feat: allow attendees to add guests to an event

src/components/Editor/Invitees/InviteesList.vue

@@ -50,7 +50,7 @@
 		</div>
 
 		<InviteesListSearch
-			v-if="!isReadOnly && hasUserEmailAddress"
+			v-if="(!isReadOnly || canAddGuests) && hasUserEmailAddress"
 			:alreadyInvitedEmails="alreadyInvitedEmails"
 			:organizer="calendarObjectInstance.organizer"
 			@addAttendee="addAttendee" />
@@ -67,6 +67,7 @@
 			:key="invitee.email"
 			:attendee="invitee"
 			:isReadOnly="isReadOnly"
+			:canRemove="isForwardedByMe(invitee)"
 			:organizerDisplayName="organizerDisplayName"
 			:members="invitee.members"
 			:isViewedByOrganizer="isViewedByOrganizer"
@@ -122,6 +123,15 @@ export default {
 			required: true,
 		},
 
+		/**
+		 * Whether the current user may add guests even though the list is
+		 * otherwise read-only for them, because they are an attendee.
+		 */
+		canAddGuests: {
+			type: Boolean,
+			default: false,
+		},
+
 		isSharedWithMe: {
 			type: Boolean,
 			required: true,
@@ -165,6 +175,9 @@ export default {
 			creatingTalkRoom: false,
 			showFreeBusyModel: false,
 			recentAttendees: [],
+			// Guests added in this session, so they can be taken off again before
+			// saving. Once saved, only the organizer can remove an attendee.
+			forwardedAttendees: [],
 		}
 	},
 
@@ -424,6 +437,23 @@ export default {
 				member,
 			})
 			this.recentAttendees.push(email)
+			if (this.canAddGuests) {
+				this.forwardedAttendees.push(email)
+			}
+		},
+
+		/**
+		 * Whether the given attendee was added by the current user and can
+		 * therefore still be removed again.
+		 *
+		 * @param {object} attendee The attendee to check
+		 * @return {boolean}
+		 */
+		isForwardedByMe(attendee) {
+			// Not once the editor switched to viewing, because the guest reached
+			// the organizer by then and only they can remove an attendee
+			return this.canAddGuests
+				&& this.forwardedAttendees.includes(removeMailtoPrefix(attendee.uri))
 		},
 
 		removeAttendee(attendee) {
@@ -441,6 +471,7 @@ export default {
 				attendee,
 			})
 			this.recentAttendees = this.recentAttendees.filter((a) => a.uri !== attendee.email)
+			this.forwardedAttendees = this.forwardedAttendees.filter((email) => email !== removeMailtoPrefix(attendee.uri))
 
 			if (this.showFreeBusyModel && this.calendarObjectInstance.attendees.length === 0) {
 				showWarning(this.$t('calendar', 'Please add at least one attendee to use the "Find a time" feature.'))

src/components/Editor/Invitees/InviteesListItem.vue

@@ -46,6 +46,16 @@
 						:size="20" />
 				</template>
 			</NcButton>
+			<NcButton
+				v-if="canRemove && !isViewedByOrganizer"
+				variant="tertiary"
+				:aria-label="removeAttendeeText"
+				:title="removeAttendeeText"
+				@click="removeAttendee(attendee)">
+				<template #icon>
+					<Delete :size="20" />
+				</template>
+			</NcButton>
 			<Actions v-if="!isReadOnly && isViewedByOrganizer">
 				<ActionCheckbox
 					v-if="!members.length"
@@ -160,6 +170,15 @@ export default {
 			required: true,
 		},
 
+		/**
+		 * Whether this attendee can be removed even though the list is read-only,
+		 * because the current user just added them.
+		 */
+		canRemove: {
+			type: Boolean,
+			default: false,
+		},
+
 		members: {
 			type: Array,
 			default: () => [],

