7 ms·

That is not how I read the specs. Let's look at an example: My handle is @mg@masto.ai What is my "AP identity" in your interpretation of the AP protocol?

by mg 3y ago

sieabahlpark 3y ago
[dead]
tedunangst 3y ago
It's https://masto.ai/users/mg https://masto.ai/users/mg. You can see it by running curl -H "Accept: application/ld+json". https://www.w3.org/TR/activitypub/#obj-id https://www.w3.org/TR/activitypub/#obj-id
- mg 3y ago
  That is one of the aliases. The same holds true for ... https://masto.ai/users/mg https://masto.ai/@mg ... and the server could povide as many aliases as it wants to. I wouldn't call those "identities". As the server could just change the aliases and the handle "@mg@masto.ai" would still work. Because it resolves to whatever aliases the server provides via the webfinger endpoint. I have not seen anything in the specs that says the aliases are identities or should stay the same over time.
  - vidarh 3y ago
    Try this: curl -H "Accept: application/json" https://masto.ai/users/mg/following?page=1 | jq . Notice the people you are following are referenced by URL. If you try /followers instead, and look up the following URLs of some of your followers, you'll find that they follow you by the URL https://masto.ai/users/mg If you do: curl -H "Accept: application/json" https://masto.ai/@mg | jq .id You'll see that the returned document shows the id of your ActivityPub Person actor as https://masto.ai/users/mg https://masto.ai/users/mg, not https://masto.ai/@mg https://masto.ai/@mg or @mg@masto.ai. @mg@masto.ai can change and nothing will happen (even old mentions should still work, as at least Mastodon resolves the mentions to the Actor url and includes a mapping in the post). But if the https://masto.ai/users/mg https://masto.ai/users/mg URL changes, you will need to trigger a move, or you'll lose your followers, because from their servers point of view, that URL is your identity or in ActivityPub speak it's the identity of your Person Actor and for most purposes that's all ActivityPub cares about. So while you can introduce aliases in webfinger, and for the purposes of webinger your id is mg@masto.ai, if the primary ID of the ActivityPub Person actor changes, you need a "movedTo" element to point to the new one, an "alsoKnownAs" to point to the old one, and trigger notifications to the servers of your followers and following for things not to break horribly. See e.g.: curl -H "Accept: application/json" https://mastodon.social/@vidarh | jq .movedTo And curl -H "Accept: application/json" https://m.galaxybound.com/users/vidar | jq .alsoKnownAs This is not in the ActivityPub spec - it was added as an extension as people started to want to be able to move more smoothly. (I personally don't like this dependency on the old server in the move process, and so one of the few things I actually like about BlueSky is the ability for a user to take their data to a new server unilaterally; that could be fixed for the Fediverse without an entirely new protocol, however - it just needs a mechanism similar to the recovery key mechanism of BlueSky to let users prove who they are on a new server) In effect, you have two identities in the Fediverse: * You have a webfinger identity acct:mg@masto.ai * You have an ActivityPub Person actor identity https://masto.ai/users/mg https://masto.ai/users/mg Changing the former, or adding more of them (you can even just add a redirect on your own domain and user@yourowndomain will work and resolve to your https://masto.ai/users/mg https://masto.ai/users/mg identity; this is how my Mastodon is on m.galaxybound.com but my preferred Mastodon handle is @vidar@galaxybound.com without the "m."), is easy. Changing the latter is complex (more than it should be).
    - mg 3y ago
      curl -H "Accept: application/json" https://masto.ai/users/mg/following?page=1 | jq . Notice the people you are following are referenced by URL. That we can see entries of the form hostname/users/username in the output of a that specific curl command is proof that it is the identity of a user as defined by the ActivityPub protocol? Shouldn't we be able to look at the ActivityPub specs and see how the identity of a users is defined?
      - vidarh 3y ago
