component AP gateway: AP <=> XMPP reactions conversions:

- Pubsub Attachments plugin has been renamed to XEP-0470 following publication
- XEP-0470 has been updated to follow 0.2 changes
- AP reactions (as implemented in Pleroma) are converted to XEP-0470
- XEP-0470 events are converted to AP reactions (again, using "EmojiReact" from Pleroma)
- AP activities related to attachments (like/reactions) are cached in Libervia because
  it's not possible to retrieve them from Pleroma instances once they have been emitted
  (doing an HTTP get on their ID returns a 404). For now those cache are not flushed, this
  should be improved in the future.
- `sharedInbox` is used when available. Pleroma returns a 500 HTTP error when ``to`` or
  ``cc`` are used in a direct inbox.
- reactions and like are not currently used for direct messages, because they can't be
  emitted from Pleroma in this case, thus there is no point in implementing them for the
  moment.

rel 371

sat/plugins/plugin_comp_ap_gateway/constants.py

@@ -30,6 +30,7 @@ TYPE_ITEM = "item"
 TYPE_TOMBSTONE = "Tombstone"
 TYPE_MENTION = "Mention"
 TYPE_LIKE = "Like"
+TYPE_REACTION = "EmojiReact"
 MEDIA_TYPE_AP = "application/activity+json"
 NS_AP = "https://www.w3.org/ns/activitystreams"
 NS_AP_PUBLIC = f"{NS_AP}#Public"
@@ -60,7 +61,9 @@ ACTIVITY_TYPES = (
     "Accept", "Add", "Announce", "Arrive", "Block", "Create", "Delete", "Dislike", "Flag",
     "Follow", "Ignore", "Invite", "Join", "Leave", "Like", "Listen", "Move", "Offer",
     "Question", "Reject", "Read", "Remove", "TentativeReject", "TentativeAccept",
-    "Travel", "Undo", "Update", "View"
+    "Travel", "Undo", "Update", "View",
+    # non-standard activities
+    "EmojiReact"
 )
 ACTIVITY_TYPES_LOWER = [a.lower() for a in ACTIVITY_TYPES]
 ACTIVITY_OBJECT_MANDATORY = (
@@ -69,7 +72,9 @@ ACTIVITY_OBJECT_MANDATORY = (
 ACTIVITY_TARGET_MANDATORY = ("Add", "Remove")
 # activities which can be used with Shared Inbox (i.e. with no account specified)
 # must be lowercase
-ACTIVIY_NO_ACCOUNT_ALLOWED = ("create", "delete", "announce", "undo")
+ACTIVIY_NO_ACCOUNT_ALLOWED = (
+    "create", "delete", "announce", "undo", "like", "emojireact"
+)
 # maximum number of parents to retrieve when comments_max_depth option is set
 COMMENTS_MAX_PARENTS = 100
 # maximum size of avatar, in bytes
@@ -77,3 +82,4 @@ MAX_AVATAR_SIZE = 1024 * 1024 * 5
 
 # storage prefixes
 ST_AVATAR = "[avatar]"
+ST_AP_CACHE = "[AP_item_cache]"