Implemented WebFinger flow and fixed incoming WebFinger

Cargo.lock

@@ -1679,6 +1679,7 @@ dependencies = [
  "tokio",
  "tokio-util",
  "tracing",
+ "url",
 ]
 
 [[package]]
@@ -1708,6 +1709,7 @@ name = "magnetar_federation"
 version = "0.3.0-alpha"
 dependencies = [
  "async-stream",
+ "async-trait",
  "chrono",
  "futures",
  "futures-core",
@@ -1727,6 +1729,8 @@ dependencies = [
  "serde_json",
  "thiserror",
  "tokio",
+ "tracing",
+ "tracing-subscriber",
  "url",
 ]
 

core/src/web_model/acct.rs

@@ -1,5 +1,8 @@
 use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
-use std::borrow::{Borrow, Cow};
+use std::{
+    borrow::{Borrow, Cow},
+    fmt::Display,
+};
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct Acct(String);
@@ -23,6 +26,12 @@ impl AsRef<str> for Acct {
     }
 }
 
+impl Display for Acct {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "acct:{}", self.0)
+    }
+}
+
 impl Serialize for Acct {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where

core/src/web_model/mod.rs

@@ -8,10 +8,12 @@ pub mod acct;
 
 pub trait ContentType: Serialize {
     fn mime_type(&self) -> &'static str;
+
+    fn alt_mime_types(&self) -> &[&'static str];
 }
 
 macro_rules! content_type {
-    ($visib:vis $typ:ident, $expression:expr) => {
+    ($visib:vis $typ:ident, $expression:expr $(,$alt:expr)*) => {
         #[derive(Copy, Clone, Eq, PartialEq, Debug, Default)]
         $visib struct $typ;
 
@@ -31,13 +33,17 @@ macro_rules! content_type {
             fn mime_type(&self) -> &'static str {
                 $expression
             }
+
+            fn alt_mime_types(&self) -> &[&'static str] {
+                &[$($alt),*]
+            }
         }
 
         impl<'de> Deserialize<'de> for $typ {
             fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
                 let content_type = String::deserialize(deserializer)?;
 
-                if matches!(content_type.as_ref(), $expression) {
+                if matches!(content_type.as_ref(), $expression $(| $alt)*) {
                     Ok(Self)
                 } else {
                     Err(Error::custom(format!(
@@ -54,7 +60,8 @@ pub mod content_type {
     use serde::de::Error;
     use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
-    content_type!(pub ContentActivityStreams, "application/activity+json");
+    content_type!(pub ContentActivityStreams, "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"", "application/activity+json");
+    content_type!(pub ContentActivityJson, "application/activity+json", "application/ld+json; profile=\"https://www.w3.org/ns/activitystreams\"");
     content_type!(pub ContentHtml, "text/html");
     content_type!(pub ContentJson, "application/json");
     content_type!(pub ContentXrdXml, "application/xrd+xml");

ext_calckey_model/Cargo.toml

@@ -13,16 +13,21 @@ ext_calckey_model_migration = { path = "./migration" }
 magnetar_common = { path = "../magnetar_common" }
 magnetar_sdk = { path = "../magnetar_sdk" }
 
-dotenvy = { workspace = true}
+dotenvy = { workspace = true }
 futures-core = { workspace = true }
 futures-util = { workspace = true }
 tokio = { workspace = true, features = ["full"] }
-tokio-util = { workspace = true}
-redis = { workspace = true, features = ["tokio-comp", "json", "serde_json"]}
-sea-orm = { workspace = true, features = ["sqlx-postgres", "runtime-tokio-rustls", "macros"] }
+tokio-util = { workspace = true }
+redis = { workspace = true, features = ["tokio-comp", "json", "serde_json"] }
+sea-orm = { workspace = true, features = [
+    "sqlx-postgres",
+    "runtime-tokio-rustls",
+    "macros",
+] }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 strum = { workspace = true }
 chrono = { workspace = true }
 tracing = { workspace = true }
 thiserror = { workspace = true }
+url = { workspace = true }

ext_calckey_model/src/lib.rs

@@ -8,6 +8,7 @@ pub mod user_model;
 pub use ck;
 use ck::*;
 pub use sea_orm;
+use url::Host;
 use user_model::UserResolver;
 
 use crate::model_ext::IdShape;
@@ -73,10 +74,10 @@ impl CalckeyModel {
     pub async fn get_user_by_tag(
         &self,
         name: &str,
-        instance: Option<&str>,
+        instance: Option<&Host>,
     ) -> Result<Option<user::Model>, CalckeyDbError> {
         let name = name.to_lowercase();
-        let instance = instance.map(str::to_lowercase);
+        let instance = instance.map(Host::to_string);
 
         let user = if let Some(instance) = instance {
             user::Entity::find()

ext_federation/Cargo.toml

@@ -13,6 +13,7 @@ magnetar_common = { path = "../magnetar_common" }
 magnetar_host_meta = { path = "../ext_host_meta" }
 magnetar_webfinger = { path = "../ext_webfinger" }
 
