Merge pull request #780 from 0xProject/feature/website/support-new-metamask

Refactor Blockchain.ts to allow arbitrary provider state changes

11 files changed, 263 insertions, 265 deletions

diff --git a/packages/website/ts/blockchain.ts b/packages/website/ts/blockchain.ts
index b65debced..d18c34c32 100644
--- a/packages/website/ts/blockchain.ts
+++ b/packages/website/ts/blockchain.ts
@@ -44,6 +44,8 @@ import {
     BlockchainErrs,
     ContractInstance,
     Fill,
+    InjectedProviderObservable,
+    InjectedProviderUpdate,
     Order as PortalOrder,
     Providers,
     ProviderType,
@@ -80,9 +82,9 @@ export class Blockchain {
     private _dispatcher: Dispatcher;
     private _web3Wrapper?: Web3Wrapper;
     private _blockchainWatcher?: BlockchainWatcher;
+    private _injectedProviderObservable?: InjectedProviderObservable;
+    private _injectedProviderUpdateHandler: (update: InjectedProviderUpdate) => Promise<void>;
     private _userAddressIfExists: string;
-    private _cachedProvider: Provider;
-    private _cachedProviderNetworkId: number;
     private _ledgerSubprovider: LedgerSubprovider;
     private _defaultGasPrice: BigNumber;
     private static _getNameGivenProvider(provider: Provider): string {
@@ -93,16 +95,62 @@ export class Blockchain {
         }
         return providerNameIfExists;
     }
-    private static async _getProviderAsync(injectedWeb3: Web3, networkIdIfExists: number): Promise<Provider> {
+    private static _getInjectedWeb3(): any {
+        return (window as any).web3;
+    }
+    private static async _getInjectedWeb3ProviderNetworkIdIfExistsAsync(): Promise<number | undefined> {
+        // Hack: We need to know the networkId the injectedWeb3 is connected to (if it is defined) in
+        // order to properly instantiate the web3Wrapper. Since we must use the async call, we cannot
+        // retrieve it from within the web3Wrapper constructor. This is and should remain the only
+        // call to a web3 instance outside of web3Wrapper in the entire dapp.
+        // In addition, if the user has an injectedWeb3 instance that is disconnected from a backing
+        // Ethereum node, this call will throw. We need to handle this case gracefully
+        const injectedWeb3IfExists = Blockchain._getInjectedWeb3();
+        let networkIdIfExists: number;
+        if (!_.isUndefined(injectedWeb3IfExists)) {
+            try {
+                networkIdIfExists = _.parseInt(await promisify<string>(injectedWeb3IfExists.version.getNetwork)());
+            } catch (err) {
+                // Ignore error and proceed with networkId undefined
+            }
+        }
+        return networkIdIfExists;
+    }
+    private static async _getProviderAsync(
+        injectedWeb3: Web3,
+        networkIdIfExists: number,
+        shouldUserLedgerProvider: boolean = false,
+    ): Promise<[Provider, LedgerSubprovider | undefined]> {
         const doesInjectedWeb3Exist = !_.isUndefined(injectedWeb3);
+        const isNetworkIdAvailable = !_.isUndefined(networkIdIfExists);
         const publicNodeUrlsIfExistsForNetworkId = configs.PUBLIC_NODE_URLS_BY_NETWORK_ID[networkIdIfExists];
         const isPublicNodeAvailableForNetworkId = !_.isUndefined(publicNodeUrlsIfExistsForNetworkId);
 
-        let provider;
-        if (doesInjectedWeb3Exist && isPublicNodeAvailableForNetworkId) {
+        if (shouldUserLedgerProvider && isNetworkIdAvailable) {
+            const isU2FSupported = await utils.isU2FSupportedAsync();
+            if (!isU2FSupported) {
+                throw new Error('Cannot update providerType to LEDGER without U2F support');
+            }
+            const provider = new ProviderEngine();
+            const ledgerWalletConfigs = {
+                networkId: networkIdIfExists,
+                ledgerEthereumClientFactoryAsync: ledgerEthereumBrowserClientFactoryAsync,
+            };
+            const ledgerSubprovider = new LedgerSubprovider(ledgerWalletConfigs);
+            provider.addProvider(ledgerSubprovider);
+            provider.addProvider(new FilterSubprovider());
+            const rpcSubproviders = _.map(configs.PUBLIC_NODE_URLS_BY_NETWORK_ID[networkIdIfExists], publicNodeUrl => {
+                return new RpcSubprovider({
+                    rpcUrl: publicNodeUrl,
+                });
+            });
+            provider.addProvider(new RedundantSubprovider(rpcSubproviders as Subprovider[]));
+            provider.start();
+            return [provider, ledgerSubprovider];
+        } else if (doesInjectedWeb3Exist && isPublicNodeAvailableForNetworkId) {
             // We catch all requests involving a users account and send it to the injectedWeb3
             // instance. All other requests go to the public hosted node.
-            provider = new ProviderEngine();
+            const provider = new ProviderEngine();
             provider.addProvider(new InjectedWeb3Subprovider(injectedWeb3.currentProvider));
             provider.addProvider(new FilterSubprovider());
             const rpcSubproviders = _.map(publicNodeUrlsIfExistsForNetworkId, publicNodeUrl => {
@@ -112,16 +160,17 @@ export class Blockchain {
             });
             provider.addProvider(new RedundantSubprovider(rpcSubproviders as Subprovider[]));
             provider.start();
+            return [provider, undefined];
         } else if (doesInjectedWeb3Exist) {
             // Since no public node for this network, all requests go to injectedWeb3 instance
-            provider = injectedWeb3.currentProvider;
+            return [injectedWeb3.currentProvider, undefined];
         } else {
             // If no injectedWeb3 instance, all requests fallback to our public hosted mainnet/testnet node
             // We do this so that users can still browse the 0x Portal DApp even if they do not have web3
             // injected into their browser.
