trivialmessage 0.0.4

A trivial message platform abstraction layer (Fastmail/IMAP/SMTP; more platforms WIP).

TrivialMessage

A small, composable library that normalizes “messages” from different platforms (email today; others later) behind a single interface.

The goal is to make it easy to:

• fetch unread messages (polling),
• listen for new messages (async generators),
• send/reply/forward when supported,
• apply consistent filtering (sender/recipient/subject/time windows),
• keep datetimes normalized to UTC.

Note: Several platforms (Gmail/Outlook/Slack/WhatsApp) are intentionally WIP and may be stubbed or absent.

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Installation

Base install (interfaces + core models/utilities):

pip install trivialmessage

Email support (Fastmail + IMAP/SMTP helpers):

pip install "trivialmessage[email]"

If you keep Protonmail Bridge support in this library (optional):

pip install "trivialmessage[protonmail]"

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Concepts

Message

All platforms yield a Message object (or a dict with the same shape, depending on your integration layer). The message is intended to be JSON-friendly and stable across sources.

Typical fields:

• message_id (stable external id if available)
• from, to, cc, bcc
• subject
• text, html
• date (send-time, if known) normalized to UTC
• internaldate (receive-time, if known) normalized to UTC
• raw_headers (dict of headers when available)
• platform-specific metadata (e.g. uid for IMAP-like sources)

Filters

Platforms accept a MessageFilter (or a list of them) to limit what you fetch/listen to.

Common filter fields:

• sender/recipient matching should be case-insensitive (addresses are normalized)
• datetime comparisons should be against UTC-aware datetimes

Example filter patterns you’ll commonly want:

• “from is in allowlist”
• “to contains support@…”
• “subject contains keyword”
• “received since ”
• “only unread”

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Platform API

All platforms implement the same general interface (some methods may raise NotImplementedError / PlatformNotSupported if the platform can’t do that operation).

Core methods

• get_unread(filters=...) -> list[Message] Fetch unread messages (polling style).

• listen(filters=..., **opts) -> AsyncIterator[Message] Yield messages as they arrive. Must not block other platforms if you compose multiple listeners.

• send(to, subject, text=None, html=None, cc=None, bcc=None, **opts) -> Message Send a new outbound message.

• reply(message, text=None, html=None, **opts) -> Message Reply to an existing inbound message.

• forward(message, to, text=None, html=None, **opts) -> Message Forward an existing message to a new recipient.

Capability notes

Not every platform can both send and receive.

• Some platforms are receive-only (e.g., IMAP if you only configure IMAP and no SMTP).
• Some platforms are send-only (e.g., SMTP-only configuration).
• If a method is unsupported, it should fail fast with a clear exception.

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Platforms

Fastmail

Fastmail is treated as a first-class platform (HTTP API).

Credentials

You’ll need an API token from Fastmail.

High-level steps:

1. Log in to Fastmail.
2. Create an API token in Fastmail settings (app/password/token section).
3. Provide it to the platform via env var or explicit constructor argument.

Common env var:

• FASTMAIL_API_TOKEN (your token)

Usage

import asyncio

from trivialmessage.platform.fastmail import FastmailPlatform
from trivialmessage.types import MessageFilter  # name may vary in your codebase

fm = FastmailPlatform.from_env()

# Poll unread
msgs = fm.get_unread(filters=[
    MessageFilter(from_email="[e-mail]"),
])

# Listen for new mail
async def main():
    async for msg in fm.listen(filters=[MessageFilter(any_recipient="[e-mail]")]):
        print(msg.subject)

asyncio.run(main())

Platform-specific concerns

• Fastmail provides stable ids; message_id should be populated.
• Datetimes are normalized to UTC.
• If you apply sender/recipient filters, they should be case-insensitive (normalize first).

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IMAP

IMAP support is typically used for receiving messages.