+async-trait = { workspace = true }
 async-stream = { workspace = true }
 futures = { workspace = true }
 futures-core = { workspace = true }
@@ -33,6 +34,8 @@ percent-encoding = { workspace = true }
 reqwest = { workspace = true, features = ["stream"] }
 
 tokio = { workspace = true, features = ["full"] }
+tracing = { workspace = true }
 
 [dev-dependencies]
+tracing-subscriber = { workspace = true }
 miette = { workspace = true, features = ["fancy"] }

ext_federation/src/lib.rs

@@ -1,56 +1,43 @@
-use std::{io::Cursor, sync::Arc};
-
-use client::federation_client::{FederationClient, FederationClientError};
-use magnetar_common::{config::MagnetarNetworkingProtocol, util::FediverseTag};
-use magnetar_host_meta::{Xrd, XrdXml};
+use magnetar_common::util::{FediverseTag, ValidName};
+use magnetar_host_meta::Xrd;
 use magnetar_webfinger::webfinger::WebFinger;
 use serde::{Deserialize, Serialize};
-use url::Url;
+use url::{Host, Url};
 
 pub mod client;
+pub mod lookup_flow;
 
 /// The *visible* domain of fediverse handles, that gets resolved by WebFinger
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(transparent)]
-pub struct HostUnmapped(String);
+pub struct HostUnmapped(Host);
+
+impl AsRef<Host> for HostUnmapped {
+    fn as_ref(&self) -> &Host {
+        &self.0
+    }
+}
 
 /// The real domain of fediverse handles used for federation
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(transparent)]
-pub struct HostMapped(String);
+pub struct HostMapped(Host);
 
-pub trait HostMetaResolverService {
+impl AsRef<Host> for HostMapped {
+    fn as_ref(&self) -> &Host {
+        &self.0
+    }
+}
+
+#[async_trait::async_trait]
+pub trait HostMetaResolverService: Send + Sync {
     type Error;
 
     async fn resolve(&self, host: &HostUnmapped) -> Result<Xrd, Self::Error>;
 }
 
-pub struct HostMetaResolverProviderDefault {
-    client: Arc<FederationClient>,
-    protocol: MagnetarNetworkingProtocol,
-}
-
-impl HostMetaResolverService for HostMetaResolverProviderDefault {
-    type Error = FederationClientError;
-
-    async fn resolve(&self, HostUnmapped(host): &HostUnmapped) -> Result<Xrd, Self::Error> {
-        let host_meta_xml = self
-            .client
-            .get(Url::parse(&format!(
-                "{}://{}/.well-known/host-meta",
-                self.protocol.as_ref(),
-                host
-            ))?)
-            .send()
-            .await?;
-
-        let XrdXml::Xrd(xrd) = quick_xml::de::from_reader(Cursor::new(host_meta_xml))?;
-
-        Ok(xrd)
-    }
-}
-
-pub trait WebFingerResolverService {
+#[async_trait::async_trait]
+pub trait WebFingerResolverService: Send + Sync {
     type Error;
 
     async fn resolve_url(&self, url: &str) -> Result<WebFinger, Self::Error>;
@@ -62,7 +49,7 @@ pub trait WebFingerResolverService {
     ) -> Result<WebFinger, Self::Error> {
         self.resolve_url(
             &template_url.replace(
-                "{}",
+                "{uri}",
                 &percent_encoding::utf8_percent_encode(
                     resolved_uri,
                     percent_encoding::NON_ALPHANUMERIC,
@@ -74,29 +61,32 @@ pub trait WebFingerResolverService {
     }
 }
 
-pub struct WebFingerResolverProviderDefault {
-    client: Arc<FederationClient>,
+#[derive(Debug)]
+pub struct UnmappedUser {
+    pub name: ValidName,
+    pub host: HostUnmapped,
 }
 
