feat(!783): Initial implementation

Adds support for extra limited-use registration tokens
stored in the database, and a new service to manage them.

src/service/registration_tokens/data.rs

@@ -0,0 +1,92 @@
+use std::{sync::Arc, time::SystemTime};
+
+use conduwuit::utils::stream::{ReadyExt, TryIgnore};
+use database::{Database, Deserialized, Json, Map};
+use futures::Stream;
+use ruma::OwnedUserId;
+use serde::{Deserialize, Serialize};
+
+pub(super) struct Data {
+	registrationtoken_info: Arc<Map>,
+}
+
+/// Metadata of a registration token.
+#[derive(Debug, Serialize, Deserialize)]
+pub struct DatabaseTokenInfo {
+	/// The admin user who created this token.
+	pub creator: OwnedUserId,
+	/// The number of times this token has been used to create an account.
+	pub uses: u64,
+	/// When this token will expire, if it expires.
+	pub expires: Option<TokenExpires>,
+}
+
+impl DatabaseTokenInfo {
+	pub(super) fn new(creator: OwnedUserId, expires: Option<TokenExpires>) -> Self {
+		Self { creator, uses: 0, expires }
+	}
+
+	/// Determine whether this token info represents a valid token, i.e. one
+	/// that has not expired according to its [`Self::expires`] property. If
+	/// [`Self::expires`] is [`None`], this function will always return `true`.
+	#[must_use]
+	pub fn is_valid(&self) -> bool {
+		match self.expires {
+			| Some(TokenExpires::AfterUses(max_uses)) => self.uses <= max_uses,
+			| Some(TokenExpires::AfterTime(expiry_time)) => {
+				let now = SystemTime::now();
+
+				expiry_time >= now
+			},
+			| None => true,
+		}
+	}
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub enum TokenExpires {
+	AfterUses(u64),
+	AfterTime(SystemTime),
+}
+
+impl Data {
+	pub(super) fn new(db: &Arc<Database>) -> Self {
+		Self {
+			registrationtoken_info: db["registrationtoken_info"].clone(),
+		}
+	}
+
+	/// Associate a registration token with its metadata in the database.
+	pub(super) fn save_token(&self, token: &str, info: &DatabaseTokenInfo) {
+		self.registrationtoken_info.put(token, Json(info));
+	}
+
+	/// Delete a registration token.
+	pub(super) fn revoke_token(&self, token: &str) { self.registrationtoken_info.del(token); }
+
+	/// Look up a registration token's metadata.
+	pub(super) async fn lookup_token_info(&self, token: &str) -> Option<DatabaseTokenInfo> {
+		self.registrationtoken_info
+			.qry(token)
+			.await
+			.deserialized()
+			.ok()
+	}
+
+	/// Iterate over all valid tokens and delete expired ones.
+	pub(super) fn iterate_and_clean_tokens(
+		&self,
+	) -> impl Stream<Item = (&str, DatabaseTokenInfo)> + Send + '_ {
+		self.registrationtoken_info
+			.stream()
+			.ignore_err()
+			.ready_filter(|item: &(&str, DatabaseTokenInfo)| {
+				if item.1.is_valid() {
+					true
+				} else {
+					self.registrationtoken_info.del(item.0);
+					false
+				}
+			})
+	}
+}