        To quote the spec: 'In ActivityPub, a user is represented by "actors" via the user's accounts on servers.' and: 'All Objects in [ActivityStreams] should have unique global identifiers. ActivityPub extends this requirement; all objects distributed by the ActivityPub protocol MUST have unique global identifiers, unless they are intentionally transient (short lived activities that are not intended to be able to be looked up, such as some kinds of chat messages or game notifications). These identifiers must fall into one of the following groups: 1. Publicly dereferencable URIs, such as HTTPS URIs, with their authority belonging to that of their originating server. (Publicly facing content SHOULD use HTTPS URIs). 2. An ID explicitly specified as the JSON null object, which implies an anonymous object (a part of its parent context)' and: 'All objects have the following properties: id The object's unique global identifier (unless the object is transient, in which case the id MAY be omitted).' So a user is represented by an Actor, an Actor must have a global identifier, and that global identifier is the "id" field in the JSON. https://masto.ai/users/mg https://masto.ai/users/mg in your case. (You may also search the ActivityPub spec for "webfinger"; it is not mentioned - it's a convenience offered by implementations like Mastodon, and not required by the ActivityPub spec at all; your interop with Mastodon will be harmed if you don't support it, but it'll work - users just need to input your url instead) EDIT: to further underline the relationship of Webfinger to ActivityPub, look at the section for Actor's [1], and how the use of webfinger lookups violate the spec ("otherwise, the entered value should be considered invalid") - it's an extension/change used by things like Mastodon for user convenience, and not part of ActivityPub itself at all. [1] https://w3c.github.io/activitypub/#actors https://w3c.github.io/activitypub/#actors
jeroenhd 3y ago
You're thinking of Mastodon. There's no mention of using @ in identities at all in the ActivityPub spec: https://www.w3.org/TR/activitypub/#actor-objects https://www.w3.org/TR/activitypub/#actor-objects Usernames can be represented as whatever, but they're not the user IDs. Peertube implements ActivityPub and uses username@server instead of @username@server, and so does Pixelfed. Funkwhale uses https://hostname.tld/federation/actors/Alice https://hostname.tld/federation/actors/Alice as their ActivityPub identifier (they support multiple federation protocols) and doesn't have a clear representation of user + domain as far as I can tell.
- mg 3y ago
  There is no mention of "identities" or "identity" in the spec either. So if a person is available via ActivityPub, how do they reference their "identity"? When you want to say "Follow me via ActivityPub: ..." - what is "..."? The most common form I see is @username@hostname. Is there a more universal form? How does a Pixelfed user do it?
  - vidarh 3y ago
    The most common form is @username@hostname, sure, because it's convenient, and also because doing a webfinger lookup of that is more generic - a webfinger response can include far more than AcrivityPub endpoints. But specifically for ActivityPub the URL works just fine (try pasting it in the Mastodon search box, for example, and up pops the user details exactly as if you'd used @user@host)
    - mg 3y ago
      You say "the url works" as if there is a clearly defined url for every Fediverse user. But the way I read the specs, that is not the case. Some servers link you to hostname/users/username, some use hostname/@username, some use hostname/username when you look up a user via webfinger. And the way I read the specs, those don't have to be permanent. A server could change their scheme from hostname/users/username to hostname/u/username and would not violate the protocol. Because the way to identify the user is via a webfinger lookup. Maybe the only way to say who you are on the Fediverse is "I am <username> on <hostname>. Look me up through Webfinger"? That might be the equivalent of saying "I am https://masto.ai/.well-known/webfinger?resource=acct%3Amg%40masto.ai https://masto.ai/.well-known/webfinger?resource=acct%3Amg%40..."
numpad0 3y ago
Since more people are trying to prove you wrong, I’d argue it can’t be too late for Mastodon to fix that username scheme used in the frontend app. And agreed that double @ is stupid.
- vidarh 3y ago
  Mastodon supports URI's in the UI, and resolves @user@host names to profile URI's when you post as it is, so the use of webfinger is almost entirely a presentation/convenience issue anyway. I also dislike the double "@", but I get the thinking that starting "@" has to some extent become a signifier that what follows is a social handle.