-            provider = new ProviderEngine();
+            const provider = new ProviderEngine();
             provider.addProvider(new FilterSubprovider());
-            const networkId = configs.IS_MAINNET_ENABLED ? constants.NETWORK_ID_MAINNET : constants.NETWORK_ID_KOVAN;
+            const networkId = constants.NETWORK_ID_MAINNET;
             const rpcSubproviders = _.map(configs.PUBLIC_NODE_URLS_BY_NETWORK_ID[networkId], publicNodeUrl => {
                 return new RpcSubprovider({
                     rpcUrl: publicNodeUrl,
@@ -129,14 +178,15 @@ export class Blockchain {
             });
             provider.addProvider(new RedundantSubprovider(rpcSubproviders as Subprovider[]));
             provider.start();
+            return [provider, undefined];
         }
-
-        return provider;
     }
     constructor(dispatcher: Dispatcher) {
         this._dispatcher = dispatcher;
         const defaultGasPrice = GWEI_IN_WEI * 30;
         this._defaultGasPrice = new BigNumber(defaultGasPrice);
+        // We need a unique reference to this function so we can use it to unsubcribe.
+        this._injectedProviderUpdateHandler = this._handleInjectedProviderUpdateAsync.bind(this);
         // tslint:disable-next-line:no-floating-promises
         this._updateDefaultGasPriceAsync();
         // tslint:disable-next-line:no-floating-promises
@@ -186,84 +236,17 @@ export class Blockchain {
         this._ledgerSubprovider.setPath(path);
     }
     public async updateProviderToLedgerAsync(networkId: number): Promise<void> {
-        utils.assert(!_.isUndefined(this._contractWrappers), 'Contract Wrappers must be instantiated.');
-
-        const isU2FSupported = await utils.isU2FSupportedAsync();
-        if (!isU2FSupported) {
-            throw new Error('Cannot update providerType to LEDGER without U2F support');
-        }
-
-        // Cache injected provider so that we can switch the user back to it easily
-        if (_.isUndefined(this._cachedProvider)) {
-            this._cachedProvider = this._web3Wrapper.getProvider();
-            this._cachedProviderNetworkId = this.networkId;
-        }
-
-        this._blockchainWatcher.destroy();
-
-        delete this._userAddressIfExists;
-        this._dispatcher.updateUserAddress(undefined); // Clear old userAddress
-
-        const provider = new ProviderEngine();
-        const ledgerWalletConfigs = {
-            networkId,
-            ledgerEthereumClientFactoryAsync: ledgerEthereumBrowserClientFactoryAsync,
-        };
-        this._ledgerSubprovider = new LedgerSubprovider(ledgerWalletConfigs);
-        provider.addProvider(this._ledgerSubprovider);
-        provider.addProvider(new FilterSubprovider());
-        const rpcSubproviders = _.map(configs.PUBLIC_NODE_URLS_BY_NETWORK_ID[networkId], publicNodeUrl => {
-            return new RpcSubprovider({
-                rpcUrl: publicNodeUrl,
-            });
-        });
-        provider.addProvider(new RedundantSubprovider(rpcSubproviders as Subprovider[]));
-        provider.start();
-        this.networkId = networkId;
-        this._dispatcher.updateNetworkId(this.networkId);
         const shouldPollUserAddress = false;
-        this._web3Wrapper = new Web3Wrapper(provider);
-        this._blockchainWatcher = new BlockchainWatcher(
-            this._dispatcher,
-            this._web3Wrapper,
-            this.networkId,
-            shouldPollUserAddress,
-        );
-        this._contractWrappers.setProvider(provider, this.networkId);
-        await this._blockchainWatcher.startEmittingNetworkConnectionAndUserBalanceStateAsync();
-        this._dispatcher.updateProviderType(ProviderType.Ledger);
+        const shouldUserLedgerProvider = true;
+        await this._resetOrInitializeAsync(networkId, shouldPollUserAddress, shouldUserLedgerProvider);
     }
     public async updateProviderToInjectedAsync(): Promise<void> {
-        utils.assert(!_.isUndefined(this._contractWrappers), 'Contract Wrappers must be instantiated.');
-
-        if (_.isUndefined(this._cachedProvider)) {
-            return; // Going from injected to injected, so we noop
-        }
-
-        this._blockchainWatcher.destroy();
-
-        const provider = this._cachedProvider;
-        this.networkId = this._cachedProviderNetworkId;
-
         const shouldPollUserAddress = true;
-        this._web3Wrapper = new Web3Wrapper(provider);
-        this._blockchainWatcher = new BlockchainWatcher(
-            this._dispatcher,
-            this._web3Wrapper,
-            this.networkId,
-            shouldPollUserAddress,
-        );
-
-        const userAddresses = await this._web3Wrapper.getAvailableAddressesAsync();
-        this._userAddressIfExists = userAddresses[0];
-
-        this._contractWrappers.setProvider(provider, this.networkId);
-
-        await this.fetchTokenInformationAsync();
-        await this._blockchainWatcher.startEmittingNetworkConnectionAndUserBalanceStateAsync();
-        this._dispatcher.updateProviderType(ProviderType.Injected);
-        delete this._ledgerSubprovider;
-        delete this._cachedProvider;
+        const shouldUserLedgerProvider = false;
+        this._dispatcher.updateBlockchainIsLoaded(false);
+        // We don't want to be out of sync with the network the injected provider declares.
