1.\"
  2.\" Copyright (c) 2019 Ted Unangst
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 16.Dd $Mdocdate$
 17.Dt ACTIVITYPUB 7
 18.Os
 19.Sh NAME
 20.Nm activitypub
 21.Nd notes about the honk implementation
 22.Sh DESCRIPTION
 23The
 24.Xr honk 1
 25utility processes status updates and other microblog activities using the
 26.Nm ActivityPub
 27protocol to exchange messages with other servers.
 28The specification is subject to interpretation, and not all implementations
 29behave in the same way.
 30This document attempts to clarify honk's behavior.
 31It is not intended to be a complete description of
 32.Nm ActivityPub ,
 33but may be useful as a guide to other implementors looking to interoperate.
 34.Ss OBJECTS
 35The following object or document types are supported.
 36.Bl -tag -width tenletters
 37.It Vt Note
 38Fully supported.
 39The default object type for honk.
 40.It Vt Article
 41Fully supported.
 42.It Vt Page
 43Supported.
 44.It Vt Question
 45Read only support.
 46Appears similar to a Note.
 47.It Vt Event
 48Supported.
 49Appears similar to a Note.
 50Can be both created and received, but
 51.Vt Invite
 52activities are ignored.
 53.It Vt Video
 54Limited support.
 55.It Vt Audio
 56Limited Support.
 57.El
 58.Pp
 59Honk primarily supports HTML content, not markdown or other formats,
 60with a wide range of permitted HTML tags in object
 61.Fa content
 62fields.
 63The following tags are supported.
 64.Bd -literal -offset indent
 65a, img, span,
 66div, h1, h2, h3, h4, h5, h6, hr,
 67table, thead, tbody, th, tr, td, colgroup, col,
 68p, br, pre, code, blockquote, q,
 69samp, mark, ins, dfn, cite, abbr, address,
 70strong, em, b, i, s, u, sub, sup, del, tt, small,
 71ol, ul, li, dl, dt, dd
 72.Ed
 73.Pp
 74The following tag attributes are permitted.
 75.Bd -literal -offset indent
 76href, src, alt, colspan, rowspan
 77.Ed
 78.Pp
 79The following class names are used for syntax highlighting code blocks.
 80.Bd -literal -offset indent
 81kw, bi, st, nm, tp, op, cm, al, dl
 82.Ed
 83.Ss ACTIVITIES
 84The following activities are supported.
 85.Bl -tag -width tenletters
 86.It Vt Create
 87Fully supported.
 88.It Vt Announce
 89Supported with share semantics.
 90.It Vt Read
 91Supported.
 92Primarily used to acknowledge replies and complete threads, without
 93additional semantics.
 94.It Vt Follow
 95Supported.
 96.Vt Accept
 97and
 98.Vt Undo
 99require that the original request be quoted, not referred to by URI.
100.It Vt Update
101Supported.
102Honk sends and receives
103.Vt Update
104activities.
105.It Vt Delete
106Does what it can.
107.It Vt Like
108Don't be ridiculous.
109.El
110.Ss METADATA
111The following additional object types are supported as
112.Fa tag
113or
114.Fa attachment .
115.Bl -tag -width tenletters
116.It Mention
117Pretty @ machine.
118.It Emoji
119Inline text :emoji: with image replacement.
120.It Place
121Attached as a
122.Fa tag
123to
124.Vt Note
125and
126.Fa location
127to
128.Vt Event .
129Supports
130.Fa name ,
131.Fa url ,
132.Fa latitude ,
133and
134.Fa longitude .
135.It Document
136Plain text and images in jpeg, gif, png, and webp formats are supported.
137Other formats are linked to origin.
138.El
139.Ss EXTENSIONS
140Honk also supports a
141.Vt Ping
142activity and will respond with a
143.Vt Pong
144activity.
145This is useful for debugging networking connectivity issues without
146visible side effects.
147See ping.txt for details.
148.Ss SECURITY
149Honk uses http signatures.
150.Ss WEBFINGER
151Honk implements the
152.Vt webfinger
153end point and will use it for @mention resolution.
154It is not required for federation.
155.Ss LD-JSON
156Not really.
157.Sh SEE ALSO
158.Xr intro 1 ,
159.Xr honk 1
160.Sh STANDARDS
161.Pp
162.Lk https://www.w3.org/TR/activitypub/ "ActivityPub"
163.Pp
164.Lk https://www.w3.org/TR/activitystreams-vocabulary/ "Activity Vocabulary"
165.Sh CAVEATS
166The ActivityPub standard is subject to interpretation, and not all
167implementations are as enlightened as honk.