add eth_balance and eth_accounts

examples/transfer_eth.rs

@@ -8,7 +8,8 @@ use std::convert::TryFrom;
 async fn main() -> Result<(), failure::Error> {
     // connect to the network
     let provider = HttpProvider::try_from("http://localhost:8545")?;
-    let from = "784C1bA9846aB4CE78E9CFa27884E29dd31d593A".parse()?;
+    let accounts = provider.get_accounts().await?;
+    let from = accounts[0];
 
     // craft the tx
     let tx = TransactionRequest {
@@ -21,6 +22,8 @@ async fn main() -> Result<(), failure::Error> {
         nonce: None,
     };
 
+    let balance_before = provider.get_balance(from, None).await?;
+
     // broadcast it via the eth_sendTransaction API
     let tx_hash = provider.send_transaction(tx).await?;
 
@@ -38,5 +41,11 @@ async fn main() -> Result<(), failure::Error> {
 
     assert!(nonce2 < nonce1);
 
+    let balance_after = provider.get_balance(from, None).await?;
+    assert!(balance_after < balance_before);
+
+    println!("Balance before {}", balance_before);
+    println!("Balance after {}", balance_after);
+
     Ok(())
 }

src/providers/mod.rs

@@ -46,6 +46,11 @@ impl<P: JsonRpcClient> Provider<P> {
         }
     }
 
+    /// Gets the accounts on the node
+    pub async fn get_accounts(&self) -> Result<Vec<Address>, P::Error> {
+        self.0.request("eth_accounts", None::<()>).await
+    }
+
     /// Gets the latest block number via the `eth_BlockNumber` API
     pub async fn get_block_number(&self) -> Result<U256, P::Error> {
         self.0.request("eth_blockNumber", None::<()>).await
@@ -71,6 +76,8 @@ impl<P: JsonRpcClient> Provider<P> {
         self.0.request("eth_sendRawTransaction", Some(rlp)).await
     }
 
+    // Account state
+
     pub async fn get_transaction_count(
         &self,
         from: Address,
@@ -82,4 +89,14 @@ impl<P: JsonRpcClient> Provider<P> {
             .request("eth_getTransactionCount", Some(&[from, block]))
             .await
     }
+
+    pub async fn get_balance(
+        &self,
+        from: Address,
+        block: Option<BlockNumber>,
+    ) -> Result<U256, P::Error> {
+        let from = utils::serialize(&from);
+        let block = utils::serialize(&block.unwrap_or(BlockNumber::Latest));
+        self.0.request("eth_getBalance", Some(&[from, block])).await
+    }
 }