-impl WebFingerResolverService for WebFingerResolverProviderDefault {
-    type Error = FederationClientError;
-
-    async fn resolve_url(&self, url: &str) -> Result<WebFinger, Self::Error> {
-        let host_meta_xml = self.client.get(Url::parse(url)?).send().await?;
-        let webfinger = serde_json::from_reader(Cursor::new(host_meta_xml))?;
-        Ok(webfinger)
+impl From<&UnmappedUser> for FediverseTag {
+    fn from(user: &UnmappedUser) -> Self {
+        FediverseTag {
+            name: user.name.clone(),
+            host: Some(user.host.as_ref().clone()),
+        }
     }
 }
 
 #[derive(Debug)]
 pub struct MappedUser {
-    pub host_meta: Xrd,
+    pub host_meta: Option<Xrd>,
     pub webfinger: WebFinger,
     pub tag_mapped: FediverseTag,
+    pub ap_url: Url,
 }
 
-pub trait FederationService {
+#[async_trait::async_trait]
+pub trait FederationLookupService {
     type Error;
 
-    async fn map_fedi_tag(&self, host: &HostUnmapped) -> Result<MappedUser, Self::Error>;
+    async fn map_fedi_tag(&self, user: &UnmappedUser) -> Result<MappedUser, Self::Error>;
 }

