Fix cli/browser.rs and allow selecting a chainspec on wasm. (#815)

* Fix browser.rs

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

polkadot/Cargo.lock

@@ -3753,7 +3753,6 @@ dependencies = [
  "sc-client-api 2.0.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",
  "sc-client-db 0.8.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",
  "sc-executor 0.8.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",
- "sc-service 0.8.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",
  "sp-api 2.0.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",
  "sp-core 2.0.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",
  "sp-runtime 2.0.0 (git+https://github.com/paritytech/substrate?branch=polkadot-master)",

polkadot/cli/Cargo.toml

@@ -12,7 +12,7 @@ crate-type = ["cdylib", "rlib"]
 log = "0.4.8"
 futures = { version = "0.3.1", features = ["compat"] }
 structopt = "0.3.8"
-sc-cli = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
+sc-cli = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master", optional = true }
 sp-api = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "polkadot-master" }
@@ -27,16 +27,17 @@ tokio = { version = "0.2.10", features = ["rt-threaded"], optional = true }
 wasm-bindgen = { version = "0.2.57", optional = true }
 wasm-bindgen-futures = { version = "0.4.7", optional = true }
 browser-utils = { package = "browser-utils", git = "https://github.com/paritytech/substrate", branch = "polkadot-master", optional = true }
-substrate-service = { package = "sc-service", git = "https://github.com/paritytech/substrate", branch = "polkadot-master", optional = true, default-features = false }
 
 [features]
 default = [ "wasmtime", "rocksdb", "cli" ]
 wasmtime = [ "sc-cli/wasmtime" ]
 rocksdb = [ "service/rocksdb" ]
-cli = [ "tokio" ]
+cli = [
+	"tokio",
+	"sc-cli",
+]
 browser = [
 	"wasm-bindgen",
 	"wasm-bindgen-futures",
 	"browser-utils",
-	"substrate-service",
 ]

polkadot/cli/browser-demo/index.html

@@ -19,7 +19,7 @@ async function start() {
 
 	// Build our client.
 	log('Starting client');
-	let client = await start_client(ws());
+	let client = await start_client('westend', ws());
 	log('Client started');
 
 	client.rpcSubscribe('{"method":"chain_subscribeNewHead","params":[],"id":1,"jsonrpc":"2.0"}',

polkadot/cli/src/browser.rs

@@ -16,44 +16,48 @@
 
 use crate::ChainSpec;
 use log::info;
-use substrate_service::Configuration;
 use wasm_bindgen::prelude::*;
-use service::CustomConfiguration;
+use service::IsKusama;
 
 /// Starts the client.
 ///
 /// You must pass a libp2p transport that supports .
 #[wasm_bindgen]
-pub async fn start_client(wasm_ext: browser_utils::Transport) -> Result<browser_utils::Client, JsValue> {
+pub async fn start_client(chain_spec: String, wasm_ext: browser_utils::Transport) -> Result<browser_utils::Client, JsValue> {
-	start_inner(wasm_ext)
+	start_inner(chain_spec, wasm_ext)
 		.await
 		.map_err(|err| JsValue::from_str(&err.to_string()))
 }
 
-async fn start_inner(wasm_ext: browser_utils::Transport) -> Result<browser_utils::Client, Box<dyn std::error::Error>> {
+async fn start_inner(chain_spec: String, wasm_ext: browser_utils::Transport) -> Result<browser_utils::Client, Box<dyn std::error::Error>> {
 	browser_utils::set_console_error_panic_hook();
 	browser_utils::init_console_log(log::Level::Info)?;
 
-	let chain_spec = ChainSpec::Kusama.load().map_err(|e| format!("{:?}", e))?;
+	let chain_spec = ChainSpec::from(&chain_spec)
-	let config: Configuration<CustomConfiguration, _, _> = browser_utils::browser_configuration(wasm_ext, chain_spec)
+		.ok_or_else(|| format!("Chain spec: {:?} doesn't exist.", chain_spec))?
+		.load()
+		.map_err(|e| format!("{:?}", e))?;
+	let config = browser_utils::browser_configuration(wasm_ext, chain_spec)
 		.await?;
 
 	info!("Polkadot browser node");
 	info!("  version {}", config.full_version());
 	info!("  by Parity Technologies, 2017-2019");
-	info!("Chain specification: {}", config.chain_spec.name());
+	if let Some(chain_spec) = &config.chain_spec {
-	if config.chain_spec.name().starts_with("Kusama") {
+		info!("Chain specification: {}", chain_spec.name());
+		if chain_spec.is_kusama() {
 			info!("----------------------------");
 			info!("This chain is not in any way");
 			info!("      endorsed by the       ");
 			info!("     KUSAMA FOUNDATION      ");
 			info!("----------------------------");
 		}
+	}
 	info!("Node name: {}", config.name);
 	info!("Roles: {:?}", config.roles);
 
 	// Create the service. This is the most heavy initialization step.
-	let service = service::kusama_new_light(config).map_err(|e| format!("{:?}", e))?;
+	let service = service::kusama_new_light(config, None).map_err(|e| format!("{:?}", e))?;
 
 	Ok(browser_utils::start_client(service))
 }