Implement backendClient object to unify calls to the portal api

5 files changed, 109 insertions, 51 deletions

diff --git a/packages/website/ts/blockchain.ts b/packages/website/ts/blockchain.ts
index 3edc00644..e90dfa747 100644
--- a/packages/website/ts/blockchain.ts
+++ b/packages/website/ts/blockchain.ts
@@ -47,6 +47,7 @@ import {
     Token,
     TokenByAddress,
 } from 'ts/types';
+import { backendClient } from 'ts/utils/backend_client';
 import { configs } from 'ts/utils/configs';
 import { constants } from 'ts/utils/constants';
 import { errorReporter } from 'ts/utils/error_reporter';
@@ -854,14 +855,13 @@ export class Blockchain {
         }
     }
     private async _updateDefaultGasPriceAsync() {
-        const endpoint = `${configs.BACKEND_BASE_URL}/eth_gas_station`;
-        const response = await fetch(endpoint);
-        if (response.status !== 200) {
-            return; // noop and we keep hard-coded default
+        try {
+            const gasInfo = await backendClient.getGasInfoAsync();
+            const gasPriceInGwei = new BigNumber(gasInfo.average / 10);
+            const gasPriceInWei = gasPriceInGwei.mul(1000000000);
+            this._defaultGasPrice = gasPriceInWei;
+        } catch (err) {
+            return;
         }
-        const gasInfo = await response.json();
-        const gasPriceInGwei = new BigNumber(gasInfo.average / 10);
-        const gasPriceInWei = gasPriceInGwei.mul(1000000000);
-        this._defaultGasPrice = gasPriceInWei;
     }
 } // tslint:disable:max-file-line-count
diff --git a/packages/website/ts/components/wallet/wallet.tsx b/packages/website/ts/components/wallet/wallet.tsx
index 8c9e3be0f..d1ae38550 100644
--- a/packages/website/ts/components/wallet/wallet.tsx
+++ b/packages/website/ts/components/wallet/wallet.tsx
@@ -36,7 +36,7 @@ import {
     TokenState,
     TokenStateByAddress,
 } from 'ts/types';
-import { configs } from 'ts/utils/configs';
+import { backendClient } from 'ts/utils/backend_client';
 import { constants } from 'ts/utils/constants';
 import { utils } from 'ts/utils/utils';
 import { styles as walletItemStyles } from 'ts/utils/wallet_item_styles';
@@ -72,11 +72,6 @@ interface AccessoryItemConfig {
     allowanceToggleConfig?: AllowanceToggleConfig;
 }
 