That is not how I read the specs. Let's look at an example: My handle is @mg@masto.ai What is my "AP identity" in your interpretation of the AP protocol?

by mg 3y ago

That is not how I read the specs. Let's look at an example: My handle is @mg@masto.ai What is my "AP identity" in your interpretation of the AP protocol?

sieabahlpark 3y ago

[dead]

tedunangst 3y ago

It's https://masto.ai/users/mg https://masto.ai/users/mg. You can see it by running curl -H "Accept: application/ld+json". https://www.w3.org/TR/activitypub/#obj-id https://www.w3.org/TR/activitypub/#obj-id

mg 3y ago
That is one of the aliases. The same holds true for ... https://masto.ai/users/mg https://masto.ai/@mg ... and the server could povide as many aliases as it wants to. I wouldn't call those "identities". As the server could just change the aliases and the handle "@mg@masto.ai" would still work. Because it resolves to whatever aliases the server provides via the webfinger endpoint. I have not seen anything in the specs that says the aliases are identities or should stay the same over time.
- vidarh 3y ago
  Try this: curl -H "Accept: application/json" https://masto.ai/users/mg/following?page=1 | jq . Notice the people you are following are referenced by URL. If you try /followers instead, and look up the following URLs of some of your followers, you'll find that they follow you by the URL https://masto.ai/users/mg If you do: curl -H "Accept: application/json" https://masto.ai/@mg | jq .id You'll see that the returned document shows the id of your ActivityPub Person actor as https://masto.ai/users/mg https://masto.ai/users/mg, not https://masto.ai/@mg https://masto.ai/@mg or @mg@masto.ai. @mg@masto.ai can change and nothing will happen (even old mentions should still work, as at least Mastodon resolves the mentions to the Actor url and includes a mapping in the post). But if the https://masto.ai/users/mg https://masto.ai/users/mg URL changes, you will need to trigger a move, or you'll lose your followers, because from their servers point of view, that URL is your identity or in ActivityPub speak it's the identity of your Person Actor and for most purposes that's all ActivityPub cares about. So while you can introduce aliases in webfinger, and for the purposes of webinger your id is mg@masto.ai, if the primary ID of the ActivityPub Person actor changes, you need a "movedTo" element to point to the new one, an "alsoKnownAs" to point to the old one, and trigger notifications to the servers of your followers and following for things not to break horribly. See e.g.: curl -H "Accept: application/json" https://mastodon.social/@vidarh | jq .movedTo And curl -H "Accept: application/json" https://m.galaxybound.com/users/vidar | jq .alsoKnownAs This is not in the ActivityPub spec - it was added as an extension as people started to want to be able to move more smoothly. (I personally don't like this dependency on the old server in the move process, and so one of the few things I actually like about BlueSky is the ability for a user to take their data to a new server unilaterally; that could be fixed for the Fediverse without an entirely new protocol, however - it just needs a mechanism similar to the recovery key mechanism of BlueSky to let users prove who they are on a new server) In effect, you have two identities in the Fediverse: * You have a webfinger identity acct:mg@masto.ai * You have an ActivityPub Person actor identity https://masto.ai/users/mg https://masto.ai/users/mg Changing the former, or adding more of them (you can even just add a redirect on your own domain and user@yourowndomain will work and resolve to your https://masto.ai/users/mg https://masto.ai/users/mg identity; this is how my Mastodon is on m.galaxybound.com but my preferred Mastodon handle is @vidar@galaxybound.com without the "m."), is easy. Changing the latter is complex (more than it should be).
  - mg 3y ago
    curl -H "Accept: application/json" https://masto.ai/users/mg/following?page=1 | jq . Notice the people you are following are referenced by URL. That we can see entries of the form hostname/users/username in the output of a that specific curl command is proof that it is the identity of a user as defined by the ActivityPub protocol? Shouldn't we be able to look at the ActivityPub specs and see how the identity of a users is defined?
    - vidarh 3y ago
      To quote the spec: 'In ActivityPub, a user is represented by "actors" via the user's accounts on servers.' and: 'All Objects in [ActivityStreams] should have unique global identifiers. ActivityPub extends this requirement; all objects distributed by the ActivityPub protocol MUST have unique global identifiers, unless they are intentionally transient (short lived activities that are not intended to be able to be looked up, such as some kinds of chat messages or game notifications). These identifiers must fall into one of the following groups: 1. Publicly dereferencable URIs, such as HTTPS URIs, with their authority belonging to that of their originating server. (Publicly facing content SHOULD use HTTPS URIs). 2. An ID explicitly specified as the JSON null object, which implies an anonymous object (a part of its parent context)' and: 'All objects have the following properties: id The object's unique global identifier (unless the object is transient, in which case the id MAY be omitted).' So a user is represented by an Actor, an Actor must have a global identifier, and that global identifier is the "id" field in the JSON. https://masto.ai/users/mg https://masto.ai/users/mg in your case. (You may also search the ActivityPub spec for "webfinger"; it is not mentioned - it's a convenience offered by implementations like Mastodon, and not required by the ActivityPub spec at all; your interop with Mastodon will be harmed if you don't support it, but it'll work - users just need to input your url instead) EDIT: to further underline the relationship of Webfinger to ActivityPub, look at the section for Actor's [1], and how the use of webfinger lookups violate the spec ("otherwise, the entered value should be considered invalid") - it's an extension/change used by things like Mastodon for user convenience, and not part of ActivityPub itself at all. [1] https://w3c.github.io/activitypub/#actors https://w3c.github.io/activitypub/#actors