ext_federation/src/lookup_flow.rs

@@ -0,0 +1,217 @@
+use std::{io::Cursor, sync::Arc};
+
+use magnetar_common::{
+    config::MagnetarNetworkingProtocol,
+    util::{FediverseTag, FediverseTagDisplay, FediverseTagParseError},
+};
+use magnetar_core::web_model::{acct::Acct, content_type::ContentJrdJson};
+use magnetar_host_meta::{Xrd, XrdXml};
+use magnetar_webfinger::webfinger::{WebFinger, WebFingerRel, WebFingerSubject};
+use thiserror::Error;
+use tracing::trace;
+use url::Url;
+
+use crate::{
+    client::federation_client::{FederationClient, FederationClientError},
+    FederationLookupService, HostMetaResolverService, HostUnmapped, MappedUser, UnmappedUser,
+    WebFingerResolverService,
+};
+
+pub struct HostMetaResolverProviderDefault {
+    client: Arc<FederationClient>,
+    protocol: MagnetarNetworkingProtocol,
+}
+
+#[async_trait::async_trait]
+impl HostMetaResolverService for HostMetaResolverProviderDefault {
+    type Error = FederationClientError;
+
+    async fn resolve(&self, HostUnmapped(host): &HostUnmapped) -> Result<Xrd, Self::Error> {
+        let host_meta_xml = self
+            .client
+            .get(Url::parse(&format!(
+                "{}://{}/.well-known/host-meta",
+                self.protocol.as_ref(),
+                host
+            ))?)
+            .send()
+            .await?;
+
+        let XrdXml::Xrd(xrd) = quick_xml::de::from_reader(Cursor::new(host_meta_xml))?;
+
+        Ok(xrd)
+    }
+}
+
+pub struct WebFingerResolverProviderDefault {
+    client: Arc<FederationClient>,
+}
+
+#[async_trait::async_trait]
+impl WebFingerResolverService for WebFingerResolverProviderDefault {
+    type Error = FederationClientError;
+
+    async fn resolve_url(&self, url: &str) -> Result<WebFinger, Self::Error> {
+        let host_meta_xml = self
+            .client
+            .get(Url::parse(url)?)
+            .content_type(ContentJrdJson)
+            .send()
+            .await?;
+        let webfinger = serde_json::from_reader(Cursor::new(host_meta_xml))?;
+        Ok(webfinger)
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum FederationLookupErrror {
+    #[error("Federation client error: {0}")]
+    FederationClientError(#[from] FederationClientError),
+    #[error("Fediverse tag parse error: {0}")]
+    FediverseTagParseError(#[from] FediverseTagParseError),
+    #[error("URL parse error: {0}")]
+    UrlParseError(#[from] url::ParseError),
+    #[error("Missing ActivityStreams URL in WebFinger")]
+    MissingApUrl,
+    #[error("Missing Acct URI in WebFinger")]
+    MissingAcctUri,
+}
+
+#[derive(Clone)]
+pub struct FederationLookupServiceProviderDefault {
+    host_meta_resolver: Arc<dyn HostMetaResolverService<Error = FederationClientError>>,
+    webfinger_resolver: Arc<dyn WebFingerResolverService<Error = FederationClientError>>,
+    protocol: MagnetarNetworkingProtocol,
+}
+
+impl FederationLookupServiceProviderDefault {
+    pub fn new(
+        host_meta_resolver: Arc<dyn HostMetaResolverService<Error = FederationClientError>>,
+        webfinger_resolver: Arc<dyn WebFingerResolverService<Error = FederationClientError>>,
+        protocol: MagnetarNetworkingProtocol,
+    ) -> Self {
+        Self {
+            host_meta_resolver,
+            webfinger_resolver,
+            protocol,
+        }
+    }
+}
+
+#[async_trait::async_trait]
+impl FederationLookupService for FederationLookupServiceProviderDefault {
+    type Error = FederationLookupErrror;
+
+    #[tracing::instrument(level = "trace", skip(self))]
+    async fn map_fedi_tag(
+        &self,
+        user: &UnmappedUser,
+    ) -> Result<MappedUser, FederationLookupErrror> {
+        trace!("Fetching flow initiated");
+        let host_meta = self.host_meta_resolver.resolve(&user.host).await;
+        let webfinger_template = match &host_meta {
+            Ok(h) => {
+                trace!("host-meta found: {:?}", h);
+                h.get_webfinger_template().map(str::to_owned)
+            }
+            Err(e) => {
+                trace!("host-meta fetch failed: {}", e);
+                None
+            }
+        }
+        .unwrap_or_else(|| {
+            Xrd::default_host_meta(self.protocol.as_ref(), &user.host.as_ref().to_string())
+                .get_webfinger_template()
+                .expect("default WebFinger template")
+                .to_owned()
+        });
+
+        let webfinger = self
+            .webfinger_resolver
+            .resolve(
+                &webfinger_template,
+                Acct::from(FediverseTag::from(user)).as_ref(),
+            )
+            .await?;
+
+        trace!("Webfinger fetched: {:?}", webfinger);
+
+        let real_tag = match &webfinger.subject {
+            WebFingerSubject::Acct(acct) => Some(acct.clone()),
+            _ => webfinger
+                .aliases
+                .iter()
+                .flatten()
+                .find_map(|alias| match alias {
+                    WebFingerSubject::Acct(acct) => Some(acct.clone()),
+                    _ => None,
+                }),
+        }
+        .ok_or(FederationLookupErrror::MissingAcctUri)?;
+
+        let ap_url = webfinger
+            .links
+            .iter()
+            .find_map(|link| match link {
+                WebFingerRel::RelSelf { href, .. } | WebFingerRel::RelSelfAlt { href, .. } => {
+                    Some(href)
+                }
+                _ => None,
+            })
+            .ok_or(FederationLookupErrror::MissingApUrl)?
+            .parse()?;
+
+        Ok(MappedUser {
+            host_meta: host_meta.ok(),
+            webfinger,
+            tag_mapped: FediverseTag::try_from(&FediverseTagDisplay::try_from(&real_tag)?)?,
+            ap_url,
+        })
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::sync::Arc;
+
+    use magnetar_common::{config::MagnetarNetworkingProtocol, util::FediverseTag};
+    use tracing::{info, Level};
+
+    use crate::{
+        client::federation_client::FederationClient, FederationLookupService, HostUnmapped,
+        UnmappedUser,
+    };
+
+    use super::{
+        FederationLookupServiceProviderDefault, HostMetaResolverProviderDefault,
+        WebFingerResolverProviderDefault,
+    };
+
+    #[tokio::test]
+    async fn should_resolve() {
+        tracing_subscriber::fmt()
+            .with_max_level(Level::TRACE)
+            .init();
+
+        let client = Arc::new(FederationClient::new(true, 64000, 20).unwrap());
+
+        let federation_lookup = FederationLookupServiceProviderDefault::new(
+            Arc::new(HostMetaResolverProviderDefault {
+                protocol: MagnetarNetworkingProtocol::Https,
+                client: client.clone(),
+            }),
+            Arc::new(WebFingerResolverProviderDefault { client }),
+            MagnetarNetworkingProtocol::Https,
+        );
+        let tag: FediverseTag = "@natty@astolfo.social".parse().unwrap();
+        info!("Resolving: {}", tag);
+        let resolved = federation_lookup
+            .map_fedi_tag(&UnmappedUser {
+                name: tag.name,
+                host: HostUnmapped(tag.host.unwrap()),
+            })
+            .await
+            .unwrap();
+        info!("Resolved: {:#?}", resolved);
+    }
+}

ext_host_meta/src/lib.rs

@@ -34,7 +34,10 @@ impl Xrd {
     pub fn get_webfinger_template(&self) -> Option<&str> {
         self.links
             .iter()
-            .find(|l| l.rel.as_deref() == Some(ContentXrdXml.as_ref()))
+            .find(|l| {
+                l.r#type.as_deref() == Some(ContentXrdXml.as_ref())
+                    && l.rel.as_deref() == Some(RelLrdd.as_ref())
+            })
             .and_then(|l| l.template.as_deref())
     }
 }

ext_webfinger/src/webfinger.rs

@@ -1,7 +1,10 @@
 use magnetar_core::web_model::acct::Acct;
-use magnetar_core::web_model::content_type::{ContentActivityStreams, ContentHtml};
+use magnetar_core::web_model::content_type::{
+    ContentActivityJson, ContentActivityStreams, ContentHtml,
+};
 use magnetar_core::web_model::rel::{RelOStatusSubscribe, RelSelf, RelWebFingerProfilePage};
 use serde::{Deserialize, Serialize};
+use serde_json::Value;
 
