool file</file>
      </folder>
      <folder name="Folder A2"></folder>
   </folder>
   <folder name="Folder B">
      <folder name="Folder B1"></folder>
      <folder name="Folder B2">
         <folder name="Folder B21">
            <file name="b.txt"></file>
         </folder>
   </folder>
</test>
xml

# Here I am collecting all folders, which has at-least one child.
parent_folders = doc.xpath("//folder").select do|folder_node|
  folder_node.xpath("./folder").size > 0
end

# Here I will iterate each parent directory, and would collect the corresponding
# sub-directories names.
parent_directory = parent_folders.each_with_object({}) do |parent_dir,dir_hash|
  dir_hash[parent_dir['name']] = parent_dir.xpath("./folder").collect do |sub_dir|
    sub_dir['name']
  end
end

parent_directory
# => {"Folder A"=>["Folder A1", "Folder A2"],
#     "Folder B"=>["Folder B1", "Folder B2", "Folder B21"],
#     "Folder B2"=>["Folder B21"]}

hash parent_directory, ()/ (). , Hash#[], . -

parent_directory['Folder A'] # => ["Folder A1", "Folder A2"]

Answer 3

, , , Linux.

doc.xpath("//folder[not(folder)]").each do |f|
   path = f.xpath("ancestor-or-self::folder").map{|f| f['name']}.join("/")
   system("mkdir -p #{path}")
end

:

• ( XML)
• , "".
• , "mkdir -p" .

Answer 4

, , .

, ​​:

def create_structure(nodeset, current_folder)
    new_folder = "#{current_folder }/#{nodeset.attributes['name']"
    Dir.makedir(new_folder)
    create_files_in_current_folder(nodeset, new_folder)
    subnodeset = nodeset.xpath('/folder')
    subnodeset.each do |node|
        create_structure(node, new_folder)
    end
end

, xml, .

, , . "//", "/folder", , xml, , node.

, . , .