pyactivesync

A Python client library exclusively for Exchange ActiveSync (EAS) 16.1, implementing enough of MS-ASCMD (the command protocol) and MS-ASWBXML (the binary XML encoding) to talk to a real Exchange server: folder listing, mail sync, item/attachment fetch, sending mail, contact writes, folder management, moving items, directory search, and push notifications via Ping.

Protocol version

Pyactivesync targets EAS 16.1 exclusively. Every request carries MS-ASProtocolVersion: 16.1; the version is not configurable and the library does not negotiate or fall back to older protocol versions. The server must advertise EAS 16.1 support.

Install

pip install pyactivesync

Usage

from email.message import EmailMessage
from pyactivesync import Client, EmailChange, FolderType, BodyType

with Client(
    server="mail.example.com",
    username=r"CORP\jdoe",       # NTLM-style domain\user, or a plain email -- both work
    password="...",
    device_id="MyApp01",          # caller-provided; persist it yourself for a stable
                                    # device identity across runs -- pyactivesync doesn't
                                    # persist anything to disk on its own
) as client:
    folders = client.list_folders()
    inbox = next(f for f in folders if f.type == FolderType.INBOX)
    drafts = next(f for f in folders if f.type == FolderType.DRAFTS)

    result = client.sync_folder(inbox.id)                              # bootstrap
    result = client.sync_folder(inbox.id, sync_key=result.sync_key)     # Add/Change/Delete

    ping = client.ping([inbox.id, drafts.id], heartbeat=60)
    print(ping.changed_folder_ids)

    for item in result.added:
        print(item.fields.get("Email.Subject"))
        fetched = client.fetch_item(inbox.id, item.server_id, body_type=BodyType.HTML)
        print(fetched.body.data if fetched.body else None)
        for attachment in fetched.attachments:
            data = client.fetch_attachment(attachment.file_reference)

    if result.added:
        # Mutations consume and advance the folder's SyncKey.
        changes = client.apply_email_changes(
            inbox.id,
            result.sync_key,
            [EmailChange(result.added[0].server_id, read=True, flagged=True)],
        )

    msg = EmailMessage()
    msg["To"] = "someone@example.com"
    msg["Subject"] = "hello from pyactivesync"
    msg.set_content("plain text body")
    client.send_mail(msg)

    # Sync Add is EAS 16.1's draft-creation operation. It consumes the
    # Drafts collection's current SyncKey and returns the next key + ServerId.
    draft_sync = client.sync_folder(drafts.id)
    created = client.create_email_draft(drafts.id, draft_sync.sync_key, msg)
    assert created.status == "1" and created.server_id

Use read=False to mark an item unread, flagged=False to clear its follow-up flag, and delete=True to delete it. Pass each returned EmailChangesResult.sync_key into the next mutation or sync request for that folder.

Client is a context manager wrapping one requests.Session -- EAS is stateless HTTP (an auth header plus a PolicyKey header), so unlike an IMAP connection there's no server-side session to tear down; __exit__ just closes the HTTP session. provision() (the device policy handshake) is called lazily on first use if you don't call it explicitly.

Folder and item ids are plain strings ("9", "9:1"), matching EAS's own ServerId format exactly -- there's no synthetic id layer to keep in sync with a local cache.

Command coverage

Not implemented: MeetingResponse, ValidateCert, SmartForward/SmartReply. Documented as unimplemented, not silently missing.

Development

pip install -e '.[dev]'
pytest
ruff check .
mypy pyactivesync tests

Unit tests (WBXML codec against golden byte fixtures, codepage table sanity checks) require no network and run in CI on every push. Live integration tests in tests/test_client_live.py are skipped unless PYACTIVESYNC_TEST_SERVER, PYACTIVESYNC_TEST_USER, and PYACTIVESYNC_TEST_PASSWORD are set, and only ever create/rename/delete objects they create themselves -- pre-existing folders and items are never touched.

License

MIT