+        const networkId = await Blockchain._getInjectedWeb3ProviderNetworkIdIfExistsAsync();
+        await this._resetOrInitializeAsync(networkId, shouldPollUserAddress, shouldUserLedgerProvider);
     }
     public async setProxyAllowanceAsync(token: Token, amountInBaseUnits: BigNumber): Promise<void> {
         utils.assert(this.isValidAddress(token.address), BlockchainCallErrs.TokenAddressIsInvalid);
@@ -539,6 +522,7 @@ export class Blockchain {
     }
     public destroy(): void {
         this._blockchainWatcher.destroy();
+        this._injectedProviderObservable.unsubscribe(this._injectedProviderUpdateHandler);
         this._stopWatchingExchangeLogFillEvents();
     }
     public async fetchTokenInformationAsync(): Promise<void> {
@@ -634,6 +618,18 @@ export class Blockchain {
     private _doesUserAddressExist(): boolean {
         return !_.isUndefined(this._userAddressIfExists);
     }
+    private async _handleInjectedProviderUpdateAsync(update: InjectedProviderUpdate): Promise<void> {
+        if (update.networkVersion === 'loading' || !_.isUndefined(this._ledgerSubprovider)) {
+            return;
+        }
+        const updatedNetworkId = _.parseInt(update.networkVersion);
+        if (this.networkId === updatedNetworkId) {
+            return;
+        }
+        const shouldPollUserAddress = true;
+        const shouldUserLedgerProvider = false;
+        await this._resetOrInitializeAsync(updatedNetworkId, shouldPollUserAddress, shouldUserLedgerProvider);
+    }
     private async _rehydrateStoreWithContractEventsAsync(): Promise<void> {
         // Ensure we are only ever listening to one set of events
         this._stopWatchingExchangeLogFillEvents();
@@ -776,49 +772,64 @@ export class Blockchain {
     }
     private async _onPageLoadInitFireAndForgetAsync(): Promise<void> {
         await utils.onPageLoadAsync(); // wait for page to load
-
-        // Hack: We need to know the networkId the injectedWeb3 is connected to (if it is defined) in
-        // order to properly instantiate the web3Wrapper. Since we must use the async call, we cannot
-        // retrieve it from within the web3Wrapper constructor. This is and should remain the only
-        // call to a web3 instance outside of web3Wrapper in the entire dapp.
-        // In addition, if the user has an injectedWeb3 instance that is disconnected from a backing
-        // Ethereum node, this call will throw. We need to handle this case gracefully
-        const injectedWeb3 = (window as any).web3;
-        let networkIdIfExists: number;
-        if (!_.isUndefined(injectedWeb3)) {
-            try {
-                networkIdIfExists = _.parseInt(await promisify<string>(injectedWeb3.version.getNetwork)());
-            } catch (err) {
-                // Ignore error and proceed with networkId undefined
+        const networkIdIfExists = await Blockchain._getInjectedWeb3ProviderNetworkIdIfExistsAsync();
+        this.networkId = !_.isUndefined(networkIdIfExists) ? networkIdIfExists : constants.NETWORK_ID_MAINNET;
+        const injectedWeb3IfExists = Blockchain._getInjectedWeb3();
+        if (!_.isUndefined(injectedWeb3IfExists) && !_.isUndefined(injectedWeb3IfExists.currentProvider)) {
+            const injectedProviderObservable = injectedWeb3IfExists.currentProvider.publicConfigStore;
+            if (!_.isUndefined(injectedProviderObservable) && _.isUndefined(this._injectedProviderObservable)) {
+                this._injectedProviderObservable = injectedProviderObservable;
+                this._injectedProviderObservable.subscribe(this._injectedProviderUpdateHandler);
             }
         }
-
-        const provider = await Blockchain._getProviderAsync(injectedWeb3, networkIdIfExists);
-        this.networkId = !_.isUndefined(networkIdIfExists)
-            ? networkIdIfExists
-            : configs.IS_MAINNET_ENABLED
-                ? constants.NETWORK_ID_MAINNET
-                : constants.NETWORK_ID_KOVAN;
-        this._dispatcher.updateNetworkId(this.networkId);
-        const zeroExConfigs = {
-            networkId: this.networkId,
-        };
-        this._contractWrappers = new ContractWrappers(provider, zeroExConfigs);
-        this._updateProviderName(injectedWeb3);
+        this._updateProviderName(injectedWeb3IfExists);
         const shouldPollUserAddress = true;
-        this._web3Wrapper = new Web3Wrapper(provider);
-        this._blockchainWatcher = new BlockchainWatcher(
-            this._dispatcher,
-            this._web3Wrapper,
-            this.networkId,
-            shouldPollUserAddress,
+        const shouldUseLedgerProvider = false;
+        await this._resetOrInitializeAsync(this.networkId, shouldPollUserAddress, shouldUseLedgerProvider);
+    }
+    private async _resetOrInitializeAsync(
+        networkId: number,
+        shouldPollUserAddress: boolean = false,
+        shouldUserLedgerProvider: boolean = false,
+    ): Promise<void> {
+        if (!shouldUserLedgerProvider) {
+            this._dispatcher.updateBlockchainIsLoaded(false);
+        }
+        this._dispatcher.updateUserWeiBalance(undefined);
+        this.networkId = networkId;
+        const injectedWeb3IfExists = Blockchain._getInjectedWeb3();
+        const [provider, ledgerSubproviderIfExists] = await Blockchain._getProviderAsync(
+            injectedWeb3IfExists,
+            networkId,
+            shouldUserLedgerProvider,
         );
-
-        const userAddresses = await this._web3Wrapper.getAvailableAddressesAsync();
-        this._userAddressIfExists = userAddresses[0];
-        this._dispatcher.updateUserAddress(this._userAddressIfExists);
-        await this.fetchTokenInformationAsync();
