docs: add docs to ethers-providers

crates/ethers-providers/Cargo.toml

@@ -17,4 +17,4 @@ url = { version = "2.1.1", default-features = false }
 
 [dev-dependencies]
 rustc-hex = "2.1.0"
-tokio = { version = "0.2.21", features = ["macros"] }
+tokio = { version = "0.2.21", default-features = false, features = ["rt-core", "macros"] }

crates/ethers-providers/src/ens.rs

@@ -1,3 +1,4 @@
+/// [Ethereum Name Service](https://docs.ens.domains/) support
 // Adapted from https://github.com/hhatto/rust-ens/blob/master/src/lib.rs
 use ethers_types::{Address, NameOrAddress, Selector, TransactionRequest, H256};
 use ethers_utils::keccak256;
@@ -6,13 +7,13 @@ use ethers_utils::keccak256;
 
 const ENS_REVERSE_REGISTRAR_DOMAIN: &str = "addr.reverse";
 
-// resolver(bytes32)
+/// resolver(bytes32)
 const RESOLVER: Selector = [1, 120, 184, 191];
 
-// addr(bytes32)
+/// addr(bytes32)
 pub const ADDR_SELECTOR: Selector = [59, 59, 87, 222];
 
-// name(bytes32)
+/// name(bytes32)
 pub const NAME_SELECTOR: Selector = [105, 31, 52, 49];
 
 /// Returns a transaction request for calling the `resolver` method on the ENS server
@@ -26,6 +27,7 @@ pub fn get_resolver<T: Into<Address>>(ens_address: T, name: &str) -> Transaction
     }
 }
 
+/// Returns a transaction request for calling
 pub fn resolve<T: Into<Address>>(
     resolver_address: T,
     selector: Selector,

crates/ethers-providers/src/lib.rs

@@ -1,16 +1,59 @@
-//! Ethereum compatible providers
+//! # Clients for interacting with Ethereum nodes
-//! Currently supported:
-//! - Raw HTTP POST requests
 //!
-//! TODO: WebSockets, multiple backends, popular APIs etc.
+//! This crate provides asynchronous [Ethereum JSON-RPC](https://github.com/ethereum/wiki/wiki/JSON-RPC)
+//! compliant clients. The client is network-specific in order to provide ENS support and EIP-155
+//! replay protection. If you are testing and do not want to use EIP-155, you may use the `Any`
+//! network type and override the provider's ENS address with the `ens` method.
+//!
+//! ```rust
+//! use ethers_providers::{HttpProvider, networks::Any};
+//! use std::convert::TryFrom;
+//! use tokio::runtime::Runtime;
+//!
+//! let provider = HttpProvider::<Any>::try_from(
+//!     "https://mainnet.infura.io/v3/9408f47dedf04716a03ef994182cf150"
+//! ).unwrap();
+//!
+//! // Since this is an async function, we need to run it from an async runtime,
+//! // such as `tokio`
+//! let mut runtime = Runtime::new().expect("Failed to create Tokio runtime");
+//! let block = runtime.block_on(provider.get_block(100u64)).unwrap();
+//! println!("Got block: {}", serde_json::to_string(&block).unwrap());
+//! ```
+//!
+//! # Ethereum Name Service
+//!
+//! The provider may also be used to resolve [Ethereum Name Service](https://ens.domains) (ENS) names
+//! to addresses (and vice versa). The address of the deployed ENS contract per network is specified in
+//! the `networks` module. If you want to use mainnet ENS, you should instantiate your provider as
+//! follows:
+//!
+//! ```rust
+//! # use ethers_providers::{HttpProvider, networks::Mainnet};
+//! # use std::convert::TryFrom;
+//! # use tokio::runtime::Runtime;
+//! # let provider = HttpProvider::<Mainnet>::try_from(
+//! #     "https://mainnet.infura.io/v3/9408f47dedf04716a03ef994182cf150"
+//! # ).unwrap();
+//! # let mut runtime = Runtime::new().expect("Failed to create Tokio runtime");
+//! // Resolve ENS name to Address
+//! let name = "vitalik.eth";
+//! let address = runtime.block_on(provider.resolve_name(name)).unwrap();
+//! let address = address.unwrap();
+//!
+//! // Lookup ENS name given Address
+//! let resolved_name = runtime.block_on(provider.lookup_address(address)).unwrap();
+//! let resolved_name = resolved_name.unwrap();
+//! assert_eq!(name, resolved_name);
+//! ```
 
 mod http;
 mod provider;
 
 pub mod networks;
 
