Use new MetaMask "ethereum" provider (#366)

lib/accountService.ts

@@ -1,7 +1,9 @@
+import { promisify } from "es6-promisify";
 import { Address } from "./commonTypes";
 import { LoggingService } from "./loggingService";
 import { IEventSubscription, PubSubEventService } from "./pubSubEventService";
-import { Utils } from "./utils";
+import { Utils, Web3 } from "./utils";
+import { UtilsInternal } from "./utilsInternal";
 
 /**
  * Watch for changes in the default account.
@@ -11,6 +13,7 @@ import { Utils } from "./utils";
 export class AccountService {
 
   public static AccountChangedEventTopic: string = "AccountService.account.changed";
+  public static NetworkChangedEventTopic: string = "AccountService.network.changed";
 
   /**
    * Initializes the system that watches for default account changes.
@@ -20,9 +23,6 @@ export class AccountService {
    *
    * Then you may request to be notified whenever the current account changes by calling
    * [AccountService.subscribeToAccountChanges](/api/classes/AccountService#subscribeToAccountChanges)
-   *
-   *
-   * @param web3
    */
   public static async initiateAccountWatch(): Promise<void> {
 
@@ -63,6 +63,56 @@ export class AccountService {
     }, 1000);
   }
 
+  /**
+   * Initializes the system that watches for blockchain network id changes.
+   *
+   * `initiateNetworkWatch` is called automatically by Arc.js when you pass `true`
+   * for `watchForNetworkChanges` to `InitializeArcJs`.  You may also call it manually yourself.
+   *
+   * Then you may request to be notified whenever the current account changes by calling
+   * [AccountService.subscribeToNetworkChanges](/api/classes/AccountService#subscribeToNetworkChanges)
+   *
+   * When the network is found to have changed you should call `InitializeArcJs` so Arc.js will set
+   * itself up with the new network and return to you a new `Web3` object.
+   */
+  public static async initiateNetworkWatch(): Promise<void> {
+
+    if (AccountService.networkChangedTimerId) {
+      return;
+    }
+
+    LoggingService.info("Initiating account watch");
+
+    if (!AccountService.currentNetworkId) {
+      try {
+        AccountService.currentNetworkId = await AccountService.getNetworkId();
+      } catch {
+        AccountService.currentNetworkId = undefined;
+      }
+    }
+
+    AccountService.networkChangedTimerId = setInterval(async () => {
+
+      if (AccountService.networkChangedLock) {
+        return; // prevent reentrance
+      }
+
+      AccountService.networkChangedLock = true;
+
+      let currentNetworkId = AccountService.currentNetworkId;
+      try {
+        currentNetworkId = await AccountService.getNetworkId();
+      } catch {
+        currentNetworkId = undefined;
+      }
+      if (currentNetworkId !== AccountService.currentNetworkId) {
+        AccountService.currentNetworkId = currentNetworkId;
+        LoggingService.info(`Network watch: network changed: ${currentNetworkId}`);
+        PubSubEventService.publish(AccountService.NetworkChangedEventTopic, currentNetworkId);
+      }
+      AccountService.networkChangedLock = false;
+    }, 1000);
+  }
   /**
    * Turn off the system that watches for default account changes.
    */
@@ -73,11 +123,20 @@ export class AccountService {
     }
   }
 
+  /**
+   * Turn off the system that watches for default account changes.
+   */
+  public static endNetworkWatch(): void {
+    if (AccountService.networkChangedTimerId) {
+      clearInterval(AccountService.networkChangedTimerId);
+      AccountService.networkChangedTimerId = undefined;
+    }
+  }
   /**
    * Subscribe to be notified whenever the current account changes, like this:
    *
-   * ```javascript
-   * AccountService.subscribeToAccountChanges((account: Address) => { ... });
+   * ```typescript
+   * AccountService.subscribeToAccountChanges((account: Address): void => { ... });
    * ```
    * @param callback
    * @returns A subscription to the event.  Unsubscribe by calling `[theSubscription].unsubscribe()`.
@@ -87,7 +146,30 @@ export class AccountService {
       (topic: string, address: Address): any => callback(address));
   }
 
+  /**
+   * Subscribe to be notified whenever the current network changes, like this:
+   *
+   * ```typescript
+   * AccountService.subscribeToAccountChanges((networkId: number): void => { ... });
+   * ```
+   * @param callback
+   * @returns A subscription to the event.  Unsubscribe by calling `[theSubscription].unsubscribe()`.
+   */
+  public static subscribeToNetworkChanges(callback: (networkId: number) => void): IEventSubscription {
+    return PubSubEventService.subscribe(AccountService.NetworkChangedEventTopic,
+      (topic: string, networkId: number): any => callback(networkId));
+  }
+
   private static currentAccount: Address | undefined;
+  private static currentNetworkId: number | undefined;
   private static accountChangedLock: boolean = false;
   private static accountChangedTimerId: any;
+  private static networkChangedLock: boolean = false;
+  private static networkChangedTimerId: any;
+
+  private static async getNetworkId(): Promise<number | undefined> {
+    const web3 = UtilsInternal.getWeb3Sync();
+    return web3 ?
+      Number.parseInt(await promisify(web3.version.getNetwork)() as string, 10) as number | undefined : undefined;
+  }
 }

lib/contractWrapperFactory.ts

@@ -18,6 +18,10 @@ export class ContractWrapperFactory<TWrapper extends IContractWrapper>
     ContractWrapperFactory.configService = configService;
   }
 
