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  4. I have deeply mixed feelings about #ActivityPub's adoption of JSON-LD, as someone who's spent way too long dealing with it while building #Fedify.

I have deeply mixed feelings about #ActivityPub's adoption of JSON-LD, as someone who's spent way too long dealing with it while building #Fedify.

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  • julian@activitypub.spaceJ julian@activitypub.space

    @sl007@digitalcourage.social eh? You use context?

    ForumWG decided to use context to represent threads in threadiverse software (and Mastodon too, now).

    Just FYI.

    sl007@digitalcourage.socialS This user is from outside of this forum
    sl007@digitalcourage.socialS This user is from outside of this forum
    sl007@digitalcourage.social
    wrote last edited by
    #65

    @julian

    hm, strange. I would really not ignore all the official ActivityPub meetings between 2016 and 2014 🙂 Maybe it would be worth to read the W3C minutes of SocialCG 2019 ff
    Think, it _should_ have been 2019 or 2021 cause 2021 it wasn't on the "waitlist" anymore :https://socialhub.activitypub.rocks/t/2021-01-09-socialcg-meeting-fep/1246

    But:
    It dates back to 2020 https://socialhub.activitypub.rocks/t/context-vs-conversation/578 and after mastodon and pleroma agreed to the us , the 2 Social CG meetings are linked by me in the thread.
    Then we had the 2020 brilliant Conf.

    So, well, we use it for ActivityPub spec says and what was decided there by all …

    mastodon is _not_ able to introduce breaking changes to a W3C standard
    Just FYI.

    sl007@digitalcourage.socialS 1 Reply Last reply
    0
    • sl007@digitalcourage.socialS sl007@digitalcourage.social

      @julian

      hm, strange. I would really not ignore all the official ActivityPub meetings between 2016 and 2014 🙂 Maybe it would be worth to read the W3C minutes of SocialCG 2019 ff
      Think, it _should_ have been 2019 or 2021 cause 2021 it wasn't on the "waitlist" anymore :https://socialhub.activitypub.rocks/t/2021-01-09-socialcg-meeting-fep/1246

      But:
      It dates back to 2020 https://socialhub.activitypub.rocks/t/context-vs-conversation/578 and after mastodon and pleroma agreed to the us , the 2 Social CG meetings are linked by me in the thread.
      Then we had the 2020 brilliant Conf.

      So, well, we use it for ActivityPub spec says and what was decided there by all …

      mastodon is _not_ able to introduce breaking changes to a W3C standard
      Just FYI.

      sl007@digitalcourage.socialS This user is from outside of this forum
      sl007@digitalcourage.socialS This user is from outside of this forum
      sl007@digitalcourage.social
      wrote last edited by
      #66

      @julian

      Can you specify "threadiverse" software cause like all properties which are not marked as "functional" in the ActivityPub Spec, `context` is an Array and I do not see any problem …

      sl007@digitalcourage.socialS 1 Reply Last reply
      0
      • julian@activitypub.spaceJ julian@activitypub.space

        @liaizon@social.wake.st actually, oddly, I did receive @silverpill@mitra.social's response, so it seems to be I can access some replies from Mitra, but not all.

        ? Offline
        ? Offline
        Guest
        wrote last edited by
        #67

        @julian @liaizon https://activitypub.space/uid/1/inbox still returns 404. Perhaps group's inbox is working?

        UPD: yes https://activitypub.space/category/5/inbox returns 202

        julian@activitypub.spaceJ 1 Reply Last reply
        0
        • ? Guest

          @julian @liaizon https://activitypub.space/uid/1/inbox still returns 404. Perhaps group's inbox is working?

          UPD: yes https://activitypub.space/category/5/inbox returns 202

          julian@activitypub.spaceJ This user is from outside of this forum
          julian@activitypub.spaceJ This user is from outside of this forum
          julian@activitypub.space
          wrote last edited by
          #68

          @silverpill@mitra.social POSTing that inbox sends a 404?

          ? 1 Reply Last reply
          0
          • hongminhee@hollo.socialH hongminhee@hollo.social

            I have deeply mixed feelings about #ActivityPub's adoption of JSON-LD, as someone who's spent way too long dealing with it while building #Fedify.

            Part of me wishes it had never happened. A lot of developers jump into ActivityPub development without really understanding JSON-LD, and honestly, can you blame them? The result is a growing number of implementations producing technically invalid JSON-LD. It works, sort of, because everyone's just pattern-matching against what Mastodon does, but it's not correct. And even developers who do take the time to understand JSON-LD often end up hardcoding their documents anyway, because proper JSON-LD processor libraries simply don't exist for many languages. No safety net, no validation, just vibes and hoping you got the @context right. Naturally, mistakes creep in.

