Add an RPC method for calling a contract. (#3563)

* Sketch

* Some work on docs.

* Doc improvements.

* More docs.

* Some more docs.

* Yet another comment.

* Bump impl_version.

* Accept the block hash

* Use NumberOrHex

* Update node/rpc/src/contracts.rs

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Move rpc/primitives

substrate/core/rpc/Cargo.toml

@@ -17,6 +17,7 @@ runtime_version = { package = "sr-version", path = "../sr-version" }
 serde_json = "1.0"
 session = { package = "substrate-session", path = "../session" }
 sr-primitives = { path = "../sr-primitives" }
+rpc-primitives = { package = "substrate-rpc-primitives", path = "primitives" }
 state_machine = { package = "substrate-state-machine", path = "../state-machine" }
 substrate-executor = { path = "../executor" }
 substrate-keystore = { path = "../keystore" }

substrate/core/rpc/api/Cargo.toml

@@ -19,3 +19,4 @@ runtime_version = { package = "sr-version", path = "../../sr-version" }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 txpool = { package = "substrate-transaction-graph", path = "../../transaction-pool/graph" }
+rpc-primitives = { package = "substrate-rpc-primitives", path = "../../rpc/primitives" }

substrate/core/rpc/api/src/chain/mod.rs

@@ -17,12 +17,12 @@
 //! Substrate blockchain API.
 
 pub mod error;
-pub mod number;
 
 use jsonrpc_core::Result as RpcResult;
 use jsonrpc_core::futures::Future;
 use jsonrpc_derive::rpc;
 use jsonrpc_pubsub::{typed::Subscriber, SubscriptionId};
+use rpc_primitives::number;
 use self::error::{FutureResult, Result};
 
 pub use self::gen_client::Client as ChainClient;

substrate/core/rpc/primitives/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "substrate-rpc-primitives"
+version = "2.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"] }
+primitives = { package = "substrate-primitives", path = "../../primitives" }

substrate/core/rpc/primitives/src/lib.rs

@@ -0,0 +1,21 @@
+// Copyright 2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Substrate RPC primitives and utilities.
+
+#![warn(missing_docs)]
+
+pub mod number;

substrate/core/rpc/src/chain/mod.rs

@@ -37,6 +37,7 @@ use client::{
 };
 use jsonrpc_pubsub::{typed::Subscriber, SubscriptionId};
 use primitives::{H256, Blake2Hasher};
+use rpc_primitives::number;
 use sr_primitives::{
 	generic::{BlockId, SignedBlock},
 	traits::{Block as BlockT, Header, NumberFor},