src/service/registration_tokens/mod.rs

@@ -0,0 +1,152 @@
+mod data;
+
+use std::sync::Arc;
+
+use conduwuit::{Err, Result, utils};
+use data::Data;
+pub use data::{DatabaseTokenInfo, TokenExpires};
+use futures::{Stream, StreamExt, stream};
+use ruma::OwnedUserId;
+
+use crate::{Dep, config};
+
+const RANDOM_TOKEN_LENGTH: usize = 64;
+
+pub struct Service {
+	db: Data,
+	services: Services,
+}
+
+struct Services {
+	config: Dep<config::Service>,
+}
+
+/// A validated registration token which may be used to create an account.
+pub struct ValidToken<'token> {
+	pub token: &'token str,
+	pub source: ValidTokenSource,
+}
+
+impl PartialEq<str> for ValidToken<'_> {
+	fn eq(&self, other: &str) -> bool { self.token == other }
+}
+
+/// The source of a valid database token.
+pub enum ValidTokenSource {
+	/// The static token set in the homeserver's config file, which is
+	/// always valid.
+	ConfigFile,
+	/// A database token which has been checked to be valid.
+	Database(DatabaseTokenInfo),
+}
+
+impl crate::Service for Service {
+	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
+		Ok(Arc::new(Self {
+			db: Data::new(args.db),
+			services: Services {
+				config: args.depend::<config::Service>("config"),
+			},
+		}))
+	}
+
+	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
+}
+
+impl Service {
+	/// Issue a new registration token and save it in the database.
+	pub fn issue_token(
+		&self,
+		creator: OwnedUserId,
+		expires: Option<TokenExpires>,
+	) -> (String, DatabaseTokenInfo) {
+		let token = utils::random_string(RANDOM_TOKEN_LENGTH);
+		let info = DatabaseTokenInfo::new(creator, expires);
+
+		self.db.save_token(&token, &info);
+		(token, info)
+	}
+
+	/// Get the registration token set in the config file, if it exists.
+	pub fn get_config_file_token(&self) -> Option<ValidToken<'_>> {
+		self.services
+			.config
+			.registration_token
+			.as_deref()
+			.map(|token| ValidToken {
+				token,
+				source: ValidTokenSource::ConfigFile,
+			})
+	}
+
+	/// Validate a registration token.
+	pub async fn validate_token<'token>(&self, token: &'token str) -> Option<ValidToken<'token>> {
+		// Check the registration token in the config first
+		if self
+			.get_config_file_token()
+			.is_some_and(|valid_token| valid_token == *token)
+		{
+			return Some(ValidToken {
+				token,
+				source: ValidTokenSource::ConfigFile,
+			});
+		}
+
+		// Now check the database
+		if let Some(token_info) = self.db.lookup_token_info(token).await
+			&& token_info.is_valid()
+		{
+			return Some(ValidToken {
+				token,
+				source: ValidTokenSource::Database(token_info),
+			});
+		}
+
+		// Otherwise it's not valid
+		None
+	}
+
+	/// Mark a valid token as having been used to create a new account.
+	pub fn mark_token_as_used(&self, ValidToken { token, source }: ValidToken<'_>) {
+		match source {
+			| ValidTokenSource::ConfigFile => {
+				// we don't track uses of the config file token, do nothing
+			},
+			| ValidTokenSource::Database(mut info) => {
+				info.uses = info.uses.saturating_add(1);
+
+				self.db.save_token(token, &info);
+			},
+		}
+	}
+
+	/// Try to revoke a valid token.
+	///
+	/// Note that some tokens (like the one set in the config file) cannot be
+	/// revoked.
+	pub fn revoke_token(&self, ValidToken { token, source }: ValidToken<'_>) -> Result {
+		match source {
+			| ValidTokenSource::ConfigFile => {
+				// the config file token cannot be revoked
+				Err!(
+					"The token set in the config file cannot be revoked. Edit the config file \
+					 to change it."
+				)
+			},
+			| ValidTokenSource::Database(_) => {
+				self.db.revoke_token(token);
+				Ok(())
+			},
+		}
+	}
+
+	/// Iterate over all valid registration tokens.
+	pub fn iterate_tokens(&self) -> impl Stream<Item = ValidToken<'_>> + Send + '_ {
+		stream::iter(self.get_config_file_token()).chain(self.db.iterate_and_clean_tokens().map(
+			|(token, info)| ValidToken {
+				token,
+				source: ValidTokenSource::Database(info),
+			},
+		))
+	}
+}