+  public static clearContractCache(): void {
+    ContractWrapperFactory.contractCache.clear();
+  }
+
   /**
    * this is a Map keyed by contract name of a Map keyed by address to an `IContractWrapper`
    */

lib/index.ts

@@ -64,31 +64,58 @@ import { WrapperService, WrapperServiceInitializeOptions } from "./wrapperServic
  * Options for [InitializeArcJs](/api/README/#initializearcjs)
  */
 export interface InitializeArcOptions extends WrapperServiceInitializeOptions {
+  /**
+   * If `true` and `window.ethereum` is present, instantiate Web3 using it as the provider.
+   * Ignored if `useWeb3` is given.
+   * Default is true.
+   */
+  useMetamaskEthereumWeb3Provider?: boolean;
   /**
    * Name of the network for which to use the defaults found in Arc.js/truffle.js.
    * Overwrites config settings network, providerUrl and providerPort.
    * See [Network settings](Home#networksettings) for more information.
    */
   useNetworkDefaultsFor?: string;
+  /**
+   * Optionally use the given Web3 instance, already initialized by a provider.
+   * `useMetamaskEthereumWeb3Provider` is ignored if this is given.
+   * Has the side-effect of setting `global.web3` to the given value.
+   */
+  useWeb3?: Web3;
   /**
    * Set to true to watch for changes in the current user account.
    * Default is false.  See [AccountService.initiateAccountWatch](/api/classes/AccountService#initiateAccountWatch).
    */
   watchForAccountChanges?: boolean;
+  /**
+   * Set to true to watch for changes in the current blockchain network.
+   * Default is false.  See [AccountService.initiateNetworkWatch](/api/classes/AccountService#initiateNetworkWatch).
+   */
+  watchForNetworkChanges?: boolean;
 }
 /**
  * You must call `InitializeArcJs` before doing anything else with Arc.js.
  * Call it again whenever the current chain changes.
  * @returns Promise of the `Web3` object for the current chain.
  */
-export async function InitializeArcJs(options?: InitializeArcOptions): Promise<Web3> {
+export async function InitializeArcJs(options: InitializeArcOptions = {}): Promise<Web3> {
   LoggingService.info("Initializing Arc.js");
   try {
 
+    if (options.useWeb3) {
+      // Utils.getWeb3 will pick this up
+      (global as any).web3 = options.useWeb3;
+    } else if (typeof (options.useMetamaskEthereumWeb3Provider) === "undefined") {
+      options.useMetamaskEthereumWeb3Provider = true;
+    }
+
+    ConfigService.set("useMetamaskEthereumWeb3Provider", options.useMetamaskEthereumWeb3Provider);
+
     /**
      * simulate dependency injection, avoid circular dependencies
      */
     ContractWrapperFactory.setConfigService(ConfigService);
+    ContractWrapperFactory.clearContractCache();
     /**
      * Initialize LoggingService here to avoid circular dependency involving ConfigService and PubSubService
      */
@@ -100,7 +127,7 @@ export async function InitializeArcJs(options?: InitializeArcOptions): Promise<W
       LoggingService.logLevel = parseInt(value as any, 10) as LogLevel;
     });
 
-    if (options && options.useNetworkDefaultsFor) {
+    if (options.useNetworkDefaultsFor) {
       const networkDefaults = ConfigService.get("networkDefaults")[options.useNetworkDefaultsFor];
       if (!networkDefaults) {
         throw new Error(`truffle network defaults not found: ${options.useNetworkDefaultsFor}`);
@@ -110,13 +137,17 @@ export async function InitializeArcJs(options?: InitializeArcOptions): Promise<W
       ConfigService.set("providerUrl", `${networkDefaults.host}`);
     }
 
-    const web3 = await Utils.getWeb3();
+    const web3 = await Utils.getWeb3(true);
     await WrapperService.initialize(options);
 
-    if (options && options.watchForAccountChanges) {
+    if (options.watchForAccountChanges) {
       await AccountService.initiateAccountWatch();
     }
 
+    if (options.watchForNetworkChanges) {
+      await AccountService.initiateNetworkWatch();
+    }
+
     return web3;
   } catch (ex) {
     /* tslint:disable-next-line:no-bitwise */