Add cast command to convert beacon payload to execution payload b2e-payload

Cargo.toml

@@ -224,6 +224,8 @@ alloy-provider = { version = "1.0.23", default-features = false }
 alloy-pubsub = { version = "1.0.23", default-features = false }
 alloy-rpc-client = { version = "1.0.23", default-features = false }
 alloy-rpc-types = { version = "1.0.23", default-features = true }
+alloy-rpc-types-beacon = { version = "1.0.30", default-features = true }
+alloy-rpc-types-engine = { version = "1.0.30", default-features = true }
 alloy-serde = { version = "1.0.23", default-features = false }
 alloy-signer = { version = "1.0.30", default-features = false }
 alloy-signer-aws = { version = "1.0.30", default-features = false }

crates/cast/Cargo.toml

@@ -47,6 +47,8 @@ alloy-provider = { workspace = true, features = [
 ] }
 alloy-rlp.workspace = true
 alloy-rpc-types = { workspace = true, features = ["eth", "trace"] }
+alloy-rpc-types-beacon.workspace = true
+alloy-rpc-types-engine.workspace = true
 alloy-serde.workspace = true
 alloy-signer-local = { workspace = true, features = ["mnemonic", "keystore"] }
 alloy-signer.workspace = true

crates/cast/src/args.rs

@@ -264,6 +264,7 @@ pub async fn run_command(args: CastArgs) -> Result<()> {
         CastSubcommand::ConstructorArgs(cmd) => cmd.run().await?,
         CastSubcommand::Artifact(cmd) => cmd.run().await?,
         CastSubcommand::Bind(cmd) => cmd.run().await?,
+        CastSubcommand::B2EPayload(cmd) => cmd.run().await?,
         CastSubcommand::PrettyCalldata { calldata, offline } => {
             let calldata = stdin::unwrap_line(calldata)?;
             sh_println!("{}", pretty_calldata(&calldata, offline).await?)?;

crates/cast/src/cmd/b2e_payload.rs

@@ -0,0 +1,82 @@
+use alloy_rpc_types_beacon::payload::execution_payload_from_beacon_str;
+use alloy_rpc_types_engine::ExecutionPayload;
+use clap::Parser;
+use eyre::{Result, eyre};
+use foundry_common::{fs, sh_print};
+use std::path::PathBuf;
+
+/// CLI arguments for `cast b2e-payload`, convert Beacon block's execution payload to Execution
+/// JSON-RPC format.
+#[derive(Parser)]
+pub struct B2EPayloadArgs {
+    /// Input data provided through JSON file path.
+    #[arg(
+        long = "json-file",
+        value_name = "FILE",
+        help = "Path to the JSON file containing the beacon block"
+    )]
+    pub json_file: PathBuf,
+}
+
+impl B2EPayloadArgs {
+    pub async fn run(self) -> Result<()> {
+        // Get input beacon block data
+        let beacon_block = fs::read_to_string(&self.json_file)
+            .map_err(|e| eyre!("Failed to read JSON file '{}': {}", self.json_file.display(), e))?;
+
+        // Extract and convert execution payload
+        let execution_payload = Self::extract_and_convert_execution_payload(&beacon_block)?;
+
+        let json_rpc_output = format_as_json_rpc(execution_payload)?;
+        sh_print!("{}", json_rpc_output)?;
+
+        Ok(())
+    }
+
+    // Extracts the execution payload from a beacon block JSON string and converts it to
+    // `ExecutionPayload` It matches `beaconcha.in` json format
+    fn extract_and_convert_execution_payload(beacon_block: &str) -> Result<ExecutionPayload> {
+        let beacon_json: serde_json::Value = serde_json::from_str(beacon_block)
+            .map_err(|e| eyre!("Failed to parse beacon block JSON: {}", e))?;
+
+        // early detection if the format is not correct
+        if beacon_json
+            .get("message")
+            .and_then(|m| m.get("body"))
+            .and_then(|b| b.get("execution_payload"))
+            .is_none()
+        {
+            return Err(eyre!("Invalid beacon block format: missing 'message' field"));
+        }
+        // Extract the "message.body.execution_payload" field from the beacon block JSON
+        // TODO: check if we extract from beacon api it works but not sure it will work with all API
+        // interfaces
+        let execution_payload_beacon_block = beacon_json
+            .get("message")
+            .and_then(|m| m.get("body"))
+            .and_then(|b| b.get("execution_payload"))
+            .ok_or_else(|| eyre!("Could not find execution_payload in beacon block"))?;
+
+        let execution_payload_str = serde_json::to_string(execution_payload_beacon_block)
+            .map_err(|e| eyre!("Failed to serialize execution payload: {}", e))?;
+
+        // Convert beacon block's execution payload to json rpc execution payload
+        let execution_payload = execution_payload_from_beacon_str(&execution_payload_str)?;
+
+        Ok(execution_payload)
+    }
+}
+
+// Helper to format the execution payload as JSON-RPC response
+fn format_as_json_rpc(execution_payload: ExecutionPayload) -> Result<String> {
+    // TODO: check if we used this format and this method engine version
+    let json_rpc_request = serde_json::json!({
+        "jsonrpc": "2.0",
+        "method": "engine_newPayloadV3",
+        "params": [execution_payload],
+        "id": 1
+    });
+
+    serde_json::to_string_pretty(&json_rpc_request)
+        .map_err(|e| eyre!("Failed to serialize JSON-RPC response: {}", e))
+}

crates/cast/src/cmd/mod.rs

@@ -7,6 +7,7 @@
 
 pub mod access_list;
 pub mod artifact;
+pub mod b2e_payload;
 pub mod bind;
 pub mod call;
 pub mod constructor_args;

crates/cast/src/opts.rs

@@ -1,9 +1,10 @@
 use crate::cmd::{
-    access_list::AccessListArgs, artifact::ArtifactArgs, bind::BindArgs, call::CallArgs,
-    constructor_args::ConstructorArgsArgs, create2::Create2Args, creation_code::CreationCodeArgs,
-    da_estimate::DAEstimateArgs, estimate::EstimateArgs, find_block::FindBlockArgs,
-    interface::InterfaceArgs, logs::LogsArgs, mktx::MakeTxArgs, rpc::RpcArgs, run::RunArgs,
-    send::SendTxArgs, storage::StorageArgs, txpool::TxPoolSubcommands, wallet::WalletSubcommands,
+    access_list::AccessListArgs, artifact::ArtifactArgs, b2e_payload::B2EPayloadArgs,
+    bind::BindArgs, call::CallArgs, constructor_args::ConstructorArgsArgs, create2::Create2Args,
+    creation_code::CreationCodeArgs, da_estimate::DAEstimateArgs, estimate::EstimateArgs,
+    find_block::FindBlockArgs, interface::InterfaceArgs, logs::LogsArgs, mktx::MakeTxArgs,
+    rpc::RpcArgs, run::RunArgs, send::SendTxArgs, storage::StorageArgs, txpool::TxPoolSubcommands,
+    wallet::WalletSubcommands,
 };
 use alloy_ens::NameOrAddress;
 use alloy_primitives::{Address, B256, Selector, U256};
@@ -1043,6 +1044,10 @@ pub enum CastSubcommand {
     #[command(visible_alias = "bi")]
     Bind(BindArgs),
 
+    /// Convert Beacon payload to execution payload.
+    #[command(visible_alias = "b2e")]
+    B2EPayload(B2EPayloadArgs),
+
     /// Get the selector for a function.
     #[command(visible_alias = "si")]
     Sig {