feat: add basic contract support

Cargo.lock

@@ -66,6 +66,16 @@ version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 
+[[package]]
+name = "bincode"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5753e2a71534719bf3f4e57006c3a4f0d2c672a4b676eec84161f763eca87dbf"
+dependencies = [
+ "byteorder",
+ "serde",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -235,6 +245,7 @@ name = "ethers"
 version = "0.1.0"
 dependencies = [
  "async-trait",
+ "bincode",
  "ethabi",
  "ethereum-types",
  "failure",

Cargo.toml

@@ -21,6 +21,7 @@ tiny-keccak = { version = "2.0.2", default-features = false }
 solc = { git = "https://github.com/paritytech/rust_solc "}
 rlp = "0.4.5"
 ethabi = "12.0.0"
+bincode = "1.2.1"
 
 [dev-dependencies]
 tokio = { version = "0.2.21", features = ["macros"] }

examples/contract.rs

@@ -1,6 +1,8 @@
 use ethers::{
+    abi::ParamType,
+    contract::Contract,
     types::{Address, Filter},
-    Contract, HttpProvider, MainnetWallet,
+    HttpProvider, MainnetWallet,
 };
 use std::convert::TryFrom;
 
@@ -10,16 +12,59 @@ async fn main() -> Result<(), failure::Error> {
     let provider = HttpProvider::try_from("http://localhost:8545")?;
 
     // create a wallet and connect it to the provider
-    let client = "15c42bf2987d5a8a73804a8ea72fb4149f88adf73e98fc3f8a8ce9f24fcb7774"
+    let client = "d22cf25d564c3c3f99677f8710b2f045045f16eccd31140c92d6feb18c1169e9"
         .parse::<MainnetWallet>()?
         .connect(&provider);
 
     // Contract should take both provider or a signer
 
-    let contract = Contract::new(
-        "f817796F60D268A36a57b8D2dF1B97B14C0D0E1d".parse::<Address>()?,
-        abi,
-    );
+    // get the contract's address
+    let addr = "683BEE23D79A1D8664dF70714edA966e1484Fd3d".parse::<Address>()?;
 
+    // get the contract's ABI
+    let abi = r#"[{"inputs":[{"internalType":"string","name":"value","type":"string"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"author","type":"address"},{"indexed":false,"internalType":"string","name":"oldValue","type":"string"},{"indexed":false,"internalType":"string","name":"newValue","type":"string"}],"name":"ValueChanged","type":"event"},{"inputs":[],"name":"getValue","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"string","name":"value","type":"string"}],"name":"setValue","outputs":[],"stateMutability":"nonpayable","type":"function"}]"#;
+
+    // instantiate it
+    let contract = Contract::new(&client, serde_json::from_str(abi)?, addr);
+
+    // get the args
+    let event = "ValueChanged(address,string,string)";
+
+    let args = &[ethabi::Token::String("hello!".to_owned())];
+
+    // call the method
+    let tx_hash = contract.method("setValue", args)?.send().await?;
+
+    #[derive(Clone, Debug)]
+    struct ValueChanged {
+        author: Address,
+        old_value: String,
+        new_value: String,
+    }
+
+    let filter = Filter::new().from_block(0).address(addr).event(event);
+    let logs = provider
+        .get_logs(&filter)
+        .await?
+        .into_iter()
+        .map(|log| {
+            // decode the non-indexed data
+            let data = ethabi::decode(&[ParamType::String, ParamType::String], log.data.as_ref())?;
+
+            let author = log.topics[1].into();
+
+            // Unwrap?
+            let old_value = data[0].clone().to_string().unwrap();
+            let new_value = data[1].clone().to_string().unwrap();
+
+            Ok(ValueChanged {
+                old_value,
+                new_value,
+                author,
+            })
+        })
+        .collect::<Result<Vec<_>, ethabi::Error>>()?;
+
+    dbg!(logs);
     Ok(())
 }

examples/local_signer.rs

@@ -7,7 +7,7 @@ async fn main() -> Result<(), failure::Error> {
     let provider = HttpProvider::try_from("http://localhost:8545")?;
 
