example: Submit raw extrinsic from polkadot.js

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

examples/examples/submit_raw_extrinsic.rs

@@ -0,0 +1,86 @@
+// Copyright 2019-2022 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+//! To run this example, a local polkadot node should be running. Example verified against polkadot v0.9.28-9ffe6e9e3da.
+//!
+//! E.g.
+//! ```bash
+//! curl "https://github.com/paritytech/polkadot/releases/download/v0.9.28/polkadot" --output /usr/local/bin/polkadot --location
+//! polkadot --dev --tmp
+//! ```
+
+use subxt::{
+    tx::SubmittableExtrinsic,
+    OnlineClient,
+    PolkadotConfig,
+};
+
+use sp_keyring::AccountKeyring;
+use subxt::tx::PairSigner;
+
+#[subxt::subxt(runtime_metadata_path = "../artifacts/polkadot_metadata.scale")]
+pub mod polkadot {}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tracing_subscriber::fmt::init();
+
+    // Create a client to communicate with the chain.
+    let api = OnlineClient::<PolkadotConfig>::new().await?;
+
+    // Note: This can be replaced with the extrinsic hex from polkadot.js directly.
+    let extrinsic_hex = {
+        let signer = PairSigner::new(AccountKeyring::Alice.pair());
+        let dest = AccountKeyring::Bob.to_account_id().into();
+
+        let api = OnlineClient::<PolkadotConfig>::new().await?;
+
+        let tx = polkadot::tx()
+            .balances()
+            .transfer(dest, 123_456_789_012_345);
+
+        let signed_tx = api
+            .tx()
+            .create_signed(&tx, &signer, Default::default())
+            .await?;
+        let bytes = signed_tx.encoded();
+        let extrinsic_hex = hex::encode(bytes);
+        println!("Extrinsic hex: {:?}", extrinsic_hex);
+
+        // TODO: Comment this.
+        extrinsic_hex
+        // TODO: Place your extrinsic here
+        // "0x..".to_string()
+    };
+
+    println!("Decoding the extrinsic bytes...");
+    // Obtain the raw bytes from the extrinsic hexadecimal representation.
+    let extrinsic_bytes = hex::decode(extrinsic_hex.trim_start_matches("0x"))?;
+
+    println!("Creating submittable extrinsic from raw bytes...");
+    // The raw bytes are wrapped into `Encoded` to ensure that `scale::encode` calls
+    // will have no effect upon the raw bytes.
+    let extrinsic = SubmittableExtrinsic::from_bytes(api.clone(), extrinsic_bytes);
+
+    println!("Submit extrinsic and wait for success...");
+    let extrinic_events = extrinsic
+        .submit_and_watch()
+        .await?
+        .wait_for_finalized_success()
+        .await?;
+
+    println!("Finding extrinsic event...");
+
+    // This presumes the extrinsic is a transfer one.
+    let transfer_event =
+        extrinic_events.find_first::<polkadot::balances::events::Transfer>()?;
+
+    if let Some(event) = transfer_event {
+        println!("Balance transfer success: {event:?}");
+    } else {
+        println!("Failed to find Balances::Transfer Event");
+    }
+
+    Ok(())
+}