 #[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct WebFinger {
@@ -34,10 +37,18 @@ pub enum WebFingerRel {
         content_type: ContentActivityStreams,
         href: String,
     },
+    // Alternative content-type for some implementations
+    RelSelfAlt {
+        rel: RelSelf,
+        #[serde(rename = "type")]
+        content_type: ContentActivityJson,
+        href: String,
+    },
     RelOStatusSubscribe {
         rel: RelOStatusSubscribe,
         template: String,
     },
+    Other(Value),
 }
 
 #[cfg(test)]

magnetar_common/src/config.rs

@@ -14,7 +14,7 @@ pub struct MagnetarNetworking {
     pub proxy_remote_files: bool,
 }
 
-#[derive(Deserialize, Debug)]
+#[derive(Deserialize, Debug, Clone, Copy)]
 #[serde(rename_all = "snake_case")]
 pub enum MagnetarNetworkingProtocol {
     Http,

magnetar_common/src/util.rs

@@ -2,21 +2,166 @@ use magnetar_core::web_model::acct::Acct;
 use magnetar_sdk::mmm;
 use magnetar_sdk::mmm::Token;
 use percent_encoding::percent_decode_str;
-use std::borrow::Cow;
+use std::fmt::Display;
+use std::str::FromStr;
 use thiserror::Error;
+use url::Host;
+
+#[derive(Clone, Debug)]
+pub struct ValidName(String);
+
+impl FromStr for ValidName {
+    type Err = FediverseTagParseError;
+
+    fn from_str(name: &str) -> Result<Self, Self::Err> {
+        if name
+            .chars()
+            .any(|c| !c.is_alphanumeric() && c != '-' && c != '_' && c != '.')
+        {
+            return Err(FediverseTagParseError::InvalidChar(name.to_owned()));
+        }
+
+        Ok(Self(name.to_owned()))
+    }
+}
+
+impl AsRef<str> for ValidName {
+    fn as_ref(&self) -> &str {
+        &self.0
+    }
+}
+
+impl Display for ValidName {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
 
 #[derive(Clone, Debug)]
 pub struct FediverseTag {
-    pub name: String,
+    pub name: ValidName,
+    pub host: Option<Host>,
+}
+
+impl FediverseTag {
+    pub fn from_parts(parts: (&str, Option<&str>)) -> Result<Self, FediverseTagParseError> {
+        Self::try_from(FediverseTagDisplay::from_parts(parts)?)
+    }
+}
+
+impl TryFrom<FediverseTagDisplay> for FediverseTag {
+    type Error = FediverseTagParseError;
+
+    fn try_from(
+        FediverseTagDisplay { name, host }: FediverseTagDisplay,
+    ) -> Result<Self, FediverseTagParseError> {
+        Ok(FediverseTag {
+            name,
+            host: host.as_deref().map(Host::parse).transpose()?,
+        })
+    }
+}
+
+impl TryFrom<&FediverseTagDisplay> for FediverseTag {
+    type Error = FediverseTagParseError;
+
+    fn try_from(
+        FediverseTagDisplay { name, host }: &FediverseTagDisplay,
+    ) -> Result<Self, FediverseTagParseError> {
+        Ok(FediverseTag {
+            name: name.clone(),
+            host: host.as_deref().map(Host::parse).transpose()?,
+        })
+    }
+}
+
+impl From<&FediverseTag> for Acct {
+    fn from(tag: &FediverseTag) -> Self {
+        Acct::new(tag.to_string().into())
+    }
+}
+
+impl FromStr for FediverseTag {
+    type Err = FediverseTagParseError;
+
+    fn from_str(tag: &str) -> Result<Self, Self::Err> {
+        Self::try_from(FediverseTagDisplay::from_str(tag)?)
+    }
+}
+
+impl Display for FediverseTag {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if let Some(ref host) = self.host {
+            write!(f, "{}@{}", self.name, host)
+        } else {
+            write!(f, "{}", self.name)
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct FediverseTagDisplay {
+    pub name: ValidName,
     pub host: Option<String>,
 }
 