     // create a wallet and connect it to the provider
-    let client = "15c42bf2987d5a8a73804a8ea72fb4149f88adf73e98fc3f8a8ce9f24fcb7774"
+    let client = "dcf2cbdd171a21c480aa7f53d77f31bb102282b3ff099c78e3118b37348c72f7"
         .parse::<MainnetWallet>()?
         .connect(&provider);
 
@@ -17,10 +17,10 @@ async fn main() -> Result<(), failure::Error> {
         .value(10000);
 
     // send it!
-    let tx = client.sign_and_send_transaction(tx, None).await?;
+    let hash = client.send_transaction(tx, None).await?;
 
     // get the mined tx
-    let tx = client.get_transaction(tx.hash).await?;
+    let tx = client.get_transaction(hash).await?;
 
     let receipt = client.get_transaction_receipt(tx.hash).await?;
 

src/abi.rs

@@ -1,8 +1,10 @@
 //! This module implements extensions to the `ethabi` API.
 //! Taken from: https://github.com/gnosis/ethcontract-rs/blob/master/common/src/abiext.rs
 
-use ethabi::{Event, Function, ParamType};
-use crate::{utils::id, types::Selector};
+pub use ethabi::Contract as Abi;
+pub use ethabi::*;
+
+use crate::{types::Selector, utils::id};
 