            But then the other part of me thinks: well, we're stuck with JSON-LD now. There's no going back. So wouldn't it be nice if people actually used it properly? Process the documents, normalize them, do the compaction and expansion dance the way the spec intended. That's what Fedify does.

            Here's the part that really gets to me, though. Because Fedify actually processes JSON-LD correctly, it's more likely to break when talking to implementations that produce malformed documents. From the end user's perspective, Fedify looks like the fragile one. “Why can't I follow this person?” Well, because their server is emitting garbage JSON-LD that happens to work with implementations that just treat it as a regular JSON blob. Every time I get one of these bug reports, I feel a certain injustice. Like being the only person in the group project who actually read the assignment.

            To be fair, there are real practical reasons why most people don't bother with proper JSON-LD processing. Implementing a full processor is genuinely a lot of work. It leans on the entire Linked Data stack, which is bigger than most people expect going in. And the performance cost isn't trivial either. Fedify uses some tricks to keep things fast, and I'll be honest, that code isn't my proudest work.

            Anyway, none of this is going anywhere. Just me grumbling into the void. If you're building an ActivityPub implementation, maybe consider using a JSON-LD processor if one's available for your language. And if you're not going to, at least test your output against implementations that do.

            #JSONLD #fedidev

            potatomeow@fosstodon.orgP This user is from outside of this forum
            potatomeow@fosstodon.orgP This user is from outside of this forum
            potatomeow@fosstodon.org
            wrote last edited by
            #69

            @hongminhee i struggling badly with rust cuz it's rust being rust... i can imagine a duck typing lang might have easier time

            potatomeow@fosstodon.orgP 1 Reply Last reply
            0
            • potatomeow@fosstodon.orgP potatomeow@fosstodon.org

              @hongminhee i struggling badly with rust cuz it's rust being rust... i can imagine a duck typing lang might have easier time

              potatomeow@fosstodon.orgP This user is from outside of this forum
              potatomeow@fosstodon.orgP This user is from outside of this forum
              potatomeow@fosstodon.org
              wrote last edited by
              #70

              @hongminhee most of the time, i cant compile if really do jsonld as it is. unless i box everything onto the heap. but then it became a de-optimization point to the rest of the software

              1 Reply Last reply
              0
              • sl007@digitalcourage.socialS sl007@digitalcourage.social

                @julian

                Can you specify "threadiverse" software cause like all properties which are not marked as "functional" in the ActivityPub Spec, `context` is an Array and I do not see any problem …

                sl007@digitalcourage.socialS This user is from outside of this forum
                sl007@digitalcourage.socialS This user is from outside of this forum
                sl007@digitalcourage.social
                wrote last edited by
                #71

                @julian

                ^ what I mean :

                "context": [
                "https://threadiversesoftware.example.org/thread/123",
                "https://www.wikidata.org/wiki/Special:EntityData/Q64 "
                ];

                then says:
                "Hi machine, I am in the context of thread 123 about Berlin."

                1 Reply Last reply
                0
                • julian@activitypub.spaceJ julian@activitypub.space

                  @sl007@digitalcourage.social eh? You use context?

                  ForumWG decided to use context to represent threads in threadiverse software (and Mastodon too, now).

                  Just FYI.

                  sl007@digitalcourage.socialS This user is from outside of this forum
                  sl007@digitalcourage.socialS This user is from outside of this forum
                  sl007@digitalcourage.social
                  wrote last edited by
                  #72

                  @julian

                  Is there a W3C minutes or kind of a meeting-protocol|spec. about this use of context?

                  julian@activitypub.spaceJ 1 Reply Last reply
                  0
                  • sl007@digitalcourage.socialS sl007@digitalcourage.social

                    @julian

                    Is there a W3C minutes or kind of a meeting-protocol|spec. about this use of context?

                    julian@activitypub.spaceJ This user is from outside of this forum
                    julian@activitypub.spaceJ This user is from outside of this forum
                    julian@activitypub.space
                    wrote last edited by
                    #73

                    @sl007@digitalcourage.social FEPs 7888 and f228 details the use of context and one use case of it, to backfill conversations.

                    sl007@digitalcourage.socialS 1 Reply Last reply
                    0
                    • julian@activitypub.spaceJ julian@activitypub.space

                      @silverpill@mitra.social POSTing that inbox sends a 404?