jeroenhd 3y ago

You're thinking of Mastodon. There's no mention of using @ in identities at all in the ActivityPub spec: https://www.w3.org/TR/activitypub/#actor-objects https://www.w3.org/TR/activitypub/#actor-objects Usernames can be represented as whatever, but they're not the user IDs. Peertube implements ActivityPub and uses username@server instead of @username@server, and so does Pixelfed. Funkwhale uses https://hostname.tld/federation/actors/Alice https://hostname.tld/federation/actors/Alice as their ActivityPub identifier (they support multiple federation protocols) and doesn't have a clear representation of user + domain as far as I can tell.

mg 3y ago
There is no mention of "identities" or "identity" in the spec either. So if a person is available via ActivityPub, how do they reference their "identity"? When you want to say "Follow me via ActivityPub: ..." - what is "..."? The most common form I see is @username@hostname. Is there a more universal form? How does a Pixelfed user do it?
- vidarh 3y ago
  The most common form is @username@hostname, sure, because it's convenient, and also because doing a webfinger lookup of that is more generic - a webfinger response can include far more than AcrivityPub endpoints. But specifically for ActivityPub the URL works just fine (try pasting it in the Mastodon search box, for example, and up pops the user details exactly as if you'd used @user@host)
  - mg 3y ago
    You say "the url works" as if there is a clearly defined url for every Fediverse user. But the way I read the specs, that is not the case. Some servers link you to hostname/users/username, some use hostname/@username, some use hostname/username when you look up a user via webfinger. And the way I read the specs, those don't have to be permanent. A server could change their scheme from hostname/users/username to hostname/u/username and would not violate the protocol. Because the way to identify the user is via a webfinger lookup. Maybe the only way to say who you are on the Fediverse is "I am <username> on <hostname>. Look me up through Webfinger"? That might be the equivalent of saying "I am https://masto.ai/.well-known/webfinger?resource=acct%3Amg%40masto.ai https://masto.ai/.well-known/webfinger?resource=acct%3Amg%40..."

numpad0 3y ago

Since more people are trying to prove you wrong, I’d argue it can’t be too late for Mastodon to fix that username scheme used in the frontend app. And agreed that double @ is stupid.

vidarh 3y ago
Mastodon supports URI's in the UI, and resolves @user@host names to profile URI's when you post as it is, so the use of webfinger is almost entirely a presentation/convenience issue anyway. I also dislike the double "@", but I get the thinking that starting "@" has to some extent become a signifier that what follows is a social handle.