feat: add anvil_setRpcUrl

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 |

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)]

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

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| {

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)]