 /// Extension trait for `ethabi::Function`.
 pub trait FunctionExt {

src/contract/contract.rs

@@ -0,0 +1,169 @@
+use crate::{
+    abi::{Abi, Function, FunctionExt},
+    providers::JsonRpcClient,
+    signers::{Client, Signer},
+    types::{Address, BlockNumber, Selector, TransactionRequest, H256, U256},
+};
+
+use rustc_hex::ToHex;
+use serde::Deserialize;
+use std::{collections::HashMap, hash::Hash};
+
+/// Represents a contract instance at an address. Provides methods for
+/// contract interaction.
+#[derive(Debug, Clone)]
+pub struct Contract<'a, S, P> {
+    client: &'a Client<'a, S, P>,
+    abi: Abi,
+    address: Address,
+
+    /// A mapping from method signature to a name-index pair for accessing
+    /// functions in the contract ABI. This is used to avoid allocation when
+    /// searching for matching functions by signature.
+    methods: HashMap<Selector, (String, usize)>,
+
+    /// A mapping from event signature to a name-index pair for resolving
+    /// events in the contract ABI.
+    events: HashMap<H256, (String, usize)>,
+}
+
+impl<'a, S, P> Contract<'a, S, P> {
+    /// Creates a new contract from the provided client, abi and address
+    pub fn new(client: &'a Client<'a, S, P>, abi: Abi, address: Address) -> Self {
+        let methods = create_mapping(&abi.functions, |function| function.selector());
+        let events = create_mapping(&abi.events, |event| event.signature());
+
+        Self {
+            client,
+            abi,
+            address,
+            methods,
+            events,
+        }
+    }
+
+    /// Returns a transaction builder for the provided function name. If there are
+    /// multiple functions with the same name due to overloading, consider using
+    /// the `method_hash` method instead, since this will use the first match.
+    pub fn method(
+        &self,
+        name: &str,
+        args: &[ethabi::Token],
+    ) -> Result<Sender<'a, S, P>, ethabi::Error> {
+        // get the function
+        let function = self.abi.function(name)?;
+        self.method_func(function, args)
+    }
+
+    /// Returns a transaction builder for the selected function signature. This should be
+    /// preferred if there are overloaded functions in your smart contract
+    pub fn method_hash(
+        &self,
+        signature: Selector,
+        args: &[ethabi::Token],
+    ) -> Result<Sender<'a, S, P>, ethabi::Error> {
+        let function = self
+            .methods
+            .get(&signature)
+            .map(|(name, index)| &self.abi.functions[name][*index])
+            .ok_or_else(|| ethabi::Error::InvalidName(signature.to_hex::<String>()))?;
+        self.method_func(function, args)
+    }
+
+    fn method_func(
+        &self,
+        function: &Function,
+        args: &[ethabi::Token],
+    ) -> Result<Sender<'a, S, P>, ethabi::Error> {
+        // create the calldata
+        let data = function.encode_input(args)?;
+
+        // create the tx object
+        let tx = TransactionRequest {
+            to: Some(self.address),
+            data: Some(data.into()),
+            ..Default::default()
+        };
+
+        Ok(Sender {
+            tx,
+            client: self.client,
+            block: None,
+        })
+    }
+
+    pub fn address(&self) -> &Address {
+        &self.address
+    }
+
+    pub fn abi(&self) -> &Abi {
+        &self.abi
+    }
+
+    // call events
+    // deploy
+}
+
+pub struct Sender<'a, S, P> {
+    tx: TransactionRequest,
+    client: &'a Client<'a, S, P>,
+    block: Option<BlockNumber>,
+}
+
+impl<'a, S, P> Sender<'a, S, P> {
+    /// Sets the `from` field in the transaction to the provided value
+    pub fn from<T: Into<Address>>(mut self, from: T) -> Self {
+        self.tx.from = Some(from.into());
+        self
+    }
+
+    /// Sets the `gas` field in the transaction to the provided value
+    pub fn gas<T: Into<U256>>(mut self, gas: T) -> Self {
+        self.tx.gas = Some(gas.into());
+        self
+    }
+
+    /// Sets the `gas_price` field in the transaction to the provided value
+    pub fn gas_price<T: Into<U256>>(mut self, gas_price: T) -> Self {
+        self.tx.gas_price = Some(gas_price.into());
+        self
+    }
+
+    /// Sets the `value` field in the transaction to the provided value
+    pub fn value<T: Into<U256>>(mut self, value: T) -> Self {
+        self.tx.value = Some(value.into());
+        self
+    }
+}
+
+impl<'a, S: Signer, P: JsonRpcClient> Sender<'a, S, P> {
+    pub async fn call<T: for<'b> Deserialize<'b>>(self) -> Result<T, P::Error> {
+        self.client.call(self.tx).await
+    }
+
+    pub async fn send(self) -> Result<H256, P::Error> {
+        self.client.send_transaction(self.tx, self.block).await
+    }
+}
+
+/// Utility function for creating a mapping between a unique signature and a
+/// name-index pair for accessing contract ABI items.
+fn create_mapping<T, S, F>(
+    elements: &HashMap<String, Vec<T>>,
+    signature: F,
+) -> HashMap<S, (String, usize)>
+where
+    S: Hash + Eq,
+    F: Fn(&T) -> S,
+{
+    let signature = &signature;
+    elements
+        .iter()
+        .flat_map(|(name, sub_elements)| {
+            sub_elements
+                .iter()
+                .enumerate()
+                .map(move |(index, element)| (signature(element), (name.to_owned(), index)))
+        })
+        .collect()
+}

src/contract/mod.rs

@@ -1,17 +1,2 @@
-use crate::types::Address;
-
-mod abi;
-
-pub struct Contract<ABI> {
-    pub address: Address,
-    pub abi: ABI,
-}
-
-impl<ABI> Contract<ABI> {
-    pub fn new<A: Into<Address>>(address: A, abi: ABI) -> Self {
-        Self {
-            address: address.into(),
-            abi,
-        }
-    }
-}
+mod contract;
+pub use contract::Contract;

src/lib.rs

@@ -18,10 +18,10 @@
 pub mod providers;
 pub use providers::HttpProvider;
 
-mod contract;
+pub mod contract;
 pub use contract::Contract;
 
-mod signers;
+pub(crate) mod signers;
 pub use signers::{AnyWallet, MainnetWallet, Signer};
 
 /// Ethereum related datatypes
@@ -32,3 +32,6 @@ pub use solc;
 
