Improve Signed Extension and Block Decoding Examples/Book (#1357)

* asset hub example and book adjustment * formatting * recursive derives * polkadot monitor example and book adjustments * formatting * adjust docs and examples, add dynamic example * james suggestions * fmt * chore(subxt/src): typo fix (#1370) * rpcmethods * followstr * mod and else * Weekly Cronjob fetching artifacts and generating polkadot.rs file. (#1352) * github CI action cronjob * add commit message * fix the CI yml files * binary crate for CI script with substrate-runner * update the CI script * correct the artifacts script * remove bash script --------- Co-authored-by: James Wilson <james@jsdw.me> Co-authored-by: Pan chao <152830401+Pan-chao@users.noreply.github.com>
2026-05-09 22:18:00 +00:00 · 2024-01-18 16:39:17 +01:00
parent e36f4ad270
commit 05825bed49
7 changed files with 243 additions and 15 deletions
@@ -0,0 +1,46 @@
+#![allow(missing_docs)]
+use subxt::{OnlineClient, PolkadotConfig};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Create a client that subscribes to blocks of the Polkadot network.
+    let api = OnlineClient::<PolkadotConfig>::from_url("wss://rpc.polkadot.io:443").await?;
+
+    // Subscribe to all finalized blocks:
+    let mut blocks_sub = api.blocks().subscribe_finalized().await?;
+    while let Some(block) = blocks_sub.next().await {
+        let block = block?;
+        let block_number = block.header().number;
+        let block_hash = block.hash();
+        println!("Block #{block_number}  ({block_hash})");
+
+        // Decode each signed extrinsic in the block dynamically
+        let extrinsics = block.extrinsics().await?;
+        for ext in extrinsics.iter() {
+            let ext = ext?;
+
+            let Some(signed_extensions) = ext.signed_extensions() else {
+                continue; // we do not look at inherents in this example
+            };
+
+            let meta = ext.extrinsic_metadata()?;
+            let fields = ext.field_values()?;
+
+            println!("  {}/{}", meta.pallet.name(), meta.variant.name);
+            println!("    Signed Extensions:");
+            for signed_ext in signed_extensions.iter() {
+                let signed_ext = signed_ext?;
+                // We only want to take a look at these 3 signed extensions, because the others all just have unit fields.
+                if ["CheckMortality", "CheckNonce", "ChargeTransactionPayment"]
+                    .contains(&signed_ext.name())
+                {
+                    println!("      {}: {}", signed_ext.name(), signed_ext.value()?);
+                }
+            }
+            println!("    Fields:");
+            println!("      {}\n", fields);
+        }
+    }
+
+    Ok(())
+}