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//! Crate `ruma_events` contains serializable types for the events in the [Matrix](https://matrix.org) //! specification that can be shared by client and server code. //! //! All data exchanged over Matrix is expressed as an event. //! Different event types represent different actions, such as joining a room or sending a message. //! Events are stored and transmitted as simple JSON structures. //! While anyone can create a new event type for their own purposes, the Matrix specification //! defines a number of event types which are considered core to the protocol, and Matrix clients //! and servers must understand their semantics. //! ruma-events contains Rust types for each of the event types defined by the specification and //! facilities for extending the event system for custom event types. //! //! # Event types //! //! ruma-events includes a Rust enum called `EventType`, which provides a simple enumeration of //! all the event types defined by the Matrix specification. Matrix event types are serialized to //! JSON strings in [reverse domain name //! notation](https://en.wikipedia.org/wiki/Reverse_domain_name_notation), although the core event //! types all use the special "m" TLD, e.g. *m.room.message*. //! `EventType` also includes a variant called `Custom`, which is a catch-all that stores a string //! containing the name of any event type that isn't part of the specification. //! `EventType` is used throughout ruma-events to identify and differentiate between events of //! different types. //! //! # Event kinds //! //! Matrix defines three "kinds" of events: //! //! 1. **Events**, which are arbitrary JSON structures that have two required keys: //! * `type`, which specifies the event's type //! * `content`, which is a JSON object containing the "payload" of the event //! 2. **Room events**, which are a superset of events and represent actions that occurred within //! the context of a Matrix room. //! They have at least the following additional keys: //! * `event_id`, which is a unique identifier for the event //! * `room_id`, which is a unique identifier for the room in which the event occurred //! * `sender`, which is the unique identifier of the Matrix user who created the event //! * Optionally, `unsigned`, which is a JSON object containing arbitrary additional metadata //! that is not digitally signed by Matrix homeservers. //! 3. **State events**, which are a superset of room events and represent persistent state //! specific to a room, such as the room's member list or topic. //! Within a single room, state events of the same type and with the same "state key" will //! effectively "replace" the previous one, updating the room's state. //! They have at least the following additional keys: //! * `state_key`, a string which serves as a sort of "sub-type." //! The state key allows a room to persist multiple state events of the same type. //! You can think of a room's state events as being a `HashMap` where the keys are the tuple //! `(event_type, state_key)`. //! * Optionally, `prev_content`, a JSON object containing the `content` object from the //! previous event of the given `(event_type, state_key)` tuple in the given room. //! //! ruma-events represents these three event kinds as traits, allowing any Rust type to serve as a //! Matrix event so long as it upholds the contract expected of its kind. //! //! # Core event types //! //! ruma-events includes Rust types for every one of the event types in the Matrix specification. //! To better organize the crate, these types live in separate modules with a hierarchy that //! matches the reverse domain name notation of the event type. //! For example, the *m.room.message* event lives at `ruma_events::room::message::MessageEvent`. //! Each type's module also contains a Rust type for that event type's `content` field, and any //! other supporting types required by the event's other fields. //! //! # Custom event types //! //! Although any Rust type that implements `Event`, `RoomEvent`, or `StateEvent` can serve as a //! Matrix event type, ruma-events also includes a few convenience types for representing events //! that are not covered by the spec and not