FastXML

Fast Ruby Hash to XML and XML to Ruby Hash converter written in pure C.

Installation

Add this line to your application's Gemfile:

gem 'fast-xml'

And then execute:

$ bundle

Or install it yourself as:

$ gem install fast-xml

Release Notes

See CHANGELOG.md

Usage

Convert hash toXML

require 'fastxml'

FastXML.hash2xml({ tag1: { tag2: 'content' } }, indent: 2)
# =>
# <?xml version="1.0" encoding="utf-8"?>
# <root>
#   <tag1>
#     <tag2>content</tag2>
#   </tag1>
# </root>

# use enumerator
FastXML.hash2xml({ enumerator: 3.times }, indent:  2)
# =>
# <?xml version="1.0" encoding="utf-8"?>
# <root>
#   <enumerator>0</enumerator>
#   <enumerator>1</enumerator>
#   <enumerator>2</enumerator>
# </root>

# output to file handle
# fh = StringIO.new
FastXML.hash2xml({ enumerator: 3.times }, indent:  2, output: fh)
fh.string
# =>
# <?xml version="1.0" encoding="utf-8"?>
# <root>
#   <enumerator>0</enumerator>
#   <enumerator>1</enumerator>
#   <enumerator>2</enumerator>
# </root>

Convert XML to hash

FastXML.xml2hash('<root><a>aaa</a><a>aaa2</a><b attr="bbb">bbb2</b></root>')
# => {"a"=>["aaa", "aaa2"], "b"=>{"attr"=>"bbb", "content"=>"bbb2"}}

# use filter
FastXML.xml2hash('<root><a>aaa</a><a>aaa2</a><b>bbb</b></root>', filter: '/root/a') do |node|
  p node
end
# =>
# {"a"=>"aaa"}
# {"a"=>"aaa2"}

Options

The following options are available to pass to FastXML.hash2xml(hash, options = {}).

• :root => 'root' # hash2xml

  • Root node name.

• :version => '1.0' # hash2xml

  • XML document version

• :encoding => 'utf-8' # hash2xml + xml2hash

  • XML input/output encoding

• :indent => 0 # hash2xml

  • if indent great than 0, XML output should be indented according to its hierarchic structure. This value determines the number of spaces.

  • if indent is 0, XML output will all be on one line.

• :output => nil # hash2xml

  • XML output method

  • if output is nil, XML document dumped into string.

  • if output is filehandle, XML document writes directly to a filehandle or a stream.

• :canonical => false # hash2xml

  • if canonical is true, the converter will be write hashes sorted by key.

  • if canonical is false, the order of the element will be pseudo-randomly.

• :use_attr => false # hash2xml

  • if use_attr is true, the converter will be use the attributes.

  • if use_attr is fale, the converter will be use tags only.

• :content => 'content' # hash2xml + xml2hash

  • The key name for the text content.

• :force_array => nil # xml2hash

  • When this option is true, the converter will be to force nested elements to be represented as arrays even when there is only one.

    FastXML.xml2hash('<root><a>aaa</a></root>', force_array: true)

    will be converted to:

    { "a" => ["aaa"] }

    instead of:

    { "a" => "aaa" }

  • When this option is an array, this allows to specify a list of element names which should always be forced into an array representation, rather than the 'all or nothing' approach above.

    FastXML.xml2hash('<root><a>aaa</a><b>bbb</b></root>', force_array: ['a'])

    will be converted to:

    { "a" => ["aaa"], "b" => "bbb" }

    FastXML.xml2hash('<root><a>aaa</a><a2>aaa</a2><b>bbb</b></root>', force_array: [/^a/])

    will be converted to:

    { "a" => ["aaa"], "a2" => ["aaa"], "b" => "bbb" }

• :force_content => false # xml2hash

  • When this options is true, this allows you to force text content to always convert to a hash value.

    FastXML.xml2hash('<root><a>value</a></root>', force_content: true)

    will be converted to:

    { "a" => { "content" => "value" } }

    instead of:

    { "a" => "value" }

• :merge_text => false # xml2hash

  • Setting this option to true will cause merge adjacent text nodes.

    FastXML.xml2hash('<root>value1<!-- comment -->value2</root>', merge_text: true)

    will be converted to:

    "value1value2"

    instead of:

    ["value1", "value2"]

• :xml_decl => true # hash2xml

  • if xml_decl is true, output will start with the XML declaration <?xml version="1.0" encoding="utf-8"?>

  • if xml_decl is false, XML declaration will not be output.

• :trim => false # hash2xml + xml2hash

  • Trim leading and trailing whitespace from text nodes.

• :utf8 => true # hash2xml + xml2hash

  • Turn on utf8 flag for strings if is true.

• :max_depth => 1024 # xml2hash

  • Maximum recursion depth.

• :buf_size => 4096 # hash2xml + xml2hash

  • Buffer size for reading end encoding data.

• :keep_root => false # xml2hash

  • Keep root element.

    FastXML.xml2hash('<root>value1</root>', keep_root: true)

    will be converted to:

    { "root" => "value1" }

    instead of:

    "value1"

• :filter => nil # xml2hash

  • Filter nodes matched by pattern and return an array of nodes.

    FastXML.xml2hash('<root><a>aaa</a><a>aaa2</a><b>bbb</b></root>', filter: '/root/a')

    will be converted to:

    [{ "a" => "aaa" }, { "a" => "aaa2" }]

    FastXML.xml2hash('<root><a>aaa</a><a>aaa2</a><b>bbb</b></root>', filter: /a|b/)

    will be converted to:

    [{ "a" => "aaa" }, { "a" => "aaa2" }, { "b" => "bbb" }]

    FastXML.xml2hash('<root><a>aaa</a><a>aaa2</a><b>bbb</b></root>', filter: ['/root/a', '/root/b'])

    will be converted to:

    [{ "a" => "aaa" }, { "a" => "aaa2" }, { "b" => "bbb" }]

  • You can pass a block as parameter.

    FastXML.xml2hash('<root><a>aaa</a><a>aaa2</a><b>bbb</b></root>', filter: '/root/a') do |node|
      p node
    end
    

    will be printed:

    {"a"=>"aaa"}
    {"a"=>"aaa2"}
    

    It may be used to parse large XML because does not require a lot of memory.

Configuration

  FastXML.configure do |config|
    config.trim = true
  end

Benchmarks

Performance benchmark in comparison with some popular gems:

Converting Hash to XML:
                           user     system      total        real
activesupport(rexml)    10.920000   0.010000  10.930000 ( 10.948205)
activesupport(libxml)   10.880000   0.000000  10.880000 ( 10.910649)
activesupport(nokogiri) 10.880000   0.000000  10.880000 ( 10.899013)
xmlsimple                1.490000   0.000000   1.490000 (  1.504655)
fastxml                  0.020000   0.000000   0.020000 (  0.018095)
Converting XML to Hash:
                 user     system      total        real
activesupport(rexml)     8.420000   0.000000   8.420000 (  8.441763)
activesupport(libxml)    1.110000   0.010000   1.120000 (  1.109242)
activesupport(nokogiri)  1.660000   0.000000   1.660000 (  1.666208)
xmlsimple                8.390000   0.010000   8.400000 (  8.427240)
nori                     2.010000   0.000000   2.010000 (  2.016399)
xmlhasher                0.440000   0.000000   0.440000 (  0.433211)
fastxml                  0.070000   0.000000   0.070000 (  0.073124)

License

The gem is available as open source under the terms of the MIT License.