ghost/members-events-service/lib/LastSeenAtUpdater.js
const {MemberPageViewEvent, MemberCommentEvent, MemberLinkClickEvent} = require('@tryghost/member-events');
const moment = require('moment-timezone');
const {IncorrectUsageError} = require('@tryghost/errors');
const {EmailOpenedEvent} = require('@tryghost/email-events');
const logging = require('@tryghost/logging');
const LastSeenAtCache = require('./LastSeenAtCache');
/**
* Listen for `MemberViewEvent` to update the `member.last_seen_at` timestamp
*/
class LastSeenAtUpdater {
/**
* Initializes the event subscriber
* @param {Object} deps dependencies
* @param {Object} deps.services The list of service dependencies
* @param {any} deps.services.settingsCache The settings service
* @param {() => object} deps.getMembersApi - A function which returns an instance of members-api
* @param {any} deps.db Database connection
* @param {any} deps.events The event emitter
* @param {any} deps.lastSeenAtCache An instance of the last seen at cache
*/
constructor({
services: {
settingsCache
},
getMembersApi,
db,
events,
lastSeenAtCache
}) {
if (!getMembersApi) {
throw new IncorrectUsageError({message: 'Missing option getMembersApi'});
}
this._getMembersApi = getMembersApi;
this._settingsCacheService = settingsCache;
this._db = db;
this._events = events;
this._lastSeenAtCache = lastSeenAtCache || new LastSeenAtCache({services: {settingsCache}});
}
/**
* Subscribe to events of this domainEvents service
* @param {any} domainEvents The DomainEvents service
*/
subscribe(domainEvents) {
domainEvents.subscribe(MemberPageViewEvent, async (event) => {
try {
await this.cachedUpdateLastSeenAt(event.data.memberId, event.data.memberLastSeenAt, event.timestamp);
} catch (err) {
logging.error(`Error in LastSeenAtUpdater.MemberPageViewEvent listener for member ${event.data.memberId}`);
logging.error(err);
}
});
domainEvents.subscribe(MemberLinkClickEvent, async (event) => {
try {
await this.cachedUpdateLastSeenAt(event.data.memberId, event.data.memberLastSeenAt, event.timestamp);
} catch (err) {
logging.error(`Error in LastSeenAtUpdater.MemberLinkClickEvent listener for member ${event.data.memberId}`);
logging.error(err);
}
});
domainEvents.subscribe(MemberCommentEvent, async (event) => {
try {
await this.updateLastCommentedAt(event.data.memberId, event.timestamp);
} catch (err) {
logging.error(`Error in LastSeenAtUpdater.MemberCommentEvent listener for member ${event.data.memberId}`);
logging.error(err);
}
});
domainEvents.subscribe(EmailOpenedEvent, async (event) => {
try {
await this.updateLastSeenAtWithoutKnownLastSeen(event.memberId, event.timestamp);
} catch (err) {
logging.error(`Error in LastSeenAtUpdater.EmailOpenedEvent listener for member ${event.memberId}, emailRecipientId ${event.emailRecipientId}`);
logging.error(err);
}
});
}
/**
* Updates the member.last_seen_at field if it wasn't updated in the current day yet (in the publication timezone)
* Example: current time is 2022-02-28 18:00:00
* - memberLastSeenAt is 2022-02-27 23:00:00, timestamp is current time, then `last_seen_at` is set to the current time
* - memberLastSeenAt is 2022-02-28 01:00:00, timestamp is current time, then `last_seen_at` isn't changed
* @param {string} memberId The id of the member to be udpated
* @param {Date} timestamp The event timestamp
*/
async updateLastSeenAtWithoutKnownLastSeen(memberId, timestamp) {
// Note: we are not using Bookshelf / member repository to prevent firing webhooks + to prevent deadlock issues
// If we would use the member repostiory, we would create a forUpdate lock when editing the member, including when fetching the member labels. Creating a possible deadlock if somewhere else we do the reverse in a transaction.