Credentials

You’ll need standard IMAP credentials:

• host (e.g., imap.fastmail.com)
• port (usually 993 for SSL)
• username
• password (or app password)
• folder (optional; often INBOX)

If you’re using env vars, you’ll typically have something like:

• IMAP_HOST
• IMAP_PORT
• IMAP_USER
• IMAP_PASSWORD
• IMAP_SECURITY (SSL / STARTTLS / PLAINTEXT)
• IMAP_FOLDER

Usage

import asyncio

from trivialmessage.platform.imap import IMAPPlatform

imap = IMAPPlatform.from_env()

# Poll unread
unread = imap.get_unread()

# Listen (async generator)
async def main():
    async for msg in imap.listen():
        print(msg.from_email, msg.subject)

asyncio.run(main())

Platform-specific concerns

• IMAP is generally receive-only.

  • send, reply, forward should fail (unsupported) unless you separately configure SMTP and use a different platform for sending.

• Depending on server behavior, “fetching” can set flags unless you use BODY.PEEK semantics; implementations should avoid accidentally marking mail seen.

• IMAP UID exists but may not be stable across folders/servers; prefer message_id when possible.

---

SMTP

SMTP is typically used for sending messages.

Credentials

You’ll need standard SMTP credentials:

• host (e.g., smtp.fastmail.com)
• port (commonly 465 for SSL or 587 for STARTTLS)
• username
• password (or app password)
• from address (optional override)

Common env vars:

• SMTP_HOST
• SMTP_PORT
• SMTP_USER
• SMTP_PASSWORD
• SMTP_SECURITY (SSL / STARTTLS / PLAINTEXT)
• SMTP_EMAIL_FROM (optional)

Usage

from trivialmessage.platform.smtp import SMTPPlatform

smtp = SMTPPlatform.from_env()

sent = smtp.send(
    to="[e-mail]",
    subject="Hello",
    text="This is a test.",
)
print(sent.message_id)

Platform-specific concerns

• SMTP is generally send-only.

  • get_unread / listen should fail (unsupported).

• If you need bidirectional email, configure both an IMAP platform (receive) and SMTP platform (send), or use a single provider platform that supports both (e.g., Fastmail API).

---

Protonmail (Bridge) (optional / legacy-compatible)

This platform exists only if you keep it around and install the extra.

Credentials

Protonmail typically requires running Protonmail Bridge locally/in-container.

This is complex and usually deployed as a dedicated variant. If you’re using it:

• ensure the Bridge is running and exposes IMAP + SMTP locally
• set the bridge IMAP/SMTP credentials (often generated by Bridge)

Typical env var contract (example):

• BRIDGE_IMAP_USER
• BRIDGE_IMAP_PASSWORD
• BRIDGE_IMAP_HOST (default 127.0.0.1)
• BRIDGE_IMAP_PORT (default 1143)
• BRIDGE_IMAP_SECURITY (STARTTLS/SSL/PLAINTEXT)
• and similar SMTP vars if sending

Usage

import asyncio
from trivialmessage.platform.protonmail import ProtonmailPlatform

pm = ProtonmailPlatform.from_env()

# Receive
msgs = pm.get_unread()

# Send (via Bridge SMTP)
pm.send(to="[e-mail]", subject="Hi", text="...")

async def main():
    async for msg in pm.listen():
        print(msg.subject)

asyncio.run(main())

Platform-specific concerns

• Running Bridge is operationally heavy; treat it as a separate deployment.
• Bridge IMAP/SMTP are local-only; don’t expose those ports publicly.
• Message ids and header behavior depend on Bridge; your implementation should normalize to the same Message shape.

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Composing listeners

A common pattern is to listen to multiple platforms concurrently and yield messages as soon as they arrive from any source.

Desired usage:

compose(
  fastmail.listen(filters=fs),
  protonmail.listen(filters=fs),
  whatsapp.listen(filters=fs),
)

The intended behavior:

• start all listeners concurrently,
• yield messages from whichever source produces next,
• do not block other sources,
• (error handling strategy is up to the caller / composition helper).

This repo expects a helper for that pattern (either provided here or in your application layer).

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Development

• Python: 3.10+ recommended
• Style: keep message payloads JSON-friendly
• Datetimes: always normalize to UTC-aware values
• Filters: normalize addresses for case-insensitive comparisons