feat(contract): interact using ContractInstance

Cargo.toml

@@ -101,3 +101,5 @@ tokio = "1"
 
 # misc
 eyre = "0.6.12"
+serde_json = "1.0.117"
+const-hex = "1.12.0"

README.md

@@ -31,6 +31,7 @@ This repository contains the following examples:
   - [x] [Math operations](./examples/big-numbers/examples/math_operations.rs)
   - [x] [Math utilities](./examples/big-numbers/examples/math_utilities.rs)
 - [x] Contracts
+  - [x] [Interact using contract instance](./examples/contracts/examples/contract_instance.rs)
   - [x] [Deploy from artifact](./examples/contracts/examples/deploy_from_artifact.rs)
   - [x] [Deploy from bytecode](./examples/contracts/examples/deploy_from_bytecode.rs)
   - [x] [Deploy from contract](./examples/contracts/examples/deploy_from_contract.rs)

examples/contracts/Cargo.toml

@@ -17,3 +17,5 @@ alloy.workspace = true
 
 eyre.workspace = true
 tokio = { workspace = true, features = ["macros", "rt-multi-thread"] }
+serde_json.workspace = true
+const-hex.workspace = true

examples/contracts/examples/contract_instance.rs

@@ -0,0 +1,94 @@
+//! This example demonstrates how to interact with a contract that is already deployed onchain using
+//! the `ContractInstance` interface.
+use alloy::{
+    contract::{ContractInstance, Interface},
+    dyn_abi::DynSolValue,
+    network::{Ethereum, TransactionBuilder},
+    primitives::U256,
+    providers::{Provider, ProviderBuilder},
+    rpc::types::TransactionRequest,
+    transports::http::{Client, Http},
+};
+use const_hex as hex;
+use eyre::Result;
+
+/**
+* solc v0.8.26; solc a.sol --via-ir --optimize --bin
+* contract Counter {
+       uint256 public number;
+
+       function setNumber(uint256 newNumber) public {
+           number = newNumber;
+       }
+
+       function increment() public {
+           number++;
+       }
+   }
+*
+*/
+#[tokio::main]
+async fn main() -> Result<()> {
+    let provider = ProviderBuilder::new().with_recommended_fillers().on_anvil_with_wallet();
+
+    // Deploy the Counter contract
+    let bytecode = hex::decode("6080806040523460135760df908160198239f35b600080fdfe6080806040526004361015601257600080fd5b60003560e01c9081633fb5c1cb1460925781638381f58a146079575063d09de08a14603c57600080fd5b3460745760003660031901126074576000546000198114605e57600101600055005b634e487b7160e01b600052601160045260246000fd5b600080fd5b3460745760003660031901126074576020906000548152f35b34607457602036600319011260745760043560005500fea2646970667358221220e978270883b7baed10810c4079c941512e93a7ba1cd1108c781d4bc738d9090564736f6c634300081a0033")?;
+    let deploy_tx = TransactionRequest::default().with_deploy_code(bytecode);
+
+    let contract_address =
+        provider.send_transaction(deploy_tx).await?.get_receipt().await?.contract_address.unwrap();
+
+    // Get the contract abi
+    let path = std::env::current_dir()?.join("examples/contracts/examples/artifacts/Counter.json");
+
+    // Read the artifact which contains `abi`, `bytecode`, `deployedBytecode`,and `metadata`
+    let artifact = std::fs::read(path).unwrap();
+    let json: serde_json::Value = serde_json::from_slice(&artifact)?;
+
+    // Get `abi` from the artifact
+    let abi_val = json.get("abi").unwrap();
+    let abi = serde_json::from_str(&abi_val.to_string())?;
+
+    // Create a new `ContractInstance` of the Counter contract from the abi
+    let counter_instance: ContractInstance<Http<Client>, _, Ethereum> =
+        ContractInstance::new(contract_address, provider.clone(), Interface::new(abi));
+
+    // Interact with the contract
+    assert_eq!(counter_instance.abi().functions().count(), 3);
+
+    // Read
+    let init_val = counter_instance.function("number", &[])?.call().await?;
+
+    // Get the Uint value from the result
+    let init_val = init_val.first().unwrap().as_uint().unwrap().0;
+
+    assert_eq!(U256::from(0), init_val);
+
+    // Increment
+    let incr_receipt =
+        counter_instance.function("increment", &[])?.send().await?.get_receipt().await?;
+
+    assert!(incr_receipt.status());
+
+    let incremented_val = counter_instance.function("number", &[])?.call().await?;
+
+    let incremented_val = incremented_val.first().unwrap().as_uint().unwrap().0;
+
+    assert_eq!(U256::from(1), incremented_val);
+
+    // Set the number
+    let set_val = DynSolValue::from(U256::from(100));
+
+    let set_receipt =
+        counter_instance.function("setNumber", &[set_val])?.send().await?.get_receipt().await?;
+
+    assert!(set_receipt.status());
+
+    let set_val = counter_instance.function("number", &[])?.call().await?;
+
+    let set_val = set_val.first().unwrap().as_uint().unwrap().0;
+
+    assert_eq!(U256::from(100), set_val);
+
+    Ok(())
+}