-        await this._blockchainWatcher.startEmittingNetworkConnectionAndUserBalanceStateAsync();
+        if (!_.isUndefined(this._contractWrappers)) {
+            this._contractWrappers.setProvider(provider, networkId);
+        } else {
+            this._contractWrappers = new ContractWrappers(provider, { networkId });
+        }
+        if (!_.isUndefined(this._blockchainWatcher)) {
+            this._blockchainWatcher.destroy();
+        }
+        this._web3Wrapper = new Web3Wrapper(provider);
+        this._blockchainWatcher = new BlockchainWatcher(this._dispatcher, this._web3Wrapper, shouldPollUserAddress);
+        if (shouldUserLedgerProvider && !_.isUndefined(ledgerSubproviderIfExists)) {
+            delete this._userAddressIfExists;
+            this._ledgerSubprovider = ledgerSubproviderIfExists;
+            this._dispatcher.updateUserAddress(undefined);
+            this._dispatcher.updateProviderType(ProviderType.Ledger);
+        } else {
+            delete this._ledgerSubprovider;
+            const userAddresses = await this._web3Wrapper.getAvailableAddressesAsync();
+            this._userAddressIfExists = userAddresses[0];
+            this._dispatcher.updateUserAddress(this._userAddressIfExists);
+            if (!_.isUndefined(injectedWeb3IfExists)) {
+                this._dispatcher.updateProviderType(ProviderType.Injected);
+            }
+            await this.fetchTokenInformationAsync();
+        }
+        await this._blockchainWatcher.startEmittingUserBalanceStateAsync();
+        this._dispatcher.updateNetworkId(networkId);
         await this._rehydrateStoreWithContractEventsAsync();
     }
     private _updateProviderName(injectedWeb3: Web3): void {
diff --git a/packages/website/ts/blockchain_watcher.ts b/packages/website/ts/blockchain_watcher.ts
index c576db6ac..df5f73fd1 100644
--- a/packages/website/ts/blockchain_watcher.ts
+++ b/packages/website/ts/blockchain_watcher.ts
@@ -6,24 +6,17 @@ import { Dispatcher } from 'ts/redux/dispatcher';
 export class BlockchainWatcher {
     private _dispatcher: Dispatcher;
     private _web3Wrapper: Web3Wrapper;
-    private _prevNetworkId: number;
     private _shouldPollUserAddress: boolean;
-    private _watchNetworkAndBalanceIntervalId: NodeJS.Timer;
+    private _watchBalanceIntervalId: NodeJS.Timer;
     private _prevUserEtherBalanceInWei?: BigNumber;
     private _prevUserAddressIfExists: string;
-    constructor(
-        dispatcher: Dispatcher,
-        web3Wrapper: Web3Wrapper,
-        networkIdIfExists: number,
-        shouldPollUserAddress: boolean,
-    ) {
+    constructor(dispatcher: Dispatcher, web3Wrapper: Web3Wrapper, shouldPollUserAddress: boolean) {
         this._dispatcher = dispatcher;
-        this._prevNetworkId = networkIdIfExists;
         this._shouldPollUserAddress = shouldPollUserAddress;
         this._web3Wrapper = web3Wrapper;
     }
     public destroy(): void {
-        this._stopEmittingNetworkConnectionAndUserBalanceState();
+        this._stopEmittingUserBalanceState();
         // HACK: stop() is only available on providerEngine instances
         const provider = this._web3Wrapper.getProvider();
         if (!_.isUndefined((provider as any).stop)) {
@@ -34,36 +27,23 @@ export class BlockchainWatcher {
     public updatePrevUserAddress(userAddress: string): void {
         this._prevUserAddressIfExists = userAddress;
     }
-    public async startEmittingNetworkConnectionAndUserBalanceStateAsync(): Promise<void> {
-        if (!_.isUndefined(this._watchNetworkAndBalanceIntervalId)) {
+    public async startEmittingUserBalanceStateAsync(): Promise<void> {
+        if (!_.isUndefined(this._watchBalanceIntervalId)) {
             return; // we are already emitting the state
         }
         this._prevUserEtherBalanceInWei = undefined;
-        this._dispatcher.updateNetworkId(this._prevNetworkId);
-        await this._updateNetworkAndBalanceAsync();
-        this._watchNetworkAndBalanceIntervalId = intervalUtils.setAsyncExcludingInterval(
-            this._updateNetworkAndBalanceAsync.bind(this),
+        await this._updateBalanceAsync();
+        this._watchBalanceIntervalId = intervalUtils.setAsyncExcludingInterval(
+            this._updateBalanceAsync.bind(this),
             5000,
             (err: Error) => {
                 logUtils.log(`Watching network and balances failed: ${err.stack}`);
-                this._stopEmittingNetworkConnectionAndUserBalanceState();
+                this._stopEmittingUserBalanceState();
             },
         );
     }
-    private async _updateNetworkAndBalanceAsync(): Promise<void> {
-        // Check for network state changes
+    private async _updateBalanceAsync(): Promise<void> {
         let prevNodeVersion: string;
-        let currentNetworkId;
-        try {
-            currentNetworkId = await this._web3Wrapper.getNetworkIdAsync();
-        } catch (err) {
-            // Noop
-        }
-        if (currentNetworkId !== this._prevNetworkId) {
-            this._prevNetworkId = currentNetworkId;
-            this._dispatcher.updateNetworkId(currentNetworkId);
-        }
-
         // Check for node version changes
         const currentNodeVersion = await this._web3Wrapper.getNodeVersionAsync();
         if (currentNodeVersion !== prevNodeVersion) {
@@ -99,9 +79,9 @@ export class BlockchainWatcher {
             this._dispatcher.updateUserWeiBalance(balanceInWei);
         }
     }
-    private _stopEmittingNetworkConnectionAndUserBalanceState(): void {
-        if (!_.isUndefined(this._watchNetworkAndBalanceIntervalId)) {
-            intervalUtils.clearAsyncExcludingInterval(this._watchNetworkAndBalanceIntervalId);
+    private _stopEmittingUserBalanceState(): void {