otherwise known by the application. //! `CustomEvent`, `CustomRoomEvent`, and `CustomStateEvent` are simple implementations of their //! respective event traits whose `content` field is simply a `serde_json::Value` value, which //! represents arbitrary JSON. //! //! # Serialization and deserialization //! //! All concrete event types in ruma-events can be serialized via the `Serialize` trait from //! [serde](https://serde.rs/) and can be deserialized from a `&str` of JSON data via the `FromStr` //! trait from the standard library. (`TryFrom<&str>` is also implemented and can be used in place //! of `FromStr` if preferred.) Supporting types for each event generally implement serde's //! `Deserialize` trait directly. In order to handle incoming data that may not conform to //! ruma-events's strict definitions of event structures, deserializing from JSON will return an //! `InvalidEvent` on error. This error covers both invalid JSON data as well as valid JSON that //! doesn't match the structure expected by ruma-events's event types. In the latter case, the error //! exposes the deserialized `serde_json::Value` so that developers can still work with the received //! event data. This also makes it possible to deserialize a collection of events without the entire //! collection failing to deserialize due to a single invalid event. The "content" type for each //! event also implements `Serialize` and either `FromStr` (for dedicated content types) or //! `Deserialize` (when the content is a type alias), allowing content to be converted to and from //! JSON indepedently of the surrounding event structure, if needed. //! //! # Collections //! //! With the trait-based approach to events, it's easy to write generic collection types like //! `Vec<Box<R: RoomEvent>>`. //! However, there are APIs in the Matrix specification that involve heterogeneous collections of //! events, i.e. a list of events of different event types. //! Because Rust does not have a facility for arrays, vectors, or slices containing multiple //! concrete types, ruma-events provides special collection types for this purpose. //! The collection types are enums which effectively "wrap" each possible event type of a //! particular event "kind." //! //! Because of the hierarchical nature of event kinds in Matrix, these collection types are divied //! into two modules, `ruma_events::collections::all` and `ruma_events::collections::only`. //! The "all" versions include every event type that implements the relevant event trait as well as //! more specific event traits. //! The "only" versions include only the event types that implement "at most" the relevant event //! trait. //! //! For example, the `ruma_events::collections::all::Event` enum includes *m.room.message*, because //! that event type is both an event and a room event. //! However, the `ruma_events::collections::only::Event` enum does *not* include *m.room.message*, //! because *m.room.message* implements a *more specific* event trait than `Event`. #![deny(missing_debug_implementations)] #![deny(missing_docs)] #![deny(warnings)] use std::{ error::Error, fmt::{Debug, Display, Error as FmtError, Formatter, Result as FmtResult}, str::FromStr, }; use js_int::UInt; use ruma_identifiers::{EventId, RoomId, UserId}; use serde::{ de::{Error as SerdeError, IntoDeserializer, MapAccess, Visitor}, ser::SerializeMap, Deserialize, Deserializer, Serialize, Serializer, }; use serde_json::Value; pub use custom::CustomEvent; pub use custom_room::CustomRoomEvent; pub use custom_state::CustomStateEvent; #[macro_use] mod macros; pub mod call; /// Enums for heterogeneous collections of events. pub mod collections { pub mod all; pub mod only; } pub mod direct; pub mod dummy; pub mod forwarded_room_key; pub mod fully_read; pub mod ignored_user_list; pub mod key; pub mod presence; pub mod push_rules; pub mod receipt; pub mod room; pub mod room_key; pub mod room_key_request; pub mod sticker; pub mod stripped; pub mod tag; pub mod typing; /// An event that is malformed or otherwise invalid. /// /// When attempting to create an event from a string of JSON data, an error in the input data may /// cause deserialization to fail, or the JSON structure may not corresponded to ruma-events's /// strict definition of the event's schema. If deserialization completely fails, this type will /// provide a message with details about the deserialization error. If deserialization succeeds but /// the event is otherwise invalid, a similar message will be provided, as well as a /// `serde_json::Value` containing the raw JSON data as it was deserialized. #[derive(Debug)] pub struct InvalidEvent(InnerInvalidEvent); impl InvalidEvent { /// A message describing why the event is invalid. pub fn message(&self) -> String { match self.0 { InnerInvalidEvent::Deserialization { ref error } => error.to_string(), InnerInvalidEvent::Validation { ref message, .. } => message.to_string(), } } /// The raw `serde_json::Value` representation of the invalid event, if available. pub fn json(&self) -> Option<&Value> { match self.0 { InnerInvalidEvent::Validation { ref json, .. } => Some(json), _ => None, } } } impl Display for InvalidEvent { fn fmt(&self, f: &mut Formatter) -> FmtResult { write!(f, "{}", self.message()) } } impl Error for InvalidEvent {} /// An event that is malformed or otherwise invalid. #[derive(Debug)] enum InnerInvalidEvent { /// An event that failed to deserialize from JSON. Deserialization { /// The deserialization error returned by serde. error: serde_json::Error, }, /// An event that deserialized but failed validation. Validation { /// The raw `serde_json::Value` representation of the invalid event. json: Value, /// An message describing why the event was invalid. message: String, }, } impl From<serde_json::Error> for InvalidEvent { fn from(error: serde_json::Error) -> Self { InvalidEvent(InnerInvalidEvent::Deserialization { error }) } } /// An error returned when attempting to create an event with data that would make it invalid. /// /// This type is similar to `InvalidEvent`, but used during the construction of a new event, as /// opposed to deserialization of an existing event from JSON. #[derive(Clone, Debug, PartialEq)] pub struct InvalidInput(String); impl Display for InvalidInput { fn fmt(&self, f: &mut Formatter) -> FmtResult { write!(f, "{}", self.0) } } impl Error for InvalidInput {} /// An error when attempting to create a value from a string via the `FromStr` trait. /// /// This error type is only used for simple enums with unit variants. Event deserialization through /// the `FromStr` trait returns an `InvalidEvent` on error. #[derive(Clone, Copy, Eq, Debug, Hash, PartialEq)] pub struct FromStrError; impl Display for FromStrError { fn fmt(&self, f: &mut Formatter) -> FmtResult { write!(f, "failed to parse type from string") } } impl Error for FromStrError {} /// A meaningless value that serializes to an empty JSON object. /// /// This type is used in a few places where the Matrix specification requires an empty JSON object, /// but it's wasteful to represent it as a `HashMap` in Rust code. #[derive(Clone, Debug, PartialEq)] pub struct Empty; impl Serialize for Empty { fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer, { serializer.serialize_map(Some(0))?.end() } } impl<'de> Deserialize<'de> for Empty { fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: Deserializer<'de>, { struct EmptyMapVisitor; impl<'de> Visitor<'de> for EmptyMapVisitor { type Value = Empty; fn expecting(&self, f: &mut Formatter) -> FmtResult { write!(f, "an object/map") } fn visit_map<A>(self, _map: A) -> Result<Self::Value, A::Error> where A: MapAccess<'de>, { Ok(Empty) } } deserializer.deserialize_map(EmptyMapVisitor) } } /// The type of an event. #[derive(Clone, Debug, Eq, Hash, PartialEq)] pub enum EventType { /// m.call.answer CallAnswer, /// m.call.candidates CallCandidates, /// m.call.hangup CallHangup, /// m.call.invite CallInvite, /// m.direct Direct, /// m.dummy Dummy, /// m.forwarded_room_key ForwardedRoomKey, /// m.fully_read FullyRead, /// m.key.verification.accept KeyVerificationAccept, /// m.key.verification.cancel KeyVerificationCancel, /// m.key.verification.key KeyVerificationKey, /// m.key.verification.mac KeyVerificationMac, /// m.key.verification.request KeyVerificationRequest, /// m.key.verification.start KeyVerificationStart, /// m.ignored_user_list IgnoredUserList, /// m.presence Presence, /// m.push_rules PushRules, /// m.receipt