251 lines
8 KiB
Markdown
251 lines
8 KiB
Markdown
# Federation
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## ActivityPub
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Mobilizon uses [ActivityPub](http://activitypub.rocks/) to federate content between instances. It only supports the server-to-server part of [the ActivityPub spec](https://www.w3.org/TR/activitypub/).
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It implements the [HTTP signatures spec](https://tools.ietf.org/html/draft-cavage-http-signatures-12) for authentication of inbox deliveries, but doesn't implement Linked Data Signatures for forwarded payloads, and instead fetches content when needed.
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To match usernames to actors, Mobilizon uses [WebFinger](https://tools.ietf.org/html/rfc7033).
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## Instance subscriptions
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Instances subscribe to each other through an internal actor named `relay@instance.tld` that publishes (through `Announce`) every created content to it's followers. Each content creation share is saved so that updates and deletes are correctly sent to every relay subscriber.
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## Activities
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Supported Activity | Supported Object or Activity
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------------ | -------------
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`Accept` | `Follow`, `Join`
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`Add` | `Document`, `ResourceCollection`
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`Announce` | any `Object`
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`Create` | any `Object`
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`Delete` | any `Object`
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`Flag` | any `Object`
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`Follow` | any `Object`
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`Invite` | `Group`
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`Join` | `Event`
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`Leave` | `Event`, `Group`
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`Move` | `Document`, `ResourceCollection`
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`Reject` | `Follow`, `Join`
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`Remove` | `Note`, `Event`, `Member`
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`Undo` | `Announce`, `Follow`
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`Update` | `Object`
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## Objects
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### Person
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Every Mobilizon profile is a [`Person`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-person).
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### Event
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Every Mobilizon event is an [`Event`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event) with [a few extensions](#event_1), especially for location information since [`Place`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-place) is limited.
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### Note
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Every Mobilizon comment showing under an event is a [`Note`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-note), as well as every element from group discussions, where the [`context` property](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-context) is used to group messages in discussions.
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### Group
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Every Mobilizon group is a [`Group`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-group).
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### Member
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Every Mobilizon group member is a `Member`, that conveys the role information that the `Person` has in the `Group`.
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```json
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%{
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"type" => "Member",
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"id" => "https://somemobilizon.instance/member/some-uuid",
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"actor" => "https://somemobilizon.instance/@some-person",
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"object" => "https://somemobilizon.instance/@some-group",
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"role" => "MODERATOR"
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}
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```
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The allowed values for `role` are: `invited`, `not_approved`, `member`, `moderator`, `administrator`, `rejected`.
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### Document
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Attached pictures and other files are represented with [`Document`](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-document).
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Group resources are also represented with `Document`.
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### Article
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Every Mobilizon group post is an [Article](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-article).
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### ResourceCollection
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Mobilizon's group resources (see [Document](#Document)) can be collected into folders named `ResourceCollection`, which have the same set of properties as a `Document`, without the `url`.
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## Extensions
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### Event
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The vocabulary for Event is based on [the Event object in ActivityStreams](https://www.w3.org/TR/activitystreams-vocabulary/#dfn-event), extended with :
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* the [Event Schema](https://schema.org/Event) from Schema.org
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* some properties from [iCalendar](https://tools.ietf.org/html/rfc5545), such as `ical:status` (see [this issue](https://framagit.org/framasoft/mobilizon/issues/320))
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The following properties are added.
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#### repliesModeration
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Disabling replies is [an ongoing issue with ActivityPub](https://github.com/w3c/activitypub/issues/319) so we use a temporary property.
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See [the corresponding issue](https://framagit.org/framasoft/mobilizon/issues/321).
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Accepted values: `allow_all`, `closed`, `moderated` (not used at the moment)
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!!! info
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We also support PeerTube's `commentEnabled` property as a fallback. It is set to `true` only when `repliesModeration` is equal to `allow_all`.