+        if (!_.isUndefined(this._watchBalanceIntervalId)) {
+            intervalUtils.clearAsyncExcludingInterval(this._watchBalanceIntervalId);
         }
     }
 }
diff --git a/packages/website/ts/components/dialogs/blockchain_err_dialog.tsx b/packages/website/ts/components/dialogs/blockchain_err_dialog.tsx
index b968a3147..c8e10303f 100644
--- a/packages/website/ts/components/dialogs/blockchain_err_dialog.tsx
+++ b/packages/website/ts/components/dialogs/blockchain_err_dialog.tsx
@@ -4,7 +4,6 @@ import FlatButton from 'material-ui/FlatButton';
 import * as React from 'react';
 import { Blockchain } from 'ts/blockchain';
 import { BlockchainErrs } from 'ts/types';
-import { configs } from 'ts/utils/configs';
 import { constants } from 'ts/utils/constants';
 
 interface BlockchainErrDialogProps {
@@ -125,8 +124,7 @@ export class BlockchainErrDialog extends React.Component<BlockchainErrDialogProp
                         Parity Signer Chrome extension
                     </a>{' '}
                     lets you connect to a locally running Parity node. Make sure you have started your local Parity node
-                    with {configs.IS_MAINNET_ENABLED && '`parity ui` or'} `parity --chain kovan ui` in order to connect
-                    to {configs.IS_MAINNET_ENABLED ? 'mainnet or Kovan respectively.' : 'Kovan.'}
+                    with `parity ui` or `parity --chain kovan ui` in order to connect to mainnet or Kovan respectively.
                 </div>
                 <div className="pt2">
                     <span className="bold">Note:</span> If you have done one of the above steps and are still seeing
@@ -142,10 +140,8 @@ export class BlockchainErrDialog extends React.Component<BlockchainErrDialogProp
                 <div>
                     The 0x smart contracts are not deployed on the Ethereum network you are currently connected to
                     (network Id: {this.props.networkId}). In order to use the 0x portal dApp, please connect to the{' '}
-                    {Networks.Kovan} testnet (network Id: {constants.NETWORK_ID_KOVAN})
-                    {configs.IS_MAINNET_ENABLED
-                        ? ` or ${constants.MAINNET_NAME} (network Id: ${constants.NETWORK_ID_MAINNET}).`
-                        : `.`}
+                    {Networks.Kovan} testnet (network Id: {constants.NETWORK_ID_KOVAN}) or ${constants.MAINNET_NAME}{' '}
+                    (network Id: ${constants.NETWORK_ID_MAINNET}).
                 </div>
                 <h4>Metamask</h4>
                 <div>
@@ -159,11 +155,8 @@ export class BlockchainErrDialog extends React.Component<BlockchainErrDialogProp
                     If using the{' '}
                     <a href={constants.URL_PARITY_CHROME_STORE} target="_blank">
                         Parity Signer Chrome extension
-                    </a>, make sure to start your local Parity node with{' '}
-                    {configs.IS_MAINNET_ENABLED
-                        ? '`parity ui` or `parity --chain Kovan ui` in order to connect to mainnet \
-                         or Kovan respectively.'
-                        : '`parity --chain kovan ui` in order to connect to Kovan.'}
+                    </a>, make sure to start your local Parity node with `parity ui` or `parity --chain Kovan ui` in
+                    order to connect to mainnet \ or Kovan respectively.
                 </div>
             </div>
         );
diff --git a/packages/website/ts/components/dialogs/ledger_config_dialog.tsx b/packages/website/ts/components/dialogs/ledger_config_dialog.tsx
index c9727b553..38e4732a4 100644
--- a/packages/website/ts/components/dialogs/ledger_config_dialog.tsx
+++ b/packages/website/ts/components/dialogs/ledger_config_dialog.tsx
@@ -282,6 +282,7 @@ export class LedgerConfigDialog extends React.Component<LedgerConfigDialogProps,
         if (didSucceed) {
             this.setState({
                 stepIndex: LedgerSteps.SELECT_ADDRESS,
+                connectionErrMsg: '',
             });
         }
         return didSucceed;
diff --git a/packages/website/ts/components/legacy_portal/legacy_portal.tsx b/packages/website/ts/components/legacy_portal/legacy_portal.tsx
index 9a54f3474..c85d97207 100644
--- a/packages/website/ts/components/legacy_portal/legacy_portal.tsx
+++ b/packages/website/ts/components/legacy_portal/legacy_portal.tsx
@@ -23,7 +23,6 @@ import { GenerateOrderForm } from 'ts/containers/generate_order_form';
 import { localStorage } from 'ts/local_storage/local_storage';
 import { Dispatcher } from 'ts/redux/dispatcher';
 import { BlockchainErrs, HashData, Order, ProviderType, ScreenWidths, TokenByAddress, WebsitePaths } from 'ts/types';
-import { configs } from 'ts/utils/configs';
 import { constants } from 'ts/utils/constants';
 import { orderParser } from 'ts/utils/order_parser';
 import { Translate } from 'ts/utils/translate';
@@ -170,67 +169,53 @@ export class LegacyPortal extends React.Component<LegacyPortalProps, LegacyPorta
                 />
                 <div id="portal" className="mx-auto max-width-4" style={{ width: '100%' }}>
                     <Paper className="mb3 mt2">
-                        {!configs.IS_MAINNET_ENABLED && this.props.networkId === constants.NETWORK_ID_MAINNET ? (
-                            <div className="p3 center">
-                                <div className="h2 py2">Mainnet unavailable</div>
-                                <div className="mx-auto pb2 pt2">
-                                    <img src="/images/zrx_token.png" style={{ width: 150 }} />
-                                </div>
-                                <div>
-                                    0x portal is currently unavailable on the Ethereum mainnet.
