bridgy-fed support Lemmy

Background:

https://join-lemmy.org/
https://join-lemmy.org/docs/en/administration/federation_getting_started.html
https://socialhub.activitypub.rocks/t/help-improving-federation-between-lemmy-and-other-projects/2308

I tried federating this like to this post on lemmy.ml (running BE 0.16.7) just now, and the AP inbox delivery to https://lemmy.ml/u/OptimusPrime/inbox returned 400 with invalid type: map, expected a string representing an URL at line 1 column 218. Bridgy Fed log here. Full AS2 object below.

Lemmy's design looks like Reddit, with up/downvotes instead of likes, so I don't know that it actually supports likes, but the error message sounds unrelated to that, more like maybe it can only handle string URLs for actors instead of compound objects.

{
  "published": "2023-01-17T13:03:52-08:00",
  "content": "likes <a class=\"u-like u-like-of\" href=\"https://lemmy.ml/post/713841\">[lemmy.ml](http://lemmy.ml/)</a>",
  "url": "https://fed.brid.gy/r/https://snarfed.org/2023-01-17_lemmy-ml",
  "actor": {
    "url": "https://fed.brid.gy/r/https://snarfed.org/",
    "image": {
      "url": "https://secure.gravatar.com/avatar/947b5f3f323da0ef785b6f02d9c265d6?s=96&d=blank&r=g",
      "type": "Image"
    },
    "type": "Person",
    "name": "Ryan Barrett",
    "icon": {
      "url": "https://secure.gravatar.com/avatar/947b5f3f323da0ef785b6f02d9c265d6?s=96&d=blank&r=g",
      "type": "Image"
    },
    "id": "https://fed.brid.gy/snarfed.org",
    "preferredUsername": "[snarfed.org](http://snarfed.org/)"
  },
  "@context": "https://www.w3.org/ns/activitystreams",
  "type": "Like",
  "object": "https://lemmy.ml/post/713841",
  "id": "https://fed.brid.gy/r/https://snarfed.org/2023-01-17_lemmy-ml",
  "cc": [
    "https://lemmy.ml/u/OptimusPrime",
    "https://lemmy.ml/c/privacy",
    "https://www.w3.org/ns/activitystreams#Public"
  ],
  "to": [
    "https://www.w3.org/ns/activitystreams#Public"
  ]
}

Jan 17 '23 21:01 snarfed

From https://socialhub.activitypub.rocks/t/help-improving-federation-between-lemmy-and-other-projects/2308/22 :

You are right this isnt complicated, in fact we are already doing the same thing in some other places. Unfortunately I dont have time to work on this, but if you want to make a contribution I would gladly guide you through the code.

Jan 20 '23 15:01 snarfed

Progress is a new error message. After #442, we're now getting HTTP 400 data did not match any variant of untagged enum PersonOrGroup on this Like:

{
  "published": "2023-10-11T21:12:28-07:00",
  "content": "Likes <a class=\"u-like-of\" href=\"https://lemmy.world/post/6663494\">https://lemmy.world/post/6663494</a>;..\n<div class=\"e-content\">\nA meme for math people – Lemmy.world\n</div>",
  "url": "https://fed.brid.gy/r/https://snarfed.org/2023-10-11_a-meme-for-math-people-lemmy-world",
  "actor": "https://fed.brid.gy/snarfed.org",
  "id": "https://fed.brid.gy/r/https://snarfed.org/2023-10-11_a-meme-for-math-people-lemmy-world",
  "@context": "https://www.w3.org/ns/activitystreams",
  "type": "Like",
  "object": "https://lemmy.world/post/6663494",
  "cc": [
    "https://lemmy.ml/c/memes",
    "https://lemmy.world/u/hypertown",
    "https://www.w3.org/ns/activitystreams#Public"
  ],
  "to": [
    "https://www.w3.org/ns/activitystreams#Public"
  ]
}

Oct 12 '23 04:10 snarfed

And for this reply, 400 Client Error: Bad Request for url: https://lemmy.world/u/hypertown/inbox ; deserializing body: ...

{
  "id": "https://fed.brid.gy/r/https://snarfed.org/2023-10-11_a-meme-for-math-people-lemmy-world-3#bridgy-fed-create",
  "actor": "https://fed.brid.gy/snarfed.org",
  "published": "2023-10-12T04:17:52.463875+00:00",
  "@context": "https://www.w3.org/ns/activitystreams",
  "type": "Create",
  "object": {
    "published": "2023-10-11T21:17:47-07:00",
    "content": "<a class=\"u-in-reply-to\" href=\"https://lemmy.world/post/6663494\"></a>\n<div class=\"e-content\">\nnice\n</div>",
    "url": "https://fed.brid.gy/r/https://snarfed.org/2023-10-11_a-meme-for-math-people-lemmy-world-3",
    "id": "https://fed.brid.gy/r/https://snarfed.org/2023-10-11_a-meme-for-math-people-lemmy-world-3",
    "type": "Note",
    "attributedTo": "https://fed.brid.gy/snarfed.org",
    "inReplyTo": "https://lemmy.world/post/6663494",
    "cc": [
      "https://lemmy.ml/c/memes",
      "https://lemmy.world/u/hypertown",
      "https://www.w3.org/ns/activitystreams#Public"
    ],
    "tag": [
      {
        "type": "Mention",
        "href": "https://lemmy.world/u/hypertown"
      }
    ],
    "to": [
      "https://www.w3.org/ns/activitystreams#Public"
    ]
  },
  "to": [
    "https://www.w3.org/ns/activitystreams#Public"
  ]
}

Oct 12 '23 04:10 snarfed

Progress is a new error message. After #442, we're now getting HTTP 400 data did not match any variant of untagged enum PersonOrGroup on this Like:

This also happens on follows.

Oct 24 '23 20:10 snarfed