Letterbox.MIME.Header (Letterbox v0.1.0-rc.0)

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The headers of an email or of one of its parts (RFC 5322 and MIME), read as mail clients write them, not only as the RFCs say they should.

  • parse/1 - a block of headers as {name, value} pairs, in their order: names in lowercase, values unfolded and not yet decoded.
  • decode/1 - a value's encoded words (RFC 2047, =?utf-8?Q?Jos=C3=A9?=) in UTF-8, adjacent ones of one charset joined before they are read, so a character split across two words survives; raw 8-bit text (RFC 6532) as UTF-8, else as Windows-1252.
  • params/1 - a structured value (Content-Type, Content-Disposition): its value and its parameters, with RFC 2231's (filename*=utf-8''praia%20%C3%A0%20tarde.jpg, and the parts of a long one, filename*0*, filename*1*) and the encoded words that Outlook and Gmail put in quoted ones.

Summary

Types

t()

A header: its name in lowercase, and its value as it came, unfolded.

Functions

decode(value)

A header's value in UTF-8: its encoded words decoded, and the spaces between two of them taken out, as RFC 2047 says.

get(headers, name)

The first value of name (lowercase) in headers, or nil.

get_all(headers, name)

Every value of name (lowercase) in headers, in their order.

params(value)

A structured value and its parameters: {"multipart/mixed", %{"boundary" => "…"}}. The value is in lowercase and so are the parameters' names; their values are decoded (RFC 2231, RFC 2047, quoted strings) to UTF-8.

parse(block)

The headers of a block of header lines (CRLF or LF), unfolded. A line that is not a header and does not continue one is left out.

Types

t()

@type t() :: {String.t(), String.t()}

A header: its name in lowercase, and its value as it came, unfolded.

Functions

decode(value)

@spec decode(String.t() | nil) :: String.t() | nil

A header's value in UTF-8: its encoded words decoded, and the spaces between two of them taken out, as RFC 2047 says.

get(headers, name)

@spec get([t()], String.t()) :: String.t() | nil

The first value of name (lowercase) in headers, or nil.

get_all(headers, name)

@spec get_all([t()], String.t()) :: [String.t()]

Every value of name (lowercase) in headers, in their order.

params(value)

@spec params(String.t() | nil) ::
  {String.t() | nil, %{required(String.t()) => String.t()}}

A structured value and its parameters: {"multipart/mixed", %{"boundary" => "…"}}. The value is in lowercase and so are the parameters' names; their values are decoded (RFC 2231, RFC 2047, quoted strings) to UTF-8.

parse(block)

@spec parse(binary()) :: [t()]

The headers of a block of header lines (CRLF or LF), unfolded. A line that is not a header and does not continue one is left out.