-interface WebsiteBackendPriceInfo {
-    price: string;
-    address: string;
-}
-
 const styles: Styles = {
     root: {
         width: 346,
@@ -496,17 +491,15 @@ export class Wallet extends React.Component<WalletProps, WalletState> {
         if (_.isEmpty(tokenAddresses)) {
             return {};
         }
-        const tokenAddressesQueryString = tokenAddresses.join(',');
-        const endpoint = `${configs.BACKEND_BASE_URL}/prices?tokens=${tokenAddressesQueryString}`;
-        const response = await fetch(endpoint);
-        if (response.status !== 200) {
+        try {
+            const websiteBackendPriceInfos = await backendClient.getPriceInfosAsync(tokenAddresses);
+            const addresses = _.map(websiteBackendPriceInfos, info => info.address);
+            const prices = _.map(websiteBackendPriceInfos, info => new BigNumber(info.price));
+            const pricesByAddress = _.zipObject(addresses, prices);
+            return pricesByAddress;
+        } catch (err) {
             return {};
         }
-        const websiteBackendPriceInfos: WebsiteBackendPriceInfo[] = await response.json();
-        const addresses = _.map(websiteBackendPriceInfos, info => info.address);
-        const prices = _.map(websiteBackendPriceInfos, info => new BigNumber(info.price));
-        const pricesByAddress = _.zipObject(addresses, prices);
-        return pricesByAddress;
     }
     private _openWrappedEtherActionRow(wrappedEtherDirection: Side) {
         this.setState({
diff --git a/packages/website/ts/pages/wiki/wiki.tsx b/packages/website/ts/pages/wiki/wiki.tsx
index 1330cbf86..7ed2b750d 100644
--- a/packages/website/ts/pages/wiki/wiki.tsx
+++ b/packages/website/ts/pages/wiki/wiki.tsx
@@ -19,6 +19,7 @@ import { SidebarHeader } from 'ts/components/sidebar_header';
 import { TopBar } from 'ts/components/top_bar/top_bar';
 import { Dispatcher } from 'ts/redux/dispatcher';
 import { Article, ArticlesBySection, WebsitePaths } from 'ts/types';
+import { backendClient } from 'ts/utils/backend_client';
 import { configs } from 'ts/utils/configs';
 import { constants } from 'ts/utils/constants';
 import { Translate } from 'ts/utils/translate';
@@ -200,34 +201,30 @@ export class Wiki extends React.Component<WikiProps, WikiState> {
         );
     }
     private async _fetchArticlesBySectionAsync(): Promise<void> {
-        const endpoint = `${configs.BACKEND_BASE_URL}${WebsitePaths.Wiki}`;
-        const response = await fetch(endpoint);
-        if (response.status === constants.HTTP_NO_CONTENT_STATUS_CODE) {
-            // We need to backoff and try fetching again later
-            this._wikiBackoffTimeoutId = window.setTimeout(() => {
-                // tslint:disable-next-line:no-floating-promises
-                this._fetchArticlesBySectionAsync();
-            }, WIKI_NOT_READY_BACKOUT_TIMEOUT_MS);
-            return;
-        }
-        if (response.status !== 200) {
-            // TODO: Show the user an error message when the wiki fail to load
-            const errMsg = await response.text();
-            logUtils.log(`Failed to load wiki: ${response.status} ${errMsg}`);
-            return;
-        }
-        const articlesBySection = await response.json();
-        if (!this._isUnmounted) {
-            this.setState(
-                {
-                    articlesBySection,
-                },
-                async () => {
-                    await utils.onPageLoadAsync();
-                    const hash = this.props.location.hash.slice(1);
-                    sharedUtils.scrollToHash(hash, sharedConstants.SCROLL_CONTAINER_ID);
-                },
-            );
+        try {
+            const articlesBySection = await backendClient.getWikiArticlesBySectionAsync();
+            if (!this._isUnmounted) {
+                this.setState(
+                    {
+                        articlesBySection,
+                    },
+                    async () => {
+                        await utils.onPageLoadAsync();
+                        const hash = this.props.location.hash.slice(1);
+                        sharedUtils.scrollToHash(hash, sharedConstants.SCROLL_CONTAINER_ID);
+                    },
+                );
+            }
+        } catch (err) {
+            const errMsg = `${err}`;
+            if (_.includes(errMsg, `${constants.HTTP_NO_CONTENT_STATUS_CODE}`)) {
+                // We need to backoff and try fetching again later
+                this._wikiBackoffTimeoutId = window.setTimeout(() => {
+                    // tslint:disable-next-line:no-floating-promises
+                    this._fetchArticlesBySectionAsync();
+                }, WIKI_NOT_READY_BACKOUT_TIMEOUT_MS);
+                return;
+            }
         }
     }
     private _getMenuSubsectionsBySection(articlesBySection: ArticlesBySection) {
diff --git a/packages/website/ts/types.ts b/packages/website/ts/types.ts
index 989c0a032..98d080afb 100644
--- a/packages/website/ts/types.ts
+++ b/packages/website/ts/types.ts
@@ -507,4 +507,13 @@ export interface RelayerInfo {
     marketShare: number;
     topTokens: Token[];
 }
+
+export interface WebsiteBackendPriceInfo {
+    price: string;
+    address: string;
+}
+
+export interface WebsiteBackendGasInfo {
+    average: number;
+}
 // tslint:disable:max-file-line-count
diff --git a/packages/website/ts/utils/backend_client.ts b/packages/website/ts/utils/backend_client.ts
new file mode 100644
index 000000000..366519856
--- /dev/null
+++ b/packages/website/ts/utils/backend_client.ts
@@ -0,0 +1,59 @@
+import { BigNumber, logUtils } from '@0xproject/utils';
+import * as _ from 'lodash';
+import * as queryString from 'query-string';
+
+import { ArticlesBySection, ItemByAddress, WebsiteBackendGasInfo, WebsiteBackendPriceInfo } from 'ts/types';
+import { configs } from 'ts/utils/configs';
+import { errorReporter } from 'ts/utils/error_reporter';
+
+const ETH_GAS_STATION_ENDPOINT = '/eth_gas_station';
+const PRICES_ENDPOINT = '/prices';
+const WIKI_ENDPOINT = '/wiki';
+
+export const backendClient = {
+    async getGasInfoAsync(): Promise<WebsiteBackendGasInfo> {
+        const result = await requestAsync(ETH_GAS_STATION_ENDPOINT);
+        return result;
+    },
+    async getPriceInfosAsync(tokenAddresses: string[]): Promise<WebsiteBackendPriceInfo[]> {
+        if (_.isEmpty(tokenAddresses)) {
+            return [];
+        }
+        const joinedTokenAddresses = tokenAddresses.join(',');
+        const queryParams = {
+            tokens: joinedTokenAddresses,
+        };
+        const result = await requestAsync(PRICES_ENDPOINT, queryParams);
+        return result;
+    },
+    async getWikiArticlesBySectionAsync(): Promise<ArticlesBySection> {
+        const result = await requestAsync(WIKI_ENDPOINT);
+        return result;
+    },
+};
+
+async function requestAsync(endpoint: string, queryParams?: object): Promise<any> {
+    const query = queryStringFromQueryParams(queryParams);
+    const url = `${configs.BACKEND_BASE_URL}${endpoint}${query}`;
+    const response = await fetch(url);
+    if (response.status !== 200) {
+        const errorText = `Error requesting url: ${url}, ${response.status}: ${response.statusText}`;
+        logUtils.log(errorText);
+        const error = Error(errorText);
+        // tslint:disable-next-line:no-floating-promises
+        errorReporter.reportAsync(error);
+        throw error;
+    }
+    const result = await response.json();
+    return result;
+}
+
+function queryStringFromQueryParams(queryParams?: object): string {
+    // if params are undefined or empty, return an empty string
+    if (_.isUndefined(queryParams) || _.isEmpty(queryParams)) {
+        return '';
+    }
+    // stringify the formatted object
+    const stringifiedParams = queryString.stringify(queryParams);
+    return `?${stringifiedParams}`;
+}