src/mixins/EditorMixin.js

@@ -4,6 +4,7 @@
  */
 
 import { showError, showSuccess } from '@nextcloud/dialogs'
+import { loadState } from '@nextcloud/initial-state'
 import { translate as t } from '@nextcloud/l10n'
 import { generateUrl } from '@nextcloud/router'
 import { mapState, mapStores } from 'pinia'
@@ -241,6 +242,41 @@ export default {
 			const organizer = this.calendarObjectInstance.organizer
 			return removeMailtoPrefix(organizer.uri) === principal
 		},
+		/**
+		 * Returns whether the organizer let attendees invite guests to this event.
+		 *
+		 * X-NC-ALLOW-ATTENDEE-GUESTS has to be turned on explicitly, so it is also
+		 * absent on invitations we could not report guests back to.
+		 *
+		 * @return {boolean}
+		 */
+		isAddingGuestsAllowed() {
+			// Our own server has to generate the reply carrying the guests
+			if (loadState('core', 'capabilities', {})?.dav?.attendee_guests !== true) {
+				return false
+			}
+
+			// isViewedByAttendee is false on read-only calendars and for non-attendees,
+			// but true for an organizer who also attends their own event
+			return this.isViewedByAttendee
+				&& this.isViewedByOrganizer !== true
+				&& this.calendarObjectInstance?.allowAttendeeGuests === 'TRUE'
+		},
+		/**
+		 * Returns whether guests added here actually reach the organizer.
+		 *
+		 * The organizer only picks up guests of the base instance, so recurring
+		 * events are left to them.
+		 *
+		 * @return {boolean}
+		 */
+		canAddGuests() {
+			// A recurrence exception is not the base instance, but it can not create
+			// one either, so both checks are needed
+			return this.isAddingGuestsAllowed
+				&& this.calendarObjectInstance?.isMasterItem === true
+				&& !this.canCreateRecurrenceException
+		},
 		/**
 		 * Returns the attendee property corresponding to the current user
 		 *

src/mixins/PropertyMixin.js

@@ -10,6 +10,7 @@
  * See inline for more documentation
  */
 
+import AccountMultiplePlusOutline from 'vue-material-design-icons/AccountMultiplePlusOutline.vue'
 import AccountPlusOutline from 'vue-material-design-icons/AccountPlusOutline.vue'
 import Bell from 'vue-material-design-icons/BellOutline.vue'
 import Briefcase from 'vue-material-design-icons/BriefcaseOutline.vue'
@@ -22,6 +23,7 @@ import TextBoxOutline from 'vue-material-design-icons/TextBoxOutline.vue'
 
 export default {
 	components: {
+		AccountMultiplePlusOutline,
 		AccountPlusOutline,
 		Briefcase,
 		Check,

src/models/event.js

@@ -74,6 +74,8 @@ function getDefaultEventObject(props = {}) {
 		attachments: [],
 		// Invitation forwarding
 		invitationForwarding: 'TRUE',
+		// Attendees inviting guests, off unless the organizer turned it on
+		allowAttendeeGuests: 'FALSE',
 		...props,
 	}
 }
@@ -179,6 +181,10 @@ function mapEventComponentToEventObject(eventComponent) {
 		eventObject.invitationForwarding = eventComponent.getFirstPropertyFirstValue('X-NC-INVITATION-FORWARDING')
 	}
 
+	if (eventComponent.hasProperty('X-NC-ALLOW-ATTENDEE-GUESTS')) {
+		eventObject.allowAttendeeGuests = eventComponent.getFirstPropertyFirstValue('X-NC-ALLOW-ATTENDEE-GUESTS')
+	}
+
 	return eventObject
 }
 

src/store/calendarObjectInstance.js

@@ -397,6 +397,18 @@ export default defineStore('calendarObjectInstance', {
 			calendarObjectInstance.invitationForwarding = invitationForwarding
 		},
 
+		/**
+		 * Change whether attendees of an event may invite guests
+		 *
+		 * @param {object} data The destructuring object
+		 * @param {object} data.calendarObjectInstance The calendarObjectInstance object
+		 * @param {string} data.allowAttendeeGuests Allow attendee guests value
+		 */
+		changeAllowAttendeeGuests({ calendarObjectInstance, allowAttendeeGuests }) {
+			calendarObjectInstance.eventComponent.updatePropertyWithValue('X-NC-ALLOW-ATTENDEE-GUESTS', allowAttendeeGuests)
+			calendarObjectInstance.allowAttendeeGuests = allowAttendeeGuests
+		},
+
 		/**
 		 * Change the customized color of an event
 		 *

src/views/EditFull.vue

@@ -255,6 +255,12 @@
 							:propModel="propInvitationForwarding"
 							:value="invitationForwarding"
 							@update:value="updateInvitationForwarding" />
+						<PropertySelect
+							v-if="showAllowAttendeeGuests"
+							:isReadOnly="isReadOnly || isRecurring"
+							:propModel="propAllowAttendeeGuests"
+							:value="allowAttendeeGuests"
+							@update:value="updateAllowAttendeeGuests" />
 					</div>
 				</div>
 