 /// Various utilities
 pub mod utils;
+
+/// ABI utilities
+pub mod abi;

src/providers/mod.rs

@@ -44,7 +44,7 @@ impl<P: JsonRpcClient> Provider<P> {
     /// Connects to a signer and returns a client
     pub fn connect<S: Signer>(&self, signer: S) -> Client<S, P> {
         Client {
-            signer,
+            signer: Some(signer),
             provider: self,
         }
     }
@@ -141,6 +141,14 @@ impl<P: JsonRpcClient> Provider<P> {
 
     // State mutations
 
+    /// Broadcasts the transaction request via the `eth_sendTransaction` API
+    pub async fn call<T: for<'a> Deserialize<'a>>(
+        &self,
+        tx: TransactionRequest,
+    ) -> Result<T, P::Error> {
+        self.0.request("eth_call", Some(tx)).await
+    }
+
     /// Broadcasts the transaction request via the `eth_sendTransaction` API
     pub async fn send_transaction(&self, tx: TransactionRequest) -> Result<TxHash, P::Error> {
         self.0.request("eth_sendTransaction", Some(tx)).await

src/signers/client.rs

@@ -1,7 +1,8 @@
 use crate::{
     providers::{JsonRpcClient, Provider},
     signers::Signer,
-    types::{Address, BlockNumber, Transaction, TransactionRequest},
+    types::{Address, BlockNumber, Overrides, TransactionRequest, TxHash},
+    utils,
 };
 
 use std::ops::Deref;
@@ -9,18 +10,52 @@ use std::ops::Deref;
 #[derive(Clone, Debug)]
 pub struct Client<'a, S, P> {
     pub(crate) provider: &'a Provider<P>,
-    pub(crate) signer: S,
+    pub(crate) signer: Option<S>,
+}
+
+impl<'a, S, P> From<&'a Provider<P>> for Client<'a, S, P> {
+    fn from(provider: &'a Provider<P>) -> Self {
+        Client {
+            provider,
+            signer: None,
+        }
+    }
 }
 
 impl<'a, S: Signer, P: JsonRpcClient> Client<'a, S, P> {
     /// Signs the transaction and then broadcasts its RLP encoding via the `eth_sendRawTransaction`
     /// API
-    pub async fn sign_and_send_transaction(
+    pub async fn send_transaction(
         &self,
         mut tx: TransactionRequest,
         block: Option<BlockNumber>,
-    ) -> Result<Transaction, P::Error> {
-        // TODO: Convert to join'ed futures
+    ) -> Result<TxHash, P::Error> {
+        // if there is no local signer, then the transaction should use the
+        // node's signer which should already be unlocked
+        let signer = if let Some(ref signer) = self.signer {
+            signer
+        } else {
+            return self.provider.send_transaction(tx).await;
+        };
+
+        // fill any missing fields
+        self.fill_transaction(&mut tx, block).await?;
+
+        // sign the transaction
+        let signed_tx = signer.sign_transaction(tx).unwrap(); // TODO
+
+        // broadcast it
+        self.provider.send_raw_transaction(&signed_tx).await?;
+
+        Ok(signed_tx.hash)
+    }
+
+    // TODO: Convert to join'ed futures
+    async fn fill_transaction(
+        &self,
+        tx: &mut TransactionRequest,
+        block: Option<BlockNumber>,
+    ) -> Result<(), P::Error> {
         // get the gas price
         if tx.gas_price.is_none() {
             tx.gas_price = Some(self.provider.get_gas_price().await?);
@@ -41,17 +76,48 @@ impl<'a, S: Signer, P: JsonRpcClient> Client<'a, S, P> {
             );
         }
 
-        // sign the transaction
-        let signed_tx = self.signer.sign_transaction(tx).unwrap(); // TODO
+        Ok(())
+    }
 
