[Rust] Capability based DbContext

crates/bindings/src/lib.rs

@@ -24,11 +24,12 @@ pub use spacetimedb_query_builder as query_builder;
 #[cfg(feature = "unstable")]
 pub use client_visibility_filter::Filter;
 pub use log;
+#[cfg(feature = "rand08")]
+use rand::distributions::{Distribution, Standard};
 #[cfg(feature = "rand")]
 pub use rand08 as rand;
 #[cfg(feature = "rand")]
 use rand08::RngCore;
-#[cfg(feature = "rand08")]
 pub use rng::StdbRng;
 pub use sats::SpacetimeType;
 #[doc(hidden)]
@@ -912,6 +913,8 @@ pub use spacetimedb_bindings_macro::view;
 pub struct QueryBuilder {}
 pub use query_builder::{Query, RawQuery};
 
+use crate::http::{HandlerContext, HttpClient};
+
 /// One of two possible types that can be passed as the first argument to a `#[view]`.
 /// The other is [`ViewContext`].
 /// Use this type if the view does not depend on the caller's identity.
@@ -1440,6 +1443,7 @@ impl ProcedureContext {
 }
 
 /// A handle on a database with a particular table schema.
+#[deprecated(note = "Use the capability based traits (CtxDbRead, CtxDbWrite) instead!")]
 pub trait DbContext {
     /// A view into the tables of a database.
     ///
@@ -1461,6 +1465,7 @@ pub trait DbContext {
     fn db_read_only(&self) -> &LocalReadOnly;
 }
 
+#[allow(deprecated)]
 impl DbContext for AnonymousViewContext {
     type DbView = LocalReadOnly;
 
@@ -1473,6 +1478,7 @@ impl DbContext for AnonymousViewContext {
     }
 }
 
+#[allow(deprecated)]
 impl DbContext for ReducerContext {
     type DbView = Local;
 
@@ -1485,6 +1491,7 @@ impl DbContext for ReducerContext {
     }
 }
 
+#[allow(deprecated)]
 impl DbContext for TxContext {
     type DbView = Local;
 
@@ -1497,6 +1504,7 @@ impl DbContext for TxContext {
     }
 }
 
+#[allow(deprecated)]
 impl DbContext for ViewContext {
     type DbView = LocalReadOnly;
 