@@ -318,6 +324,7 @@
 							:calendar="selectedCalendar"
 							:calendarObjectInstance="calendarObjectInstance"
 							:isReadOnly="isReadOnly || isViewedByOrganizer === false"
+							:canAddGuests="canAddGuests"
 							:isSharedWithMe="isSharedWithMe"
 							:showHeader="true"
 							@updateDates="updateDates" />
@@ -345,6 +352,7 @@
 import IconCancel from '@mdi/svg/svg/cancel.svg?raw'
 import IconDelete from '@mdi/svg/svg/delete.svg?raw'
 import { Parameter } from '@nextcloud/calendar-js'
+import { loadState } from '@nextcloud/initial-state'
 import { translate as t } from '@nextcloud/l10n'
 import moment from '@nextcloud/moment'
 import { generateUrl } from '@nextcloud/router'
@@ -476,6 +484,23 @@ export default {
 				info: t('calendar', 'Choose "Only invited attendees can respond" to prevent attendees from forwarding the invitation to others.'),
 				defaultValue: 'TRUE',
 			},
+
+			propAllowAttendeeGuests: {
+				// TRANSLATORS Setting of an event, deciding whether the people invited to it may invite further people
+				readableName: t('calendar', 'Allow attendees to invite guests'),
+				icon: 'AccountMultiplePlusOutline',
+				options: [
+					// TRANSLATORS A guest is someone invited by an attendee rather than by the organizer
+					{ value: 'TRUE', label: t('calendar', 'Attendees can invite guests') },
+					// TRANSLATORS "you" is the organizer of the event, who is reading this setting
+					{ value: 'FALSE', label: t('calendar', 'Only you can invite attendees') },
+				],
+
+				multiple: false,
+				// TRANSLATORS "you" is the organizer of the event, who is reading this setting
+				info: t('calendar', 'Attendees can add other people, who are then invited to the event just like the attendees you added yourself.'),
+				defaultValue: 'FALSE',
+			},
 		}
 	},
 
@@ -508,6 +533,10 @@ export default {
 			return this.calendarObjectInstance?.invitationForwarding ?? null
 		},
 
+		allowAttendeeGuests() {
+			return this.calendarObjectInstance?.allowAttendeeGuests ?? null
+		},
+
 		subTitle() {
 			if (!this.calendarObjectInstance) {
 				return ''
@@ -542,6 +571,29 @@ export default {
 		showInvitationForwarding() {
 			return isAfterVersion(34)
 		},
+
+		showAllowAttendeeGuests() {
+			return loadState('core', 'capabilities', {})?.dav?.attendee_guests === true
+				&& this.isViewedByOrganizer !== false
+		},
+
+		/**
+		 * Guests are only reported to the organizer for the whole event, so they
+		 * are not offered for a recurring one.
+		 *
+		 * @return {boolean}
+		 */
+		isRecurring() {
+			return this.calendarObjectInstance?.recurrenceRule?.frequency !== 'NONE'
+		},
+	},
+
+	watch: {
+		isRecurring(isRecurring) {
+			if (isRecurring && this.allowAttendeeGuests === 'TRUE') {
+				this.updateAllowAttendeeGuests('FALSE')
+			}
+		},
 	},
 
 	mounted() {
@@ -633,6 +685,18 @@ export default {
 			})
 		},
 
+		/**
+		 * Updates whether attendees may invite guests
+		 *
+		 * @param {string} allowAttendeeGuests Allow attendee guests value
+		 */
+		updateAllowAttendeeGuests(allowAttendeeGuests) {
+			this.calendarObjectInstanceStore.changeAllowAttendeeGuests({
+				calendarObjectInstance: this.calendarObjectInstance,
+				allowAttendeeGuests,
+			})
+		},
+
 		/**
 		 * Adds a category to the event
 		 *

src/views/EditSimple.vue

@@ -208,6 +208,7 @@
 							:hideErrors="true"
 							:showHeader="true"
 							:isReadOnly="isReadOnlyOrViewing || isViewedByOrganizer === false"
+							:canAddGuests="canAddGuests && !isReadOnlyOrViewing"
 							:isSharedWithMe="isSharedWithMe"
 							:calendar="selectedCalendar"
 							:calendarObjectInstance="calendarObjectInstance" />