Awesome

SAXMap

Converts an XML String or an XML file stream to a Map.

Benefit from Saxy's SAX mode, this library has a good conversion efficiency.

Installation

def deps do
  [
    {:sax_map, "~> 1.4"}
  ]
end

Example

iex(1)> xml = """
...(1)> <?xml version="1.0" encoding="UTF-8"?>
...(1)> <thread>
...(1)>   <title>Hello</title>
...(1)>   <items>
...(1)>     <item>item1</item>
...(1)>     <item>item2</item>
...(1)>   </items>
...(1)> </thread>
...(1)> """
iex(2)> SAXMap.from_string(xml)
{:ok,
 %{
   "thread" => %{"items" => %{"item" => ["item1", "item2"]}, "title" => "Hello"}
 }}

By default SAXMap.from_string will ignore all attributes of elements in the result, if you want to merge the attributes as the child elements, please use ignore_attribute option to achieve this:

xml = """
  <thread version="1">
    <title color="red" font="16">Hello</title>
    <items size="3">
      <item font="12">item1</item>
      <item font="12">item2</item>
      <item font="12">item3</item>
    </items>
  </thread>
"""

SAXMap.from_string(xml, ignore_attribute: false)

{:ok,
  %{
    "thread" => %{
      "content" => %{
        "items" => %{
          "content" => %{
            "item" => [
              %{"content" => "item1", "font" => "12"},
              %{"content" => "item2", "font" => "12"},
              %{"content" => "item3", "font" => "12"}
            ]
          },
          "size" => "3"
        },
        "title" => %{"color" => "red", "content" => "Hello", "font" => "16"}
      },
      "version" => "1"
    }
  }}

SAXMap.from_string(xml, ignore_attribute: {false, "@"})
{:ok,
  %{
    "thread" => %{
      "@version" => "1",
      "content" => %{
        "items" => %{
          "@size" => "3",
          "content" => %{
            "item" => [
              %{"@font" => "12", "content" => "item1"},
              %{"@font" => "12", "content" => "item2"},
              %{"@font" => "12", "content" => "item3"}
            ]
          }
        },
        "title" => %{"@color" => "red", "@font" => "16", "content" => "Hello"}
      }
    }
  }}

Please note: The ignore_attribute: false equals ignore_attribute: {false, ""}, in this case, the child elements will be automatically naming with "content" as the key of the key-value pair to distinct this key-value pair is from XML text content or attribute. Currently, the "content" naming is a reserved keyword, please be careful to distinguish it from the XML node name when transfer an XML to a Map be with XML attributes.

Benchmark

Only for your reference, all credit goes to Saxy, the details of benchmark can be found in the bench directory of the repository.

Run:

mix run xml_to_map.exs

Output:

Operating System: macOS
CPU Information: Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
Number of Available Cores: 16
Available memory: 32 GB
Elixir 1.12.2
Erlang 24.0.4

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 10 s
memory time: 2 s
parallel: 1
inputs: none specified
Estimated total run time: 42 s

Benchmarking SAXMap.from_string ignore attribute...
Benchmarking SAXMap.from_string with attribute...
Benchmarking XmlToMap.naive_map...

Name                                          ips        average  deviation         median         99th %
SAXMap.from_string ignore attribute      105.03 K        9.52 μs   ±129.42%           9 μs          33 μs
SAXMap.from_string with attribute         96.74 K       10.34 μs   ±110.08%           9 μs          35 μs
XmlToMap.naive_map                        26.31 K       38.01 μs    ±46.21%          33 μs         105 μs

Comparison:
SAXMap.from_string ignore attribute      105.03 K
SAXMap.from_string with attribute         96.74 K - 1.09x slower +0.82 μs
XmlToMap.naive_map                        26.31 K - 3.99x slower +28.49 μs

Memory usage statistics:

Name                                   Memory usage
SAXMap.from_string ignore attribute        14.61 KB
SAXMap.from_string with attribute          16.69 KB - 1.14x memory usage +2.08 KB
XmlToMap.naive_map                         40.90 KB - 2.80x memory usage +26.29 KB

**All measurements for memory usage were the same**