=> AP: contentMap values should be HTML

[Tamschi]

Current example with plaintext in #1607. It should have the same semantics as content: #1607 (comment)

The properties are in fact mapped to the same key in https://www.w3.org/ns/activitystreams, just with different transforms:

"content": "as:content",
"contentMap": {
    "@id":"as:content",
    "@container":"@language"
},

(This is valid, they just become an array after expansion like this:

"https://www.w3.org/ns/activitystreams#content": [
  {
    "@value": "<p>OMG OMG OMG we're able to bridge our threads accounts into Blue sky via federation <a class=\"mention\" href=\"https://ap.brid.gy/ap.brid.gy\">@ap.brid.gy</a>  & <a class=\"mention\" href=\"https://bsky.app/profile/snarfed.org\">@snarfed.org</a><br><br>RE: <a href=\"https://bsky.app/profile/did:plc:4ghwklnin2mvmam4ditdwv2o/post/3lclod7ptodd2\">https://bsky.app/profile/did:plc:4ghwklnin2mvmam4ditdwv2o/post/3lclod7ptodd2</a></p>"
  },
  {
    "@value": "OMG OMG OMG we're able to bridge our threads accounts into Blue sky via federation @ap.brid.gy  & @snarfed.org",
    "@language": "en"
  }
],

(via https://json-ld.org/playground/)

[panosda]

This is probably related to why links in bridged posts don't work in firefish and catodon. More context: https://chat.iceshrimp.dev/#narrow/stream/6-support/topic/.E2.9C.94.20Links.20from.20Bridgy.20Fed.20not.20working.20on.20-js

[Tamschi]

Do Firefish and Catodon allow toggling the post display language if there's a contentMap?

[Tamschi]

I had a look at Catodon's code. In order of decreasing priority it uses:

• source.content iff source.mediaType is "text/x.misskeymarkdown", language-tagged¹ with the first key in contentMap.
• The first entry in contentMap.
• Nothing if contentMap is present but empty.²
• _misskey_content.
• content

So no, no mutli-language support, it just picks the content a bit differently.³
It appears to use MFM as native storage format, so any HTML is converted into that representation.

Footnotes

1. Language-tagging is subject to an allow-list of supported languages. If not supported, the information is discarded entirely, I think. ↩

2. This directly mismatches JSON-LD processing rules, I think. Oh well. Interestingly though, I think this could cause it to treat a quote as a boost/renote in some cases. ↩

3. Which isn't a vulnerability because you can present distinct content to different servers in ActivityPub anyway. ↩

[panosda]

Hey, sorry for not being more helpful, but I'm not a dev. I just asked in Iceshrimp and a dev told me that bridgy fed doesn't include the correct link in contentmap, and that this is the reason links don't work for us. Do you think this could be fixed on your side? Thanks!

[Tamschi]

Yes, this is squarely a bug on our side. Catodon's behaviour is correct here, just a little unusual.