Developers Meeting 7 : A standard way to query in ActivityPub

Following Developers Meeting 6 : Groups and Improving C2S (ended) :

Please note: Due to upcoming holidays it will be the first TUE of the month, July 5.

(not the second one)


  • 5pm UTC / 12am EST / 9am PST

with an open end.

We had a very long meeting, 2.5 hours.
We spoke about the context field and “Potential Actions attached to objects” and Sebastian demoed approaches to taxonomies. Nilesh Trivedi demoed things which he built from and an editor for graphs. Will Murphy solved a thing with and talked about how is doing it and Guy started GitHub - guysoft/fedigroup: A federated simple group and Chris Moser does GitHub - yuforium/api: Yuforium API Server and GitHub - yuforium/ui etc.

We discovered further how we can use the context field for Groups and Topics and give meaning to it.
In the next meeting we would like to find a standard way to query and have a look into SPARQL and GraphQL and other possibilities.


  • 5min : 40s-introductions/reintroductions

  • maybe quick brainstorming about the CFP/sessions for Fedi Camp

  • demos

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Upcoming, August
Bildschirmfoto 2022-06-09 um 17.43.46

The event was announced in German and it will take place “on the ass of the heath”.

It filled quickly, so there is no english version but I’m happy to answer any questions in any language.

Any reason SPARQL can’t be used for this? Would be good not to invent something new unless required.

The reason is that at the moment nobody uses SPARQL.

Would be good not to invent something new unless required.

Said the same in the meeting.

at the moment nobody uses SPARQL

That sounds like a testable hypothesis that can be invalidated by an existence proof. RDF and SPARQL: New in Wolfram Language 12

Argh, in ActivityPub I meant, man.
Fine things do use it of course.

Personally I am using SPARQL each day for and its implementation in redaktor. As I said in the meeting, I like SPARQL (but fine with GraphQL as well) …

I don’t mean to be pedantic. Just trying to understand the argument.

GraphQL Foundation is hosted by Linux Foundation.
Not a bad choice but then you’ll have to convince them to care about rdf (or not).

Still think: just use Sparql.

There’s an argument to be made that sparql is ‘more expressive than needed’ for activitypub use cases.
In that case, profile sparql, i.e. define a subset of sparql that is strictly needed, e.g. some common queries that activitypub deployments need.

Which begs the question?

What do people need to query that isn’t in the AP spec (or other community specs)?

“General purpose querying” is much harder than domain-specific querying. The former is solved by SPARQL, but it’s hard to implement because it’s so general. Let’s learn from that and define the domain-specific queries that people are ostensibly blocked by?

What do people need to query that isn’t in the AP spec (or other community specs)?

Pops up nearly each day, so will ask the next.
Personally same things than e.g. in twitter
“posted before/after/between”
“posted from/to”
“only type=Image”
“context about Harold and Maude or Robert Frank”

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I’m using SPARQL! rdf-pub is supporting SPARQL.

I’m struggeling with some issues in the moment and currently the auth server is down ;-(
But in principle you can query the public collection.
There is certainly still a lot to learn and, if necessary, to optimise.
From an authentication point of view, it will be exciting.
I’ll have to test that soon, but at the moment I’m still testing the public collection query.

The karte von morgen (kvm) adapter, that is doing a one way sync kvm → rdf-pub uses “hardcore” SPARQL to check, what entries are already in rdf-pub.


getting all kvm identifiers that are in the public collection
get some activities → the object names are currently bad!