feat(instant): fallback to an empty wallet provider when none is injected

3 files changed, 51 insertions, 16 deletions

diff --git a/packages/instant/src/util/asset_buyer_factory.ts b/packages/instant/src/util/asset_buyer_factory.ts
new file mode 100644
index 000000000..5ba46223c
--- /dev/null
+++ b/packages/instant/src/util/asset_buyer_factory.ts
@@ -0,0 +1,17 @@
+import { AssetBuyer, AssetBuyerOpts } from '@0x/asset-buyer';
+import { Provider } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { Network, OrderSource } from '../types';
+
+export const assetBuyerFactory = {
+    getAssetBuyer: (provider: Provider, orderSource: OrderSource, network: Network): AssetBuyer => {
+        const assetBuyerOptions: Partial<AssetBuyerOpts> = {
+            networkId: network,
+        };
+        const assetBuyer = _.isString(orderSource)
+            ? AssetBuyer.getAssetBuyerForStandardRelayerAPIUrl(provider, orderSource, assetBuyerOptions)
+            : AssetBuyer.getAssetBuyerForProvidedOrders(provider, orderSource, assetBuyerOptions);
+        return assetBuyer;
+    },
+};
diff --git a/packages/instant/src/util/injected_provider.ts b/packages/instant/src/util/injected_provider.ts
deleted file mode 100644
index 40f9e2da5..000000000
--- a/packages/instant/src/util/injected_provider.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-import { Provider } from 'ethereum-types';
-import * as _ from 'lodash';
-
-export const getInjectedProvider = (): Provider => {
-    const injectedProviderIfExists = (window as any).ethereum;
-    if (!_.isUndefined(injectedProviderIfExists)) {
-        // TODO: call enable here when implementing wallet connection flow
-        return injectedProviderIfExists;
-    }
-    const injectedWeb3IfExists = (window as any).web3;
-    if (!_.isUndefined(injectedWeb3IfExists.currentProvider)) {
-        return injectedWeb3IfExists.currentProvider;
-    } else {
-        throw new Error(`No injected web3 found`);
-    }
-};
diff --git a/packages/instant/src/util/provider_factory.ts b/packages/instant/src/util/provider_factory.ts
new file mode 100644
index 000000000..603f7674d
--- /dev/null
+++ b/packages/instant/src/util/provider_factory.ts
@@ -0,0 +1,34 @@
+import { EmptyWalletSubprovider, RPCSubprovider, Web3ProviderEngine } from '@0x/subproviders';
+import { Provider } from 'ethereum-types';
+import * as _ from 'lodash';
+
+import { BLOCK_POLLING_INTERVAL_MS, ETHEREUM_NODE_URL_BY_NETWORK } from '../constants';
+import { Maybe, Network } from '../types';
+
+export const providerFactory = {
+    getInjectedProviderIfExists: (): Maybe<Provider> => {
+        const injectedProviderIfExists = (window as any).ethereum;
+        if (!_.isUndefined(injectedProviderIfExists)) {
+            return injectedProviderIfExists;
+        }
+        const injectedWeb3IfExists = (window as any).web3;
+        if (!_.isUndefined(injectedWeb3IfExists) && !_.isUndefined(injectedWeb3IfExists.currentProvider)) {
+            return injectedWeb3IfExists.currentProvider;
+        }
+        return undefined;
+    },
+    getFallbackNoSigningProvider: (network: Network): Provider => {
+        const providerEngine = new Web3ProviderEngine({
+            pollingInterval: BLOCK_POLLING_INTERVAL_MS,
+        });
+        // Intercept calls to `eth_accounts` and always return empty
+        providerEngine.addProvider(new EmptyWalletSubprovider());
+        // Construct an RPC subprovider, all data based requests will be sent via the RPCSubprovider
+        // TODO(bmillman): make this more resilient to infura failures
+        const rpcUrl = ETHEREUM_NODE_URL_BY_NETWORK[network];
+        providerEngine.addProvider(new RPCSubprovider(rpcUrl));
+        // // Start the Provider Engine
+        providerEngine.start();
+        return providerEngine;
+    },
+};