mailibex

Library containing Email related implementations in Elixir : dkim, spf, dmark, mimemail, smtp

MimeMail

%MimeMail{headers: [{key::atom, {:raw,binary} | MimeMail.Header.t}], body: binary | [MimeMail.t] | {:raw,binary}}
# headers contains a keywordlist of either the raw form of the header, 
# or an encodable version of the header (a term with a module implementing MimeMail.Header.to_ascii)
# body contains either the raw binary body, the decoded body as a binary (using content-transfer-encoding), 
# or a list of MimeMail struct to encode in case of a multipart
# If body is a text, then the decoded body binary will be the UTF8 version of the text converted from the source charset

• MimeMail.from_string parse the mimemail binary into a MimeMail struct explained above, with all the headers and body in their encoded form ({:raw,binary})
• MimeMail.encode_headers(mail) apply the MimeMail.Header.to_ascii to every header to convert them into a {:raw,binary} form.
• MimeMail.decode_headers(mail,[Mod1,Mod2]) applies successively Mod1.decode_headers(mail) the Mod2.decode_headers(mail) to the result.
• MimeMail.encode_body(mail) encodes the mail body from a decoded form (binary | [MimeMail]) into a {:raw,binary}form
• MimeMail.decode_body(mail) does the opposite.
• MimeMail.to_string(mail) encode headers and body of a MimeMail into an ascii mail binary.

Currently, the library contains three types of acceptable header value (implementing MimeMail.Header) :

• binary : simple binary headers are utf8 strings converted into encoded words
• {value,%{}=params} are only acceptable tuple as header, converted into a 'content-*' style header ( value; param1=value1, param2=value2)
• [%MimeMail.Address{name="toto", address: "[email protected]"}] : lists are encoded into mailbox list header
• %DKIM{} : Converted into a dkim header

So for instance :

%MimeMail{headers: [
    to: [%MimeMail.Address{name: "You",address: "[email protected]"}],
    from: [%MimeMail.Address{name: "Me",address: "[email protected]"}],
    cc: "[email protected]", # only ascii so ok to encode it as a simple encoded word
    'content-type': {'text/plain',%{charset: "utf8"}},
  ],
  body: "Hello world"}
|> MimeMail.to_string

FlatMail

Flat mail representation of MimeMail is simply a KeywordList where all the keys [:txt,:html,:attach,:attach_in,:include] are used to construct the body tree of alternative/mixed/related multiparts in the body field of the MimeMail struct, and the rest of the KeywordList became the header field.

MimeMail.Flat.to_mail(from: "[email protected]", txt: "Hello world", attach: "attached plain text", attach: File.read!("attachedfile"))
|> MimeMail.to_string

Need more explanations here...

MimeTypes

ext2mime and mime2ext are functions generated at compilation time from the apache mime configuration file https://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types .

"image/png" = MimeTypes.ext2mime(".png")
".png" = MimeTypes.mime2ext("image/png")

bin2ext matches the begining of the binary and sometimes decode the binary in order to determine the file extension (then we can use ext2mimeto find the mime type if needed.

".webm" = MimeTypes.bin2ext(File.read!("path/to/my/webm/file.webm"))

DKIM

[rsaentry] =  :public_key.pem_decode(File.read!("test/mails/key.pem"))
mail = MimeMail.from_string(data)

mail = DKIM.sign(mail,:public_key.pem_entry_decode(rsaentry), d: "order.brendy.fr", s: "cobrason")
case DKIM.check(mail) do
  :none      ->IO.puts("no dkim signature")
  {:pass,{key,org}}      ->IO.puts("the mail is signed by #{key} at #{org}")
  :tempfail  -> IO.puts("the dns record is unavailable, try later")
  {:permfail,msg}->IO.puts("the sender is not authorized because #{msg}")
end

Need more explanations here...

DMARC

Organizational Domain implementation using public suffix database : (https://publicsuffix.org/list/effective_tld_names.dat)

"orga2.gouv.fr" = DMARK.organization "orga0.orga1.orga2.gouv.fr"

SPF

Full implementation of the Sender Policy Framework (https://tools.ietf.org/html/rfc7208).

case SPF.check("[email protected]",{1,2,3,4}, helo: "relay.com", server_domain: "me.com") do
  :none      ->IO.puts("no SPF information")
  :neutral   ->IO.puts("nor authorized neither not authorized")
  :pass      ->IO.puts("the sender is authorized")
  {:fail,msg}->IO.puts("the sender is not authorized because #{msg}")
  :softfail  ->IO.puts("not authorized but don't be rude")
  :temperror ->IO.puts("temporary error, try again latter")
  :permerror ->IO.puts("spf error, ask to remote admin")
end

Current Status

• DKIM is fully implemented (signature/check), missing DKIM-Quoted-Printable token management
• mimemail encoding/decoding of headers and body are fully implemented
• flat mime body representation for easy mail creation / modification
• DMARC implementation of organizational domains
• SPF is fully implemented

TODO :

• DMARC report
• smtp client implementation
• smtp server implementation over Ranch

CONTRIBUTING

Hi, and thank you for wanting to contribute. Please refer to the centralized informations available at: https://github.com/kbrw#contributing