                      ? Offline
                      ? Offline
                      Guest
                      wrote last edited by
                      #74

                      @julian Yes, POST to personal inbox sends a 404, POST to group inbox sends a 202 (I guess group inbox is how we communicate now).

                      julian@activitypub.spaceJ 1 Reply Last reply
                      0
                      • julian@activitypub.spaceJ julian@activitypub.space

                        @sl007@digitalcourage.social FEPs 7888 and f228 details the use of context and one use case of it, to backfill conversations.

                        sl007@digitalcourage.socialS This user is from outside of this forum
                        sl007@digitalcourage.socialS This user is from outside of this forum
                        sl007@digitalcourage.social
                        wrote last edited by
                        #75

                        @julian

                        well, but that is _exactly_ the same of the official Social CG meetings !

                        "This context property is the URL of the NodeBB topic."
                        vs.
                        "The context property should be used to identify the context in which the object appears in, form a common topic or group content. This can be a well known JSON-LD vocabulary or any ActivityPub Object useful for the implementation."
                        vs
                        https://www.w3.org/TR/activitystreams-vocabulary/#dfn-context :

                        „Identifies the context within which the object exists or an activity was performed.
                        The notion of "context" used is intentionally vague. The intended function is to serve as a means of grouping objects and activities that share a common originating context or purpose. An example could be all activities relating to a common project or event. “

                        and I am glad cause, as said
                        "context": [
                        "https://threadiversesoftware.example.org/thread/123",
                        "https://www.wikidata.org/wiki/Special:EntityData/Q64 "
                        ];
                        then says:
                        "Hi machine, I am in the context of thread 123 about Berlin."

                        and then

                        🧵 1/2

                        sl007@digitalcourage.socialS 1 Reply Last reply
                        0
                        • sl007@digitalcourage.socialS sl007@digitalcourage.social

                          @julian

                          well, but that is _exactly_ the same of the official Social CG meetings !

                          "This context property is the URL of the NodeBB topic."
                          vs.
                          "The context property should be used to identify the context in which the object appears in, form a common topic or group content. This can be a well known JSON-LD vocabulary or any ActivityPub Object useful for the implementation."
                          vs
                          https://www.w3.org/TR/activitystreams-vocabulary/#dfn-context :

                          „Identifies the context within which the object exists or an activity was performed.
                          The notion of "context" used is intentionally vague. The intended function is to serve as a means of grouping objects and activities that share a common originating context or purpose. An example could be all activities relating to a common project or event. “

                          and I am glad cause, as said
                          "context": [
                          "https://threadiversesoftware.example.org/thread/123",
                          "https://www.wikidata.org/wiki/Special:EntityData/Q64 "
                          ];
                          then says:
                          "Hi machine, I am in the context of thread 123 about Berlin."

                          and then

                          🧵 1/2

                          sl007@digitalcourage.socialS This user is from outside of this forum
                          sl007@digitalcourage.socialS This user is from outside of this forum
                          sl007@digitalcourage.social
                          wrote last edited by
                          #76

                          @julian

                          and then
                          1) machine gets thread (cause is JSON-LD by known/allowed `generator`)
                          2) machine fetches or gets cached wikidata entry about Berlin and displays the card (kind of "infobox" then).
                          .. from the named "SpecialEntitiyData" of wikidata which is JSON-LD as well.
                          3) machine is happy

                          apart from our tools, I need to credit Max Lath who is doing inventaire, the federated book library and did a lot of previous work for wiki JSON-LD like the wonderful https://github.com/maxlath/wikibase-sdk

                          sl007@digitalcourage.socialS 1 Reply Last reply
                          0
                          • sl007@digitalcourage.socialS sl007@digitalcourage.social

                            @julian

                            and then
                            1) machine gets thread (cause is JSON-LD by known/allowed `generator`)
                            2) machine fetches or gets cached wikidata entry about Berlin and displays the card (kind of "infobox" then).
                            .. from the named "SpecialEntitiyData" of wikidata which is JSON-LD as well.
                            3) machine is happy

                            apart from our tools, I need to credit Max Lath who is doing inventaire, the federated book library and did a lot of previous work for wiki JSON-LD like the wonderful https://github.com/maxlath/wikibase-sdk

                            sl007@digitalcourage.socialS This user is from outside of this forum
                            sl007@digitalcourage.socialS This user is from outside of this forum
                            sl007@digitalcourage.social
                            wrote last edited by
                            #77

                            @julian

                            PS - just btw;
                            about inventaire I am sharing currently photobooks for free rent in Dortmund, Germany
                            https://inventaire.io/users/sl007
                            they have also nice use for JSON-LD re. books /authors etc. https://data.inventaire.io/ like so many software in fedi.
                            If you ask the redaktor Service Actor for Place (`Question`) to find you a waffle restaurant in Amsterdam serving blue syrup near a train station then we do also use SPARQL like them - without the AI bullshit - just cause millions of friendly humans contributing to wd and OSM …

                            1 Reply Last reply
                            0
                            • hongminhee@hollo.socialH hongminhee@hollo.social

                              I have deeply mixed feelings about #ActivityPub's adoption of JSON-LD, as someone who's spent way too long dealing with it while building #Fedify.