@@ -1526,6 +1534,279 @@ impl Local {
     }
 }
 
+/// Contexts which provide read access to the database.
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from views, reducers, and transactions started by procedures and HTTP handlers.
+///
+/// When operating on a concrete-typed [`ViewContext`], [`ReducerContext`] or [`TxContext`],
+/// this trait is not necessary, as the context's `db` field provides the same (or greater, read-write) access.
+pub trait CtxDbRead {
+    fn db_read_only(&self) -> &LocalReadOnly;
+}
+
+impl CtxDbRead for TxContext {
+    fn db_read_only(&self) -> &LocalReadOnly {
+        &LocalReadOnly {}
+    }
+}
+
+impl CtxDbRead for ReducerContext {
+    fn db_read_only(&self) -> &LocalReadOnly {
+        &LocalReadOnly {}
+    }
+}
+
+impl CtxDbRead for ViewContext {
+    fn db_read_only(&self) -> &LocalReadOnly {
+        &LocalReadOnly {}
+    }
+}
+
+impl CtxDbRead for AnonymousViewContext {
+    fn db_read_only(&self) -> &LocalReadOnly {
+        &LocalReadOnly {}
+    }
+}
+
+/// Contexts which provide read-write access to the database.
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from reducers and from transactions started by procedures and HTTP handlers.
+///
+/// When operating on a concrete-typed [`ReducerContext`] or [`TxContext`], this trait is not necessary,
+/// as the context's `db` field provides the same access.
+pub trait CtxDbWrite: CtxDbRead {
+    fn db(&self) -> &Local;
+}
+
+impl CtxDbWrite for TxContext {
+    fn db(&self) -> &Local {
+        &Local {}
+    }
+}
+
+impl CtxDbWrite for ReducerContext {
+    fn db(&self) -> &Local {
+        &Local {}
+    }
+}
+
+/// Contexts which can retrieve the sender [`Identity`].
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from views, reducers, and transactions started by procedures and HTTP handlers.
+///
+/// When operating on a concrete-typed [`ViewContext`], [`ReducerContext`], [`ProcedureContext`] or [`TxContext`], this trait is not necessary,
+/// as the context's inherent `sender` method provides the same access.
+pub trait CtxWithSender {
+    fn sender(&self) -> Identity;
+}
+
+impl CtxWithSender for ViewContext {
+    fn sender(&self) -> Identity {
+        self.sender
+    }
+}
+
+impl CtxWithSender for ReducerContext {
+    fn sender(&self) -> Identity {
+        self.sender
+    }
+}
+
+impl CtxWithSender for TxContext {
+    fn sender(&self) -> Identity {
+        self.0.sender
+    }
+}
+
+impl CtxWithSender for ProcedureContext {
+    fn sender(&self) -> Identity {
+        self.sender
+    }
+}
+
+/// Contexts which can retrieve the current [`Timestamp`].
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from reducers, procedures, HTTP handlers,
+/// and transactions started by procedures and HTTP handlers.
+///
+/// When operating on a concrete-typed [`ReducerContext`], [`ProcedureContext`], [`HandlerContext`] or [`TxContext`],
+/// this trait is not necessary, as the context's `timestamp` field provides the same access.
+pub trait CtxWithTimestamp {
+    fn timestamp(&self) -> Timestamp;
+}
+
+impl CtxWithTimestamp for ReducerContext {
+    fn timestamp(&self) -> Timestamp {
+        self.timestamp
+    }
+}
+
+impl CtxWithTimestamp for TxContext {
+    fn timestamp(&self) -> Timestamp {
+        self.timestamp
+    }
+}
+
+impl CtxWithTimestamp for ProcedureContext {
+    fn timestamp(&self) -> Timestamp {
+        self.timestamp
+    }
+}
+
+impl CtxWithTimestamp for HandlerContext {
+    fn timestamp(&self) -> Timestamp {
+        self.timestamp
+    }
+}
+
+/// Contexts which can retrieve the current [`AuthCtx`].
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from reducers and procedures.
+///
+/// When operating on a concrete-typed [`ReducerContext`], [`ProcedureContext`], [`TxContext`],
+/// this trait is not necessary, as the context's sender_auth method provides the same access.
+pub trait CtxWithSenderAuth {
+    fn sender_auth(&self) -> &AuthCtx;
+}
+
+impl CtxWithSenderAuth for ReducerContext {
+    fn sender_auth(&self) -> &AuthCtx {
+        self.sender_auth()
+    }
+}
+
+impl CtxWithSenderAuth for TxContext {
+    fn sender_auth(&self) -> &AuthCtx {
+        self.0.sender_auth()
+    }
+}
+
+/// Contexts which can enter a start a transaction with a [`TxContext`] inside the function.
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from reducers and procedures.
+///
+/// When operating on a concrete-typed [`HandlerContext`], [`ProcedureContext`],
+/// this trait is not necessary, as the context's methods provide the same access.
+pub trait CtxWithTxManagement {
+    fn with_tx<T>(&mut self, body: impl Fn(&TxContext) -> T) -> T;
+    fn try_with_tx<T, E>(&mut self, body: impl Fn(&TxContext) -> Result<T, E>) -> Result<T, E>;
+}
+
+impl CtxWithTxManagement for ProcedureContext {
+    fn with_tx<T>(&mut self, body: impl Fn(&TxContext) -> T) -> T {
+        self.with_tx(body)
+    }
+
+    fn try_with_tx<T, E>(&mut self, body: impl Fn(&TxContext) -> Result<T, E>) -> Result<T, E> {
+        self.try_with_tx(body)
+    }
+}
+
+impl CtxWithTxManagement for HandlerContext {
+    fn with_tx<T>(&mut self, body: impl Fn(&TxContext) -> T) -> T {
+        self.with_tx(body)
+    }
+
+    fn try_with_tx<T, E>(&mut self, body: impl Fn(&TxContext) -> Result<T, E>) -> Result<T, E> {
+        self.try_with_tx(body)
+    }
+}
+
+/// Contexts which can retrieve the current [`StdbRng`] state.
+///
+/// This trait is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from reducers and procedures.
+///
+/// When operating on a concrete-typed [`HandlerContext`], [`ProcedureContext`], [`ReducerContext`], [`TxContext`]
+/// this trait is not necessary, as the context's methods provide the same access.
+pub trait CtxWithRng {
+    fn rng(&self) -> &StdbRng;
+    fn random<T>(&self) -> T
+    where
+        Standard: Distribution<T>;
+}
+
+impl CtxWithRng for ProcedureContext {
+    fn rng(&self) -> &StdbRng {
+        self.rng()
+    }
+
+    fn random<T>(&self) -> T
+    where
+        Standard: Distribution<T>,
+    {
+        self.random()
+    }
+}
+
+impl CtxWithRng for HandlerContext {
+    fn rng(&self) -> &StdbRng {
+        self.rng()
+    }
+
+    fn random<T>(&self) -> T
+    where
+        Standard: Distribution<T>,
+    {
+        self.random()
+    }
+}
+
+impl CtxWithRng for ReducerContext {
+    fn rng(&self) -> &StdbRng {
+        self.rng()
+    }
+
+    fn random<T>(&self) -> T
+    where
+        Standard: Distribution<T>,
+    {
+        self.random()
+    }
+}
+
+impl CtxWithRng for TxContext {
+    fn rng(&self) -> &StdbRng {
+        self.0.rng()
+    }
+
+    fn random<T>(&self) -> T
+    where
+        Standard: Distribution<T>,
+    {
+        self.0.random()
+    }
+}
+
+/// Contexts which can perform outgoing HTTP requests.
+///
+/// This type is useful for writing reusable logic which is generic over the context type,
+/// allowing it to be used from procedures and HTTP handlers.
+///
+/// When operating on a concrete-typed [`ProcedureContext`] or [`HandlerContext`], this trait is not necessary,
+/// as the context's `http` field provides the same access.
+pub trait CtxWithHttp {
+    fn http(&self) -> &HttpClient;
+}
+
+impl CtxWithHttp for HandlerContext {
+    fn http(&self) -> &HttpClient {
+        &self.http
+    }
+}
+
+impl CtxWithHttp for ProcedureContext {
+    fn http(&self) -> &HttpClient {
+        &self.http
+    }
+}
+
 /// The [JWT] of an [`AuthCtx`].
 ///
 /// [JWT]: https://en.wikipedia.org/wiki/JSON_Web_Token