live federation example

Cargo.toml

@@ -67,3 +67,7 @@ debug = 0
 [[example]]
 name = "local_federation"
 path = "examples/local_federation/main.rs"
+
+[[example]]
+name = "live_federation"
+path = "examples/live_federation/main.rs"

docs/03_federating_users.md

@@ -65,6 +65,7 @@ Besides we also need a second struct to represent the data which gets stored in
 
 ```rust
 # use url::Url;
+# use chrono::NaiveDateTime;
 
 pub struct DbUser {
     pub id: i32,
@@ -76,8 +77,9 @@ pub struct DbUser {
     pub inbox: Url,
     pub outbox: Url,
     pub local: bool,
-    public_key: String,
-    private_key: Option<String>,
+    pub public_key: String,
+    pub private_key: Option<String>,
+    pub last_refreshed_at: NaiveDateTime,
 }
 ```
 

examples/README.md

@@ -11,3 +11,28 @@ Use one of the following commands to run the example with the specified web fram
 `cargo run --example local_federation axum`
 
 `cargo run --example local_federation actix-web`
+
+## Live Federation
+
+A minimal application which can be deployed on a server and federate with other platforms such as Mastodon. For this it needs run at the root of a (sub)domain which is available over HTTPS. Edit `main.rs` to configure the server domain and your Fediverse handle.
+
+Setup instructions:
+
+- Deploy the project to a server. For this you can clone the git repository on the server and execute `cargo run --example live_federation`. Alternatively run `cargo build --example live_federation` and copy the binary at `target/debug/examples/live_federation` to the server.
+- Create a TLS certificate. With Let's Encrypt certbot you can use a command like `certbot certonly --nginx -d 'example.com' -m '*[email protected]*'` (replace with your actual domain and email).
+- Setup a reverse proxy which handles TLS and passes requests to the example project. With nginx you can use the following basic config, again using your actual domain:
+```
+server {
+    listen 443 ssl http2;
+    listen [::]:443 ssl http2;
+    server_name example.com;
+    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
+    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
+    location / {
+        proxy_pass "http://localhost:8003";
+        proxy_set_header Host $host;
+    }
+}
+```
+- Test with `curl -H 'Accept: application/activity+json' https://example.com/alison | jq` and `curl -H 'Accept: application/activity+json' "https://example.com/.well-known/webfinger?resource=acct:[email protected]" | jq` that the server is setup correctly and serving correct responses.
+- Login to a Fediverse platform like Mastodon, and search for `@[email protected]`, with the actual domain and username from your `main.rs`. If you send a message, it will automatically send a response.

examples/live_federation/activities/create_post.rs

@@ -0,0 +1,72 @@
+use crate::{
+    database::DatabaseHandle,
+    error::Error,
+    objects::{person::DbUser, post::Note},
+    utils::generate_object_id,
+    DbPost,
+};
+use activitypub_federation::{
+    activity_queue::send_activity,
+    config::RequestData,
+    fetch::object_id::ObjectId,
+    kinds::activity::CreateType,
+    protocol::{context::WithContext, helpers::deserialize_one_or_many},
+    traits::{ActivityHandler, ApubObject},
+};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+#[derive(Deserialize, Serialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct CreatePost {
+    pub(crate) actor: ObjectId<DbUser>,
+    #[serde(deserialize_with = "deserialize_one_or_many")]
+    pub(crate) to: Vec<Url>,
+    pub(crate) object: Note,
+    #[serde(rename = "type")]
+    pub(crate) kind: CreateType,
+    pub(crate) id: Url,
+}
+
+impl CreatePost {
+    pub async fn send(
+        note: Note,
+        inbox: Url,
+        data: &RequestData<DatabaseHandle>,
+    ) -> Result<(), Error> {
+        print!("Sending reply to {}", &note.attributed_to);
+        let create = CreatePost {
+            actor: note.attributed_to.clone(),
+            to: note.to.clone(),
+            object: note,
+            kind: CreateType::Create,
+            id: generate_object_id(data.domain())?,
+        };
+        let create_with_context = WithContext::new_default(create);
+        let private_key = data
+            .local_user()
+            .private_key
+            .expect("local user always has private key");
+        send_activity(create_with_context, private_key, vec![inbox], data).await?;
+        Ok(())
+    }
+}
+
+#[async_trait::async_trait]
+impl ActivityHandler for CreatePost {
+    type DataType = DatabaseHandle;
+    type Error = crate::error::Error;
+
+    fn id(&self) -> &Url {
+        &self.id
+    }
+
+    fn actor(&self) -> &Url {
+        self.actor.inner()
+    }
+
+    async fn receive(self, data: &RequestData<Self::DataType>) -> Result<(), Self::Error> {
+        DbPost::from_apub(self.object, data).await?;
+        Ok(())
+    }
+}

examples/live_federation/activities/mod.rs

@@ -0,0 +1 @@
+pub mod create_post;

examples/live_federation/database.rs

@@ -0,0 +1,26 @@
+use crate::{objects::person::DbUser, Error};
+use anyhow::anyhow;
+use std::sync::{Arc, Mutex};
+
+pub type DatabaseHandle = Arc<Database>;
+
+/// Our "database" which contains all known users (local and federated)
+pub struct Database {
+    pub users: Mutex<Vec<DbUser>>,
+}
+
+impl Database {
+    pub fn local_user(&self) -> DbUser {
+        let lock = self.users.lock().unwrap();
+        lock.first().unwrap().clone()
+    }
+
+    pub fn read_user(&self, name: &str) -> Result<DbUser, Error> {
+        let db_user = self.local_user();
+        if name == db_user.name {
+            Ok(db_user)
+        } else {
+            Err(anyhow!("Invalid user {name}").into())
+        }
+    }
+}