Receipt, /// m.room.aliases RoomAliases, /// m.room.avatar RoomAvatar, /// m.room.canonical_alias RoomCanonicalAlias, /// m.room.create RoomCreate, /// m.room.encrypted RoomEncrypted, /// m.room.encryption RoomEncryption, /// m.room.guest_access RoomGuestAccess, /// m.room.history_visibility RoomHistoryVisibility, /// m.room.join_rules RoomJoinRules, /// m.room.member RoomMember, /// m.room.message RoomMessage, /// m.room.message.feedback RoomMessageFeedback, /// m.room.name RoomName, /// m.room.pinned_events RoomPinnedEvents, /// m.room.power_levels RoomPowerLevels, /// m.room.redaction RoomRedaction, /// m.room.server_acl RoomServerAcl, /// m.room.third_party_invite RoomThirdPartyInvite, /// m.room.tombstone RoomTombstone, /// m.room.topic RoomTopic, /// m.room_key RoomKey, /// m.room_key_request RoomKeyRequest, /// m.sticker Sticker, /// m.tag Tag, /// m.typing Typing, /// Any event that is not part of the specification. Custom(String), /// Additional variants may be added in the future and will not be considered breaking changes /// to ruma-events. #[doc(hidden)] __Nonexhaustive, } /// A basic event. pub trait Event where Self: Debug + FromStr + Serialize, { /// The type of this event's `content` field. type Content: Debug + Serialize; /// The event's content. fn content(&self) -> &Self::Content; /// The type of the event. fn event_type(&self) -> EventType; } /// An event within the context of a room. pub trait RoomEvent: Event { /// The unique identifier for the event. fn event_id(&self) -> &EventId; /// Timestamp (milliseconds since the UNIX epoch) on originating homeserver when this event was /// sent. fn origin_server_ts(&self) -> UInt; /// The unique identifier for the room associated with this event. /// /// This can be `None` if the event came from a context where there is /// no ambiguity which room it belongs to, like a `/sync` response for example. fn room_id(&self) -> Option<&RoomId>; /// The unique identifier for the user who sent this event. fn sender(&self) -> &UserId; /// Additional key-value pairs not signed by the homeserver. fn unsigned(&self) -> Option<&Value>; } /// An event that describes persistent state about a room. pub trait StateEvent: RoomEvent { /// The previous content for this state key, if any. fn prev_content(&self) -> Option<&Self::Content>; /// A key that determines which piece of room state the event represents. fn state_key(&self) -> &str; } mod custom { use ruma_events_macros::ruma_event; use serde_json::Value; ruma_event! { /// A custom basic event not covered by the Matrix specification. CustomEvent { kind: Event, event_type: Custom, content_type_alias: { /// The payload for `CustomEvent`. Value }, } } } mod custom_room { use ruma_events_macros::ruma_event; use serde_json::Value; ruma_event! { /// A custom room event not covered by the Matrix specification. CustomRoomEvent { kind: RoomEvent, event_type: Custom, content_type_alias: { /// The payload for `CustomRoomEvent`. Value }, } } } mod custom_state { use ruma_events_macros::ruma_event; use serde_json::Value; ruma_event! { /// A custom state event not covered by the Matrix specification. CustomStateEvent { kind: StateEvent, event_type: Custom, content_type_alias: { /// The payload for `CustomStateEvent`. Value }, } } } impl Display for EventType { fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), FmtError> { let event_type_str = match *self { EventType::CallAnswer => "m.call.answer", EventType::CallCandidates => "m.call.candidates", EventType::CallHangup => "m.call.hangup", EventType::CallInvite => "m.call.invite", EventType::Direct => "m.direct", EventType::Dummy => "m.dummy", EventType::ForwardedRoomKey => "m.forwarded_room_key", EventType::FullyRead => "m.fully_read", EventType::KeyVerificationAccept => "m.key.verification.accept", EventType::KeyVerificationCancel => "m.key.verification.cancel", EventType::KeyVerificationKey => "m.key.verification.key", EventType::KeyVerificationMac => "m.key.verification.mac", EventType::KeyVerificationRequest => "m.key.verification.request", EventType::KeyVerificationStart => "m.key.verification.start", EventType::IgnoredUserList => "m.ignored_user_list", EventType::Presence => "m.presence", EventType::PushRules => "m.push_rules", EventType::Receipt => "m.receipt", EventType::RoomAliases => "m.room.aliases", EventType::RoomAvatar => "m.room.avatar", EventType::RoomCanonicalAlias => "m.room.canonical_alias", EventType::RoomCreate => "m.room.create", EventType::RoomEncrypted => "m.room.encrypted", EventType::RoomEncryption => "m.room.encryption", EventType::RoomGuestAccess => "m.room.guest_access", EventType::RoomHistoryVisibility => "m.room.history_visibility", EventType::RoomJoinRules => "m.room.join_rules", EventType::RoomMember => "m.room.member", EventType::RoomMessage => "m.room.message", EventType::RoomMessageFeedback => "m.room.message.feedback", EventType::RoomName => "m.room.name", EventType::RoomPinnedEvents => "m.room.pinned_events", EventType::RoomPowerLevels => "m.room.power_levels", EventType::RoomRedaction => "m.room.redaction", EventType::RoomServerAcl => "m.room.server_acl", EventType::RoomThirdPartyInvite => "m.room.third_party_invite", EventType::RoomTombstone => "m.room.tombstone", EventType::RoomTopic => "m.room.topic", EventType::RoomKey => "m.room_key", EventType::RoomKeyRequest => "m.room_key_request", EventType::Sticker => "m.sticker", EventType::Tag => "m.tag", EventType::Typing => "m.typing", EventType::Custom(ref event_type) => event_type, EventType::__Nonexhaustive => { panic!("__Nonexhaustive enum variant is not intended for use.") } }; write!(f, "{}", event_type_str) } } impl<'a> From<&'a str> for EventType { fn from(s: &'a str) -> EventType { match s { "m.call.answer" => EventType::CallAnswer, "m.call.candidates" => EventType::CallCandidates, "m.call.hangup" => EventType::CallHangup, "m.call.invite" => EventType::CallInvite, "m.direct" => EventType::Direct, "m.dummy" => EventType::Dummy, "m.forwarded_room_key" => EventType::ForwardedRoomKey, "m.fully_read" => EventType::FullyRead, "m.key.verification.accept" => EventType::KeyVerificationAccept, "m.key.verification.cancel" => EventType::KeyVerificationCancel, "m.key.verification.key" => EventType::KeyVerificationKey, "m.key.verification.mac" => EventType::KeyVerificationMac, "m.key.verification.request" => EventType::KeyVerificationRequest, "m.key.verification.start" => EventType::KeyVerificationStart, "m.ignored_user_list" => EventType::IgnoredUserList, "m.presence" => EventType::Presence, "m.push_rules" => EventType::PushRules, "m.receipt" => EventType::Receipt, "m.room.aliases" => EventType::RoomAliases, "m.room.avatar" => EventType::RoomAvatar, "m.room.canonical_alias" => EventType::RoomCanonicalAlias, "m.room.create" => EventType::RoomCreate, "m.room.encrypted" => EventType::RoomEncrypted, "m.room.encryption" => EventType::RoomEncryption, "m.room.guest_access" => EventType::RoomGuestAccess, "m.room.history_visibility" => EventType::RoomHistoryVisibility, "m.room.join_rules" => EventType::RoomJoinRules, "m.room.member" => EventType::RoomMember, "m.room.message" => EventType::RoomMessage, "m.room.message.feedback" => EventType::RoomMessageFeedback, "m.room.name" => EventType::RoomName, "m.room.pinned_events" => EventType::RoomPinnedEvents, "m.room.power_levels" => EventType::RoomPowerLevels, "m.room.redaction" => EventType::RoomRedaction, "m.room.server_acl" => EventType::RoomServerAcl, "m.room.third_party_invite" => EventType::RoomThirdPartyInvite, "m.room.tombstone" => EventType::RoomTombstone, "m.room.topic" => EventType::RoomTopic, "m.room_key" => EventType::RoomKey, "m.room_key_request" => EventType::RoomKeyRequest, "m.sticker" => EventType::Sticker, "m.tag" => EventType::Tag, "m.typing" => EventType::Typing, event_type => EventType::Custom(event_type.to_string()), } } } impl Serialize for EventType { fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer, { serializer.serialize_str(&self.to_string()) } } impl<'de> Deserialize<'de> for EventType { fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: Deserializer<'de>, { struct EventTypeVisitor; impl<'de> Visitor<'de> for EventTypeVisitor { type Value = EventType; fn expecting(&self, formatter: &mut Formatter<'_>) -> FmtResult { write!