lemmy/crates/apub/src/fetcher/search.rs

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use anyhow::anyhow;
use chrono::NaiveDateTime;
use itertools::Itertools;
use serde::Deserialize;
use url::Url;
use lemmy_api_common::blocking;
use lemmy_apub_lib::{
traits::ApubObject,
webfinger::{webfinger_resolve_actor, WebfingerType},
};
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use lemmy_db_schema::{
source::{community::Community, person::Person as DbPerson},
DbPool,
};
use lemmy_utils::LemmyError;
use lemmy_websocket::LemmyContext;
use crate::{
fetcher::object_id::ObjectId,
objects::{
comment::ApubComment,
community::ApubCommunity,
person::{ApubPerson, Person},
post::ApubPost,
},
protocol::objects::{group::Group, note::Note, page::Page},
};
/// Attempt to parse the query as URL, and fetch an ActivityPub object from it.
///
/// Some working examples for use with the `docker/federation/` setup:
/// http://lemmy_alpha:8541/c/main, or !main@lemmy_alpha:8541
/// http://lemmy_beta:8551/u/lemmy_alpha, or @lemmy_beta@lemmy_beta:8551
/// http://lemmy_gamma:8561/post/3
/// http://lemmy_delta:8571/comment/2
pub async fn search_by_apub_id(
query: &str,
context: &LemmyContext,
) -> Result<SearchableObjects, LemmyError> {
let query_url = match Url::parse(query) {
Ok(u) => u,
Err(_) => {
let (kind, name) = query.split_at(1);
let kind = match kind {
"@" => WebfingerType::Person,
"!" => WebfingerType::Group,
_ => return Err(anyhow!("invalid query").into()),
};
// remote actor, use webfinger to resolve url
if name.contains('@') {
let (name, domain) = name.splitn(2, '@').collect_tuple().expect("invalid query");
webfinger_resolve_actor(
name,
domain,
kind,
context.client(),
context.settings().get_protocol_string(),
)
.await?
}
// local actor, read from database and return
else {
return find_local_actor_by_name(name, kind, context.pool()).await;
}
}
};
let request_counter = &mut 0;
ObjectId::new(query_url)
.dereference(context, request_counter)
.await
}
async fn find_local_actor_by_name(
name: &str,
kind: WebfingerType,
pool: &DbPool,
) -> Result<SearchableObjects, LemmyError> {
let name: String = name.into();
Ok(match kind {
WebfingerType::Group => SearchableObjects::Community(
blocking(pool, move |conn| Community::read_from_name(conn, &name))
.await??
.into(),
),
WebfingerType::Person => SearchableObjects::Person(
blocking(pool, move |conn| DbPerson::find_by_name(conn, &name))
.await??
.into(),
),
})
}
/// The types of ActivityPub objects that can be fetched directly by searching for their ID.
#[derive(Debug)]
pub enum SearchableObjects {
Person(ApubPerson),
Community(ApubCommunity),
Post(ApubPost),
Comment(ApubComment),
}
#[derive(Deserialize)]
#[serde(untagged)]
pub enum SearchableApubTypes {
Group(Group),
Person(Person),
Page(Page),
Note(Note),
}
#[async_trait::async_trait(?Send)]
impl ApubObject for SearchableObjects {
type DataType = LemmyContext;
type ApubType = SearchableApubTypes;
type TombstoneType = ();
fn last_refreshed_at(&self) -> Option<NaiveDateTime> {
match self {
SearchableObjects::Person(p) => p.last_refreshed_at(),
SearchableObjects::Community(c) => c.last_refreshed_at(),
SearchableObjects::Post(p) => p.last_refreshed_at(),
SearchableObjects::Comment(c) => c.last_refreshed_at(),
}
}
// TODO: this is inefficient, because if the object is not in local db, it will run 4 db queries
// before finally returning an error. it would be nice if we could check all 4 tables in
// a single query.
// we could skip this and always return an error, but then it would always fetch objects
// over http, and not be able to mark objects as deleted that were deleted by remote server.
async fn read_from_apub_id(
object_id: Url,
context: &LemmyContext,
) -> Result<Option<Self>, LemmyError> {
let c = ApubCommunity::read_from_apub_id(object_id.clone(), context).await?;
if let Some(c) = c {
return Ok(Some(SearchableObjects::Community(c)));
}
let p = ApubPerson::read_from_apub_id(object_id.clone(), context).await?;
if let Some(p) = p {
return Ok(Some(SearchableObjects::Person(p)));
}
let p = ApubPost::read_from_apub_id(object_id.clone(), context).await?;
if let Some(p) = p {
return Ok(Some(SearchableObjects::Post(p)));
}
let c = ApubComment::read_from_apub_id(object_id, context).await?;
if let Some(c) = c {
return Ok(Some(SearchableObjects::Comment(c)));
}
Ok(None)
}
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async fn delete(self, data: &Self::DataType) -> Result<(), LemmyError> {
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match self {
SearchableObjects::Person(p) => p.delete(data).await,
SearchableObjects::Community(c) => c.delete(data).await,
SearchableObjects::Post(p) => p.delete(data).await,
SearchableObjects::Comment(c) => c.delete(data).await,
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}
}
async fn to_apub(&self, _data: &Self::DataType) -> Result<Self::ApubType, LemmyError> {
unimplemented!()
}
fn to_tombstone(&self) -> Result<Self::TombstoneType, LemmyError> {
unimplemented!()
}
async fn from_apub(
apub: &Self::ApubType,
context: &LemmyContext,
ed: &Url,
rc: &mut i32,
) -> Result<Self, LemmyError> {
use SearchableApubTypes as SAT;
use SearchableObjects as SO;
Ok(match apub {
SAT::Group(g) => SO::Community(ApubCommunity::from_apub(g, context, ed, rc).await?),
SAT::Person(p) => SO::Person(ApubPerson::from_apub(p, context, ed, rc).await?),
SAT::Page(p) => SO::Post(ApubPost::from_apub(p, context, ed, rc).await?),
SAT::Note(n) => SO::Comment(ApubComment::from_apub(n, context, ed, rc).await?),
})
}
}