examples/live_federation/error.rs

@@ -0,0 +1,20 @@
+use std::fmt::{Display, Formatter};
+
+/// Necessary because of this issue: https://github.com/actix/actix-web/issues/1711
+#[derive(Debug)]
+pub struct Error(pub(crate) anyhow::Error);
+
+impl Display for Error {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(&self.0, f)
+    }
+}
+
+impl<T> From<T> for Error
+where
+    T: Into<anyhow::Error>,
+{
+    fn from(t: T) -> Self {
+        Error(t.into())
+    }
+}

examples/live_federation/http.rs

@@ -0,0 +1,69 @@
+use crate::{
+    database::DatabaseHandle,
+    error::Error,
+    objects::person::{DbUser, Person, PersonAcceptedActivities},
+};
+use activitypub_federation::{
+    axum::{
+        inbox::{receive_activity, ActivityData},
+        json::ApubJson,
+    },
+    config::RequestData,
+    fetch::webfinger::{build_webfinger_response, extract_webfinger_name, Webfinger},
+    protocol::context::WithContext,
+    traits::ApubObject,
+};
+use axum::{
+    extract::{Path, Query},
+    response::{IntoResponse, Response},
+    Json,
+};
+use axum_macros::debug_handler;
+use http::StatusCode;
+use serde::Deserialize;
+
+impl IntoResponse for Error {
+    fn into_response(self) -> Response {
+        (StatusCode::INTERNAL_SERVER_ERROR, format!("{}", self.0)).into_response()
+    }
+}
+
+#[debug_handler]
+pub async fn http_get_user(
+    Path(name): Path<String>,
+    data: RequestData<DatabaseHandle>,
+) -> Result<ApubJson<WithContext<Person>>, Error> {
+    let db_user = data.read_user(&name)?;
+    let apub_user = db_user.into_apub(&data).await?;
+    Ok(ApubJson(WithContext::new_default(apub_user)))
+}
+
+#[debug_handler]
+pub async fn http_post_user_inbox(
+    data: RequestData<DatabaseHandle>,
+    activity_data: ActivityData,
+) -> impl IntoResponse {
+    receive_activity::<WithContext<PersonAcceptedActivities>, DbUser, DatabaseHandle>(
+        activity_data,
+        &data,
+    )
+    .await
+}
+
+#[derive(Deserialize)]
+pub struct WebfingerQuery {
+    resource: String,
+}
+
+#[debug_handler]
+pub async fn webfinger(
+    Query(query): Query<WebfingerQuery>,
+    data: RequestData<DatabaseHandle>,
+) -> Result<Json<Webfinger>, Error> {
+    let name = extract_webfinger_name(&query.resource, &data)?;
+    let db_user = data.read_user(&name)?;
+    Ok(Json(build_webfinger_response(
+        query.resource,
+        db_user.ap_id.into_inner(),
+    )))
+}

examples/live_federation/main.rs

@@ -0,0 +1,69 @@
+use crate::{
+    database::Database,
+    http::{http_get_user, http_post_user_inbox, webfinger},
+    objects::{person::DbUser, post::DbPost},
+    utils::generate_object_id,
+};
+use activitypub_federation::config::{ApubMiddleware, FederationConfig};
+use axum::{
+    routing::{get, post},
+    Router,
+};
+use error::Error;
+use std::{
+    net::ToSocketAddrs,
+    sync::{Arc, Mutex},
+};
+use tracing::log::{info, LevelFilter};
+
+mod activities;
+mod database;
+mod error;
+#[allow(clippy::diverging_sub_expression, clippy::items_after_statements)]
+mod http;
+mod objects;
+mod utils;
+
+const DOMAIN: &str = "example.com";
+const LOCAL_USER_NAME: &str = "alison";
+const BIND_ADDRESS: &str = "localhost:8003";
+
+#[actix_rt::main]
+async fn main() -> Result<(), Error> {
+    env_logger::builder()
+        .filter_level(LevelFilter::Warn)
+        .filter_module("activitypub_federation", LevelFilter::Info)
+        .filter_module("live_federation", LevelFilter::Info)
+        .format_timestamp(None)
+        .init();
+
+    info!("Setup local user and database");
+    let local_user = DbUser::new(DOMAIN, LOCAL_USER_NAME)?;
+    let database = Arc::new(Database {
+        users: Mutex::new(vec![local_user]),
+    });
+
+    info!("Setup configuration");
+    let config = FederationConfig::builder()
+        .domain(DOMAIN)
+        .app_data(database)
+        .build()?;
+
+    info!("Listen with HTTP server on {BIND_ADDRESS}");
+    let config = config.clone();
+    let app = Router::new()
+        .route("/:user", get(http_get_user))
+        .route("/:user/inbox", post(http_post_user_inbox))
+        .route("/.well-known/webfinger", get(webfinger))
+        .layer(ApubMiddleware::new(config));
+
+    let addr = BIND_ADDRESS
+        .to_socket_addrs()?
+        .next()
+        .expect("Failed to lookup domain name");
+    axum::Server::bind(&addr)
+        .serve(app.into_make_service())
+        .await?;
+
+    Ok(())
+}

examples/live_federation/objects/mod.rs

@@ -0,0 +1,2 @@
+pub mod person;
+pub mod post;