-                                    <div>To try it out, switch to the Kovan test network (networkId: 42).</div>
-                                    <div className="py2">Check back soon!</div>
-                                </div>
+                        <div className="mx-auto flex">
+                            <div className="col col-2 pr2 pt1 sm-hide xs-hide" style={portalMenuContainerStyle}>
+                                <LegacyPortalMenu menuItemStyle={{ color: colors.white }} />
                             </div>
-                        ) : (
-                            <div className="mx-auto flex">
-                                <div className="col col-2 pr2 pt1 sm-hide xs-hide" style={portalMenuContainerStyle}>
-                                    <LegacyPortalMenu menuItemStyle={{ color: colors.white }} />
-                                </div>
-                                <div className="col col-12 lg-col-10 md-col-10 sm-col sm-col-12">
-                                    <div className="py2" style={{ backgroundColor: colors.grey50 }}>
-                                        {this.props.blockchainIsLoaded ? (
-                                            <Switch>
-                                                <Route
-                                                    path={`${WebsitePaths.Portal}/weth`}
-                                                    render={this._renderEthWrapper.bind(this)}
-                                                />
-                                                <Route
-                                                    path={`${WebsitePaths.Portal}/fill`}
-                                                    render={this._renderFillOrder.bind(this)}
-                                                />
-                                                <Route
-                                                    path={`${WebsitePaths.Portal}/balances`}
-                                                    render={this._renderTokenBalances.bind(this)}
-                                                />
-                                                <Route
-                                                    path={`${WebsitePaths.Portal}/trades`}
-                                                    render={this._renderTradeHistory.bind(this)}
-                                                />
-                                                <Route
-                                                    path={`${WebsitePaths.Home}`}
-                                                    render={this._renderGenerateOrderForm.bind(this)}
-                                                />
-                                            </Switch>
-                                        ) : (
-                                            <div className="pt4 sm-px2 sm-pt2 sm-m1" style={{ height: 500 }}>
-                                                <div
-                                                    className="relative sm-px2 sm-pt2 sm-m1"
-                                                    style={{ height: 122, top: '50%', transform: 'translateY(-50%)' }}
-                                                >
-                                                    <div className="center pb2">
-                                                        <CircularProgress size={40} thickness={5} />
-                                                    </div>
-                                                    <div className="center pt2" style={{ paddingBottom: 11 }}>
-                                                        Loading Portal...
-                                                    </div>
+                            <div className="col col-12 lg-col-10 md-col-10 sm-col sm-col-12">
+                                <div className="py2" style={{ backgroundColor: colors.grey50 }}>
+                                    {this.props.blockchainIsLoaded ? (
+                                        <Switch>
+                                            <Route
+                                                path={`${WebsitePaths.Portal}/weth`}
+                                                render={this._renderEthWrapper.bind(this)}
+                                            />
+                                            <Route
+                                                path={`${WebsitePaths.Portal}/fill`}
+                                                render={this._renderFillOrder.bind(this)}
+                                            />
+                                            <Route
+                                                path={`${WebsitePaths.Portal}/balances`}
+                                                render={this._renderTokenBalances.bind(this)}
+                                            />
+                                            <Route
+                                                path={`${WebsitePaths.Portal}/trades`}
+                                                render={this._renderTradeHistory.bind(this)}
+                                            />
+                                            <Route
+                                                path={`${WebsitePaths.Home}`}
+                                                render={this._renderGenerateOrderForm.bind(this)}
+                                            />
+                                        </Switch>
+                                    ) : (
+                                        <div className="pt4 sm-px2 sm-pt2 sm-m1" style={{ height: 500 }}>
+                                            <div
+                                                className="relative sm-px2 sm-pt2 sm-m1"
+                                                style={{ height: 122, top: '50%', transform: 'translateY(-50%)' }}
+                                            >
+                                                <div className="center pb2">
+                                                    <CircularProgress size={40} thickness={5} />
+                                                </div>
+                                                <div className="center pt2" style={{ paddingBottom: 11 }}>
+                                                    Loading Portal...