-        // broadcast it
-        self.provider.send_raw_transaction(&signed_tx).await?;
+    /// client.call_contract(
+    ///     addr,
+    ///     "transfer(address,uint256)"
+    ///     vec![0x1234, 100]
+    ///     None,
+    ///     None,
+    /// )
+    pub async fn call_contract(
+        &self,
+        to: impl Into<Address>,
+        signature: &str,
+        args: &[ethabi::Token],
+        overrides: Option<Overrides>,
+        block: Option<BlockNumber>,
+    ) -> Result<TxHash, P::Error> {
+        // create the data field from the function signature and the arguments
+        let data = [&utils::id(signature)[..], &ethabi::encode(args)].concat();
 
-        Ok(signed_tx)
+        let overrides = overrides.unwrap_or_default();
+        let tx = TransactionRequest {
+            to: Some(to.into()),
+            data: Some(data.into()),
+
+            // forward the overriden data
+            from: overrides.from, // let it figure it out itself
+            gas: overrides.gas,
+            gas_price: overrides.gas_price,
+            nonce: overrides.nonce,
+            value: overrides.value,
+        };
+
+        self.send_transaction(tx, block).await
     }
 
     pub fn address(&self) -> Address {
-        self.signer.address()
+        self.signer
+            .as_ref()
+            .map(|s| s.address())
+            .unwrap_or_default()
     }
 }
 

src/signers/wallet.rs

@@ -52,7 +52,7 @@ impl<N: Network> Wallet<N> {
     /// Connects to a provider and returns a client
     pub fn connect<P: JsonRpcClient>(self, provider: &Provider<P>) -> Client<Wallet<N>, P> {
         Client {
-            signer: self,
+            signer: Some(self),
             provider,
         }
     }

src/types/bytes.rs

@@ -12,6 +12,12 @@ pub struct Bytes(
     pub Vec<u8>,
 );
 
+impl AsRef<[u8]> for Bytes {
+    fn as_ref(&self) -> &[u8] {
+        &self.0[..]
+    }
+}
+
 impl Bytes {
     /// Returns an empty bytes vector
     pub fn new() -> Self {

src/types/mod.rs

@@ -7,7 +7,7 @@ pub use ethereum_types::H256 as TxHash;
 pub use ethereum_types::{Address, Bloom, H256, U256, U64};
 
 mod transaction;
-pub use transaction::{Transaction, TransactionReceipt, TransactionRequest};
+pub use transaction::{Overrides, Transaction, TransactionReceipt, TransactionRequest};
 
 mod keys;
 pub use keys::{PrivateKey, PublicKey, TxError};
@@ -23,5 +23,3 @@ pub use block::{Block, BlockId, BlockNumber};
 
 mod log;
 pub use log::{Filter, Log};
-
-

src/types/transaction.rs

@@ -7,6 +7,31 @@ use rlp::RlpStream;
 use serde::{Deserialize, Serialize};
 use std::str::FromStr;
 
+/// Override params for interacting with a contract
+#[derive(Clone, Default, Serialize, Deserialize, PartialEq, Eq, Debug)]
+pub struct Overrides {
+    /// Sender address or ENS name
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) from: Option<Address>,
+
+    /// Supplied gas (None for sensible default)
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) gas: Option<U256>,
+
+    /// Gas price (None for sensible default)
+    #[serde(rename = "gasPrice")]
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) gas_price: Option<U256>,
+
+    /// Transfered value (None for no transfer)
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) value: Option<U256>,
+
+    /// Transaction nonce (None for next available nonce)
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) nonce: Option<U256>,
+}
+
 /// Parameters for sending a transaction
 #[derive(Clone, Default, Serialize, Deserialize, PartialEq, Eq, Debug)]
 pub struct TransactionRequest {

src/utils.rs

@@ -1,5 +1,5 @@
 //! Various utilities for manipulating Ethereum related dat
-use crate::types::{H256, Selector};
+use crate::types::{Selector, H256};
 use tiny_keccak::{Hasher, Keccak};
 
 const PREFIX: &str = "\x19Ethereum Signed Message:\n";