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Example:
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```json
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{
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"@context": [
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"...",
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{
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"mz": "https://joinmobilizon.org/ns#",
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"pt": "https://joinpeertube.org/ns#",
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"repliesModerationOption": {
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"@id": "mz:repliesModerationOption",
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"@type": "mz:repliesModerationOptionType"
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},
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"repliesModerationOptionType": {
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"@id": "mz:repliesModerationOptionType",
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"@type": "rdfs:Class"
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},
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"commentsEnabled": {
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"@id": "pt:commentsEnabled",
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"@type": "sc:Boolean"
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}
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}
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],
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"...": "...",
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"repliesModerationOption": "allow_all",
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"commentsEnabled": true,
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"type": "Event",
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"url": "http://mobilizon1.com/events/8cf76e9f-c426-4912-9cd6-c7030b969611"
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}
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```
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#### joinMode
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Indicator of how new members may be able to join.
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See [the corresponding issue](https://framagit.org/framasoft/mobilizon/issues/321).
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Accepted values: `free`, `restricted`, `invite` (not used at the moment)
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Example:
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```json
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{
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"@context": [
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"...",
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{
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"mz": "https://joinmobilizon.org/ns#",
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"joinMode": {
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"@id": "mz:joinMode",
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"@type": "mz:joinModeType"
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},
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"joinModeType": {
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"@id": "mz:joinModeType",
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"@type": "rdfs:Class"
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}
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}
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],
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"...": "...",
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"joinMode": "restricted",
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"type": "Event",
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"url": "http://mobilizon1.com/events/8cf76e9f-c426-4912-9cd6-c7030b969611"
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}
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```
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#### location
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We use Schema.org's `location` property on `Event`.
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[The ActivityStream vocabulary to represent places](https://www.w3.org/TR/activitystreams-vocabulary/#places) is quite limited so instead of just using `Place` from ActivityStreams we also add a few properties from Schema.org's `Place` vocabulary.
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We add [an `address` property](https://schema.org/address), which we assume to be [of `PostalAddress` type](https://schema.org/PostalAddress).
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```json
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{
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"@context": [
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"...",
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{
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"PostalAddress": "sc:PostalAddress",
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"address": {
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"@id": "sc:address",
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"@type": "sc:PostalAddress"
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},
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"addressCountry": "sc:addressCountry",
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"addressLocality": "sc:addressLocality",
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"addressRegion": "sc:addressRegion",
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"postalCode": "sc:postalCode",
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"sc": "http://schema.org#",
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"streetAddress": "sc:streetAddress",
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}
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],
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"id": "http://mobilizon2.com/events/945f350d-a3e6-4bcd-9bf2-0bd2e4d353c5",
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"location": {
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"address": {
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"addressCountry": "France",
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"addressLocality": "Lyon",
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"addressRegion": "Auvergne-Rhône-Alpes",
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"postalCode": "69007",
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"streetAddress": "10 Rue Jangot",
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"type": "PostalAddress"
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},
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"latitude": 4.8425657,
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"longitude": 45.7517141,
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"id": "http://mobilizon2.com/address/bdf7fb53-7177-46f3-8fb3-93c25a802522",
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"name": "10 Rue Jangot",
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"type": "Place"
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},
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"type": "Event"
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}
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```
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#### maximumAttendeeCapacity
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We use Schema.org's [`maximumAttendeeCapacity`](https://schema.org/maximumAttendeeCapacity) to know how many places there can be for an event.
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#### anonymousParticipationEnabled
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We add this boolean field to know whether or not anonymous participants can participate to an event.
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!!! note
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Even though this information is federated, we redirect anonymous participants to the original instance so they can participate.
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### Join
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#### participationMessage
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We add a `participationMessage` property on a `Join` activity so that participants may transmit a note to event organizers, to motivate their participation when event participations are manually approved. This field is restricted to plain text.
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```json
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{
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"type": "Join",
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"object": "http://mobilizon.test/events/some-uuid",
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"id": "http://mobilizon2.test/@admin/join/event/1",
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"actor": "http://mobilizon2.test/@admin",
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"participationMessage": "I want to join !",
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"@context": [
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{
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"participationMessage": {
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"@id": "mz:participationMessage",
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"@type": "sc:Text"
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}
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}
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]
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}
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``` |