From 7e9b07714471a46c181c5df617e1c3c2a3f99469 Mon Sep 17 00:00:00 2001
From: Daniyar Itegulov <ditegulov@gmail.com>
Date: Fri, 29 Nov 2024 19:29:03 +1100
Subject: [PATCH] add `anvil_setRpcUrl`

---
 SUPPORTED_APIS.md         |  1 +
 src/fork.rs               |  5 +++++
 src/namespaces/anvil.rs   |  8 ++++++++
 src/node/anvil.rs         |  9 +++++++++
 src/node/in_memory_ext.rs | 25 +++++++++++++++++++++++++
 5 files changed, 48 insertions(+)

diff --git a/SUPPORTED_APIS.md b/SUPPORTED_APIS.md
index 5cf4f405..66b8ecf0 100644
--- a/SUPPORTED_APIS.md
+++ b/SUPPORTED_APIS.md
@@ -14,6 +14,7 @@ The `status` options are:
 
 | Namespace | API | <div style="width:130px">Status</div> | Description |
 | --- | --- | --- | --- |
+| `ANVIL` | `anvil_setRpcUrl` | `SUPPORTED` | Sets the fork RPC url. Assumes the underlying chain is the same as before |
 | `ANVIL` | `anvil_setNextBlockBaseFeePerGas` | `SUPPORTED` | Sets the base fee of the next block |
 | `ANVIL` | `anvil_dropTransaction` | `SUPPORTED` | Removes a transaction from the pool |
 | `ANVIL` | `anvil_dropAllTransactions` | `SUPPORTED` | Remove all transactions from the pool |
diff --git a/src/fork.rs b/src/fork.rs
index dc7c2526..691bfc25 100644
--- a/src/fork.rs
+++ b/src/fork.rs
@@ -729,6 +729,11 @@ impl ForkDetails {
             }
         }
     }
+
+    /// Sets fork's internal URL. Assumes the underlying chain is the same as before.
+    pub fn set_rpc_url(&mut self, url: String) {
+        self.fork_source = Box::new(HttpForkSource::new(url, self.cache_config.clone()));
+    }
 }
 
 #[cfg(test)]
diff --git a/src/namespaces/anvil.rs b/src/namespaces/anvil.rs
index 8a20480f..deb24f07 100644
--- a/src/namespaces/anvil.rs
+++ b/src/namespaces/anvil.rs
@@ -6,6 +6,14 @@ use crate::utils::Numeric;
 
 #[rpc]
 pub trait AnvilNamespaceT {
+    /// Sets the fork RPC url. Assumes the underlying chain is the same as before.
+    ///
+    /// # Arguments
+    ///
+    /// * `url` - Fork's new URL
+    #[rpc(name = "anvil_setRpcUrl")]
+    fn set_rpc_url(&self, url: String) -> RpcResult<()>;
+
     /// Sets the base fee of the next block.
     ///
     /// # Arguments
diff --git a/src/node/anvil.rs b/src/node/anvil.rs
index 1837da4e..f5fdc821 100644
--- a/src/node/anvil.rs
+++ b/src/node/anvil.rs
@@ -12,6 +12,15 @@ use crate::{
 impl<S: ForkSource + std::fmt::Debug + Clone + Send + Sync + 'static> AnvilNamespaceT
     for InMemoryNode<S>
 {
+    fn set_rpc_url(&self, url: String) -> RpcResult<()> {
+        self.set_rpc_url(url)
+            .map_err(|err| {
+                tracing::error!("failed setting RPC url: {:?}", err);
+                into_jsrpc_error(Web3Error::InternalError(err))
+            })
+            .into_boxed_future()
+    }
+
     fn set_next_block_base_fee_per_gas(&self, base_fee: U256) -> RpcResult<()> {
         self.set_next_block_base_fee_per_gas(base_fee)
             .map_err(|err| {
diff --git a/src/node/in_memory_ext.rs b/src/node/in_memory_ext.rs
index 24202d32..b1b81c61 100644
--- a/src/node/in_memory_ext.rs
+++ b/src/node/in_memory_ext.rs
@@ -423,6 +423,31 @@ impl<S: ForkSource + std::fmt::Debug + Clone + Send + Sync + 'static> InMemoryNo
             .set_base_fee(base_fee.as_u64());
         Ok(())
     }
+
+    pub fn set_rpc_url(&self, url: String) -> Result<()> {
+        let inner = self
+            .inner
+            .read()
+            .map_err(|err| anyhow!("failed acquiring lock: {:?}", err))?;
+        let mut fork_storage = inner
+            .fork_storage
+            .inner
+            .write()
+            .map_err(|err| anyhow!("failed acquiring lock: {:?}", err))?;
+        if let Some(fork) = &mut fork_storage.fork {
+            let old_url = fork.fork_source.get_fork_url().map_err(|e| {
+                anyhow::anyhow!(
+                    "failed to resolve current fork's RPC URL: {}",
+                    e.to_string()
+                )
+            })?;
+            fork.set_rpc_url(url.clone());
+            tracing::info!("Updated fork rpc from \"{}\" to \"{}\"", old_url, url);
+        } else {
+            tracing::info!("Non-forking node tried to switch RPC URL to '{url}'. Call `anvil_reset` instead if you wish to switch to forking mode");
+        }
+        Ok(())
+    }
 }
 
 #[cfg(test)]