+impl FediverseTagDisplay {
+    pub fn from_parts((name, host): (&str, Option<&str>)) -> Result<Self, FediverseTagParseError> {
+        Ok(FediverseTagDisplay {
+            name: name.parse()?,
+            host: host.map(str::to_owned),
+        })
+    }
+}
+
+impl From<&FediverseTag> for FediverseTagDisplay {
+    fn from(FediverseTag { name, host }: &FediverseTag) -> Self {
+        FediverseTagDisplay {
+            name: name.clone(),
+            host: host
+                .as_ref()
+                .map(Host::to_string)
+                .as_deref()
+                .map(idna::domain_to_unicode)
+                .map(|v| v.0),
+        }
+    }
+}
+
+impl TryFrom<&Acct> for FediverseTagDisplay {
+    type Error = FediverseTagParseError;
+
+    fn try_from(acct: &Acct) -> Result<Self, Self::Error> {
+        acct.as_ref().parse()
+    }
+}
+
+impl FromStr for FediverseTagDisplay {
+    type Err = FediverseTagParseError;
+
+    fn from_str(tag: &str) -> Result<Self, Self::Err> {
+        Self::from_parts(split_tag_inner(tag))
+    }
+}
+
+impl Display for FediverseTagDisplay {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if let Some(ref host) = self.host {
+            write!(f, "{}@{}", self.name, host)
+        } else {
+            write!(f, "{}", self.name)
+        }
+    }
+}
+
 #[derive(Debug, Error)]
 pub enum FediverseTagParseError {
     #[error("Invalid char in tag: {0}")]
     InvalidChar(String),
     #[error("Invalid UTF-8 in tag: {0}")]
     InvalidUtf8(#[from] std::str::Utf8Error),
+    #[error("Invalid host in tag: {0}")]
+    InvalidHost(#[from] url::ParseError),
 }
 
 impl From<&FediverseTagParseError> for &str {
@@ -25,94 +170,30 @@ impl From<&FediverseTagParseError> for &str {
     }
 }
 
-impl<S1: AsRef<str>, S2: AsRef<str>> From<(S1, Option<S2>)> for FediverseTag {
-    fn from((name, host): (S1, Option<S2>)) -> Self {
-        Self {
-            name: name.as_ref().to_owned(),
-            host: host.as_ref().map(S2::as_ref).map(str::to_owned),
-        }
-    }
-}
-
 impl From<FediverseTag> for Acct {
     fn from(value: FediverseTag) -> Self {
         value.to_string().into()
     }
 }
 
-impl ToString for FediverseTag {
-    fn to_string(&self) -> String {
-        if let Some(ref host) = self.host {
-            format!("{}@{host}", self.name)
-        } else {
-            self.name.clone()
-        }
-    }
-}
-
-pub fn lenient_parse_acct(acct: &Acct) -> Result<FediverseTag, FediverseTagParseError> {
-    lenient_parse_tag(acct.as_ref())
-}
-
-fn split_tag_inner(tag: impl AsRef<str>) -> (String, Option<String>) {
-    let tag = tag.as_ref();
+fn split_tag_inner(tag: &str) -> (&str, Option<&str>) {
     let tag = tag.strip_prefix('@').unwrap_or(tag.as_ref());
 
     match tag.split_once('@') {
-        Some((name, "")) => (name.to_owned(), None),
-        Some((name, host)) => (name.to_owned(), Some(host.to_owned())),
-        None => (tag.to_owned(), None),
+        Some((name, "")) => (name, None),
+        Some((name, host)) => (name, Some(host)),
+        None => (tag, None),
     }
 }
 
-fn validate_tag_inner((name, host): (&str, Option<&str>)) -> Result<(), FediverseTagParseError> {
-    if name
-        .chars()
-        .any(|c| !c.is_alphanumeric() && c != '-' && c != '_' && c != '.')
-    {
-        return Err(FediverseTagParseError::InvalidChar(name.to_owned()));
-    }
-
-    if let Some(host_str) = host {
-        if host_str
-            .chars()
-            .any(|c| c.is_control() || c.is_whitespace() || c == '/' || c == '#')
-        {
-            return Err(FediverseTagParseError::InvalidChar(name.to_owned()));
-        }
-    }
-
-    Ok(())
-}
-
-pub fn lenient_parse_tag(tag: impl AsRef<str>) -> Result<FediverseTag, FediverseTagParseError> {
-    let (name, host) = split_tag_inner(tag);
-
-    validate_tag_inner((&name, host.as_ref().map(String::as_ref)))?;
-
-    Ok(FediverseTag { name, host })
-}
-
-pub fn lenient_parse_acct_decode(acct: &Acct) -> Result<FediverseTag, FediverseTagParseError> {
-    lenient_parse_tag_decode(acct.as_ref())
-}
-
 pub fn lenient_parse_tag_decode(
     tag: impl AsRef<str>,
 ) -> Result<FediverseTag, FediverseTagParseError> {
-    let (name, host) = split_tag_inner(tag);
+    percent_decode_str(tag.as_ref()).decode_utf8()?.parse()
+}
 
