From 13ce18fd3b0f995183ce5cc14a85133e28f994dc Mon Sep 17 00:00:00 2001
From: James Prestwich <10149425+prestwich@users.noreply.github.com>
Date: Sun, 17 Jul 2022 11:26:16 -0700
Subject: [PATCH] feature: allow event builder to stream with meta (#1483)

* feature: allow event builder to stream with meta

* doc: improve rustdoc

* feature: subscribe_with_meta

* chore: fmt
---
 CHANGELOG.md                 |  4 +++-
 ethers-contract/src/event.rs | 42 ++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 092dfb3b..13d57870 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -106,7 +106,7 @@
 
 - Make `ethers-solc` optional dependency of `ethers`, needs `ethers-solc` feature to activate
   [#1463](https://github.com/gakonst/ethers-rs/pull/1463)
-- Add `rawMetadata:String` field to configurable contract output 
+- Add `rawMetadata:String` field to configurable contract output
   [#1365](https://github.com/gakonst/ethers-rs/pull/1365)
 - Use relative source paths and `solc --base-path`
   [#1317](https://github.com/gakonst/ethers-rs/pull/1317)
@@ -237,6 +237,8 @@
 
 ### Unreleased
 
+- Add `Event::stream_with_meta` and `Event::subscribe_with_meta`
+  [#1483](https://github.com/gakonst/ethers-rs/pull/1483)
 - Added tx builder methods to `ContractFactory`
   [#1289](https://github.com/gakonst/ethers-rs/pull/1289)
 - Relax Clone requirements when Arc<Middleware> is used
diff --git a/ethers-contract/src/event.rs b/ethers-contract/src/event.rs
index bc393e70..01fc23f0 100644
--- a/ethers-contract/src/event.rs
+++ b/ethers-contract/src/event.rs
@@ -164,6 +164,26 @@ where
             self.provider.watch(&self.filter).await.map_err(ContractError::MiddlewareError)?;
         Ok(EventStream::new(filter.id, filter, Box::new(move |log| self.parse_log(log))))
     }
+
+    /// As [`Self::stream`], but does not discard [`Log`] metadata.
+    pub async fn stream_with_meta(
+        &'a self,
+    ) -> Result<
+        // Wraps the FilterWatcher with a mapping to the event
+        EventStream<'a, FilterWatcher<'a, M::Provider, Log>, (D, LogMeta), ContractError<M>>,
+        ContractError<M>,
+    > {
+        let filter =
+            self.provider.watch(&self.filter).await.map_err(ContractError::MiddlewareError)?;
+        Ok(EventStream::new(
+            filter.id,
+            filter,
+            Box::new(move |log| {
+                let meta = LogMeta::from(&log);
+                Ok((self.parse_log(log)?, meta))
+            }),
+        ))
+    }
 }
 
 impl<'a, M, D> Event<'a, M, D>
@@ -189,6 +209,28 @@ where
             .map_err(ContractError::MiddlewareError)?;
         Ok(EventStream::new(filter.id, filter, Box::new(move |log| self.parse_log(log))))
     }
+
+    pub async fn subscribe_with_meta(
+        &'a self,
+    ) -> Result<
+        // Wraps the SubscriptionStream with a mapping to the event
+        EventStream<'a, SubscriptionStream<'a, M::Provider, Log>, (D, LogMeta), ContractError<M>>,
+        ContractError<M>,
+    > {
+        let filter = self
+            .provider
+            .subscribe_logs(&self.filter)
+            .await
+            .map_err(ContractError::MiddlewareError)?;
+        Ok(EventStream::new(
+            filter.id,
+            filter,
+            Box::new(move |log| {
+                let meta = LogMeta::from(&log);
+                Ok((self.parse_log(log)?, meta))
+            }),
+        ))
+    }
 }
 
 impl<M, D> Event<'_, M, D>