Fediseer ActivityPub user cannot be resolved by Lemmy 0.19.4+

[Nothing4You]

Since activitypub-federation-rust v0.5.1, Lemmys ActivityPub library validates the content type header when resolving objects. Lemmy updated this library in v0.19.4, so all instances running Lemmy 0.19.4 and above enforce content type header validation when resolving objects.

Fediseer currently returns application/json instead of e.g. application/activity+json for the identity used to send PMs.

curl -I -H'accept: application/activity+json' https://fediseer.com/api/v1/user/fediseer

HTTP/2 200
access-control-allow-headers: Accept, Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, apikey, Client-Agent, X-Fields
access-control-allow-methods: POST, GET, OPTIONS, PUT, DELETE, PATCH
access-control-allow-origin: *
content-length: 933
content-type: application/json
date: Sat, 22 Jun 2024 14:34:54 GMT
etag: 5b324547be870344bd33c01d93eb722588f3eba0
fediseer-node: fediseer:10001:0.23.0
retry-after: 60
server: waitress
x-ratelimit-limit: 90
x-ratelimit-remaining: 89
x-ratelimit-reset: 1719066955
x-cache-status: MISS

The result of this is a cryptic

There was an api error: API Key PM failed

in the web interface and

WARN Error encountered while processing the incoming HTTP request: lemmy_server::root_span_builder: Unknown: Attempted to fetch object from https://fediseer.com/api/v1/user/fediseer which doesn't have valid ActivityPub Content-Type

in Lemmy logs.

[db0]

Thanks for letting me know. I'll fix