Saxon (not released yet!)

Saxon is a highly opinionated XML request parser for Plug. It only supports parsing the HTTP requests whose Content-Type is application/vnd.saxon+xml.

The content type that Saxon handles is application/vnd.saxon+xml. Base64 encoded files can be embedded in the XML at any level. For flat request bodies with file upload, multipart/form-data is good. For hierarchical request bodies without embedded files, you should stick to application/json.

<map>
  <map name="article">
    <string name="title">Elixir Rocks</string>
    <integer name="author_id">1</integer>
    <timestamp name="published_at">2017-03-29T10:23:35Z</timestamp>
    <boolean name="private">false</boolean>
    <file name="logo" filename="logo.png" content-type="image/png">
      (Base64 encoded file content here)
    </file>
    <list name="sections">
      <map>
        <string name="content">Elixir really rocks.</string>
        <file name="photo" filename="awesome.jpg" content-type="image/jpeg">
          (Base64 encoded file content here)
        </file>
      </map>
      <map>
        <string name="content">Lorem ipsum ...</string>
        <file name="photo" filename="cool.png" content-type="image/png">
          (Base64 encoded file content here)
        </file>
      </map>
    </list>
  </map>
</map>

The parser parses such XML and yields

%{
  "article" => %{
    "title" => "Elixir Rocks",
    "author_id" => 1,
    "published_at" => %DateTime{year: 2017, month: 3, day: 29, hour: 10, minute: 23, second: 35, time_zone: "Etc/UTC", ...},
    "private" => false,
    "logo" => %Plug.Upload{filename: "logo.png", content_type: "image/png", ...},
    "sections" => [
      %{
        "content" => "Elixir really rocks.",
        "photo" => %Plug.Upload{filename: "awesome.jpg", content_type: "image/jpeg", ...}
      },
      %{
        "content" => "Lorem ipsum ...",
        "photo" => %Plug.Conn{filename: "cool.png" content_type: "image/png"}
      }
    ]
  }
}

Currently supported XML elements:

• string
• integer
• float
• boolean
• timestamp, the format of which must be ISO 8601. Timezone is required.
• file, allows attributes filename and content-type.
• list
• map, all the child elements of which must have a unique name attribute.

Installation

If available in Hex, the package can be installed by adding saxon to your list of dependencies in mix.exs:

def deps do
  [{:saxon, "~> 0.1.0"}]
end

NOT AVAILABLE ON HEX YET!

How to use

Just add Saxon to the parsers. Note that if you have a general XML parser in your parser chain, be sure to add Saxonbefore that parser.

plug Parsers, 
  parsers: [Saxon, :urlencoded, :multipart, :json],
  pass: ["*/*"],
  json_decoder: Poison

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/saxon.