cx-platform-mail

Why reach for it

Both halves of mail, each in one call. cx-platform-mail is SMTP and IMAP as a CX program meets them: a submission client that dials, greets, upgrades, authenticates, sends and quits in one verb, a mailbox client that connects and reads by UID in one verb, the two server cores a CX process serves either protocol from, and the SASL registry they share — byte-pinned to the RFC vectors.

The common way a mail client is broken is a step its author forgot, so submit and connect have no steps to forget: there is no separate STARTTLS verb, no login verb, no ENABLE verb. Partial acceptance is a value — submit answers a row per recipient — and the IMAP surface is UID-only, because a sequence number renumbers on every EXPUNGE and a client that computed one is a client about to act on the wrong message.

The server cores decide meaning and open nothing, which is what lets the corpus grade them without a socket: the message terminator and its near-misses, dot-stuffing and its inverse, the RFC 5321 minimums for line, path and recipient counts, size claims that overflow, AUTH refused on a cleartext connection under a TLS policy. sasl carries the mechanism registry for both: PLAIN, OAUTHBEARER and XOAUTH2 emission pinned to the published vectors, the GS2 refusals, and a downgrade — a token offered to a password-only server, or the reverse — refused before a credential is sent.

What it gives you

Three modules: the two protocols, in the platform group, and sasl, a Ring 1 module that keeps its cx-stdlib namespace because a program imports it the same way whichever repository carries it. Each links to the reference page projected from the module's own documentation.

Try it

The first exchange of RFC 4616 §4, derived by hand in the case and graded byte for byte: the PLAIN initial response for tim, as the wire carries it and as the decoded octets, the two NULs where the standard puts them.

        [?lib 'cx-stdlib/sasl']
[?lib 'cx-stdlib/bytes']
[?let [= $a [sasl-auth mechanism=:plain authcid="tim" secret="tanstaaftanstaaf"]]
      [= $ir [$bytes:to-string-utf8 [$sasl:initial-response $a]]]
  [probe [wire $ir] [clear [$bytes:to-hex [$bytes:from-base64 $ir]]]]]
      

        $ cx prog.cx
[probe [wire AHRpbQB0YW5zdGFhZnRhbnN0YWFm] [clear 0074696d0074616e737461616674616e7374616166]]
      

Status

The mail repository builds on the wire and is built on by the application host; the front door compiles its V module from the pin, and the module's own initialisation registers the two pure server cores with the language, so the core names no product.

Links

• github.com/cx-home/cx-platform-mail — the repository
• README — what it is, how to install it, what it pins
• spec/03-approved — the specification, the only truth
• spec/03-approved/platform — the specification, the only truth
• conformance — the conformance corpus, the executable truth
• conformance/platform — the conformance corpus, the executable truth