                                                 </div>
                                             </div>
-                                        )}
-                                    </div>
+                                        </div>
+                                    )}
                                 </div>
                             </div>
-                        )}
+                        </div>
                     </Paper>
                     <BlockchainErrDialog
                         blockchain={this._blockchain}
@@ -249,16 +234,14 @@ export class LegacyPortal extends React.Component<LegacyPortalProps, LegacyPorta
                         onToggleDialog={this._onPortalDisclaimerAccepted.bind(this)}
                     />
                     <FlashMessage dispatcher={this.props.dispatcher} flashMessage={this.props.flashMessage} />
-                    {this.props.blockchainIsLoaded && (
-                        <LedgerConfigDialog
-                            providerType={this.props.providerType}
-                            networkId={this.props.networkId}
-                            blockchain={this._blockchain}
-                            dispatcher={this.props.dispatcher}
-                            toggleDialogFn={this.onToggleLedgerDialog.bind(this)}
-                            isOpen={this.state.isLedgerDialogOpen}
-                        />
-                    )}
+                    <LedgerConfigDialog
+                        providerType={this.props.providerType}
+                        networkId={this.props.networkId}
+                        blockchain={this._blockchain}
+                        dispatcher={this.props.dispatcher}
+                        toggleDialogFn={this.onToggleLedgerDialog.bind(this)}
+                        isOpen={this.state.isLedgerDialogOpen}
+                    />
                 </div>
                 <Footer translate={this.props.translate} dispatcher={this.props.dispatcher} />
             </div>
diff --git a/packages/website/ts/components/onboarding/portal_onboarding_flow.tsx b/packages/website/ts/components/onboarding/portal_onboarding_flow.tsx
index 10d4af30e..296b410fe 100644
--- a/packages/website/ts/components/onboarding/portal_onboarding_flow.tsx
+++ b/packages/website/ts/components/onboarding/portal_onboarding_flow.tsx
@@ -159,9 +159,11 @@ class PlainPortalOnboardingFlow extends React.Component<PortalOnboardingFlowProp
         const ethToken = utils.getEthToken(this.props.tokenByAddress);
         const zrxToken = utils.getZrxToken(this.props.tokenByAddress);
         if (ethToken && zrxToken) {
-            const ethTokenAllowance = this.props.trackedTokenStateByAddress[ethToken.address].allowance;
-            const zrxTokenAllowance = this.props.trackedTokenStateByAddress[zrxToken.address].allowance;
-            return ethTokenAllowance > new BigNumber(0) && zrxTokenAllowance > new BigNumber(0);
+            const ethTokenState = this.props.trackedTokenStateByAddress[ethToken.address];
+            const zrxTokenState = this.props.trackedTokenStateByAddress[zrxToken.address];
+            if (ethTokenState && zrxTokenState) {
+                return ethTokenState.allowance.gt(0) && zrxTokenState.allowance.gt(0);
+            }
         }
         return false;
     }
@@ -221,12 +223,15 @@ class PlainPortalOnboardingFlow extends React.Component<PortalOnboardingFlowProp
         if (!token) {
             return null;
         }
-        const tokenState = this.props.trackedTokenStateByAddress[token.address];
+        const tokenStateIfExists = this.props.trackedTokenStateByAddress[token.address];
+        if (_.isUndefined(tokenStateIfExists)) {
+            return null;
+        }
         return (
             <AllowanceToggle
                 token={token}
-                tokenState={tokenState}
-                isDisabled={!tokenState.isLoaded}
+                tokenState={tokenStateIfExists}
+                isDisabled={!tokenStateIfExists.isLoaded}
                 blockchain={this.props.blockchain}
                 // tslint:disable-next-line:jsx-no-lambda
                 refetchTokenStateAsync={async () => this.props.refetchTokenStateAsync(token.address)}
diff --git a/packages/website/ts/components/portal/portal.tsx b/packages/website/ts/components/portal/portal.tsx
index 9498cb388..438c7b52f 100644
--- a/packages/website/ts/components/portal/portal.tsx
+++ b/packages/website/ts/components/portal/portal.tsx
@@ -152,9 +152,8 @@ export class Portal extends React.Component<PortalProps, PortalState> {
     }
     public componentDidUpdate(prevProps: PortalProps): void {
         if (!prevProps.blockchainIsLoaded && this.props.blockchainIsLoaded) {
-            const trackedTokenAddresses = _.keys(this.state.trackedTokenStateByAddress);
             // tslint:disable-next-line:no-floating-promises
-            this._fetchBalancesAndAllowancesAsync(trackedTokenAddresses);
+            this._fetchBalancesAndAllowancesAsync(this._getCurrentTrackedTokensAddresses());
         }
     }
     public componentWillReceiveProps(nextProps: PortalProps): void {
@@ -182,14 +181,14 @@ export class Portal extends React.Component<PortalProps, PortalState> {
                 prevPathname: nextProps.location.pathname,
             });
         }
+
+        // If the address changed, but the network did not, we can just refetch the currently tracked tokens.
         if (
-            nextProps.userAddress !== this.props.userAddress ||
-            nextProps.networkId !== this.props.networkId ||
+            (nextProps.userAddress !== this.props.userAddress && nextProps.networkId === this.props.networkId) ||
             nextProps.lastForceTokenStateRefetch !== this.props.lastForceTokenStateRefetch
         ) {
-            const trackedTokenAddresses = _.keys(this.state.trackedTokenStateByAddress);
             // tslint:disable-next-line:no-floating-promises
-            this._fetchBalancesAndAllowancesAsync(trackedTokenAddresses);
+            this._fetchBalancesAndAllowancesAsync(this._getCurrentTrackedTokensAddresses());
         }
 
         const nextTrackedTokens = utils.getTrackedTokens(nextProps.tokenByAddress);
@@ -200,7 +199,7 @@ export class Portal extends React.Component<PortalProps, PortalState> {