-    let name_decoded = percent_decode_str(&name).decode_utf8()?;
-    let host_decoded = host
-        .map(|host| percent_decode_str(&host).decode_utf8().map(Cow::into_owned))
-        .transpose()?;
-
-    validate_tag_inner((&name_decoded, host_decoded.as_deref()))?;
-
-    Ok(FediverseTag {
-        name: name_decoded.into_owned(),
-        host: host_decoded,
-    })
+pub fn lenient_parse_acct_decode(acct: &Acct) -> Result<FediverseTag, FediverseTagParseError> {
+    lenient_parse_tag_decode(acct.as_ref())
 }
 
 #[derive(Debug)]

src/api_v1/user.rs

@@ -79,14 +79,14 @@ pub async fn handle_user_info_by_acct(
     MaybeUser(self_user): MaybeUser,
 ) -> Result<Json<Res<GetUserByAcct>>, ApiError> {
     let mut tag = lenient_parse_tag_decode(&tag_str)?;
-    if matches!(&tag.host, Some(host) if host == &service.config.networking.host) {
+    if matches!(&tag.host, Some(host) if host.to_string() == service.config.networking.host) {
         tag.host = None;
     }
 
     let ctx = PackingContext::new(service.clone(), self_user).await?;
     let user_model = service
         .db
-        .get_user_by_tag(&tag.name, tag.host.as_deref())
+        .get_user_by_tag(tag.name.as_ref(), tag.host.as_ref())
         .await?
         .ok_or(ObjectNotFound(tag_str))?;
 

src/webfinger.rs

@@ -7,11 +7,14 @@ use magnetar_calckey_model::CalckeyModel;
 use magnetar_common::config::MagnetarConfig;
 use magnetar_common::util::{lenient_parse_acct_decode, FediverseTag};
 use magnetar_core::web_model::acct::Acct;
-use magnetar_core::web_model::content_type::{ContentActivityStreams, ContentHtml, ContentJrdJson};
+use magnetar_core::web_model::content_type::{
+    ContentActivityJson, ContentActivityStreams, ContentHtml, ContentJrdJson,
+};
 use magnetar_core::web_model::rel::{RelOStatusSubscribe, RelSelf, RelWebFingerProfilePage};
 use magnetar_webfinger::webfinger::{WebFinger, WebFingerRel, WebFingerSubject};
 use serde::Deserialize;
 use tracing::error;
+use url::Url;
 
 #[derive(Deserialize)]
 pub struct WebFingerQuery {
@@ -19,11 +22,13 @@ pub struct WebFingerQuery {
     rel: Option<Vec<String>>,
 }
 
+// TODO: We don't have this endpoint in Magnetar yet, but make sure it's not hardcoded when
+// we do
+const USER_AP_ENDPOINT: &str = "/users/";
+
 // TODO: Filter by rel
 pub async fn handle_webfinger(
-    Query(WebFingerQuery {
-        resource, rel: _, ..
-    }): Query<WebFingerQuery>,
+    Query(WebFingerQuery { resource, .. }): Query<WebFingerQuery>,
     State((config, ck)): State<(&'static MagnetarConfig, CalckeyModel)>,
 ) -> Result<impl IntoResponse, StatusCode> {
     let resource = match resource {
@@ -42,79 +47,104 @@ pub async fn handle_webfinger(
                 StatusCode::UNPROCESSABLE_ENTITY
             })?;
 
