Java

client.liveEvents()

Every method in this namespace: its signature, its parameters, what it returns and an example.

Methods

Follow the mailbox as it changes, without polling: one event each time a message arrives or is sent and each time a conversation changes or is deleted, resumed where it left off after a dropped connection.

`liveEvents().stream`

Follow the mailbox as it changes

threads:read

Signature

LiveEventStream stream(RequestOptions options)

Opens the live event stream, GET /live-events as server-sent events, and returns a LiveEventStream that yields one event at a time for as long as you read it: message.received when a message is filed for an address, message.sent when a message sent from an address is filed in its Sent folder, thread.changed when a conversation gains or loses labels (read, starred, archived, moved, snoozed or labelled), thread.deleted when one is deleted for good, and message.status_changed when the delivery of an email sent from an address moves on, with its status: delivered, delivery_delayed, bounced, complained, failed, suppressed or cancelled. The types are in sh.nextmail.constants.LiveEventTypes and the statuses in sh.nextmail.constants.LiveSendStatuses. Each event is a map with id, type, occurredAt and data, where data.addresses names the addresses it concerns and threadId and messageId the conversation and the message, where there is one. No content travels in an event, so read the conversation with threads().get or the message with threads().getMessage when you need it.

The stream never ends by itself. The server closes it after 30 minutes, when the credential stops being valid, or when the connection drops, and the stream opens it again and resumes where it left off through Last-Event-ID: at once after the server closes it, and with backoff after a failure. When the server can no longer replay from that point, which happens once the event is more than 10 minutes or 1,000 events back, the stream yields a reset event, whose type is LiveEventStream.RESET and whose data.reason is expired or unknown, before the next events: anything may have changed in between, so list again what you keep in sync.

A LiveEventStream is an Iterator and an Iterable of maps, so a for loop walks it, and it is AutoCloseable, so open it in a try-with-resources block. Break out of the loop or call close() to close the connection. close() works from any thread, and interrupting the thread that reads the stream closes it too. stream() returns it as a java.util.stream.Stream that closes it when closed, and lastEventId() returns the id it would resume after, to pass as lastEventId to a later stream.

A key or an app limited to particular addresses gets only the events of the addresses it reaches, enforced on the server for every event.

Parameters

options.typesString or List<String>: Only these kinds of event: message.received, message.sent, thread.changed, thread.deleted and message.status_changed, as in sh.nextmail.constants.LiveEventTypes. A list is sent comma separated. Left out, all of them. A reset is always delivered.
options.addressString: Only the events of this address. One the key does not reach delivers nothing rather than failing.
options.lastEventIdString: Resume after this event id, one an earlier stream yielded or returned from lastEventId(). It is sent as the Last-Event-ID header. Left out, the stream starts with what happens from now on.
options.apiKeyString: Overrides the client's API key for this stream only, on every reconnection.

Returns

A LiveEventStream that yields each event as a map with id, type, occurredAt and data. data has addresses, threadId and messageId, and by type labelIds (received), emailId (sent), addedLabelIds and removedLabelIds (changed), or emailId, status and recipients (status changed, where threadId may be null). A reset yields a map with id, type set to reset, occurredAt and data holding reason.

Example

try (LiveEventStream events = client.liveEvents().stream(RequestOptions.of("types", List.of(LiveEventTypes.MESSAGE_RECEIVED)))) {    for (Map<String, Object> event : events) {        if (LiveEventStream.RESET.equals(event.get("type"))) {            System.out.println("Resync: the stream could not resume");             continue;        }         Map<?, ?> data = (Map<?, ?>) event.get("data");        Map<String, Object> thread = client.threads().get((String) data.get("threadId"));         System.out.println(data.get("addresses") + " " + thread.get("id"));         break;    }}

Notes

One key, app or session holds at most 5 open streams, and a workspace at most 50. Past that the stream is refused with 429 too_many_streams, which it retries.
The server sends a keepalive every 25 seconds and a retry hint of 3 seconds. Events are kept for resuming for 10 minutes and at most 1,000 per workspace.
A network failure, a 408, a 429 and a 5xx answer are retried for as long as you read, waiting about a second at first and doubling up to 30 seconds, or longer when Retry-After asks, and the client's maxRetries does not limit it. When no byte arrives for 60 seconds, the stream drops the connection and opens it again.
A 400, 401, 403, 404 or 422 throws the ApiException from hasNext() instead of retrying, so an expired or revoked credential ends the stream on the next attempt to open it. A 200 that is not an event stream throws one too, with the code unrecognised_response.
The connection opens on the first call to hasNext(), and the client's timeout bounds only the wait for the server to answer, never how long the stream stays open.

Also available in

API: GET /live-events
TypeScript: liveEvents.stream()
Python: live_events.stream()
Ruby: live_events.stream
PHP: liveEvents->stream
Go: LiveEvents.Stream
C#: LiveEvents.StreamAsync
CLI: nextmail live-events stream