(formatter, "a Matrix event type as a string") } fn visit_str<E>(self, v: &str) -> Result<Self::Value, E> where E: SerdeError, { Ok(EventType::from(v)) } } deserializer.deserialize_str(EventTypeVisitor) } } /// An encryption algorithm to be used to encrypt messages sent to a room. #[derive(Clone, Debug, PartialEq)] pub enum Algorithm { /// Olm version 1 using Curve25519, AES-256, and SHA-256. OlmV1Curve25519AesSha2, /// Megolm version 1 using AES-256 and SHA-256. MegolmV1AesSha2, /// Any algorithm that is not part of the specification. Custom(String), /// Additional variants may be added in the future and will not be considered breaking changes /// to `ruma-events`. #[doc(hidden)] __Nonexhaustive, } impl Display for Algorithm { fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult { let algorithm_str = match *self { Algorithm::OlmV1Curve25519AesSha2 => "m.olm.v1.curve25519-aes-sha2", Algorithm::MegolmV1AesSha2 => "m.megolm.v1.aes-sha2", Algorithm::Custom(ref algorithm) => algorithm, Algorithm::__Nonexhaustive => { panic!("__Nonexhaustive enum variant is not intended for use.") } }; write!(f, "{}", algorithm_str) } } impl<'a> From<&'a str> for Algorithm { fn from(s: &'a str) -> Algorithm { match s { "m.olm.v1.curve25519-aes-sha2" => Algorithm::OlmV1Curve25519AesSha2, "m.megolm.v1.aes-sha2" => Algorithm::MegolmV1AesSha2, algorithm => Algorithm::Custom(algorithm.to_string()), } } } impl Serialize for Algorithm { fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer, { serializer.serialize_str(&self.to_string()) } } impl<'de> Deserialize<'de> for Algorithm { fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: Deserializer<'de>, { struct CancelCodeVisitor; impl<'de> Visitor<'de> for CancelCodeVisitor { type Value = Algorithm; fn expecting(&self, formatter: &mut Formatter<'_>) -> FmtResult { write!(formatter, "an encryption algorithm code as a string") } fn visit_str<E>(self, v: &str) -> Result<Self::Value, E> where E: SerdeError, { Ok(Algorithm::from(v)) } } deserializer.deserialize_str(CancelCodeVisitor) } } /// Serde deserialization decorator to map empty Strings to None, /// and forward non-empty Strings to the Deserialize implementation for T. /// Useful for the typical /// "A room with an X event with an absent, null, or empty Y field /// should be treated the same as a room with no such event." /// formulation in the spec. /// /// To be used like this: /// `#[serde(deserialize_with = "empty_string_as_none"]` /// Relevant serde issue: https://github.com/serde-rs/serde/issues/1425 fn empty_string_as_none<'de, D, T>(de: D) -> Result<Option<T>, D::Error> where D: serde::Deserializer<'de>, T: serde::Deserialize<'de>, { let opt = Option::<String>::deserialize(de)?; let opt = opt.as_ref().map(String::as_str); match opt { None | Some("") => Ok(None), // If T = String, like in m.room.name, the second deserialize is actually superfluous. // TODO: optimize that somehow? Some(s) => T::deserialize(s.into_deserializer()).map(Some), } } /// Used to default the `bool` fields to `true` during deserialization. fn default_true() -> bool { true } #[cfg(test)] mod tests { use serde_json::{from_str, to_string}; use super::{Algorithm, EventType}; #[test] fn event_types_serialize_to_display_form() { assert_eq!( to_string(&EventType::RoomCreate).unwrap(), r#""m.room.create""# ); } #[test] fn custom_event_types_serialize_to_display_form() { assert_eq!( to_string(&EventType::Custom("io.ruma.test".to_string())).unwrap(), r#""io.ruma.test""# ); } #[test] fn event_types_deserialize_from_display_form() { assert_eq!( from_str::<EventType>(r#""m.room.create""#).unwrap(), EventType::RoomCreate ); } #[test] fn custom_event_types_deserialize_from_display_form() { assert_eq!( from_str::<EventType>(r#""io.ruma.test""#).unwrap(), EventType::Custom("io.ruma.test".to_string()) ) } #[test] fn algorithms_serialize_to_display_form() { assert_eq!( to_string(&Algorithm::MegolmV1AesSha2).unwrap(), r#""m.megolm.v1.aes-sha2""# ); } #[test] fn custom_algorithms_serialize_to_display_form() { assert_eq!( to_string(&Algorithm::Custom("io.ruma.test".to_string())).unwrap(), r#""io.ruma.test""# ); } #[test] fn algorithms_deserialize_from_display_form() { assert_eq!( from_str::<Algorithm>(r#""m.megolm.v1.aes-sha2""#).unwrap(), Algorithm::MegolmV1AesSha2 ); } #[test] fn custom_algorithms_deserialize_from_display_form() { assert_eq!( from_str::<Algorithm>(r#""io.ruma.test""#).unwrap(), Algorithm::Custom("io.ruma.test".to_string()) ) } }