-/// ENS support
+// ENS support
-pub mod ens;
+mod ens;
 
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
@@ -22,11 +65,13 @@ pub use provider::Provider;
 pub type HttpProvider<N> = Provider<http::Provider, N>;
 
 #[async_trait]
-/// Implement this trait in order to plug in different backends
+/// Trait which must be implemented by data transports to be used with the Ethereum
+/// JSON-RPC provider.
 pub trait JsonRpcClient: Debug {
+    /// A JSON-RPC Error
     type Error: Error;
 
-    /// Sends a request with the provided method and the params serialized as JSON
+    /// Sends a request with the provided JSON-RPC and parameters serialized as JSON
     async fn request<T: Serialize + Send + Sync, R: for<'a> Deserialize<'a>>(
         &self,
         method: &str,

crates/ethers-providers/src/networks.rs

@@ -1,16 +1,21 @@
-//! Networks are used inside wallets to ensure type-safety across networks. That way
+//! Networks are used inside wallets and providers to ensure replay protection across networks,
-//! a transaction that is designed to work with testnet does not accidentally work
+//! as well as to allow functions to be called with ENS names instead of Addresses.
-//! with mainnet because the URL was changed.
-
 use ethers_types::{Address, H160, U64};
 
+/// Trait for specifying network specific metadata, such as the Chain Id or the ENS
+/// address.
 pub trait Network {
+    /// The network's Chain Id. If None, then EIP-155 is not used and as a result
+    /// transactions **will not have replay protection**
     const CHAIN_ID: Option<U64>;
+
+    /// The network's ENS address.
     const ENS_ADDRESS: Option<Address>;
 
     // TODO: Default providers? e.g. `mainnet.infura.io/XXX`?
 }
 
+/// Ethereum Mainnet, pre-specified ENS address and ChainID = 1 (for EIP-155)
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct Mainnet;
 
@@ -24,7 +29,9 @@ impl Network for Mainnet {
     ]));
 }
 
-/// No EIP155
+/// Any other network, ChainID is not specified so **there is no replay protection when
+/// using this network type**. ENS is also not specified, so any calls to the provider's
+/// `lookup_address` and `resolve_name` _will fail_.
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct Any;
 

crates/ethers-providers/src/provider.rs

@@ -13,7 +13,9 @@ use url::{ParseError, Url};
 use std::{convert::TryFrom, fmt::Debug, marker::PhantomData};
 
 /// An abstract provider for interacting with the [Ethereum JSON RPC
-/// API](https://github.com/ethereum/wiki/wiki/JSON-RPC)
+/// API](https://github.com/ethereum/wiki/wiki/JSON-RPC). Must be instantiated
+/// with a [`Network`](networks/trait.Network.html) and a data transport
+/// (e.g. HTTP, Websockets etc.)
 #[derive(Clone, Debug)]
 pub struct Provider<P, N>(P, PhantomData<N>, Option<Address>);
 
@@ -204,6 +206,10 @@ impl<P: JsonRpcClient, N: Network> Provider<P, N> {
     }
 
     /// Returns the ENS name the `address` resolves to (or None if not configured).
+    /// # Panics
+    ///
+    /// If the bytes returned from the ENS registrar/resolver cannot be interpreted as
+    /// a string. This should theoretically never happen.
     pub async fn lookup_address(&self, address: Address) -> Result<Option<String>, P::Error> {
         let ens_name = ens::reverse_address(address);
         self.query_resolver(ParamType::String, &ens_name, ens::NAME_SELECTOR)
@@ -244,6 +250,7 @@ impl<P: JsonRpcClient, N: Network> Provider<P, N> {
         Ok(Some(decode_bytes(param, data)))
     }
 
+    /// Overrides the default ENS address set by the provider's `Network` type.
     pub fn ens<T: Into<Address>>(mut self, ens: T) -> Self {
         self.2 = Some(ens.into());
         self

crates/ethers-types/src/chainstate/block.rs

@@ -74,6 +74,12 @@ pub enum BlockId {
     Number(BlockNumber),
 }
 
+impl From<u64> for BlockId {
+    fn from(num: u64) -> Self {
+        BlockNumber::Number(num.into()).into()
+    }
+}
+
 impl From<U64> for BlockId {
     fn from(num: U64) -> Self {
         BlockNumber::Number(num).into()