             const newTokenAddresses = _.map(newTokens, token => token.address);
             // Add placeholder entry for this token to the state, since fetching the
             // balance/allowance is asynchronous
-            const trackedTokenStateByAddress = this.state.trackedTokenStateByAddress;
+            const trackedTokenStateByAddress = { ...this.state.trackedTokenStateByAddress };
             for (const tokenAddress of newTokenAddresses) {
                 trackedTokenStateByAddress[tokenAddress] = {
                     balance: new BigNumber(0),
@@ -265,16 +264,16 @@ export class Portal extends React.Component<PortalProps, PortalState> {
                         networkId={this.props.networkId}
                     />
                     <FlashMessage dispatcher={this.props.dispatcher} flashMessage={this.props.flashMessage} />
-                    {this.props.blockchainIsLoaded && (
-                        <LedgerConfigDialog
-                            providerType={this.props.providerType}
-                            networkId={this.props.networkId}
-                            blockchain={this._blockchain}
-                            dispatcher={this.props.dispatcher}
-                            toggleDialogFn={this._onToggleLedgerDialog.bind(this)}
-                            isOpen={this.state.isLedgerDialogOpen}
-                        />
-                    )}
+
+                    <LedgerConfigDialog
+                        providerType={this.props.providerType}
+                        networkId={this.props.networkId}
+                        blockchain={this._blockchain}
+                        dispatcher={this.props.dispatcher}
+                        toggleDialogFn={this._onToggleLedgerDialog.bind(this)}
+                        isOpen={this.state.isLedgerDialogOpen}
+                    />
+
                     <AssetPicker
                         userAddress={this.props.userAddress}
                         networkId={this.props.networkId}
@@ -608,11 +607,12 @@ export class Portal extends React.Component<PortalProps, PortalState> {
         const isSmallScreen = this.props.screenWidth === ScreenWidths.Sm;
         return isSmallScreen;
     }
-
     private _getCurrentTrackedTokens(): Token[] {
         return utils.getTrackedTokens(this.props.tokenByAddress);
     }
-
+    private _getCurrentTrackedTokensAddresses(): string[] {
+        return _.map(this._getCurrentTrackedTokens(), token => token.address);
+    }
     private _getInitialTrackedTokenStateByAddress(trackedTokens: Token[]): TokenStateByAddress {
         const trackedTokenStateByAddress: TokenStateByAddress = {};
         _.each(trackedTokens, token => {
diff --git a/packages/website/ts/components/top_bar/top_bar.tsx b/packages/website/ts/components/top_bar/top_bar.tsx
index 537edc7bb..fac6c131f 100644
--- a/packages/website/ts/components/top_bar/top_bar.tsx
+++ b/packages/website/ts/components/top_bar/top_bar.tsx
@@ -13,7 +13,6 @@ import { ProviderDisplay } from 'ts/components/top_bar/provider_display';
 import { TopBarMenuItem } from 'ts/components/top_bar/top_bar_menu_item';
 import { DropDown } from 'ts/components/ui/drop_down';
 import { Dispatcher } from 'ts/redux/dispatcher';
-import { zIndex } from 'ts/style/z_index';
 import { Deco, Key, ProviderType, WebsiteLegacyPaths, WebsitePaths } from 'ts/types';
 import { constants } from 'ts/utils/constants';
 import { Translate } from 'ts/utils/translate';
@@ -58,7 +57,6 @@ const styles: Styles = {
         width: '100%',
         position: 'relative',
         top: 0,
-        zIndex: zIndex.topBar,
         paddingBottom: 1,
     },
     bottomBar: {
diff --git a/packages/website/ts/types.ts b/packages/website/ts/types.ts
index 11ae2e0ba..2db947ba3 100644
--- a/packages/website/ts/types.ts
+++ b/packages/website/ts/types.ts
@@ -488,6 +488,16 @@ export enum Providers {
     Mist = 'MIST',
 }
 
+export interface InjectedProviderUpdate {
+    selectedAddress: string;
+    networkVersion: string;
+}
+
+export interface InjectedProviderObservable {
+    subscribe(updateHandler: (update: InjectedProviderUpdate) => void): void;
+    unsubscribe(updateHandler: (update: InjectedProviderUpdate) => void): void;
+}
+
 export interface TimestampMsRange {
     startTimestampMs: number;
     endTimestampMs: number;
diff --git a/packages/website/ts/utils/configs.ts b/packages/website/ts/utils/configs.ts
index 36c067f84..2f89f8ccb 100644
--- a/packages/website/ts/utils/configs.ts
+++ b/packages/website/ts/utils/configs.ts
@@ -63,7 +63,6 @@ export const configs = {
         TKN: '/images/token_icons/tokencard.png',
         TRST: '/images/token_icons/trust.png',
     } as { [symbol: string]: string },
-    IS_MAINNET_ENABLED: true,
     GOOGLE_ANALYTICS_ID: 'UA-98720122-1',
     LAST_LOCAL_STORAGE_FILL_CLEARANCE_DATE: '2017-11-22',
     LAST_LOCAL_STORAGE_TRACKED_TOKEN_CLEARANCE_DATE: '2018-6-25',
diff --git a/yarn.lock b/yarn.lock
index 996dd28a9..e2c5ae483 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -44,6 +44,24 @@
     ethereumjs-util "5.1.5"
     lodash "4.17.10"
 
+"@0xproject/order-watcher@^0.0.6":
+  version "0.0.6"
+  resolved "https://registry.npmjs.org/@0xproject/order-watcher/-/order-watcher-0.0.6.tgz#85a8fb21e5755bb555f427b12d64d10b89b332e6"
+  dependencies:
+    "@0xproject/assert" "^0.2.12"
+    "@0xproject/base-contract" "^0.3.4"
+    "@0xproject/contract-wrappers" "^0.0.5"
+    "@0xproject/fill-scenarios" "^0.0.4"
+    "@0xproject/json-schemas" "^0.8.1"
+    "@0xproject/order-utils" "^0.0.7"
+    "@0xproject/types" "^0.8.1"
+    "@0xproject/typescript-typings" "^0.4.1"
+    "@0xproject/utils" "^0.7.1"
+    "@0xproject/web3-wrapper" "^0.7.1"
+    bintrees "1.0.2"
+    ethers "3.0.22"
+    lodash "4.17.10"
+
 "@0xproject/types@^0.5.0":
   version "0.5.0"
   resolved "https://registry.yarnpkg.com/@0xproject/types/-/types-0.5.0.tgz#ba3cfbc11a8c6344b57c9680aa7df2ea84b9bf05"
@@ -1708,7 +1726,7 @@ bindings@^1.2.1, bindings@^1.3.0:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/bindings/-/bindings-1.3.0.tgz#b346f6ecf6a95f5a815c5839fc7cdb22502f1ed7"
 
-bintrees@^1.0.2:
+bintrees@1.0.2, bintrees@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/bintrees/-/bintrees-1.0.2.tgz#49f896d6e858a4a499df85c38fb399b9aff840f8"