PlugMultipartRelated

Parses multipart/related request body.

This is a partial implementation of RFC2387. This implementation is heavily influence by Plug.Parsers.MULTIPART which is shipped with Plug.

The following choices have been made regarding support for the RFC2387 specification:

• start-info parameter - The start-info parameter is ignored if specified.
• If no start parameter is given the first MIME part is marked as the root part.
• The Content-ID part header is REQUIRED for each part. If Content-ID is not present the part will be ignored.
• Content-Disposition is used to create Plug.Upload structs in the output

A HTTP request with the following Content-Type header and body:

Content-Type: multipart/related; type="application/soap+xml"; boundary=----w58EW1cEpjzydSCq; start="part1"

------w58EW1cEpjzydSCq\r
Content-Disposition: form-data; name=\"info\"; filename=\"foo.txt\"\r
Content-ID: part1\r
Content-Type: text/plain\r
\r
bar
\r
------w58EW1cEpjzydSCq\r
Content-ID: part2\r
Content-Type: text/plain\r
\r
foobar\r
------w58EW1cEpjzydSCq\r
Content-Type: text/plain\r
\r
ignored\r
------w58EW1cEpjzydSCq--\r

Will be available in Plug.Conn as follows:

%{
  "part1" => %{
    "body" => %Plug.Upload{
      content_type: "text/plain",
      filename: "foo.txt",
      path: "/var/folders/hf/pd3rksm54wj6hfznxz9tv36c0000gn/T//plug-1540/multipart-1540203239-599604070647209-1"
    },
    "start" => true
},
  "part2" => %{
    "body" => "foobar"
  }
}

Options

All options supported by Plug.Conn.read_body/2 are also supported here. They are repeated here for convenience:

• :length - sets the maximum number of bytes to read from the request, defaults to 8_000_000 bytes
• :read_length - sets the amount of bytes to read at one time from the underlying socket to fill the chunk, defaults to 1_000_000 bytes
• :read_timeout - sets the timeout for each socket read, defaults to 15_000ms

So by default, Plug.Parsers will read 1_000_000 bytes at a time from the socket with an overall limit of 8_000_000 bytes.

Besides the options supported by Plug.Conn.read_body/2, the multipart parser also checks for :headers option that contains the same :length, :read_length and :read_timeout options which are used explicitly for parsing multipart headers.

Installation

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

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

Configure in a Phoenix.Endpoint for example:

plug Plug.Parsers,
  parsers: [PlugMultipartRelated],
  pass: ["multipart/related"],
  read_length: 500_000, length: 4_000_000

Documentation can be found at https://hexdocs.pm/plug_multipart_related.