-            ck.get_user_by_tag(
-                &tag.name,
-                tag.host
-                    .filter(|host| *host != config.networking.host)
-                    .as_deref(),
-            )
-            .await
-            .map_err(|e| {
-                error!("Data error: {e}");
-                StatusCode::INTERNAL_SERVER_ERROR
-            })?
+            ck.get_user_by_tag(tag.name.as_ref(), tag.host.as_ref())
+                .await
+                .map_err(|e| {
+                    error!("Data error: {e}");
+                    StatusCode::INTERNAL_SERVER_ERROR
+                })?
+        }
+        WebFingerSubject::Url(url) => {
+            let object_url = url.parse::<Url>().map_err(|e| {
+                error!("URL parse error: {e}");
+                StatusCode::UNPROCESSABLE_ENTITY
+            })?;
+
+            // FIXME: Jank
+            let path = object_url.path().strip_prefix(USER_AP_ENDPOINT);
+            match path {
+                Some(user_id) if !user_id.is_empty() && user_id.chars().all(|c| c != '/') => {
+                    ck.get_user_by_id(user_id).await.map_err(|e| {
+                        error!("Data error: {e}");
+                        StatusCode::INTERNAL_SERVER_ERROR
+                    })?
+                }
+                _ => ck.get_user_by_uri(&url).await.map_err(|e| {
+                    error!("Data error: {e}");
+                    StatusCode::INTERNAL_SERVER_ERROR
+                })?,
+            }
         }
-        // TODO: Make this work for local users
-        WebFingerSubject::Url(url) => ck.get_user_by_uri(&url).await.map_err(|e| {
-            error!("Data error: {e}");
-            StatusCode::INTERNAL_SERVER_ERROR
-        })?,
     };
 
-    if user.is_none() {
+    let Some(user) = user else {
         return Err(StatusCode::NOT_FOUND);
-    }
+    };
 
-    let user = user.unwrap();
-    let tag = FediverseTag::from((
+    let tag = FediverseTag::from_parts((
         &user.username,
-        user.host.as_ref().or(Some(&config.networking.host)),
-    ));
+        user.host.as_deref().or(Some(&config.networking.host)),
+    ))
+    .map_err(|e| {
+        error!("URL parse error: {e}");
+        StatusCode::INTERNAL_SERVER_ERROR
+    })?;
 
     let mut links = Vec::new();
     let mut aliases = Vec::new();
 
-    match tag.host {
-        Some(ref host) if host != &config.networking.host => {
-            if let Some(uri) = user.uri {
-                links.push(WebFingerRel::RelSelf {
-                    rel: RelSelf,
-                    content_type: ContentActivityStreams,
-                    href: uri,
-                });
-            }
-        }
-        _ => {
-            links.push(WebFingerRel::RelOStatusSubscribe {
-                rel: RelOStatusSubscribe,
-                template: format!(
-                    "{}://{}/authorize-follow?acct={{uri}}",
-                    config.networking.protocol, config.networking.host
-                ),
-            });
-
-            let user_url = format!(
-                "{}://{}/@{}",
-                config.networking.protocol, config.networking.host, tag.name
-            );
-
-            links.push(WebFingerRel::RelWebFingerProfilePage {
-                rel: RelWebFingerProfilePage,
-                content_type: ContentHtml,
-                href: user_url.clone(),
-            });
-
-            aliases.push(WebFingerSubject::Url(user_url));
-
+    if user.host.is_some() {
+        if let Some(uri) = user.uri {
             links.push(WebFingerRel::RelSelf {
                 rel: RelSelf,
                 content_type: ContentActivityStreams,
-                href: format!(
-                    "{}://{}/users/{}",
-                    config.networking.protocol, config.networking.host, user.id
-                ),
+                href: uri.clone(),
+            });
+
+            links.push(WebFingerRel::RelSelfAlt {
+                rel: RelSelf,
+                content_type: ContentActivityJson,
+                href: uri,
             });
         }
+    } else {
+        links.push(WebFingerRel::RelOStatusSubscribe {
+            rel: RelOStatusSubscribe,
+            template: format!(
+                "{}://{}/authorize-follow?acct={{uri}}",
+                config.networking.protocol, config.networking.host
+            ),
+        });
+
+        let user_url = format!(
+            "{}://{}/@{}",
+            config.networking.protocol, config.networking.host, tag.name
+        );
+
+        links.push(WebFingerRel::RelWebFingerProfilePage {
+            rel: RelWebFingerProfilePage,
+            content_type: ContentHtml,
+            href: user_url.clone(),
+        });
+
+        aliases.push(WebFingerSubject::Url(user_url));
+
+        let self_url = format!(
+            "{}://{}{}{}",
+            config.networking.protocol, config.networking.host, USER_AP_ENDPOINT, user.id
+        );
+
+        links.push(WebFingerRel::RelSelf {
+            rel: RelSelf,
+            content_type: ContentActivityStreams,
+            href: self_url.clone(),
+        });
+
+        links.push(WebFingerRel::RelSelfAlt {
+            rel: RelSelf,
+            content_type: ContentActivityJson,
+            href: self_url,
+        });
     }
 
     Ok((