const timezone = this._settingsCacheService.get('timezone') || 'Etc/UTC';
const startOfDayInSiteTimezone = moment.utc(timestamp).tz(timezone).startOf('day').utc().format('YYYY-MM-DD HH:mm:ss');
const formattedTimestamp = moment.utc(timestamp).format('YYYY-MM-DD HH:mm:ss');
await this._db.knex('members')
.where('id', '=', memberId)
.andWhere(builder => builder
.where('last_seen_at', '<', startOfDayInSiteTimezone)
.orWhereNull('last_seen_at')
)
.update({
last_seen_at: formattedTimestamp
});
}
/**
* Updates the member.last_seen_at field if it wasn't updated in the current day yet (in the publication timezone)
*/
async cachedUpdateLastSeenAt(memberId, memberLastSeenAt, timestamp) {
if (this._lastSeenAtCache.shouldUpdateMember(memberId)) {
await this.updateLastSeenAt(memberId, memberLastSeenAt, timestamp);
}
}
/**
* Updates the member.last_seen_at field if it wasn't updated in the current day yet (in the publication timezone)
* Example: current time is 2022-02-28 18:00:00
* - memberLastSeenAt is 2022-02-27 23:00:00, timestamp is current time, then `last_seen_at` is set to the current time
* - memberLastSeenAt is 2022-02-28 01:00:00, timestamp is current time, then `last_seen_at` isn't changed
* @param {string} memberId The id of the member to be udpated
* @param {Date} timestamp The event timestamp
*/
async updateLastSeenAt(memberId, memberLastSeenAt, timestamp) {
const timezone = this._settingsCacheService.get('timezone');
// First, check if memberLastSeenAt is null or before the beginning of the current day in the publication timezone
// This isn't strictly necessary since we will fetch the member row for update and double check this
// This is an optimization to avoid unnecessary database queries if last_seen_at is already after the beginning of the current day
if (memberLastSeenAt === null || moment(moment.utc(timestamp).tz(timezone).startOf('day')).isAfter(memberLastSeenAt)) {
try {
// Pre-emptively update local cache so we don't update the same member again in the same day
this._lastSeenAtCache.add(memberId);
const membersApi = this._getMembersApi();
await this._db.knex.transaction(async (trx) => {
// To avoid a race condition, we lock the member row for update, then the last_seen_at field again to prevent simultaneous updates
const currentMember = await membersApi.members.get({id: memberId}, {require: true, transacting: trx, forUpdate: true});
const currentMemberLastSeenAt = currentMember.get('last_seen_at');
if (currentMemberLastSeenAt === null || moment(moment.utc(timestamp).tz(timezone).startOf('day')).isAfter(currentMemberLastSeenAt)) {
const memberToUpdate = await currentMember.refresh({transacting: trx, forUpdate: false, withRelated: ['labels', 'newsletters']});
const updatedMember = await memberToUpdate.save({last_seen_at: moment.utc(timestamp).format('YYYY-MM-DD HH:mm:ss')}, {transacting: trx, patch: true, method: 'update'});
// The standard event doesn't get emitted inside the transaction, so we do it manually
this._events.emit('member.edited', updatedMember);
return Promise.resolve(updatedMember);
}
return Promise.resolve(undefined);
});
} catch (err) {
// Remove the member from the cache if an error occurs
// This is to ensure that the member is updated on the next event if this one fails
this._lastSeenAtCache.remove(memberId);
// Bubble up the error to the event listener
throw err;
}
}
}
/**
* Updates the member.last_seen_at field if it wasn't updated in the current day yet (in the publication timezone)
* Example: current time is 2022-02-28 18:00:00
* - memberLastSeenAt is 2022-02-27 23:00:00, timestamp is current time, then `last_seen_at` is set to the current time
* - memberLastSeenAt is 2022-02-28 01:00:00, timestamp is current time, then `last_seen_at` isn't changed
* @param {string} memberId The id of the member to be udpated
* @param {Date} timestamp The event timestamp
*/
async updateLastCommentedAt(memberId, timestamp) {
const membersApi = this._getMembersApi();
const member = await membersApi.members.get({id: memberId}, {require: true});
const timezone = this._settingsCacheService.get('timezone');
const memberLastSeenAt = member.get('last_seen_at');
const memberLastCommentedAt = member.get('last_commented_at');
if (memberLastSeenAt === null || moment(moment.utc(timestamp).tz(timezone).startOf('day')).isAfter(memberLastSeenAt) || memberLastCommentedAt === null || moment(moment.utc(timestamp).tz(timezone).startOf('day')).isAfter(memberLastCommentedAt)) {
await membersApi.members.update({
last_seen_at: moment.utc(timestamp).format('YYYY-MM-DD HH:mm:ss'),
last_commented_at: moment.utc(timestamp).format('YYYY-MM-DD HH:mm:ss')
}, {
id: memberId
});
}
}
}
module.exports = LastSeenAtUpdater;