                              Part of me wishes it had never happened. A lot of developers jump into ActivityPub development without really understanding JSON-LD, and honestly, can you blame them? The result is a growing number of implementations producing technically invalid JSON-LD. It works, sort of, because everyone's just pattern-matching against what Mastodon does, but it's not correct. And even developers who do take the time to understand JSON-LD often end up hardcoding their documents anyway, because proper JSON-LD processor libraries simply don't exist for many languages. No safety net, no validation, just vibes and hoping you got the @context right. Naturally, mistakes creep in.

                              But then the other part of me thinks: well, we're stuck with JSON-LD now. There's no going back. So wouldn't it be nice if people actually used it properly? Process the documents, normalize them, do the compaction and expansion dance the way the spec intended. That's what Fedify does.

                              Here's the part that really gets to me, though. Because Fedify actually processes JSON-LD correctly, it's more likely to break when talking to implementations that produce malformed documents. From the end user's perspective, Fedify looks like the fragile one. “Why can't I follow this person?” Well, because their server is emitting garbage JSON-LD that happens to work with implementations that just treat it as a regular JSON blob. Every time I get one of these bug reports, I feel a certain injustice. Like being the only person in the group project who actually read the assignment.

                              To be fair, there are real practical reasons why most people don't bother with proper JSON-LD processing. Implementing a full processor is genuinely a lot of work. It leans on the entire Linked Data stack, which is bigger than most people expect going in. And the performance cost isn't trivial either. Fedify uses some tricks to keep things fast, and I'll be honest, that code isn't my proudest work.

                              Anyway, none of this is going anywhere. Just me grumbling into the void. If you're building an ActivityPub implementation, maybe consider using a JSON-LD processor if one's available for your language. And if you're not going to, at least test your output against implementations that do.

                              #JSONLD #fedidev

                              mcc@mastodon.socialM This user is from outside of this forum
                              mcc@mastodon.socialM This user is from outside of this forum
                              mcc@mastodon.social
                              wrote last edited by
                              #78

                              @hongminhee How hard would it be for a future version of ActivityPub to simply back out JSON-LD support? Would there be a downside to this?

                              julian@activitypub.spaceJ hongminhee@hollo.socialH 2 Replies Last reply
                              0
                              • mcc@mastodon.socialM mcc@mastodon.social

                                @hongminhee How hard would it be for a future version of ActivityPub to simply back out JSON-LD support? Would there be a downside to this?

                                julian@activitypub.spaceJ This user is from outside of this forum
                                julian@activitypub.spaceJ This user is from outside of this forum
                                julian@activitypub.space
                                wrote last edited by
                                #79

                                @mcc@mastodon.social asking the important questions 🤣

                                @hongminhee@hollo.social

                                1 Reply Last reply
                                0
                                • ? Guest

                                  @julian Yes, POST to personal inbox sends a 404, POST to group inbox sends a 202 (I guess group inbox is how we communicate now).

                                  julian@activitypub.spaceJ This user is from outside of this forum
                                  julian@activitypub.spaceJ This user is from outside of this forum
                                  julian@activitypub.space
                                  wrote last edited by
                                  #80

                                  @silverpill@mitra.social okay! That's a little concerning because all of those routes just end up going to the same controller... but this gives me enough to debug, so thank you!

                                  1 Reply Last reply
                                  0
                                  • mcc@mastodon.socialM mcc@mastodon.social

                                    @hongminhee How hard would it be for a future version of ActivityPub to simply back out JSON-LD support? Would there be a downside to this?

                                    hongminhee@hollo.socialH This user is from outside of this forum
                                    hongminhee@hollo.socialH This user is from outside of this forum
                                    hongminhee@hollo.social
                                    wrote last edited by
                                    #81

                                    @mcc@mastodon.social I'm not sure, but that would break some ActivityPub implementations relying on JSON-LD processors. 🤔

                                    1 Reply Last reply
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