@spec add_part(t(), Multipart.Part.t()) :: t()

Adds a part to the Multipart message.

@spec body_binary(t()) :: binary()

Returns a binary of the Multipart message body.

This uses body_stream/1 under the hood.

@spec body_stream(t()) :: Enum.t()

Returns a Stream of the Multipart message body.

@spec content_length(t()) :: pos_integer()

Returns the length of the Multipart message in bytes.

It uses the content_length property in each of the message parts to calculate the length of the multipart message without reading the entire body into memory. content_length is set on the Multipart.Part by the constructor functions when possible, such as when the in-memory binary or the file on disk can be inspected.

This will throw an error if any of the parts does not have content_length defined.

@spec content_type(t(), String.t(), Keyword.t()) :: String.t()

Returns the Content-Type header for the Multipart message.

Pass in Keyword option :quote_boundary set false to disable quoting the boundary.

iex> multipart = Multipart.new("abc123")
iex> Multipart.content_type(multipart, "multipart/mixed")
"multipart/mixed; boundary=\"abc123\""
iex> Multipart.content_type(multipart, "multipart/mixed", quote_boundary: false)
"multipart/mixed; boundary=abc123"

@spec new(String.t()) :: t()

Create a new Multipart request.

Pass in the boundary as the first argument to set it explicitly, otherwise it will default to a random 16 character alphanumeric string padded by == on either side.

The boundary must conform to the RFC 2046 boundary grammar (1-70 of the allowed bcharsnospace characters); anything else raises ArgumentError. The default boundary is a 128-bit random token, so it is safe against a part body that happens to contain the boundary. If you supply a custom boundary you are responsible for ensuring it cannot appear in any part body.